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Avian ecology as it relates to the bird hazard problem at Vancouver Airport Halladay, Delbert Raymond 1968

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AVIAN ECOLOGY AS IT RELATES TO THE BIRD HAZARD PROBLEM AT VANCOUVER AIRPORT by DELBERT RAYMOND HALLADAY B.S.A., U n i v e r s i t y of B r i t i s h Columbia, 1965. A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master's of Science i n A g r i c u l t u r e i n the Department of Plant Science 'We accept t h i s t h e s i s as conforming to the req u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1968 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e qu i r emen t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag ree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r ag ree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y pu rposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n -t a t i v e s . I t i s u nde r s t o od t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department n f Plant Science The U n i v e r s i t y o f B r i t i s h Co lumb ia Vancouve r 8, Canada Date A p r i l 2 2 . 1 9 6 8 i ABSTRACT A general survey and analysis of the avian ecology and control problem of Vancouver International Airport was attempted. The approach followed i n t h i s study entailed consideration of as many bioenvironmental factors as possible to permit a broad understanding of bi r d a c t i v i t y i n the area. Important aspects of weather, s o i l s , drainage, f l o r a and fauna were considered as objectively as possible. Records of bi r d occurrence, a c t i v i t i e s (including behavior) and food habits were made by making regular count surveys, observations and col l e c t i o n s respectively. The information gathered during the study period and from e a r l i e r work i n the "study area" enabled the writer to designate each b i r d as either a problem or non-problem type. The l a t t e r types are not discussed i n t h i s thesis but the results of the food analysis for collected species i s given i n the form of an appendix. Problem b i r d species are discussed i n d i v i d u a l l y with information for most consisting of seasonal occurrence nesting and breeding a c t i v i t y , sex and age, d a i l y a c t i v i t y , food habits, hazard to a i r c r a f t and possible control. General observations on d a i l y a c t i v i t y of eleven problem b i r d species were also supported by a simple c o r r e l a t i o n analysis. One problem b i r d species, the American Widgeon, was studied experimentally. Live birds were encouraged to indicate t h e i r grazing preferences f o r f i v e experimental ground cover •plants. Unfortunately these experiments were met with a series of set backs which eventually forced t h e i r termination. Very i i l i t t l e information gathered on grazing was considered worthwhile. However, there was some in d i c a t i o n that birds preferred the grasses to the forbs used i n the experiment. An analysis was made of experimental techniques used and suggestions were made f o r future work of t h i s type. The majority of these suggestions are directed toward l i m i t i n g the stress on experimental animals i n l i g h t of the importance of t h i s factor i n determining the success of the present work. In addition to the above,field experiments were conducted using ground cover species thought to have features which q u a l i f i e d them f o r use on Vancouver Airport to reduce attractions f o r birds . The unattractive, and adaptive features of each species are presented along with the res u l t s of the experiments. In a l l cases the experimental plants were rated f o r competitive a b i l i t y and vigour. Generally a l l plants used were found to be inade-quate as an airport ground cover because of t h e i r i n a b i l i t y to become dominant during the study period. However, there i s some ind i c a t i o n that future experiments might have d i f f e r e n t r e s u l t s . I f the ground cover species were afforded a more adequate start they might be able to become dominant. Therefore, t h i s approach i s s t i l l considered v a l i d to help solve the b i r d hazard problem, p a r t i c u l a r l y i f species used can be e a s i l y and cheaply propagated over large areas. Generally i t i s concluded that the b i r d hazard problem on Vancouver International Airport i s complex. The results of the present study indicate possible means of solving the problems associated with certain species but they also serve to indicate i i i how limited an effect control e f f o r t s have on others. In a number of cases the means of control f o r some birds may actually a t t r a c t other birds. In l i g h t of the present study the writer believes the most i d e a l control measure would be to maintain a l l of the "study area" as a short well drained t u r f free of open ditches. It was noted that future e f f o r t s should include a more detailed quantitative information for computer analysis on variables found important during the present study, consider-ations f o r control of persistant food species and periodic reassessment of changes i n b i r d number and species using the "Airport" zone and "bird s t r i k e s " r e s u l t i n g from t h i s use. These e f f o r t s may eventually enable control of the b i r d hazard problem to a tolerable l e v e l . i v TABLE OF CONTENTS Page ABSTRACT i TABLE OF CONTENTS i v LIST OF TABLES v i i i LIST OF FIGURES x ACKNOWLEDGEMENTS x i i i 1. INTRODUCTION 1 2. REVIEW OF LITERATURE 4 2.1 Avian c o n t r o l 4 2.2 Avian ecology 10 2.2.1 M i g r a t i o n 10 a. Long pe r i o d m i g r a t i o n 11 b. Short p e r i o d m i g r a t i o n 17 2.2.2 Habitat f a c t o r s 20 2.2.3 Behaviour 26 2.3 Plant ecology 32 3 . THE VANCOUVER AIRPORT AND ITS ENVIRONS. 33 3.1 Location 33 3.2 Climate and weather 36 3.3 Land use 45 4. FAUNAL OBSERVATIONS AND TRIALS 48 4.1 Zonation 48 4.2 Methods of e v a l u a t i n g b i r d a c t i v i t y 49 4.2.1 Count study 49 a. " D a i l y counts" 50 V Page b. "Station counts" 51 c, "Environs counts" 53 4,2,2 C o l l e c t i o n study 54 a. Food habit study 55 b. Sex and age study 59 4.3 Results 60 4.3.1 General statement 60 4.3.2 Problem birds 63 a. Mallard 63 b. P i n t a i l 69 c. American Widgeon 74 d. Green-winged Teal 78 e. Marsh Hawk • 82 f. Rough-legged Hawk 86 g. Ring-necked Pheasant 89 h. Great-blue Heron 94 i . K i l l d e e r Plover 98 j . S h o r t - b i l l e d Dowitcher 102 k. Dunlin 106 1. Western Sandpiper 110 m. Glaucous-winged Gull 116 n. Herring Gull 121 o. C a l i f o r n i a Gull 125 p. Mew Gull 129 q. Short-eared Owl 132 r . Snowy Owl 136 v i Page s. Barn Swallow 139 t . Water P i p i t 142 u. Common S t a r l i n g 145 v. House Finch 148 w. American Goldfinch 152 4.4 Control Measures 155 4.5 Grazing by captive Widgeon 162 4.5.1 General statement 162 4.5.2 Methods 163 4.5.3 Observation 167 4.5.4 Experimental plants 168 4.5.5 Results 168 4.5.6 Discussion 170 5. VEGETATION OBSERVATIONS AND TRIALS 176 5.1 Survey of Sea Island 176 5.1.1 Methods 176 a. "Study area" 176 b. "Airport" zone 177 c. "Intensive" zone 177 5.1.2 Results 183 5.1.3 Discussion 185 5.2 Experimental ground covers 193 5.2.1 General statement 193 5.2.2 Methods 195 5.2.3 Results 200 5.2.4 Discussion 205 v i i Page 6. PHYSIOGRAPHIC OBSERVATIONS AND TRIALS 215 6.1 Previous s t u d i e s 215 6.1.1 S o i l s 215 6.1.2 Drainage 220 6.2 Survey of study area 221 6.2.1 Methods 221 a. S o i l s 221 b. Drainage 223 6.2.2 Results 223 a. S o i l s 223 b. Drainage 225 6.2.3 D i s c u s s i o n 226 7. GENERAL DISCUSSION 229 8. SUMMARY 236 9. BIBLIOGRAPHY 239 10. APPENDICES 10.1 Cover map of Sea I s l a n d 247 10.2 Drainage map of Sea I s l a n d 248 10.3 Food a n a l y s i s t a b l e s 249 10.3.1 Monthly t o t a l s ( f o r s e v e r a l problem b i r d species) 250 10.3.2 Year t o t a l s ( f o r s e v e r a l problem and non problem b i r d s ) 284 10.4 Data a n a l y s i s sheets 302 v i i i LIST OF.TABLES Table # Page 1 Pressure systems f o r Southwestern B r i t i s h Columbia. 37 2 Basic meteorological data f o r months of the study period and normals for Vancouver International Airport ( 1 9 6 6 - 1 9 6 7 ) . 41 3 D a i l y counts-made during each month of the study period. 51 4 Observations on control measures used by the Department of Transport during the study p e r i o d , 157 5 Experimental plants used i n widgeon grazing t r i a l s . 169 6 Results of grazing "Series A" using two l i v e widgeon 171-7 Results of grazing "Series A " using one l i v e widgeon 172 8 Dissections of casualties which occurred during widgeon grazing "Series A" and "A^". 173 9 Major plants found i n the vegetation group-ings depicted i n Appendix 1 0 . 1 . 178 10 Percent coverage by plants i n two t u r f areas of d i f f e r e n t o r i g i n compared to the "climax t u r f " . 186 11 Resultscof point transects made i n the "Intensive" zone on "Dry", "Moist" and "Wet" subzones. Figures given are percentages of the t o t a l area sampled. 189 12 Results of " S o i l s " Plots T r i a l s , the es-timated percent cover.and vigour given for the dates indicated. 201 13 Comparative information on experimental ground covers chosen for " S o i l s " p l o t s . 206 14 Comparative information on experimental ground covers chosen f o r the "Barn" plots and "Din-smore" p l o t s . 207 Readings made of "Barn" plots and "Dinsmore" plots f o r dates shown. The averages and extremes of pH. s a l i n i t y and texture determinations f o r anthropic and native s o i l s . X LIST OF FIGURES Figure § Page 1 Routes and l o c a t i o n s of b i r d counts made during the study p e r i o d . 52 2 Insect c o l l e c t i o n t r a p s i n . s i t u . From top to bottom: " S t i c k y board" trap and water t r a p . 58 3 M a l l a r d 68 4 P i n t a i l 73 5 American Widgeon 77 6 Green-winged Teal 81 7 Marsh Hawk 85 8 Rough-legged Hawk 88 9 Ring-necked Pheasant 92 10 T y p i c a l f i e l d border and hedgerow i n the " A i r p o r t " zone. Note the extensive shrubby growth beside d i t c h e s and the broad uncut f i e l d borders. 93 11 Great Blue Heron 97 12 K i l l d e e r 101 13 S h o r t - b i l l e d Dowitcher 105 14 D u n l i n 109 15 Western Sandpiper 114 16 Large f l o c k of Western Sandpiper (+2000) which has j u s t a r r i v e d on the Sea I s l a n d foreshore a f t e r f l y i n g through the " A i r p o r t " zone. 115 17 Glaucous-winged G u l l 119 18 S t r a g g l e r s from a f l o c k of +300 Glaucous-winged G u l l s f eeding on earthworms beside surface pools near the east approach of the main runway, 120 Herring Gull C a l i f o r n i a Gull Mew Gull Short-eared Owl Snowy Owl Barn Swallow Water P i p i t S t a r l i n g House Finch Plants of Brassica campestris and Rapharms  raphanistrum growing i n recently disturbed areas. (Light areas•from mid l e f t to upper right of p i c t u r e ) . American Goldfinch "Weed" areas northwest of the "button" of 12 with large numbers of Cirsium arvense and Sonchus arvense -setting seed. "Main Pen" "Transport Pen" "Grazing Pen" Typical "Wet" subzone where bent grass and Water f o x t a i l dominate. The t a l l grass on either side i s i n the "moist" subzone. Dried pond area where Psilocarphus e l a t i o r i s germinating. T a l l grass areas mark the edge of the "Moist" subzone. View of "Dry" ( l e f t ) and "Moist" (right) subzones i n mid August, The vegetation i n the "DryJ.! subzone has "browned o f f " . Experimental ground cover plot locations on Vancouver Airport x i i Figure # 38 39 40 41 42 43 Page Plot plan of the " S o i l s " p l o t s . 197 Plot plan of the "Barn" plots and "Dinsmore" pl o t s . 197 " S o i l s " plots i n l a t e May 1966 showing height and density of sod grasses and forbs. Behind the writer are', the "dyke" plo t s . 204 I n f i e l d flooding west of observation tower #3 during high tid e and immediately after, a heavy r a i n f a l l . The large pool to the l e f t i s actually a ditch which has more than 8 feet of water. 231 Typical weed area beside a recently constructed taxiway. Note the flowering Brassica campes-t r i s i n the foreground and the extensive car-pet of Spurgula arvensis f i l l i n g most of the picture. 231 A e r i a l view (2500') of the Sea Island t i d a l f l a t s looking south. Note: airport on l e f t and middle arm of the Fraser River i n upper picture. 232 x i i i ACKNOWLEDGEMENTS I wish to thank Mr. R.D. H a r r i s , W i l d l i f e B i o l o g i s t , Canadian W i l d l i f e S e r v i c e , f o r h i s encouragement to undertake t h i s p r o j e c t and the Canadian W i l d l i f e S e rvice f o r supporting i t . My thanks also to Dr. V.C. B r i n k , Head of the Depart-ment of Plant Science at the U n i v e r s i t y of B r i t i s h Columbia, f o r the i n t e r e s t , guidance, and philosophy that he provided through-out our a s s o c i a t i o n , and f o r the use of the f a c i l i t i e s of the Department of Plant Science. To the l a t e Mr. Wm. M. Hughes, I wish to express s i n c e r e thanks f o r h i s kindness, i n t e r e s t and a s s i s t a n c e throughout the study and f o r h i s permission to use h i s b i r d count data c o l l e c t e d at Vancouver A i r p o r t . I wish to acknowledge the as s i s t a n c e of Mr. L. F i s h e r , who helped to t r a p and to pen l i v e widgeon, the Canada Department of A g r i c u l t u r e Research S t a t i o n (Campus, U n i v e r s i t y of B r i t i s h Columbia) f o r advice on c o l l e c t i n g i n s e c t s and Miss Kathleen S t u a r t , Curator of the G.J. Spencer Entomological Museum, Department of Zoology, U n i v e r s i t y of B r i t i s h Columbia, and Dr. L. Lazorko, a l o c a l a u t h o r i t y on Coleoptera, f o r i d e n t i f i c a -t i o n of i n v e r t e b r a t e m a t e r i a l . I would a l s o l i k e to acknowledge the as s i s t a n c e of the Department of Transport personnel at Vancouver A i r p o r t , i n par-t i c u l a r the "ramp" attendants, who k i n d l y provided a f i e l d o f f i c e and permitted me to have f r e e access to a l l areas of the a i r p o r t . x i v F i n a l l y , my thanks to my wife Donna f o r typing f i e l d notes and the rough copy of the thesis and f o r her encouragement and patience. 1 1 . INTRODUCTION From the e a r l i e s t days of human f l i g h t there have been c o l l i s i o n s between birds and airplanes (Lane 1 9 4 6 ) . However, with the recent rapid increases i n a i r t r a v e l , f l y i n g speed and airplane size the problem has become acute. The ad-vent of the jet engine has further complicated the problem because of i t s v u l n e r a b i l i t y to i n t e r n a l damage from b i r d c o l l i s i o n s (Hereinafter referred to as "b i r d s t r i k e s " ) . As a resu l t of increasing "bird s t r i k e s " , A i r Canada and the Department of Transport i n I 9 6 0 began gathering data on a l l such incidences (Bird 1 9 6 5). As the rapidl y increasing seriousness was r e a l i z e d and as the enormous complexity of the problem came to be appreciated, the Deputy Minister of Transport i n November, 1 9 6 2 , requested the Canadian National Research Council to set up a group to study the problem. Follow-ing the request there was established the "National Research Council Associate Committee on A i r c r a f t Engine Bird Strikes"; i t was l a t e r renamed the "Associate Committee on Bird Hazards to A i r c r a f t " . The committee members represent various scien-t i f i c , t echnical, m i l i t a r y and private organizations concerned with the problem or which might aid i n the amelioration of the hazard. The b i r d hazard problem i s an inte r n a t i o n a l one and as a resu l t the committee exchanges information with hundreds of individuals or groups i n twenty-five countries (Bird 1 9 6 5 ) . Major areas of investigation are: a) the a l t e r a t i o n of a i r c r a f t structure to withstand b i r d s t r i k e s , b) the reduction of b i r d 2 s t r i k e s between a i r p o r t s using radar and c) the c o n t r o l of b i r d numbers on a i r p o r t s . By f a r the greatest b i r d hazards occur on and around a i r p o r t s . Commercial a i r l i n e operators i n 1963 reported 75% to 80% of the t o t a l " b i r d s t r i k e s " i n these areas. As a r e s u l t of these s t a t i s t i c s , members of the committee from the Canadian W i l d l i f e Service were asked to place prime emphasis on the i n -v e s t i g a t i o n of a i r p o r t hazards. Their work began w i t h a p r e l i m i n a r y survey of b i r d s t r i k e s at Royal Canadian A i r Force and commercial a i r p o r t s across Canada. Recommendations f o r obvious h a b i t a t a l t e r a t i o n s to l i m i t b i r d numbers f o l l o w e d . Vancouver I n t e r n a t i o n a l A i r p o r t , which i s l o c a t e d on d e l t a i c Sea I s l a n d 7 m i l e s south of Vancouver c i t y at the mouth of the Fraser R i v e r , i s one of the problem areas. In 1961 R.D. H a r r i s of the Canadian W i l d l i f e S ervice began to gather informa-t i o n about b i r d s i n the area through a cooperative volunteer e f f o r t w i t h l o c a l b i r d watchers. Between J u l y of 1963 and June of 1967, one vo l u n t e e r , the l a t e Win. M. Hughes, was em-ployed on a c o n t r a c t u a l b a s i s by the Canadian W i l d l i f e S e r v i c e , under the d i r e c t i o n of R.D. H a r r i s , a) to make re g u l a r counts of b i r d s f r e q u e n t i n g the a i r p o r t , b) to t r a p and band b i r d s of prey and rel e a s e them w e l l away from the a i r p o r t and c) to attempt and to make recommendations on various c o n t r o l measures. As a r e s u l t of t h i s work s e v e r a l a c t i o n s were taken to reduce b i r d numbers on the a i r p o r t , a) hedgrows were removed, b) farming leases were changed or c a n c e l l e d , c) t a l l grass was cut, d) rough areas were smoothed, e) di t c h e s were cleaned, f ) the 3 l o c a l garbage dump was moved,, g) p i l i n g s on the r i v e r were removed, h) major b u i l d i n g s were covered i n areas where b i r d s nested, i ) acetylene cannons ("zon-guns") were set up i n winter months, and j ) a system u s i n g Very f l a r e s , c r a c k e r - s h e l l s and tape-recorded d i s t r e s s c a l l s of s e v e r a l g u l l species and s t a r -l i n g s was i n s t i t u t e d f o r use by a i r p o r t personnel. As a r e s u l t of the ac t i o n s taken there was a n o t i c e -able r e d u c t i o n i n " b i r d s t r i k e s " . However, i t was b e l i e v e d that w i t h f u r t h e r study of b i r d s and t h e i r environment the knowledge gained would enable a more e f f e c t i v e long-term s o l u t i o n . Inasmuch as s i m i l a r r e s u l t s were obtained on other a i r p o r t s the committee began to d i r e c t i t s a t t e n t i o n to a more i n t e n s i v e e c o l o g i c a l approach. A i r p o r t v e getation i n r e l a t i o n to b i r d use became the f o c a l point of t h e i r long range e f f o r t s . The present study was i n i t i a t e d i n May of 1966 to gather b a s i c i n f o r m a t i o n about avian ecology on Vancouver a i r -port w i t h s p e c i f i c a t t e n t i o n being paid to the r e l a t i o n s h i p s between ground covers and b i r d a c t i v i t y i n the immediate area of the runways and taxiways. Studied also were experimental ground covers e s t a b l i s h e d i n p l o t s by the w r i t e r on the a i r p o r t i n the summers of 1965 and 1966, and gra z i n g by l i v e widgeon c a r r i e d out i n the s p r i n g of 1967. 4 2. REVIEW OF LITERATURE 2 . 1 Avian control Birds, l i k e many other forms of l i f e , become pests when they transmit diseases to man and domestic animals, damage and eat a g r i c u l t u r a l products, roost or nest on and around human habitations, compete with more desirable animals or i n other ways become undesirable to men. However, b i o l o g i c a l l y no animal i s i n fact a pest (McCabe 1966). Environments or situations are created whereby the animal interacts with the interests of man causing the animal to be considered a pest. Such i n t e r -actions may range i n occurrence from temporary or occasional, to regular, to hazardous or to l e t h a l . Interaction may involve only a f r a c t i o n or a l l of a given animal population and i t may occur i n a r e s t r i c t e d area or throughout the animals range. Control measures against birds f a l l into one of four major types: chemical, b i o l o g i c a l , mechanical and genetical. Each of these types i n turn encompasses a number of techniques. Chemical controls include ingested poisons, such as strychnine, sodium fluoroacetate (Compound 1 0 8 0 ) , thallium s u l f a t e , TEPP and DRC 1 3 3 9 (McAtee 1 9 3 2 , Rudd 1 9 6 4 , Penn 1 9 6 5 , McCabe 1 9 6 6 , and Levingston 1967), sprayed poisons, such as a 25% solution of parathion (Cole 1966), oral anesthetics, such as chloroalase and tribromoethanol ("Avertin") (Ridpath and Murton 1 9 5 6 and Penn 1965) and repellents such as 4-amino pyridine ("Avitrol"), "Rid-a-bird" and "Queletox" (Goodhue and Baumgartmer 1 9 6 5 and Anon. 1967). In A f r i c a , where weaver finches attack cereal 5 crops i n thousands, control has been e f f e c t i v e using i n s e c t i -cides (Ordish 1 9 6 7 ) . I t has been estimated that 7 4 m i l l i o n finches to t h i s date have been k i l l e d and that cereal losses have been reduced by 4 , 0 0 0 tons per day. The basic d i f f i c u l t y in the use of chemical substances i s an i n a b i l i t y to confine the ingestion to the target animal except i n the case of DRC 1339 which i s said to be s p e c i f i c f o r starlings. (McCabe 1966). B i o l o g i c a l control effects control of a given b i r d species by using another b i o l o g i c a l agent. For example the U.S. Fish and W i l d l i f e Service has had some success i n con-t r o l l i n g herring g u l l s i n Boston Harbor using foxes and raccoons (McCabe 1966). The mammals, of one sex only, were placed on islands which were the exclusive breeding ground of the g u l l s . This action reduced breeding success by as much as 95 percent on the test i s l a n d s . Elsewhere se l e c t i o n for grain sorghums with sharp awns and milo high i n tannin has turned blackbirds to an easier diet (Garnett 1 9 6 3 ) . Farmers i n Arizona now time the planting of grain sorghum so that the crop matures i n mid or late October and thus they avoid de-predations by the white-winged doves which by that time have departed f o r t h e i r wintering grounds i n Mexico (Carlson 1966) . Mechanical control measures include some of the oldest and most recent techniques f o r r e p e l l i n g birds from a given area. Generally these measures include reducing problem birds by permanent removal through shooting, trapping, fencing and destroying food and cover or by temporary removal through scaring. An excellent review of the former i s given i n the 6 work of McAtee ( 1 9 3 2 ) , Schick ( 1 9 5 5 ) , and de Vos ( 1 9 6 3 ) . Nelson and Seubert (1966) give an excellent review of scaring devices. Therefore, these methods are not discussed further at t h i s time, Genetical control has been described by McCabe (1966) as an attempt to i n t e r f e r e with the reproductive a b i l i t y of animals and reduce the population through an elimination of po t e n t i a l o f f s p r i n g . This interference requires the solving of two problems; 1 . to develop a physiological chemical capable of preventing conception or b i r t h , and 2 . to administer such a chemical to the problem animal at the right time and place. Elder (1964) (referred to by McCabe 1966) , examined a wide variety of potential o r a l contraceptive substances i n an attempt to prevent reproduction i n f e r a l pigeons. One substance, an an t i c h o l e s t e r a l agent ( 2 2 . 2 5 , - d i a z acholestonol dyhydrochloride), was found to prevent reproduction for a period of s i x months. Birds received the chemical i n spring and f a l l as part of a grain d i e t . Many authorities agree that i n most cases chemical and mechanical control measures are l a r g e l y " t r e a t i n g the symptoms of the disease" (birds unwanted) rather than the cause. The "long-term" solution, "treatment of the cause of the disease", i s considered to be possible through an ecological approach using bioenvironmental control methods (Ridpath and Murton 1 9 5 6 , Decker et a l . 1 9 6 1 , Knipling 1 9 6 6 , Carleton and Brazee 1 9 6 6 , McCabe 1 9 6 6 , Anon. 1 9 6 7 , and 7 S t e f f e r u d 1966) . However, i t i s a l s o g e n e r a l l y agreed that any c o n t r o l measure must lend i t s e l f to p r a c t i c a l - a p p l i c a t i o n where time and costs are i n v o l v e d . Mechanical and chemical c o n t r o l s , on a short-term b a s i s f u l f i l l t h i s requirement and are s t i l l very much a p r a c t i c a l s o l u t i o n to many problems. One example where mechanical c o n t r o l measures are very important i s the c o n t r o l of b i r d s on and around a i r p o r t s . Here b i r d s i n t e r a c t w i t h the best i n t e r e s t s of men by causing " b i r d s t r i k e s " which r e s u l t i n considerable damage and an alarming hazard to a i r c r a f t . Methods of c o n t r o l have l a r g e l y r e l i e d on the general s e n s i t i v i t y of b i r d s to d i s t u r b i n g s i g h t s and sounds. In t h i s regard techniques i n v o l v e d have i n c l u d e d , cracker s h e l l s , shot gun b l a s t s , very f l a r e s , car-bide or acetylene cannons ("zon-guns"), recorded d i s t r e s s c a l l s ( s i n g l e species or mixed species) and h e l i c o p t e r noise (Nelson and Seubert 1966). In a d d i t i o n , e c o l o g i c a l p r i n c i p l e s have been employed where the s o l u t i o n was p r a c t i c a l ( i e . where costs were not excessive and b i r d numbers were demonstrably reduced). D e t a i l e d d i s c u s s i o n s on the methods developed to c o n t r o l b i r d s on a i r p o r t s i n Canada and on a few a i r p o r t s out-s i d e Canada are recorded i n the r e g u l a r minutes of "The A s s o c i a t e Committee on B i r d Hazards to A i r c r a f t " ( N a t i o n a l Research Co u n c i l - Canada, M.S. K i i h r i n g , Chairman, Ottawa, Canada). The e c o l o g i c a l s o l u t i o n most f r e q u e n t l y employed i s that which deals w i t h the pheomenon known as "edge e f f e c t " . 8 Under natural conditions, the kind, amount, and arrangement of vegetative cover i n a given area determines the carrying capacity (numbers) and the d i v e r s i t y (species) of the animal population ( P e t i n g i l l 1 9 6 6 , McCabe 1 9 6 6 ) . This p r i n c i p l e was argued p r a c t i c a l l y by Elton (1958) and on.theoretical grounds by MacArthur (1955) for hedgerow habitats against monocultural practices. Moore (1962) also recognized "edge e f f e c t " to be a major cause for the abundance and d i v e r s i t y of B r i t i s h b i r d s . For f u l l discussions on the subject see Leopold (1933), MacFadyen ( 1 9 6 3 ) and Odum ( 1 9 5 9 ) . Simply, "edge e f f e c t " refers to the tendency for greater numbers and variety of plants and animals to occur on border areas (ecotones) between major habitats. In these areas one finds plants and animals t y p i c a l of both major habitats and a few which are c h a r a c t e r i s t i c a l l y ecotone types. Many airports have an abundance of t r a n s i t i o n a l habi-tat, from hedgerows to t i d a l marshes to ditches to ponds or to f i e l d borders. As a r e s u l t , many animals, birds included, are attracted to these areas. Corrective measures therefore have been towards the removal of ecotones. This practice tends to create a more s i m p l i f i e d monotypic habitat f o r large areas of the a i r p o r t s , a practice which may a l l e v i a t e an immediate problem but which may create another. Generally, ecologists agree that the more simple a community the more unstable i t i s in terms of marked fluctuations i n numbers between and/or within species ( T o t h i l l 1 9 6 6 ) . Therefore i t i s conceivable that, while.elimination of "edge e f f e c t s " from an airport might remove a current problem of b i r d species i t could encourage 9 others by way of enhancing some aspect of t h e i r ecology such as removing predators and competitors and/or creating more abundant food, nesting habitat, l o a f i n g areas, required v i s a -b i l i t y for security, etc. A few investigators have anticipated t h i s r e s u l t i n some cases by i n d i c a t i n g that ground cover (grass mostly) should be cut to between 4 - 5 inches to reduce pheasants which prefer t a l l grass habitats and yet l i m i t the a t t r a c t i o n of g u l l s which prefer short grass habitats (Anon. 1967). Another ecological or b i o l o g i c a l technique has involved the use of falcons to scare birds, mainly seagulls, from airports (Drury 1 9 6 6 ) . However, t h i s l a t t e r technique has l a r g e l y proved unsuccessful because falcons are rare, d e l i c a t e , and expensive to t r a i n and inclement weather r e s t r i c t s t h e i r use. In practice, the control of birds on airports has been most s a t i s f a c t o r y where more than one technique was em-ployed (Kuhring 1 9 6 3 , Drury 1 9 6 6 , and Anon. 1 9 6 7 ) . The most common combination has been the use of recorded distress c a l l s and various pyrotechniques simultaneously to reinforce the " f l i g h t " reaction. In Canada, though the tests were l i m i t e d , Very f l a r e s appeared to be more e f f e c t i v e than s h e l l crackers, since they l e f t a t r a i l of smoke or sparks (Kuhring 1 9 6 3 ) . How-ever, the strength of the " f l i g h t " reaction of various birds appears to change i n r e l a t i o n to what has been termed by Nelson and Seubert (1966) as " s i t e tenacity". Birds also vary t h e i r f l i g h t reaction i n accordance with the strength of the s t i m u l i , the a v a i l a b i l i t y and s u i t a b i l i t y of alternate s i t e s to which birds may be dispersed, the presence of abnormal or non-reacting 10 i n d i v i d u a l s (decoys), weather factors and the stage of the birds annual cycle whether migration, breeding or wintering (Nelson and Seubert 1 9 6 6 , r e f e r r i n g to the work of Kadlee 1 9 6 4 ) . Therefore, care must be exercised when ra t i n g the effectiveness of a given technique, p a r t i c u l a r l y when experimentation i s l i m i t e d . In Canada and the United States since 1963 control measures have effected a reduction i n hazard and "bird s t r i k e s " per unit f l y i n g time have been reduced (Bird 1965, and Anon. 1967). However, more recently "bird s t r i k e s " have again i n -creased i n the case of at least one major Canadian a i r l i n e (R.D. Harris, Canadian W i l d l i f e Service, Vancouver, B.C. per-sonal communication, January, 1968). Therefore, t h i s further indicates the value of extended long-term ecological approaches to the problem. 2.2 Avian ecology 2.2.1 Migration P e t i n g i l l (I96l) defines migration as, "any regular movement between two areas"^". He suggests that i t i s an innate response of the animal populations to periodic changes i n environmental conditions. In birds, he considers there to be two common kinds of migration, seasonal and d a i l y . Seasonal migration involves a passage at one season from a place of hatching and a return at another season to the same general area. Daily migration, on the other hand, Is a movement to 1 P e t i n g i l l , O.S. J r . (1961). "A laboratory and f i e l d manual of ornithology". Burgess Pub. Co., Minna, Minn., U.S.A. p g . 1 7 7 . 11. and from a f a m i l i a r place each day. In the f o l l o w i n g d i s -c ussion, seasonal migrations are considered to be permanent long period h a b i t s of b i r d s while d a i l y migrations are con-si d e r e d to be reg u l a r but short period h a b i t s . Apart from t h i s m o d i f i c a t i o n the d e f i n i t i o n s given by P e t i n g i l l are fo l l o w e d . A complete review of informati o n concerning e i t h e r form of migra t i o n i s not attempted i n t h i s d i s c u s s i o n . Only f a c t o r s which have a p p l i c a t i o n to the present study are con-s i d e r e d . For a more complete review, the subject and i t s l i t -e r a t u r e , the reader may consult the e x c e l l e n t d i s c u s s i o n of Bagg et a l . (1950), L i n c o l n (1950), Drost (1951), P h i l l i p s (1951), P e t i n g i l l (196l) and Welty (1962). a.- Long period m i g r a t i o n The o r i g i n of mi g r a t i o n has been the subject of much s p e c u l a t i o n . Many persons b e l i e v e that m i g r a t i o n i n b i r d s of the northern hemisphere was i n i t i a t e d by the i c e age. This theory considers that w i t h the advancement of the g l a c i e r s b i r d s p r e v i o u s l y r e s i d e n t i n the North were g r a d u a l l y f o r c e d to r e t r e a t . Each s p r i n g , when the g l a c i e r s r e t r e a t e d due to the m i l d e r c l i m a t e , previous r e s i d e n t s would r e t u r n to f u l f i l l or i n s t i n c t i v e attachment to t h e i r breeding place. Other t h e o r i e s have considered i t a response to various c e l e s t i a l phenomenon such as sun spots, daylength or p o s i t i o n of the s t a r s . In s t i l l another theory, the h y p o t h e t i c a l " d r i f t " of the continents was used to e x p l a i n the seasonal phenomenon 1 2 (Welty, 1962). More recently s c i e n t i s t s consider that migra-t i o n originated several times and i n di f f e r e n t birds f o r di f f e r e n t reasons. This i s obvious i f one considers such facts as the following ( 1 - 6 , P e t i n g i l l 1 9 6 1 , 7 - 8 , P h i l l i p s 1 9 5 1 ) : 1. Many species migrate i n directions other than North-South . 2. Some species are not dependent on daylength for migra-t i o n stimulus. 3. Many species migrate when food and temperatures are un-favorable while others migrate under opposite conditions (includes invasions or i r r u p t i o n s ) . 4. Some species migrate when there i s a seasonal a l t e r a t i o n in r a i n f a l l and drought. 5. Some species migrate i r r e g u l a r l y or not at a l l . 6. Individual populations of a given species often migrate while others do not. 7. Some species migrate at di f f e r e n t times or extent depending on age and sex, 8. Many birds migrate i n d i f f e r n t ways - i n fl o c k s , family groups, or single; by day or night; feeding or f a s t i n g as they go. 9. Certain species carry out t h e i r seasonal migration with remarkable r e g u l a r i t y while others are noticeably opposite, It i s also obvious that certain h i s t o r i c a l factors and ex i s t i n g factors today - day-length, a i r temperature, wind d i r e c t i o n , land forms and food supply - have influenced some migrations i n d i r e c t l y through a f f e c t i n g the environment (Stevenson 1 9 3 3 , Neff 1 9 4 7 , Lincoln 1 9 5 0 , Drost 1 9 5 1 , P h i l l i p s 1 9 5 1 , Sowls 1 9 5 5 , P e t i n g i l l 1 9 6 1 , Welty 1 9 6 2 ) . 1 3 -Th e stimulation for migration can only be effec-t i v e i f the b i r d i s i n i t s proper physiological state ( P e t i n g i l l 1961). The most outstanding feature about t h i s state i s that i t prepares a bi r d f o r the energy require-ments of prolonged f l i g h t by encouraging a heavy deposition of f a t . The i n t e r i o r lobe of the p i t u i t a r y gland, whose a c t i v i t y i s effected by day length i n some species, i s res-ponsible f o r the process leading toward t h i s state ( P h i l l i p s 1 9 5 1 , r e f e r r i n g to the work of Farner 1 9 5 0 ) . Stanchinskii ( 1 9 2 6 ) considered migrating birds to f a l l into either of three groups depending on t h e i r pattern f o r migratory stim-ulation: 1 . those which migrate soutward very early and northward very l a t e , t h e i r migration dates being rather d e f i n i t e i n a given month and apparently independent of temperature but induced by in t e r n a l factors such as periodic hormones (eg. Hirundo r u s t i c a ) . 2 . those which migrate i n -dependently of the weather, due to a migratory i n s t i n c t c a l l e d into a c t i v i t y by climatic change (eg. Anser sp., many insectivores and many granivores), and 3 . those which migrate when forced to by inclement changes i n the weather (eg. many ducks). It should be noted that spring and f a l l migration are not necessarily the same. Many writers note that there i s much less r e g u l a r i t y i n the a r r i v a l and departure of transient b i r d species i n the f a l l than i n the spring. F a l l migration i s more l e i s u r e l y and more dispersed than spring migration. 14 The routes taken by birds when migrating are almost as variable as t h e i r directions and extents and i n a few species the routes taken i n f a l l and spring are widely d i f f e r e n t . P e t i n g i l l (1961) considered that i n spite of t h i s d i v e r s i t y many species tend to follow general routes for at least part of t h e i r migration. In North America there are four main routes or "flyways" used by birds moving from northern areas to the South and they are; A t l a n t i c , M i s s i s s i p p i , Central and P a c i f i c (Lincoln 1950). Welty (1962) considers that migra-t i o n routes are probably determined more by climatic change with i t s power to vary food supply, than by any other environ-mental fa c t o r . This may account for the marked concentrations of many bi r d species along coastal areas where food i s more abundant as a result of the moderating influence of the oceans and "edge e f f e c t " . He further comments that "this i s why the majority of migration paths trend North and South"-*-. Such major objects as sea shores, mountain ranges, large r i v e r s , desert rims, or forest edges act as guidelines for many migrating b i r d s . However, i t i s now known that such guidelines are not s t r i c t l y followed. Instead the majority of birds f l y i n broad fronts with channeling occurring r a r e l y (Welty 1962). In view of t h i s discovery i t would seen that Lincoln's flyways represent the centres of such fronts. Drost (1951) notes that when two guidelines meet at one point there i s a tendency for them to act as a funnel such that b i r d numbers may r i s e to m i l l i o n s i n these areas. He s i t e s the •Welty, J.C. (1962). "The l i f e of birds", W.B. Saunders, Co., London & Ph.P. 451. 15 example of ducks being funnelled through Wiborg Finland (Drost 1951, r e f e r r i n g to the work of Putkonen 1942). Another generality which seems to hold true f o r migrating birds i s that the more severe the climate the greater the percentage of birds that migrate. This i s why many birds migrate i n Canada, but, fewer migrate i n the United States and s t i l l fewer migrate i n Mexico. By the time one has reached the Amazon jungle of South America one finds that p r a c t i c a l l y no birds migrate (Welty 1962). How do birds orient and navigate when migrating? It has already been mentioned that the urge to migrate has i t s o r i g i n i n the "physiological cycle" of the birds and that the stimulus to migrate i s often external, but, what enables birds to make t h e i r journies without l o s i n g t h e i r way? In a few species, such as.some shorebirds, there navigational feats are carried out by young birds who are unguided by experienced adults. Many species t r a v e l over, what are to man, featureless expanses of land or water and often at night. It i s obvious therefore that birds must know where they are and i n what d i r e c t i o n they are t r a v e l l i n g . Theories con-cerning t h i s phenomenon have considered the b i r d to have a sp e c i a l sense f o r detecting differences i n the earths magnetic f i e l d , c e n trifugal force and c o r i o l i s force ( l a t e r a l force generated by bodies moving North or South over the earths' surface). However, none of these theories has been proven conclusively and there i s s t i l l much c r i t i c i s m concerning them among o r n i t h o l o g i s t s . Various displacement experiments 16 using hooded crows, Corvus cornix (Welty 1962, r e f e r r i n g to Riippell 1944), S t a r l i n g s , Sturnus vulgaris, and White storks, Ciconia ciconia, have shown that they have an innate tendency to migrate i n certain compass directions (Welty 1962). Other experiments have revealed that certain species orientate and navigate v i s u a l l y using topography, cloud formations and c e l e s t i a l bodies such as the sun and st a r s . Whatever the o r i g i n , forms, stimulation, routes or the means of navigation and orientation for migration, i t i s important, for the purpose of t h i s study at l e a s t , to be aware that these factors can affect b i r d numbers i n a given area. It i s through being aware of the complexity of avian migration that we are able to explain the persistent, periodic or rare occurrence of species i n a given area. Records of b i r d occurrence, d i s t r i b u t i o n and long term seasonal habits are given for B r i t i s h Columbia i n "A review of the b i r d fauna of B r i t i s h Columbia", by Munro and Cowan (1947). This review i s most informative about many birds occurring i n the study area. More recently the unpublished b i r d count data recorded by the late Wm. M. Hughes, between July 1963 and October 1966, on Vancouver International Airport, gives an up-to-date account of the abundance, and seasonal occurrence of b i r d species i n the study area. Both of these records are referred to ex-tensively under i n d i v i d u a l problem b i r d species i n section 4 . 3 . 17 b.- Short p e r i o d m i g r a t i o n Short term or d a i l y migrations i n b i r d s occur i n many forms. They can develop r a p i d l y i n a response to some immediate but temporary f a c t o r and p e r s i s t f o r only a few days or they may occur r e g u l a r l y at a given time i n the seasonal c y c l e of a c t i v i t y f o r a p a r t i c u l a r s p e c i e s . Dalke (1937), w h i l e studying pheasants i n Michigan noted that a habi t of feed i n g i n a p a r t i c u l a r area was q u i c k l y developed I f b i r d s discovered abundant food. Such areas were v i s i t e d repeatedly, o f t e n at r e g u l a r i n t e r v a l s u n t i l the food was depleted. This type of immediate response i s al s o t y p i c a l of many b i r d s v i s i t i n g f e e d i n g traps or b a i t e d t r a p s . The d a i l y migra-t i o n s f o r food of sea gulls and other scavengers to f i e l d s being ploughed or cut f o r hay i s another w e l l know event i l l u s t r a t i n g a short term migratory response. The r e g u l a r movements of many shorebirds between t i d a l f l a t s and higher ground duri n g seasonal migrations or when on w i n t e r i n g areas i s w e l l documented as a response to the c y c l i c e f f e c t of t i d e s (Storer 1951, Recher 1966). Shorebirds are forced o f f the fe e d i n g area ( t i d a l f l a t s ) when t i d e s r i s e , onto areas above the t i d e l e v e l , u n t i l the cy c l e reverses i t s e l f and the t i d e drops to expose the feeding area once again. I n another case nonbreeding Red-winged B l a c k b i r d s were found to exodus to feeding grounds twice d a i l y from t h e i r winter roost l o c a t e d i n c a t t a i l s (Orions 1961). Such f l i g h t s between winter r o o s t s and fe e d i n g areas are al s o w e l l known i n other b i r d s , p a r t i c u l a r l y the S t a r l i n g , Sturnus v u l g a r i s . In s e v e r a l cases 18 migrations between the roost and the feeding area were found to be c l o s e l y r e l a t e d to a p a r t i c u l a r sense of d r i v e o f f the b i r d s themselves. Nice (1935) concluded that S t a r l i n g s , Sturnus v u l g a r i s and Bronzed C r a c k l e s , Quiscalus q u i s c u l a , v a r i e d t h e i r a r r i v a l and departure times to and from t h e i r w i n t e r roosts w i t h the i n t e n s i t y of i l l u m i n a t i o n . On c l e a r days the b i r d s were found to leave the roost 10 to 15 minutes before s u n r i s e (7-9.9 foot, candles) and on cloudy days 5 minutes before s u n r i s e (9.9 f o o t c a n d l e s ) . A study of St a r -l i n g s by Davis (1963 ) revealed that they d i r e c t l y vary t h e i r time of a r r i v a l on feeding grounds w i t h the i n t e n s i t y of morning i l l u m i n a t i o n and temperature. In England, S t a r -l i n g s were found to a r r i v e and depart from roosts at d i f -f e r e n t times depending on the season (Brown 1946). Brown found that as winter approached, time consuming communal f l i g h t s and assemblies were dropped, d e f i n i t e f l i g h t times to feeding areas developed and b i r d s t r a v e l l i n g f u r t h e r from the roost l e f t f i r s t i n morning and a r r i v e d l a s t i n the evening. As a r e s u l t of these observations Brown (1946) concluded that the b i r d s t r y to maintain a req u i r e d period f o r feeding throughout the year. The seasonal response of b i r d s to nest and rea r young a l s o presupposes the development of s e v e r a l short term m i g r a t i o n s . The a c t i v i t y of passing between nest and feeding area i s w e l l known. I t i s p a r t i c u l a r l y n o t i c e a b l e i n species which nest some distance from feeding grounds (eg. Great blue heron). In a d d i t i o n many species of g a l l i f o r m e s migrate 19 d a i l y between night roosts and the leek during the breeding season. S p e c i f i c examples of b i r d s showing short term migra-t i o n h a b i t s are also a v a i l a b l e through s t u d i e s c a r r i e d out i n the general area of the present study. C o t t l e (1949) while s t u d y i n g the fee d i n g behaviour of pond ducks w i n t e r i n g i n the Lower Fraser V a l l e y , observed that they tended to concen-t r a t e on open water areas during the day, but, f l e w to nearby f i e l d s to feed i n the morning and evening. When hunt-i n g pressure became heavy the evening f l i g h t was delayed u n t i l the approach of darkness. This delayed m i g r a t i o n to feeding areas i s commonly termed the "night f l i g h t " and i t was very n o t i c e a b l e along areas bordering Georgia S t r a i g h t and Boundary Bay. S i m i l a r changes i n waterfowl f e e d i n g h a b i t s have been recorded by Yocum (1951) near Cheney, Washington. The p r e l i m i n a r y study d i r e c t e d by R.D. H a r r i s (per-sonal communication 1965) on Vancouver A i r p o r t revealed that Gloucous-winged g u l l s migrated each morning and evening between t h e i r r o o s t i n g area at the north of the Fraser River and Vancouver C i t y Dump, 6 miles Northwest of Sea I s l a n d . The f l i g h t of these b i r d s was d i r e c t l y across the a i r p o r t and as such created a considerable hazard to a i r c r a f t . I n 1966 the d i s p o s a l of f r e s h garbage was stopped at t h i s dump as a new dump became a v a i l a b l e i n D e l t a M u n i c i p a l i t y , 8 miles south of the previous s i t e . The e f f e c t t h i s change has had on the a c t i v i t y of g u l l s on Vancouver i s discussed i n s e c t i o n 4 . 3 . 3 . 20 2.2.2 H a b i t a t f a c t o r s I t has l o n g been known t h a t a v i a n d i s t r i b u t i o n s a r e s t r o n g l y l i m i t e d g e o g r a p h i c a l l y and e c o l o g i c a l l y . The d i s t r i b u -t i o n i s dynamic and c o n s t a n t l y c h a n g i n g . I n one r e g i o n a g i v e n s p e c i e s o r f a m i l y may be dominant w h i l e i n a n o t h e r nearby r e g i o n i t may be s c a r c e o r n o n - e x i s t e n t . The f a c t o r s s e t t i n g g e ographic l i m i t a t i o n a r e b r o a d l y s i m i l a r f o r a l l forms of a n i m a l l i f e . S t a n c h i n s k i i (1926) r e c o g n i z e d t h e s e f a c t o r s as b e i n g of f o u r , main t y p e s ; ( l ) c l i m a t i c ( t e m p e r a t u r e , l i g h t , a t m o s p h e r i c p r e s s u r e ) ; (2) o e k o t r o p i c , t h o s e e x t e r n a l f a c t o r s which v a r y w i t h i n a g i v e n g e o g r a p h i c a r e a ( t o p o g r a p h y , c h a r a c t e r o f s o i l , d i s t r i b u t i o n of w a t e r masses); (3) b i o c o e n o s i c ( c h a r a c t e r of f l o r a and f a u n a ) ; and (4) a n t h r o p o c u l t u r a l , t h o s e a t t r i b u t a b l e t o human a c t i v i t y . More r e c e n t l y e c o l o g i s t s have tended t o r e c o g n i z e , as a d d i t i o n a l , the i n f l u e n c e of h i s t o r i c a l p r i n c i p l e s i n v o l v i n g e c o l o g y , geology and e v o l u t i o n and p h y s i o l o g i c a l a d a p t a t i o n . An e x h a u s t i v e r e v i e w o f t h e l i t e r a t u r e on a v i a n d i s t r i b u t i o n would be volumous and i s d e c i d e d l y beyond t h e scope of t h i s ' . d i s c u s s i o n . T h e r e f o r e , t h e r e v i e w f o l l o w i n g i s p r i m a r i l y concerned w i t h f a c t o r s of d i r e c t and l o c a l i n t e r e s t . B a r r i e r s and t y p e s of d i s p e r s a l are ommitted f r o m t h i s d i s c u s s i o n but the r e a d e r s may r e f e r t o W e l t y (1962) f o r an e x c e l l e n t r e v i e w . S t a n c h i n s k i i (1926) c o n s i d e r s t h a t s i n c e b i r d s a r e homeothermic t h e i r d i s t r i b u t i o n i s l e s s s i g n i f i c a n t l y i n -f l u e n c e d by t h e d i r e c t e f f e c t s of c l i m a t e t h a n by t h e d i r e c t e f f e c t s of o e k o t r o p i c and b i o c o e n o s i c f a c t o r s . T h i s however does not l i m i t t he s i g n i f i c a n c e of t h e d i r e c t e f f e c t s of 21 weather. For example the Bobolink (Dolichonyx oryzivorus) of North America has markedly altered i t s d i s t r i b u t i o n and abundance with man made changes i n vegetation. This species has expanded, following white manVs' footsteps, from the M i s s i s s i p p i Valley p r a i r i e s to the western United States and B r i t i s h Columbia l a r g e l y as a result of grain c u l t i v a t i o n . This expansion, naturally, presupposes that the species was adapted to various climates encountered. However i n order to survive harsh weather, these birds migrate each winter east-ward to the M i s s i s s i p p i Valley then southward and return each spring. The effect of oekotropic and biocoenosic factors on the d i s t r i b u t i o n and abundance of various birds i s often quite marked. For example, i n the early 1900's extensive portions of s o l i d forest of peninsular upper Michigan were burned, r e s u l t i n g i n an increase i n habitat available for Sharp-tailed Grouse, Pediocetes phasianellus (Welty 1962). As quickly as the habitat became available the Sharp-tailed Grouse expanded into i t . Locally, Munro (1943), i n his discussion on the Mallard of the northern Okanagan Valley, mentions how the population depends almost e n t i r e l y on grain f i e l d s for i t s food. He considered that during the early days of settlement, feeding i n the grain f i e l d s occurred seldom, i f ever, but that the habit developed slowly with the expansion of acreage sown to grain. The influence of a change i n vegetation i s often very great i n many species. Since only plants can manufacture 22 t h e i r own food from i n o r g a n i c raw m a t e r i a l s , a l l animals must e v e n t u a l l y depend on s u n l i g h t and the food manufacturing photosynthesis of green p l a n t s f o r t h e i r energy ( P e t i n g i l l 1966). Food may be the vege t a t i o n i t s e l f or the animal species a s s o c i a t e d w i t h i t . Many b i r d s respond s e n s i t i v e l y to changes i n a v a i l a b i l i t y and nature of food because of h i g h l y adapted s t r u c t u r e , such as f e e t and beaks. Wel l i n g t o n (1945) found i n s e c t feeding b i r d s , such as chimney s w i f t s , to d i s t r i b u t e themselves i n zones or areas of i n s e c t abundance which were the r e s u l t of convective currents caused by l o c a l weather con-d i t i o n s . The accuracy of t h i s a s s o c i a t i o n was such that he f e l t such b i r d s could be used as i n d i c a t o r s of i n s e c t d i s t r i -b u t i o n i n the atmosphere. S i m i l a r l y , Neronov (1963) concluded th a t the use of predatory b i r d s as i n d i c a t o r s of rodent abun-dance over l a r g e or small areas was f u l l y j u s t i f i e d . In h i s study he sampled both animal populations (counting b i r d s ; t r a p -ping rodents) and found t h e i r d i s t r i b u t i o n s h i g h l y a s s o c i a t e d . The e a r l i e r work of Fromozov (1936) a l s o i n d i c a t e d an extremely cl o s e connection between the d i s t r i b u t i o n s of various b i r d s of prey and c e r t a i n rodents. Many b i r d s are e c o l o g i c a l l y a s s o c i a t e d w i t h a wide v a r i e t y of food sources (euryphogous -eg. Hummingbirds, many shorebirds and Woodpeckers). Pla n t s a l s o supply n e s t i n g m a t e r i a l s , n e s t i n g s i t e s , lookout posts, s i n g i n g s t a t i o n s and p r o t e c t i v e cover. The character of the s o i l has been found to d i r e c t l y i n f l u e n c e the d i s t r i b u t i o n of b i r d s . Recent s t u d i e s have shown a d i r e c t r e l a t i o n s h i p between the mineral content of 23 s o i l s and the e c o l o g i c a l d i s t r i b u t i o n of c e r t a i n g a l l i f o r m e s . Wilson (1959) was able to c o r r e l a t e the d i s t r i b u t i o n of the Hungarian P a r t r i d g e , P e r d i x p e r d i x , to s o i l s of limestone o r i g i n i n New York. I n another study both f i e l d observations and l a b o r a t o r y feeding experiments showed that calcium i s req u i r e d i n the d i e t of the Ring-necked Pheasant, Phasianus  c o l c h i c u s (Dale 1955). In two f i e l d areas studied the presence or absence of calcium was the only v a r i a b l e which would account f o r the d i s t r i b u t i o n and abundance of the b i r d s . A l i m i t i n g e f f e c t of a low calcium d i e t was apparently a marked r e d u c t i o n i n egg production. Other b i r d s are i n f l u e n c e d by the t e x t u r e of the s o i l . For example, K i l l d e e r , Charadrius  v o c i f e r o u s . p r e f e r to nest i n f l a t , coarse, g r a v e l l y areas whi l e a few b i r d s r e q u i r e mud that can be molded and w i l l not crumble on d r y i n g so that they can b u i l d t h e i r nests ( C l i f f swallow). The topography of the substrate i s al s o of e c o l o g i -c a l importance to the d i s t r i b u t i o n of b i r d s . This i s par-t i c u l a r l y n o t i c e a b l e during the n e s t i n g season. Many b i r d s such as swallows and k i n g f i s h e r s r e q u i r e v e r t i c a l banks of s o i l i n t o which they can d i g t h e i r nest burrows. Many A l c i d s and the Peregrine Falcon, Falco paregrinus, p r e f e r to nest on v e r t i c a l c l i f f s , w h i l e , most g u l l s p r e f e r to nest on shores which slope g r a d u a l l y to the edge. Water i s another substrate to which many b i r d s are a t t r a c t e d and h i g h l y adapted. Many species have webbed f e e t , powerful l e g muscles, l a r g e u r o p y g i a l glands, and dense water-2 4 proof plumage to enable them to thrive i n and around water. Some species are quite exclusive to fresh water or s a l t water while others are able to u t i l i z e both habitats. Water by en-couraging or discouraging various plant communities can also influence the food, cover and nesting s u i t a b i l i t y of the area f o r various bir d s . The grebes, for example, require shallow water with vegetative cover i n which they can build t h e i r f l o a t i n g nests. They also require the water area to obtain food and to provide protection from many predators. Temporary water areas, which come and go with a par-t i c u l a r season, can also be a t t r a c t i v e to various water-adapted b i r d s . In the southeastern United States, controlled flooding of mast-producing timber i n winter provides excellent habitat f o r Mallards and wood ducks (Rudolph and Hunter, page 6 1 1 , i n 'Waterfowl Tomorrow', the U.S. Fish and W i l d l i f e Service 1 9 6 4 ) . Locally, wintering waterfowl were found to have a decided preference f o r f i e l d s which were flooded (Cottle 1 9 4 9 ) . Areas about ponds were often heavily grazed by them. Weather can also influence the l o c a l d i s t r i b u t i o n of many bi r d s . The type of weather and avifauna of the area, determines the extent and type of i n t e r a c t i o n . I f a species of b i r d present i n an area i s neither favoured or adversely effected by a given weather change there w i l l be no response. Shaver ( 1 9 3 3 ) studied the influences of climate and weather factors on the numbers of birds on a depositing creek bank f i v e miles from Nashville, Tennessee. His study was planned 2F> e s p e c i a l l y to investigate the l o c a l mobility or change of habitat of birds as the weather changed. Shaver's c l a s s i f i -cation was as follows: a) permanent residents, b) winter v i s i t -ants, c) summer residents, d) migrants and e) t o t a l birds; he smoothed the counts so as to get the slow seasonal rhythm un-modified by d a i l y f l u c t u a t i o n s . These, smoothed curves of b i r d abundance were compared with smoothed normal climatic curves of weather factors which included temperature, r e l a t i v e humidity, p r e c i p i t a t i o n , wind v e l o c i t y , wind d i r e c t i o n , sunshine duration and atmospheric pressure. From these comparisons correlation c o e f f i c i e n t s were obtained. For a l l groups of birds, the c o e f f i c i e n t s of co r r e l a t i o n ranked as follows: (l) temperature, (2) sunshine duration (plus i n f a l l and winter but minus i n spring and summer), [1+) wind v e l o c i t y , (5) atmospheric pressure and (6) p r e c i p i t a t i o n . Deviations from the smoothed curves of bi r d abundance were considered to be due to condi-tions that fluctuated from day to day and the most important of these were thought to be weather fa c t o r s . Using the same seven factors as were used f o r climate, Shaver found l i t t l e i n the way of co r r e l a t i o n between them and b i r d numbers. He noted that there were high probable errors and hence he regarded the c o e f f i c i e n t s as being much less important than the correlations with climatic f actors. The main point outlined i n Shaver's review of the l i t e r a t u r e was that a l l observations and analysis (except Bretscher's 1916, who used mean monthly temperatures) indicated the very great importance of temperature f l u c t u a t i o n i n determining b i r d a c t i v i t y . In 26 his own study, however, there seemed to be l i t t l e r e l a t i o n between temperature and the numbers of birds present. The highest correlation between any two factors was between "summer residents" and "sunshine duration". Associations of "permanent residents" and "winter v i s i t a n t s " with climatic variables were not discerned or were of l i t t l e s i g n i f i c a n c e . "Total i n d i -viduals" or "summer residents" on the other hand did relate i n a small degree to climatic variables. To summarize Shaver's study one could say that b i r d abundance on a pa r t i c u l a r area within a regular migratory route, appears to vary d i r e c t l y with climatic factors while d a i l y fluctuations or movements appear to vary with factors other than weather .(except where severe weather dominates p e r i o d i c a l l y - cold, high wind, e t c . ) . Locally, a study of the winter feeding habits of waterfowl i n the Lower Fraser Valley revealed that cold weather, with heavy snows, limited normal food a v a i l a b i l i t y on inland areas and forced the birds to move to the l i t t o r a l zones (Cottle 1949). Over certain areas, about Ladner v i l l a g e and Boundary Bay where snow f a l l was lower than at other points i n the valley,unusually great concentrations of birds were noted. Fields which had food available i n these areas, were reported as being "black" with bir d s . 2.2,3 Behavior Other factors which can l i m i t b i r d numbers i n a given area are related to the behavior of the birds themselves; these include t e r r i t o r y (intra-or i n t e r s p e c i f i c ) , predation (including man) and security (Welty 1962). 2.7 The maintenance of t e r r i t o r y sets a carrying capacity fo r the environment. This capacity therefore d i r e c t l y depends on the function of the t e r r i t o r i a b i l i t y which i n turn can d i f f e r from the i n d i v i d u a l b i r d , the mated -pair or i t s family, a colony of birds, or a species. T e r r i t o r y has no single, simple o v e r - a l l function. Generally, t e r r i t o r y produces i t s effects through the i s o l a t i o n of birds by spreading them apart, by providing geographic s t a b i l i t y and by giving i t s owners certain psychol-o g i c a l advantages. I s o l a t i o n of birds presupposes unmolested courtship, copulation, nest building, and rearing of young. I t ensures more or less a monopoly of the food resources nearby and nesting materials. In the long run t e r r i t o r y also reduces i n t e r s p e c i f i c s t r i f e . The dispersion of the species serves to regulate population density and prevents overpopula-t i o n . It thus promotes the e f f i c i e n t exploitation of food, nest materials, nest s i t e s , and provides a standby population ready to take over i n times of emergency and to keep the optimum habitats producing b i r d s . Predation can d i r e c t l y affect the numbers of any species i n a given area by l i m i t i n g the numbers of survivors. However, i t i s s t i l l a moot point among ornithologists as to the degree to which predators regulate b i r d population l e v e l s . Welty (1962) cites a number of cases of varying predation as follows; 40% loss of eggs i n the Jackass Penguin, Spheniscus  denersus (Kearton 1930); 54$ loss of Blue-winged Teal, Anas  discors, nests i n Iowa (Glover 1956); 52$ loss of 333 duck nests 28 and 54% of 150 coot nests i n the Sacramento V a l l e y of C a l i -f o r n i a (Anderson 1 9 5 7 ) ; 70% l o s s of eggs and young of the A d e l i e Penquins, P y g o s c e l i s a d e l i a e , mainly by skuas on Adelie Land i n the A n t a r c t i c (Sapin, J a l o u s t r e and B o u r l i e r e 1 9 5 1 ) ; and 95% l o s s young Wandering A l b a t r o s s e s , Diomedea exulans. on Gough I s l a n d i n the South A t l a n t i c by skuas and Fulmars (Comer 1 8 9 5 ) . Prey numbers can play a part i n the degree of predation i n a given area because the more e a s i l y they are found by predators, probably the more intense the predation. Lack (1954) showed that the greater the summer population of Bobwhite Q u a i l i n Wisconsin (data from E r r i n g t o n 1945) the higher the percent l o s s of b i r d s by f a l l . On the other hand increased d e n s i t y i n Common Terns of Cape Cod i n 1934 r e s u l t e d i n greater success i n producing young (Welty 1962, r e f e r r i n g to work of A u s t i n 1 9 4 9 ) . Perhaps, i n t h i s case, the a b i l i t y to defend the young i s more important when co n s i d e r i n g the s i z e of the breeding p o p u l a t i o n . In t h i s regard i t should be noted th a t many b i r d s have evolved adaptations to reduce predation and some of these i n c l u d e ; t i m i n g of l a y i n g eggs, r e c o g n i t i o n of enemies, " f r e e z i n g " at the s i g h t of enemies, and defence of nest and contents ( s i n g l y or group). Such responses i n b i r d s are as they are i n other animals, b e h a v i o r a l responses l a r g e l y d i r e c t e d towards s e l f -and r a c i a l - s u r v i v a l . While, b i r d s show an e x t r a - o r d i n a r y v a r i e t y of behavior patterns the most c h a r a c t e r i s t i c response i s f l i g h t i t s e l f . This enormously, s u c c e s s f u l , a b i l i t y to f l y has reduced the n e c e s s i t y f o r cleverness. As a r e s u l t b i r d 29 behavior i s broken, stereotyped and often "stupid" i f compared to mammalian behavior. It suggests that birds responses are lar g e l y hereditary or innate. Innate behavior (reflex, k i n e s i s , taxis or i n s t i n c t ) i s highly developed i n many birds and doubtless has su r v i v a l value (Welty 1962) . Innate be-havior i s often a s p e c i f i c action pattern where the birds' response i s a matter of r e f l e x or i n s t i n c t reaction. For example, tameness, shyness and belligerence, common to b i r d f a m i l i e s , are l i k e l y hereditary behavior patterns (Welty 1962) . Penquins as a group are reasonably unafraid of animals on land as are many shorebirds, while waterfowl are extremely wary and show immediately apparent inse c u r i t y when presented with an unfamiliar s i t u a t i o n . In some species of birds an a b i l i t y to learn waryness i s evident and they are capable of p r o f i t i n g from previous experiences ( d i r e c t l y or v i a experienced com-panions); they can a l t e r a response of security to one of i n -security or vise versa. Whatever the source of the behavior, innate or learned, many birds are able to "assess" t h e i r en-vironmental situations and respond favourably for s e l f preser-vation while others do not. This suggests why scaring devices have variable effects on d i f f e r e n t species of birds or on even d i f f e r e n t (inexperienced) indiv i d u a l s of the same species. Resident birds, because of t h e i r f a m i l i a r i t y with the l o c a l environment (including the a c t i v i t y of man), often display bold a c t i v i t y as compared to inexperienced transients. This difference i n reaction i s commonly observed when resident "park waterfowl" and t h e i r transient (migratory) r e l a t i v e s are compared. 30. Welty ( 1 9 6 2 ) , r e f e r r i n g to the contributions of Thorpe (1956), d i f f e r e n t i a t e s such types of learning as a) habituation, b) t r i a l and error, c) ins i g h t , d) imprinting, and e) other behavioral forms. The f i r s t two types are con-sidered b r i e f l y below because of t h e i r application to the present study. Habituation i s learning not to respond to s t i m u l i . I t i s a common observation that many birds learn to be undisturbed i n such areas as busy highways, r a i l r o a d s , and ai r p o r t s . Markgren (i960) considers that any b i r d species may, through t r a i n i n g , i n h i b i t escape from harmless vehicles, just as bad experiences may accentuate an innate f u g i t i v e reaction (ins e c u r i t y followed by " f l i g h t " ) . Various birds such as pig-eons, k i l l d e e r , and Bobwhite Quail have adjusted to the sound of near-by gunfire (Welty 1 9 6 2 ) . On the other hand, Markgren (i960) , r e f e r r i n g to the work of Edelstam and Ramel (1956) and Curry-Lindahl ( 1 9 5 3 , 1 9 5 4 , 1 9 5 8 ) , noted that several species of birds have been forced to migrate as a resu l t of hunting pressure. In one case a quantitative study of habituation i n the Chaffinch was made by placing a l i v e L i t t l e Owl (Athene noctua) i n the aviary for 2 0 minutes each day for a number of days and recording the number of alarm notes ("Chinks") they made (Welty 1962, r e f e r r i n g to the work of Itinde 1954). After f i v e days of presentations the alarm notes dropped to less than 3 0 $ of the rates of the f i r s t day, and aft e r 1 2 days to about 1 0 $ . Welty ( 1 9 6 2 ) suggests, there-fore, that birds are more l i k e l y to remain responsive to s i g n i f i c a n t or meaningful stimuli when they are followed by 31 reinforcement such as punishment or reward. " T r i a l and error" i s learning to select one response from among several responses to solve a p a r t i c u l a r problem. Thorpe (1956) considers that the b i r d needs appetitive motiva-t i o n before the process of t r i a l and error can begin. That i s , the b i r d must f i r s t of a l l be i n c l i n e d to perform the response such as eating seeds or insects to learn to l a t e r discriminate between palatable from unpalatable types. "Play", an important component of " t r i a l and error learning" i n mammals, i s also performed by a number of b i r d species. Munro (1934) observed a young P r a i r i e Falcon playing with a prey-sized" piece of dried cow manure. I t repeatedly dropped the manure i n mid-air and immediately swooped down to retrieve i t before i t had f a l l e n more than a few meters. The young falcon also played with i t on the ground by tossing i t ahead and then rushing forward to pounce on i t . Such a learning process can f a c i l i t a t e increased a c t i v i t y of a b i r d or b i r d species i n a given area once the favorable response has been discovered. Therefore, security f o r a b i r d i n a given area i s dependent on the b i r d species, age, experience, learning a b i l i t y and a v a i l a b i l i t y of response i n i t i a t i n g materials. I f the opportunity f o r forming a secure response i n an area i s available then birds w i l l u t i l i z e i t when present. Conversely l i m i t a t i o n of the opportunity or materials necessary to create a secure response w i l l maintain i n s e c u r i t y i n the b i r d species and thus res u l t i n t h e i r reduced use of an area. 3 1 2 2 . 3 Plant ecology The general ecological p r i n c i p l e s which are used to describe the d i s t r i b u t i o n and composition of vegetation under the extensive and varied influences of man also apply to the study area. Sea Island and i t s environs are dominated by the a c t i v i t i e s of man. These p r i n c i p l e s are amply described i n the lengthy discussion of Daubenmire (1959) and Braun-Blanquet (1932) and f o r that reason they are not discussed further here. More extensive information concerning s o i l -plant relationships i s available i n the discussions of Russell ( 1 9 5 0 ) and Geiger ( 1 9 6 5 ) . Unfortunately the writer found no s p e c i f i c coverage of vegetation ecology f o r the Lower Fraser Valley. 3. THE VANCOUVER AIRPORT AND ITS ENVIRONS 33 3.1 Location Vancouver International Airport i s located on Sea Island six miles south of Vancouver c i t y centre i n B r i t i s h Columbia. The coordinates given for the meteorological station located within the airport complex are i ^ U ' N , 123°10T¥ (see drainage map, Appendix 10.2). This i s l a n d i s the outermost, major, dyked, area on the northwest edge of the,Fraser River delta. Arms of the Fraser River flow on the north (North Arm) and the south (Middle Arm) and the abrupt western edge faces Georgia S t r a i t , The land i s naturally f l a t and l i e s below sea l e v e l but, the a c t i v i t y of man has created a few prominant elevated sections such as; dykes, dredged sand deposits, runways and taxiways. Between Vancouver c i t y centre and the North Arm of the Fraser River there i s located an extensive g l a c i a l out-wash and t i l l deposit which today averages 250 feet above sea l e v e l . This deposit extends from the f o o t h i l l s of the Coast Range at Port Moody c i t y and Coquitlam municipality, approximately 25 miles east of Sea Island, to Point Gray approximately 4.5 miles northwest of Sea Island. This upland r i s e s rather abruptly to f u l l height on i t s south and west edges but tends to drop gradually northward to Burrard In l e t . Most of t h i s area i s r e s i d e n t i a l but extensive secondary growth of mixed coastal forest occurs along the south slope 34 and over a l a r g e area of the U n i v e r s i t y of B r i t i s h Columbia endowment lands at Point Gray. The land areas to the south and east of Sea I s l a n d are f l a t d e l t a i c deposits which are f u l l y dyked and used f o r farming except where business and r e s i d e n t i a l centres occur. Ten miles to the north of Sea I s l a n d , across Burrard I n l e t , there are the extensive Coast Mountains. L o c a l l y these are c a l l e d the North Shore Mountains, and they r i s e r a p i d l y to e l e v a t i o n s between 4000 and 8000 f e e t . Other land scape fe a t u r e s important to t h i s study, i n the immediate v i c i n i t y of Sea I s l a n d , can best be described by beginning at the northwest corner and proceeding clockwise around the i s l a n d (see Appendix 10.1 or 10,2). A man made isthmus j o i n s Sea I s l a n d to l o n g , narrow, Iona I s l a n d . This i s l a n d i s a recent undyked deposit which has been e x t e n s i v e l y covered by sand dredged from the North Arm of the Fraser R i v e r . The a d d i t i o n of the dredged m a t e r i a l has placed most of the i s l a n d surface above the high t i d e and f r e s h e t l e v e l s . I t i s on t h i s i s l a n d that the c i t y of Vancouver has constructed i t s modern sewage treatment p l a n t . As part of the sewage plant complex there i s a 20 f o o t wide, 2.6 mile long rock j e t t y p a r a l l e l i n g a 40 f o o t wide, 10 f o o t deep, sewage channel which heads i n t o Georgia S t r a i t . There are al s o four sewage lagoons and two extensive "pothole" formations to the west of the main plan t and three small "potholes" to the east. The potholes are the r e s u l t of c o n s t r u c t i o n a c t i v i t y . Another fe a t u r e of importance on Iona I s l a n d i s the long breakwater which extends 35 northwest from the main body of the i s l a n d , for approximately four miles. This structure has encouraged the deposition of sand between i t s e l f and the sewage j e t t y and i t also serves to maintain a strong flow of water i n the North Arm of the Fraser River. Along the north edge of Sea Island, an extensive dredged sand deposit l i e s above the high tid e l e v e l . This area i s p a r t i a l l y covered by poplar trees, Populus trichocarpa. and a grassy sward. I t presently serves as a park for r e s i -dents of Richmond municipality on Sea Island; formerly i t was known as Wood Island. Along the southeastern shore of Sea Island are located two more small d e l t a i c deposits which have been per-manently joined along t h e i r f u l l lengths to each other and to Sea Island. These islands are named Dinsmore and Pheasant and both are deeply covered with sand dredged from the Middle Arm of the Fraser River p r i o r to I 9 6 0 . Their importance to the present study i s that they are i n part heavily vegetated; an extensive willow-forb community occurs around the periphery and a large c a t t a i l , Typha, marsh occupies the middle. Lulu Island, which i s the closest of the afore-mentioned d e l t a i c deposits to the southeast, terminates abruptly on i t s western edge just 1 0 0 0 feet east of Sea Island, with the dyke system c l e a r l y marking the boundary between t i d a l f l a t s (foreshore) and the r e s i d e n t i a l or farm areas. Its west dyke runs d i r e c t l y south i n a straight l i n e f o r approximately four miles u n t i l i t reaches Steveston 36 v i l l a g e and the South Arm of the Fraser R i v e r . Between L u l u I s l a n d and Sea I s l a n d In mid stream of the Middle Arm of the Fraser River are two d e l t a i c d e p o s i t s , u n i t e d by a low isthmus, c o l l e c t i v e l y named Swish'swash I s l a n d . The eastern p o r t i o n s of these deposits remain above high water and f r e s h e t l e v e l s because of an extensive covering of dredged sand which supports some shrubby w i l l o w . On t h e i r n o rth and south edges and more e x t e n s i v e l y on t h e i r common western edge the deposits are t i d a l marsh and mud f l a t . F i n a l l y , connected to the west dyke of Sea I s l a n d , approximately $ 0 0 f e e t north of i t s southwest corner there i s lo c a t e d a 2 0 f o o t wide, 2 0 0 0 f o o t l o n g , rock j e t t y running west i n t o the S t r a i t of Georgia. This s t r u c t u r e i s covered f o r i t s f u l l l e n g t h w i t h approach l i g h t s l e a d i n g to the main runway on the a i r p o r t . 3 . 2 Climate and Weather The c l i m a t o l o g i c a l record f o r Sea I s l a n d dates from 1 9 3 7 when a major observing s t a t i o n was e s t a b l i s h e d i n connec-t i o n w i t h the Vancouver A i r p o r t . The general climate and weather of t h i s area i s w e l l described by Kerr ( 1 9 5 0 ) . Kerr describes four regions f o r the climate of southern B r i t i s h Columbia: the study area occurs i n h i s "Southern Coastal Trench" r e g i o n . The "Southern Coastal Trench" l i e s between the I n s u l a r Mountains of Queen C h a r l o t t e and Vancouver Islands and the Coast-Cascade Mountains. Areas above sea l e v e l 37 i n c l u d e the northeastern lowlands of Graham I s l a n d , the Lower Fraser V a l l e y and the eastern lowlands of Vancouver I s l a n d . This region also i n c l u d e s the offshore Gulf I s l a n d s . Kerr notes t h a t t h i s zone "probably o r i g i n a t e d as a s y n c l i n e be-tween the fo l d e d Coast and I n s u l a r Ranges during the J u r a s s i c period""'". The drainage system of the western C o r d i l l e r a eroded the depression i n p r e - g l a c i a l times w i t h the ancient Fraser Ri v e r f o l l o w i n g the S t r a i t of Jaun de Fuca and di s c h a r g i n g 50 m i l e s o f f the present Washington Coast. In the region of the present study the massive b a r r i e r formed by the Coast-Cascade Mountains i s broken by the Fraser River V a l l e y . The p r e v a i l i n g f l o w of a i r f o r a l l l e v e l s over B r i t i s h Columbia i s w e s t e r l y ( K e r r 1950). However the lower troposphere c i r c u l a t i o n i s c o n t r o l l e d by two pressure systems; "the A l e u t i a n low" and "the Hawaiian high". Kerr (1950) notes that the p r e v a i l i n g west to east p a t t e r n may o c c a s s i o n a l l y be dis r u p t e d by three l e s s important pressure systems: "the Polar A n t i c y c l o n i c Ridge", "the Great Basin High" and "the Thermal Trough". The i n t e n s i t y of these pressure f i e l d s f l u c t u a t e from day to day but they do appear d i s t i n c t l y on the average annual sea l e v e l pressure chart and more p e r s i s t e n t l y on the seasonal c h a r t s . The seasonal occurrence of these sys-tems i s given i n Table 1. "The A l e u t i a n Low" dominates the climate of B r i t i s h Columbia during a l l months except J u l y and August when i t covers the e n t i r e Northern P a c i f i c Ocean. During s p r i n g and autumn t h i s system o c c a s i o n a l l y covers the North 1 K e r r , D.P. "The r e g i o n a l c l i m a t o l o g y of southern B r i t i s h Columbia, 1950" (Ph.D. Thesis, U. of Toronto), p.4. TABLE 1 . P r e s s u r e Systems f o r S o u t h w e s t e r n C o a s t a l B r i t i s h C o l u m b i a ; ' P r e s s u r e Sys tems S e a s o n Mon th Dominant I r r u p t i v e Comment C o l d J a n u a r y ( w i n t e r ) A l e u t i a n Low C o o l P a c i f i c ( H a w a i i a n ) h i g h A g e n e r a l c y c l o n i c c i r c u l a t i o n c a u s i n g g e o t r o p i c w i n d s t o be s o u t h w e s t e r l y i n S o u t h w e s t e r n B . C . As a r u l e s o u t h e a s t e r l y w i n d s p r e v a i l i n most s e c t i o n s b e c a u s e t h e g e n e r a l t r e n d o f t h e : - t o p o g r a p h y i s s o u t h e a s t - n o r t h w e s t . A s y s t e m l o c a t e d o f f S o u t h e r n ' C a l i f o r n i a C o a s t w h i c h o c c a s i o n a l l y b u i l d s a r i d g e a l o n g t h e P a c i f i c C o a s t . ( s p r i n g ) A p r i l C o l d n o r t h e a s t e r l y w i n d s s e l d o m b l o w o v e r S o u t h e r n B . C . a f t e r e a r l y s p r i n g . Warm (Summer) J u l y P a c i f i c ( H a w a i i a n ) H i g h T h e r m a l T rough A f a i r l y s t e a d y f l o w o f N o r t h w e s t e r l y a i r ensues o v e r B . C . O c c a s i o n a l l y t h e deep t h e r m a l l o w o f s o u t h e r n C a l i f o r n i a w i l l d e v e l o p a l o n g t h e W i l l a m e t t e and Puge t T r e n c h e s , b e -tween t h e O l y m p i c and Cascade M o u n t a i n s r e s u l t i n g i n an o f f s h o r e f l o w o f warm, d r y , s t a b l e a i r o v e r t h e s o u t h e r n c o a s t o f B . C . Such a p r e s s u r e a l i g n m e n t w i l l b r i n g a t e m p o r a r y h e a t wave t o t h e C o a s t (Autumn) September-O c t o b e r A l e u t i a n Low The P a c i f i c a n t i c y c l o n e weakens r a p i d l y w i t h t h e coming o f autumn and by O c t o b e r t h e s e a l e v e l p r e s s u r e map shows c l o s e r a f f i n i t i e s t o t h e w i n t e r p a t t e r n t h a n t h e summer. The t r a n s i t i o n p e r i o d i s s h o r t and c o n f i n e d t o m a i n l y S e p t e m b e r . * T h i s i n f o r m a t i o n i s condensed f r o m a d i s c u s s i o n b y ; K e r r , D . P . , "The r e g i o n a l c l i m a t o l o g y o f s o u t h e r n B r i t i s h C o l u m b i a " (1950) P h . D . T h e s i s , U . o f T o r o n t o , pages 2 0 - 2 2 . ' 38 P a c i f i c Ocean or parts of the Coast tem p o r a r i l y ; i t i s u s u a l l y q u i c k l y replaced by "the A l e u t i a n Low". The dominant a i r masses i n southern B r i t i s h Columbia are P o l a r P a c i f i c and Polar C o n t i n e n t a l a i r and they are only s i g n i f i c a n t i n the wi n t e r season. In a d d i t i o n T r o p i c a l P a c i f i c a i r and T r o p i c a l C o n t i n e n t a l a i r i n f l u e n c e the climate very s l i g h t l y during the summer season. I n a normal year Polar C o n t i n e n t a l a i r covers a l l of B.C. once or twice i n a win t e r but i t i s u s u a l l y r a p i d l y replaced by Polar P a c i f i c a i r . Kerr (1950) recognizes s i x major weather types i n southern B r i t i s h Columbia: the Cyclonic Storm, the I n t e r -f r o n t a l . , ,the Gold wave, the P a c i f i c A n t i c y c l o n i c f l o w , the Thermal Trough flow and the Upper Level Gold flow. The f i r s t three dominate the weather during the cool season and the l a s t three are more e f f e c t i v e during the summer. The f o l l o w i n g quote i s from Kerr (1950) and i t des-c r i b e s a t y p i c a l storm p a t t e r n f o r the general study area. 1"A t y p i c a l sequence of weather begins w i t h a drop i n pressure, a strengthening of south e a s t e r l y winds along the coast and high clouds over western and c e n t r a l B r i t i s h Columbia. As the storm approaches, the clouds lower and t h i c k e n and r a i n f a l l s along the coast sometimes as f a r as 500 miles ahead of the surface f r o n t . I f the c o a s t a l area i s i n the g r i p of a co l d wave from e i t h e r c o o l modified P o l a r P a c i f i c a i r or Polar C o n t i n e n t a l a i r , heavy, wet snow comes down. With a f r o n t a l passage along the coast, c o n t i n -uous r a i n stops but low, dense clouds p e r s i s t . Showers f r e q u e n t l y develop. Strong surface winds accompany the general f a l l of r a i n i n advance of the f r o n t . .They flow i n t o the approaching low pressure system and are normally s o u t h e a s t e r l y f o l l o w i n g the alignment of the coast. Extremely high wind v e l o c i t i e s often Kerr' , D.P. "The r e g i o n a l c l i m a t o l o g y of southern B r i t i s h Columbia", 1950. (Ph.D. Thesis, U. of Toronto) pp.41-43. 39 occur i n the Coastal Trench because of the funnel e f f e c t . Well-marked wind s h i f t s are not common with the passage of a f r o n t . But, southwesterly or wester-l y winds along the coast usually indicate the termination of a stormy period i n which a series of occlusions has moved eastward". Actually storms reach the south coast v i a two main tracks: the Westerly and Southwesterly. The westerly storms develop as ".waves on the polar front i n the middle A s i a t i c coast or off the Aleutians and they occlude quickly or move rapidly on shore. Storms of t h i s type usually come i n groups of three or four or i n a family of waves which occlude to become a storm i n i t s e l f (Kerr 1 9 5 0 ) . The importance of t h i s group i s r e a l i z e d when one notes that these storms account for the largest positive p r e c i p i t a t i o n anomally along the coast of B.C. Kerr notes that these systems are most frequent during the autumn, winter and early spring months. The storms of the Southwesterly Track approach the Gulf of Alaska, i n a southwest-northeast l i n e from the Hawaiian Islands and they commonly consist of a family of waves. These storms influence northern coastal B r i t i s h Columbia f i r s t and they are marked by heavy r a i n , strong winds and moderately high temperatures. Their occurrence i s most frequent i n winter but they p e r i o d i c a l l y appear i n spring and autumn and, r a r e l y , i n summer. Polar P a c i f i c a i r i s moist and unstable over the North P a c i f i c Ocean and i t moves landward behind an occlusion, bringing cloudy, showery weather to the coast. Showers from such unstable i n t e r - f r o n t a l weather are usually heavy because 4 0 of t h e i r forced ascent over the coastal high land areas and as a r e s u l t they account for more than half of the r a i n that f a l l s on the coast. During autumn, winter and early spring months modified Polar P a c i f i c (stable) a i r develops frequently be-tween f r o n t s . Light winds and evening cooling (radiation) i s common; as a r e s u l t , fog develops over low areas. The Fraser River Delta d i s t r i c t has many thick fogs from early September to l a t e January (Table 2 ). Vancouver airport reports, on the average, approximately 3 5 0 hours of dense fog ( v i s i -b i l i t y < 0 . 3 miles). Greater than 7 5 % of a l l foggy days occur between the f i r s t of October and the end of December. In i n d u s t r i a l areas such as, Burrard I n l e t , False creek, the North Arm of the Fraser River and New Westminster, especially dense fog i s experienced. This moist blanket forms i n the evening and persists u n t i l l a t e morning unless increased stagnation occurs to encourage thicker fog of longer dura-t i o n . Dry Tropical Continental a i r may p e r i o d i c a l l y flow i n from the south when a pattern of deep, low pressure i s es-tablished i n the Southern I n t e r i o r Uplands of B.C. Easterly winds can then transfer these conditions to the coast where, modified by sea breezes, they can form a secondary Thermal Trough i n the Puget Lowlands. This results i n high tempera-tures i n the Lower Fraser Valley and adjacent d i s t r i c t s . The normal seasonal d i s t r i b u t i o n of p r e c i p i t a t i o n , as i s indicated by the number of days with measurable pre-Table 2 . Basic meteorological data for months of the study period and normals for Vancouver International Airport* ( 1 9 6 6 - 1 9 6 7 ) . MONTH May June July Aug. Sept. Oct. Nov. Dec. Jan. Days with minimum temperature above freezing °F (normals not given) 31 30 31 31 30 30 27 24 22 Mean monthly temperatures °F Normal 5 2 . 7 5 0 . 0 5 7 . 1 6 0 . 4 6 0 . 7 6 3 . 8 6 2 . 9 6 3 . 6 5 9 . 0 5 7 . 8 49 .3 5 0 . 3 4 3 . 7 4 3 . 1 4 2 . 5 3 9 . 6 4 0 . 1 3 7 . 2 Total monthly p r e c i p i t a t i o n Normal (inches 1 .49 1 .92 2 . 0 4 1 . 8 4 2 . 5 1 1 . 0 4 1 . 18 1 .37 2 .75 2.13 5 . 2 1 4 . 6 2 6 . 69 5 . 4 4 9 . 5 8 6 . 4 4 8 . 9 9 5 . 5 2 Total days with p r e c i p i t a t i o n Normal 7 10 17 9 10 6 5 8 11 9 15 15 23 18 27 20 23 19 P r e v a i l i n g wind di r e c t i o n by Hours Normal NW E E E SE E SE E SE E E E E 'E E E E E Total hours of bright sunshine Normal 279 .2 253 .8 1 8 8 . 7 2 3 7 . 9 2 5 9 . 3 3 0 1 . 1 289 .3 2 5 1 . 1 1 4 6 . 2 188.6 1 1 2 . 9 1 1 5 . 6 4 8 . 2 69 . 1 3 0 . 8 4 3 . 8 4 6 . 7 5 4 . 8 % Relative Humidity ( 1 0 : 0 0 AM) (P.S.T.) Normal 71 72 73 73 78 72 81 74 84 79 & 84 90 86 89 88 87 Total snowfall (inches) Normal n i l T n i l n i l n i l n i l n i l n i l n i l n i l n i l T T 1 2 .5 3 . 5 3 . 7 7 . 4 Days with fog Normal n i l n i l n i l n i l 3 1 n i l n i l 10 11 8 12 5 10 3 10 1 9 . Temperature -Maximum °F Normal 6 1 . 1 6 2 . 9 6 4 . 8 6 7 . 7 6 8 . 5 7 2 . 3 7 1 . 7 7 1 . 6 6 5 . 9 6 5 . 2 5 5 . 6 5 6 . 5 49 .2 4 8 . 6 4 6 . 7 4 4 . 4 4 4 . 5 4 1 . 8 Temperature -Minimum °F Normal 4 4 . 2 4 7 . 1 4 9 . 4 5 3 . 0 5 2 . 8 5 5 . 3 5 4 . 0 5 5 . 5 5 2 . 0 5 0 . 4 4 2 . 9 4 4 . 0 3 8 . 2 3 7 . 6 3 8 . 3 3 4 . 8 3 5 . 7 3 2 . 5 * A l l records taken from monthly meteorological summaries made by the Meteorological Branch -Depart-ment of Transport - Vancouver International Airport, B.C. (May 1 9 6 6-July 1 9 6 7 ) . T a b l e 2 . C o n t i n u e d . MONTH F e b . M a r . A p r . May June J u l y T o t a l Days w i t h minimum t e m p e r a t u r e above f r e e z i n g °F (Normals no t g i v e n ) 18 2 2 2 9 3 1 3 0 3 8 6 4 2 6 Mean m o n t h l y t e m p e r a t u r e s °F Norma l 4 1 . 2 3 9 . 4 4 1 . 3 4 3 . 2 4 5 . 3 4 8 . 3 5 3 . 8 5 5 . 0 6 2 . 1 6 0 . 4 T o t a l m o n t h l y p r e c i p i t a t i o n Norma l ( i n c h e s ) 3 . 5 8 4 . 7 4 3 . 9 4 3 . 7 6 2 . 2 5 2 . 3 0 1 . 4 6 1 . 9 2 O . 4 6 1 . 8 4 52 '11 4 4 . 8 8 T o t a l days w i t h p r e c i p i t a t i o n Norma l 1 4 1 6 1 8 1 6 1 3 1 3 1 0 1 0 4 9 1 9 6 1 8 8 P r e v a i l i n g w i n d d i r e c t i o n by h o u r s No rma l E E E E E E E E SE E T o t a l h o u r s o f b r i g h t s u n s h i n e No rma l 8 9 . 2 8 7 . 7 1 3 5 . 2 1 2 7 . 9 1 6 7 . 5 1 8 2 . 5 1 9 4 . 2 2 5 0 . 9 2 9 1 . 2 2 4 0 . 0 2 , 2 7 8 . 6 2 , 4 0 4 . 4 % R e l a t i v e h u m i d i t y ( 1 0 : 0 0 AM) ( P . S . T . ) No rma l 8 4 8 4 7 9 7 8 80 7 4 7 9 7 2 7 5 7 3 T o t a l s n o w f a l l ( i n c h e s ) Norma l 1 . 0 4 . 4 1 . 0 1 . 5 0 . 1 T n i l T n i l n i l 8 . 3 1 3 . 1 Days w i t h f o g No rma l 4 6 2 3 1 1 n i l n i l n i l n i l 3 7 6 3 Tempera tu re - Maximum °F Norma l 4 7 . 3 4 . 5 . 5 4 7 . 9 4 9 . 5 5 2 . 5 5 5 . 7 6 0 . 9 6 2 . 9 7 0 . 3 6 7 . 7 7 2 . 8 . 7 2 . 3 Tempera tu re - Minimum °F Norma l 3 5 . 0 3 3 . 2 3 4 . 7 3 6 . 9 3 8 . 1 4 0 . 8 4 6 . 7 4 7 . 1 5 3 . 9 5 3 . 0 5 4 . 2 5 5 . 3 4 3 c i p i t a t i o n f o r each month, i s given f o r the study area i n Table 2 . The winter maximum i s marked and 7 5 $ or more of the p r e c i p i t a t i o n comes i n the s i x month period between October and March, In comparison there i s a pronounced summer dry period. Although the flow of a i r along the southern coast i s on shore during the summer months, l i t t l e r a i n results because the cool, off-shore water tends to s t a b i l i z e the a i r i n the low lev e l s and t h i s necessitates a considerable l i f t to release the moisture i n the form of r a i n (Kerr 1 9 5 0 ) . Kerr ( 1 9 5 0 ) considers the general r a i n -f a l l pattern along southern B.C. to be f a i r l y stable; co-e f f i c i e n t s of v a r i a b i l i t y average only 1 2 $ (January < 3 0 $ ; A p r i l s 3 5 $ ; July 6 9 - 8 0 $ ; October ^ 3 0 $ ) . Normal hours of bright sunshine vary inversely with the p r e c i p i t a t i o n regime as i s indicated by noramls " t o t a l inches of r a i n per month" or "days with measurable p r e c i p i t a t i o n per month" (Table 2 ) . It i s of p a r t i c u l a r significance that the coastal region, i n which the study area i s located, has average temperatures above freezing i n the winter season (Table 2 ). Even extreme temperatures recorded at the Sea Island weather sta t i o n indicate a moderate climate; extreme winter minimum of 0 . 0 ° F , normal winter minimum of 1 7 . 4 ° F , extreme i summer maximum of 9 2 . 1 ° F and normal summer maximum of 81.5°F (Annual Meteorological Summery, Department of Transport, 1 9 6 7 , at Vancouver International A i r p o r t ) . Kerr (1950) indicates graphically that Sea Island i s on the boundary between Cfb and Csb climate by the Koppen c l a s s i f i c a t i o n . Therefore, on the one hand i t can be desig-nated as a TMartine West Coast' (Cfb), while on the other hand i t could be considered to be 'Cool Mediterranean' (Csb). Krajina, (1965) i n discussing the biogeoclimatic zones of B r i t i s h Columbia, places t h i s area i n the Coastal Douglas F i r Zone and states that i t s climate i s to be regarded as "Mediter-ranean subhumid" to "Mediterranean humid". Both designations can be regarded as one of the same; the former i s primarily tempera-ture orientated while the l a t t e r i s primarily p r e c i p i t a t i o n orientated. To generalize one can say that the area has a cool mesothermal climate with heavy winter p r e c i p i t a t i o n and a deficiency of r a i n f a l l i n July and August. Kerr (1950) notes that the zero i s o l i n e of average annual water deficiency coincides with the boundary of the region and that Sea Island has an average annual water deficiency of between 1 5 and 1 0 inches. Temperatures i n the region are characterized by a "mean annual" of approximately 5 0 ° F , a July average between 6 0 and 6 5 ° F and above fre e z i n g January averages (Table 2 ) . Heat waves are uncommon and of short duration as are periods of intense cold i n winter. This area experiences the largest f r o s t free period i n Canada (Table 2 ) . The weather during the course of the present study from May I 966 to June of 1 9 6 7 displayed few marked changes from long term averages; the most noticeable departures are given i n Table 2 . P r e c i p i t a t i o n was above normal from September 1 9 6 6 to January 1 9 6 7 by 8 . 4 5 inches with November as the second d u l l e s t on record. Below normal p r e c i p i t a t i o n 45 occurred from February to June of 1 9 6 7 by 2 . 8 7 inches. The days of p r e c i p i t a t i o n varied accordingly. Hours of sunshine varied inversely with the p r e c i p i t a t i o n for each month with below normal values i n the winter months and above normal values i n the spring of 1 9 6 7 . Mean monthly temperatures were close to the normal as were average monthly wind di r e c t i o n and mean monthly r e l a t i v e humidity readings ( 1 0 A M . P.S.T.). With such a generally wet mild winter, snowfall, as one might ex-pect, was below the normal of 18 . 1 inches. This was the f i r s t occurrence of below normal snowfall i n the l a s t three years. With these few exceptions l i t t l e v a r i a t i o n between the weather of the study period and normal records for t h i s period occurred; the weather may be considered to be well within the normal range f o r the area. 3.3 Land use Sea Island i s t o t a l l y u t i l i z e d by man for some pur-pose. Prior to I 9 6 0 , 2400 acres of the t o t a l 36OO acres were used int e n s i v e l y for private agriculture (truck gardening, l i v e -stock, cereal crops, e t c . ) , 1 0 0 0 acres for airport and 2 0 0 acres for r e s i d e n t i a l and i n d u s t r i a l purposes. By 1 9 6 6 these figures had s h i f t e d as follows: private agriculture 7 0 0 acres, airport 2700 acres, and r e s i d e n t i a l and i n d u s t r i a l 2 0 0 acres. These simple s t a t i s t i c s i l l u s t r a t e the rapid ex-pansion of the airport but they do not accurately portray the changing land use. For example, the present airport property has approximately 1 0 2 0 acres farmed under a "zero 4 6 grazing" plan, 2 3 0 acres as a sand stockpile area, 1 4 0 0 acre for airport u t i l i t i e s ( < 5 0 0 acres maintained as short lawn and 4 0 0 acres as a grass-forb sward cut to 6 " or less i n height) and 5 0 acres as wild waste area ( t a l l , weedy, growth with some shrubs). The projected plan of change i s for more of the is l a n d to come under airport control with an increased area f o r buildings, runways and various technical apparatus. As expansion occurs more area w i l l be farmed as zero grazing or maintained as a short grass sward and less area w i l l be available f o r d i v e r s i f i e d farming or for r e s i d e n t i a l pur-poses. Higher standards of vegetation control w i l l be ex-tended to newly acquired areas and w i l l r e s u l t i n nearly com plete removal of a l l shrubby vegetation and hedgerows. The t i d a l marshes of Sea Island (outside the dykes are used seasonally for waterfowl hunting. This a c t i v i t y , which occurs annually from October to January and February to March, i s only intensive during October, with a maximum of 5 0 people hunting f o r the f i r s t one or two days. The average hunter number f o r the remaining period i s less than one per day. By f a r the major day to day a c t i v i t y of man i n the area i s governed by the location of ground access to the i s l a n d . At present t h i s i s by way of a two lane swing span bridge over the Middle Arm of the Fraser River 2 , 0 0 0 feet south of where the subsidiary Middle Arm branches from the North Arm. The two major roads of the Island, which service 47 the r e s i d e n t i a l and commercial centres, j o i n near the bridge which i n turn unites the is l a n d to the main r e s i d e n t i a l and commercial area of Richmond municipality. Each day thousands of commuters move between the airport or r e s i d e n t i a l section of the i s l a n d and the greater Vancouver area. In addition during the course of t h i s study, several hundred workers have come to work on the new airport terminal which i s being con-structed near the middle of the i s l a n d . Other minor human a c t i v i t i e s and u t i l i t i e s associated with the island are fur trapping (carried out by one man with the catch being almost a l l muskrat), a marina (located on the Middle Arm just below the bridge to the island) and small business area along the northeast edge near the bridge (includes small golf course and dr i v i n g range, tug boat mooring, stores and small petroleum depot). 48 4. FAUNAL OBSERVATIONS AND TRIALS •4.1 Zonation For the purpose of t h i s t h e s i s the term "study area" r e f e r s to those d e l t a i c deposits w i t h t h e i r a s s o c i a t e d s t r u c t u r e s , surrounding t i d a l marshes and water areas, known as; Sea I s l a n d , Iona I s l a n d , Wood I s l a n d , Pheasant I s l a n d , Dinsmore I s l a n d and Swishswash I s l a n d . Due to the s i z e of the "study area", i t was nec-essary to designate three separate zones of study i n t e n s i t y -a) "Environs", b) " A i r p o r t " and b) " I n t e n s i v e " . The l a r g e s t of these zones i s the "Environs" and i t i n c l u d e s a l l areas i n the "study area" surrounding the " a i r p o r t " zone. The " a i r p o r t " zone i n c l u d e s most of the land on Sea I s l a n d leased from the m u n i c i p a l i t y of Richmond by the Department of Transport and used f o r present a i r p o r t f a c i l i -t i e s . The boundaries of t h i s zone are described as f o l l o w s ; a) the Northwest corner of Sea I s l a n d at the point where i t s west dyke meets the isthmus to Iona I s l a n d and the western terminus of Ferguson Road; b) due east along Ferguson Road to Shannon Road; c) south on Shannon Road to the hedgerow which i s the westward c o n t i n u a t i o n of Grauer Road; d) east along t h i s hedgerow to McDonald Road; e) south along McDonald Road to M i l l e r Road; f ) east along M i l l e r Road to the a i r p o r t boundary running south from M i l l e r Road; g) f o l l o w i n g t h i s boundary southward u n t i l reaching A i r p o r t Road; h) southwest along A i r p o r t Road to the P a c i f i c Western A i r l i n e s and 49 Canadian P a c i f i c A i r l i n e s ramps; i ) south to the Middle Arm of the Fraser River; excluding those areas designated as Airport I n d u s t r i a l i n AppendixlO.l. F i n a l l y , within the " a i r -port" zone there i s a d i v i s i o n known as the "intensive" zone and i t includes a l l short-cut "grassy" areas adjacent to the airport runways and taxiways. The term "Airport" zone w i l l include t h i s area unless otherwise noted, The in t e n s i t y of study for these zones varies i n the extent and/or frequency of b i r d counts, observations, c o l l e c t i o n s , and vegetation analysis. 4 . 2 Methods of Evaluating Bird A c t i v i t y 4 . 2 . 1 Count study A l l b i r d numbers given i n t h i s study represent actual counts except where the notation + follows; i n such cases the figure was obtained by counting a section of the flo c k and then estimating the t o t a l size by multiples of the number counted. A l l counts included the time of observation the b i r d species,location and a c t i v i t y unless otherwise noted. Three types of count records were made ("Daily", "Station" and "Environs") and they are discussed separately. The raw data from the three counts i s i n the f i l e s of the Canadian W i l d l i f e Service located on the University of B r i t i Columbia campus. It became quite obvious aft e r the study had pro-gressed that the t o t a l counts of each species varied i n 50 accuracy. This v a r i a b i l i t y i s largely accounted for i n variations i n the d a i l y and seasonal habits, i n variations i n the habitat of i n d i v i d u a l species, i n weather variations and i n the d i f f e r i n g a b i l i t i e s of birds to remain concealled. Therefore, some birds such as Savannah sparrows, Passerculus  sandwichensis and Pheasants, Phasianus colchicus were con-s i s t e n t l y underestimated; Mallards, Anas platyrhynchos and Short-eared Owls, Asio flammeus were p e r i o d i c a l l y under-estimated; Snowy Owls, Nyctea scandiaca and species of sea g u l l s , Larus species, were hardly ever underestimated. Those counts deemed to be i n error were checked by p e r i o d i c a l l y making immediate "follow up counts" of a l l areas using a motor-cycle and a hunting dog. Intensive coverage by t h i s means was made of those areas where topography and/or vegetation afforded the greatest concealment f o r various b i r d s . Those counts found i n error were not changed i n the inter e s t of keeping a l l counts comparable. Therefore, follow up counts were recorded separately to serve as a guide. (a) "Daily counts" In order to develop a continuous record of b i r d species occuring within the " a i r p o r t " and "intensive" zones a system of "d a i l y counts" was established at the 'beginning of the study. These counts were not taken every day of the study period because of the involvement of time and cost, but, they were made as frequently as possible (Table 3 ). For each count an established route was followed using an automobile 51 or a motorcycle depending on weather (Figure l ) . Counting occurred a l l along t h i s route, but, at predetermined locations temporary stops were made to count birds on large areas which were v i s i b l e but otherwise inaccessible to the observer, i e , large water areas. It i s believed that the route used enabled the observer to count and i d e n t i f y 90$ of a l l birds i n the study area, Daily counts, i n accordance with known abundance peaks of most birds i n the area (Wm. M. Hughes, working f o r the Canadian W i l d l i f e Service on Vancouver Airport, personal communication, May 1966) , were made most often i n the early morning. Exceptions occurred when morning counts were not possible or when a count i n the afternoon was for special reasons j u s t i f i e d . On a number of occasions counts were made more than once a day. Table 3. Daily counts made during each month of the study period. Year 1966 1967 Total Month M J J A S O N D J F M A M 13 # of Counts 4 10 6 10 20 18 15 12 8 13 13 14 6 149 (b) "Station counts" As an aid to determining d a i l y a c t i v i t y of various b i r d species on the " a i r p o r t " zone, ten observation stations were established; eight were elevated structures and two were ground locations. These stations were as follows; (see Figure 1 f o r exact location i n study area). igure 1. Routes and locations of b i r d counts made during the study period. 53 S t a t i o n # Loc a t i o n Height i n Feet 1 A i r p o r t road 5 2 Bomb dump #2 20 3 T a l l radar 40 4 Short radar 40 5 A i r p o r t j e t t y ( d i s t a l end) 12 6 West dyke (@ Ferguson gate) 12 7 Temporary tower #1 (Ryegrass f i e l d ) 20 8 Temporary tower #2 (White barn) 22 9 Temporary tower §3 (Shannon Rd.) 20 10 Taxiway N 5 Each s t a t i o n was used p e r i o d i c a l l y to gather i n f o r -mation to complement ground records e s t a b l i s h e d through the " d a i l y counts", and to provide i n f o r m a t i o n about d i r e c t i o n s , height and frequency of b i r d f l i g h t s i n the " A i r p o r t " zone. In a d d i t i o n , some i n f o r m a t i o n was gathered on the fee d i n g h a b i t s of the Great-blue Heron, Ardea herodias. the Rough-legged Hawks, Buteo lagopus. and the Marsh Hawk, C i r c u s cyaneus, using these s t a t i o n s . (c) "Environs counts" B i r d counts were p e r i o d i c a l l y made f o r the "Environs" zone. For these counts an automobile was used along a route which f o l l o w e d the main road system of Sea I s l a n d and Iona I s l a n d and which i n c l u d e d the f u l l length of Iona j e t t y (Figure 1 ). The Pheasant and Dinsmore I s l a n d portions of t h i s zone had to be covered by using a motorcycle and dog. In a d d i t i o n to the p e r i o d i c ground counts of the environs, as s t a t e d above, r e g u l a r a e r i a l water fowl surveys were made of the Lower Fraser V a l l e y , i n c l u d i n g the "study area", 54 by the writer and a fellow graduate student. These counts were conducted between September 15 , 1966 and A p r i l 15, 1967 on behalf of the Canadian W i l d l i f e Service which normally carried them out each year as•part of t h e i r regular winter waterfowl survey. I n i t i a l l y the census was conducted each week. However, following an analysis of cost versus count value i n November, the i n t e r v a l between counts was extended to two weeks. The information gathered by these counts gave the general d i s t r i b u t i o n of waterfowl i n the Fraser delta and, therefore, added to information on comparative abundance and a c t i v i t y of these species i n and around the study> area. It was also possible to make a mental note of the abundance of various l i t t o r a l species while counting waterfowl and, as a r e s u l t , i t aided interpretation of t h e i r ecology i n the "study area". The accuracy of these counts were somewhat doubtful, p a r t i c u l a r l y when large numbers i n dense flocks were involved. For example, counts made from photographs of snow geese i n -dicated an error of as much as 60$ below actual numbers. However, the error was believed to be f a i r l y constant through-out the census period and thus the figures were believed to indicate at least general trends i n waterfowl abundance and d i s t r i b u t i o n . 4.2.2 C o l l e c t i o n study As a part of the regular f i e l d survey of bird a c t i v i t y , c o l l e c t i o n s were made using a 12 gauge shotgun. The frequency and extent of the c o l l e c t i o n s l a r g e l y depended on the judgement 55 of the observer. Generally, however, species of low abundance which regularly frequented the area were collected i n small numbers regularly, while species which were abundant periodic-a l l y were collected extensively during the time of t h e i r stay. Species which were regular v i s i t o r s and were also abundant were collected accordingly. When a c o l l e c t i o n was made the time, location and a c t i v i t y of the b i r d was recorded. The majority of co l l e c t i o n s were made i n the "A i r p o r t " zone, but some collections were also made i n the "Environs" zone, p a r t i c u l a r l y on the l i t t o r a l areas. (a) Food habit study To understand what various b i r d species were taking as food i n the "study area", crop and gizzard contents were removed from collected birds and the material l a b e l l e d and preserved i n seven dram glass v i a l s f o r l a t e r i d e n t i f i c a t i o n . I f the food material was re a d i l y i d e n t i f i a b l e and of one kind (e.g. earthworms), the number of items were recorded without p r e s e r v i n g the contents. Volumes of these items were l a t e r determined by using standardized volume to number r a t i o s . The method of preserving the food contents was standardized, to accommodate the wide vari e t y of food items. Soft bodied invertebrates are known to be the most perishable food item so the preservation technique was designed i n t h e i r favour. Beirne ( 1 9 6 3 ) considered 7 0 % ethyl alcohol or 1 0 % formalin to safely preserve such specimens. However, formalin tends to harden such materials and i t s fumes are i r r i t a t i n g 5 6 when working with materials preserved i n it. Therefore, ethyl alcohol (90%) was used. Because the digestive juices of the birds tended to continue working after the materials were placed i n preservative, contents were f i r s t thoroughly mixed with the strong solution of ethyl alcohol (90%). Animal and vegetable materials preserved t h i s way remained i n good condition u n t i l they were i d e n t i f i e d . Labels made of onion skin paper and marked with waterproof, India ink were placed inside the v i a l s . By t h i s method no labels were l o s t or misplaced and l e t t e r i n g was not obli t e r a t e d as was found by Spencer (1948). In most cases crop and gizzard contents were com-bined; however, where obvious differences were observed the contents were preserved separately. A l l items collected, were i d e n t i f i e d where possible. A l l animal material was i d e n t i f i e d by K.M. Stuart, Curator of the G.J. Spencer Ento-mological Museum, Department of Zoology, University of B r i t i s h Columbia and eight species were i d e n t i f i e d by Dr. L. Lazorko, a l o c a l authority on Coleoptera. A l l vegetable material was i d e n t i f i e d by the writer with the aid of the excellent works o f Ward ( 1 9 0 8 ) , Carrier ( 1 9 1 7 ) , Pechanec ( 1 9 3 6 ) , Hitchcock and Chase ( 1 9 5 0 ) , Yocum ( 1 9 5 1 ) , Jaques ( 1 9 5 9 ) , Martin ( 1 9 6 1 ) and Frankton (1963). I d e n t i f i c a t i o n of in e r t materials such as g r i t and lead shot was also attempted. In addition, a quanti-t a t i v e appraisal was made of the material using a volumetric determination by water displacement. Prior to making the volumetric determination a l l food materials were a i r dried so 57 as to l i m i t e r r o r due to absorbed p r e s e r v a t i v e . Most seeds were separated by using assorted mesh screens while i n v e r t e -brates and mixed seeds were sorted by hand. G r i t was removed from the other contents by f l u s h i n g w i t h water; g r i t s e t t l e d r e a d i l y w h i l e most food m a t e r i a l s were washed away. Records were a l s o kept of the numbers of i n d i v i d u a l u n i t s per each food item i n each b i r d ( i e . 10 seeds, 15 i n s e c t s , e t c . ) . Because of the r e l a t i v e u n i f o r m i t y of food m a t e r i a l s ingested by one b i r d s p e c i e s , at one time, and from one l o c a t i o n , i t was thought unnecessary t o separate i n d i v i d u a l food contents. Therefore, b i r d s food contents were combined i f these c o n d i t i o n s were met. In many cases where i d e n t i f i c a t i o n of plant m a t e r i a l s was a problem and i t was ofte n necessary to go to the c o l l e c t i o n area, as was prerecorded, to analyze the plant m a t e r i a l s i n s i t u . This was very h e l p f u l when t r y i n g t o i d e n t i f y some leaves and small seeds. As a f u r t h e r a i d a c o l l e c t i o n of many seeds and f r u i t s i n the study area was made. In a d d i t i o n to the above, a system of c o l l e c t i n g i n -v e r t e b r a t e s was e s t a b l i s h e d so that monthly samples were a v a i l a b l e to help i d e n t i f i c a t i o n of the species taken from b i r d stomachs. Several methods of c o l l e c t i o n were attempted (Turf sampling, net sweeping, portable vaccum t r a p , water traps and " s t i c k y board" t r a p ) . However only water traps and " s t i c k y " boards were con-sid e r e d p r a c t i c a l and t h e r e f o r e , used throughout the study; Figure 2 shows r e l a t i v e p o s i t i o n i n the f i e l d . Water traps were simply l a r g e 2T -x 1.5T x 2" cooking Insect c o l l e c t i o n traps i n s i t u . From top to bottom: " S t i c k y board" t r a p and water t r a p . pans painted yellow, set i n the ground with the upper edge f l u s h with the ground surface, and l / 2 f i l l e d with tap water. These devices primarily caught ground insects which would walk into the trap and were unable to crawl up the smooth sides or f l y out. "Sticky" boards consisted of 4 pieces of 1 f t . x 1 f t . x 1/4 inch plywood, united into a cube with the top and bottom open, attached to a 2 f t . stake on one side painted yellow and covered with a " v a s o l i n e - l i k e " material known as " s t i c k y " (chemical name not a v a i l a b l e ) . These boards primarily trapped f l y i n g insects. The yellow colour was recommended by Entomologists at the Canada Department of Agriculture Research Station on the campus of the University of B r i t i s h Columbia. This colour was considered to attr a c t the greatest variety of in s e c t s . The material " s t i c k y " was provided by the Research Station, Canada Agriculture. Insects caught i n "sticky board" traps were separated from the " s t i c k y " by using s p i r i t s of petroleum as a solvent. Insects obtained using these traps were preserved and l a b e l l e d i n the same way as were food contents taken from the digestive tracts of the bir d s . In each case the l a b e l indicated the date, period of c o l l e c t i o n and loca t i o n . (b) Sex and age study A l l birds c o l l e c t e d during the course of the study were sexed by direct examination and where possible the age determined. The method of determining age varied with the b i r d species involved. A l l passerines, and shorebirds were 60 aged by the degree of o s s i f i c a t i o n i n the s k u l l ( M i l l e r 1945, Kessel 1951). Waterfowl, g u l l species and hawks were aged primarily through differences i n plumage, while pheasants were aged only i f there was a marked difference i n body size or an immature colouration i n the case of males (Taverner 1947, Godfrey 1966). Sex and age records f o r owls and herons are not given because they were not collected to determine food habits. 4.3 Results 4.3.1 General statement In the following section those species found to be a considerable hazard on the Vancouver International Airport are termed "problem b i r d s " and are discussed i n d e t a i l . Other species omitted from t h i s discussion were considered to be "non-problem b i r d s " . The o r i g i n a l records of .observations and coll e c t i o n s con-cerning "non-problem bi r d s " made during the study period are on f i l e i n the o f f i c e of the Canadian W i l d l i f e Service, Campus, U.B.C. In addition, information concerning t h e i r seasonal occurrence on the Vancouver Airport between May 1963 and October 1966 i s available i n the records of Hughes (1966). The c r i t e r i a used to judge whether a given b i r d was a "problem" or "non-problem" species was la r g e l y based on the e a r l i e r records of b i r d " s t r i k e s " (Hughes, May 1966 and Harris 1966 personal communication). In addition the general observations on bird 61 a c t i v i t y and the r eco rd of " b i r d s t r i k e s " du r ing the study p e r i o d were cons idered i n t h i s c l a s s i f i c a t i o n . B i r d s i z e i t should be no ted , i s not n e c e s s a r i l y the only c r i t e r i o n f o r d i s -t i n g u i s h i n g a "problem" from a "non-problem" s p e c i e s . " S t r i k e s " i n v o l v i n g f l o c k s of s m a l l b i r d s can be as hazardous as " s t r i k e s " i n v o l v i n g fewer l a r g e r b i r d s . Food i n t a k e , as determined by the examinat ion of crop and g i z z a r d contents of problem and non-problem b i r d s du r ing the s tudy p e r i o d , i s presented i n t a b l e form i n appendix 1 0 . 3 . In each t a b l e a l i s t of i nges t ed m a t e r i a l i s g iven i n the l e f t hand column. The numbers of b i r d s (#) found to have inges ted a g iven m a t e r i a l and the t o t a l volume i n m i l l i l i t e r s (Vol ) recovered from these b i r d s f o r tha t m a t e r i a l are g iven under the name of the b i r d spec ies concerned. At the bottom of each t a b l e i s g iven the t o t a l number of b i r d s and the t o t a l volume of food recovered from these b i r d s . Larger numbers of b i r d s should be c o l l e c t e d over a p e r i o d of years to more a c c u r a t e l y determine the food h a b i t s of a g iven spec ies i n a g iven area would be d e s i r a b l e . Appendix 10.3 i s d i v i d e d i n t o two s e c t i o n s . The f i r s t s e c t i o n (10 .3 .1 ) i s food a n a l y s i s , by months, f o r e leven problem b i r d spec ies cons idered the most hazardous and common i n the " I n t e n s i v e " zone. The second s e c t i o n (10 .3 .2) i n c l u d e s the t o t a l food a n a l y s i s r e s u l t s not presented i n s e c t i o n 10 .3 .1 f o r seven problem and twenty-e igh t non-problem b i r d spec ies c o l l e c t e d du r ing the s tudy p e r i o d . In the f o l l o w i n g i n d i v i d u a l d i s c u s s i o n s on the twenty-three problem b i r d spec ies i n f o r m a t i o n i s g iven under the genera l 62 headings of seasonal occurrence, hazard to a i r c r a f t , food and control . The data presented are lar g e l y the resu l t of informa-t i o n gathered as objectively as possible i n the course of the study period. In addition, observations on thirteen species found to be common and hazardous i n the "Intensive" zone were supported by the results of a simple co r r e l a t i o n analyses of the data collected f o r each species during the study period. The d a i l y a c t i v i t y of each of these species was considered to be affected by one or more measured physical aspects of the envir-onment fo r which there were records av a i l a b l e . The eleven factors considered were: 1 . the numbers of birds counted i n the "Airport" zone,, 2 . the numbers of birds counted i n the "study area", 3 . the r a t i o between 1 and 2 , 4 . the number of minutes afte r sunrise, 5 . the previous nightime minimum temperature, ,6. the following daytime maximum temperature, 7. the wind speed, 8 . the t o t a l previous 24 hour -precipitation, 9 . the t o t a l previous 48 hour p r e c i p i t a t i o n , 1 0 . the previous tid e extreme 1 1 . the current tide l e v e l . Only those bird counts which were made for the whole study area were used for t h i s analysis so as to keep the data comparable. The computer sheets from t h i s analysis are given i n appendix 1 0 . 4 , a copy of which i s on f i l e i n the Special Collections (Thesis materials) section of the Main Library of the University of B r i t i s h Columbia. Correlations of apparent b i o l o g i c a l significance only are given i n the following section. Following the discussion of each problem b i r d species there i s given a generalized graphic representation of the b i r d 63 :counts made i n the "study area" between May of 1963 and June of 1967. Information shown for. the period between May of 1963 and May of 1966 i s from the records of Hughes (1966) and that shown for the period between June of 1966 and June of 1967 i s from the records of the writer. In a l l cases the information i s given by years ( l e f t abscissa) with b i r d numbers indicated on the right abscissa and months indicated on the ordinate. The trends i n -dicated by l i n e s ( i e . /vv-'/V/v\ ) are for numbers of birds i n the "a i r p o r t " zone and i n d i v i d u a l counts indicated by dots ( i e . 0 ) are f o r numbers of birds i n the "environs" zone. 4.3.2 Problem birds a. Mallard (Anas platyrhynchos Linnaeus) Seasonal occurrence: Summer resident, spring and f a l l migrant and winter v i s i t a n t (Figure 3 ) . Summer residents number?; less than f i f t e e n breeding pairs i n the "study area". The e a r l i e s t nest recorded during the study period was on A p r i l 20, 1967 and i t contained 8 eggs. The f i r s t young recorded during the study period were observed i n the main ditch beside the west dyke on May 9, 1967. There were ten young counted. Records of f i r s t young for other years were available from the notes of Hughes (1966) and are as follows; June 8, 1964 - 11 young, May 12, 1965 - 11 young, and May 12, 1966 - 11 young. Hen birds with young spend the f i r s t few days i n the major ditches i n the " a i r p o r t " zone and then migrate to the foreshore. However, birds raised i n the Iona pools appeared .to have ample escape area and remained on them. 6 4 By l a t e July the population had r i s e n to approximately iOO birds i n the "study area". Analysis revealed that the counts of numbers of birds i n the "Airport" zone between May and August of 1 9 6 6 were negatively correlated with the minimum nighttime temperatures recorded at the Sea Island meteorological station during nights previous to the b i r d counts (r = - O . 3 6 2 6 ) , that i s , Mallards were less abundant on the "Airport" zone when the previous minimum temperature was high. F a l l transients began a r r i v i n g i n the "study area" by mid August and continued to pass through the area i n waves u n t i l early November. A e r i a l waterfowl surveys of the Lower Fraser Valley made during the study period support t h i s conclusion. As many as + 2 , 5 0 0 Mallards were counted at one time i n the "study area". The a c t i v i t y of these birds i n the "Airport" zone was l a r g e l y dependent on the location of various bodies of water. During l a t e August and early September, before f i e l d s become flooded, birds using the "Airport" zone confined t h e i r a c t i v i t y to ditches. When surface pools began forming i n mid September birds used them f o r feeding and lounging. The significance of t h i s a t t r a c t i o n i s borne out by the correlations between b i r d numbers i n the "Airport" zone and the t o t a l previous 2 4 hour p r e c i p i t a t i o n (r = + 0 . 3 8 9 9 ) and the t o t a l previous 4 8 hour pre-c i p i t a t i o n (r = + O . 3 8 4 6 ) . In addition, there was a low negative c o r r e l a t i o n between the numbers of birds counted on the "Airport" zone and the tide l e v e l at the time of recording (r = -0.2131). This c o r r e l a t i o n quite unexpectedly may suggest that there were fewer birds i n the "Airport" zone when tides were high. Area wide observations indicated that the converse would be 6 5 expected. There may be one or more other variables not pro-vided i n t h i s program. The pressure of hunting, which began on October 8 , 1 9 6 6 , affected mallards i n the study area by reducing t h e i r numbers, by causing birds i n the "Airport" zone to react more strongly to scaring devices such as very f l a r e s , cracker she l l s and "zon guns" and by e f f e c t i n g a more nocturnal feeding habit. Winter v i s i t a n t s were considered to occur between December and February with less than 1000 birds i n the study area. Daily a c t i v i t y at t h i s time was s i m i l a r to that described f o r f a l l migrants. The numbers of birds i n the "Airport" zone were found to be correlated with the t o t a l previous 24 hour pre-c i p i t a t i o n (r = +O.464I) and with the t o t a l previous 48 hour p r e c i p i t a t i o n (r = + 0 . 3 0 7 5 ) . In addition the numbers of birds i n the "Airport" zone were correlated with wind speed (r = +0.3189) and to a lesser extent with minutes following sunrise (r = +0.2440). A l l these factors suggest that during stormy weather when temperatures rose, wind speeds increased cloud cover increased (duller day) and p r e c i p i t a t i o n increased, more birds occurred i n the "Airport" zone. In support of this con-clusion, i t i s i n t e r e s t i n g to note that negative correlations occurred between b i r d numbers i n the "study area" and wind speed (r = -0.2812) t o t a l previous 24 hour p r e c i p i t a t i o n (r = -0.2887) and t o t a l previous 48 hour p r e c i p i t a t i o n (r = -0.3147). Spring migrants occurred i n the study area between March and May and numbered less than +500 at one time. Daily a c t i v i t y at t h i s time was much the same as that mentioned for 66 f a l l t r a n s i e n t s and w i n t e r v i s i t a n t s except b i r d s generally-spent more time on the foreshore areas and l e s s time on the " A i r p o r t " zone. Because of below normal r a i n f a l l at t h i s time b i r d numbers i n the " A i r p o r t " zone were found to be c o r r e l a t e d w i t h the t o t a l previous 48 hour - p r e c i p i t a t i o n ( r = + 0 , 4 1 3 3 ) . Storms occurred l e s s f r e q u e n t l y than they had e a r l i e r i n w i nter and t h e r e f o r e more r a i n f a l l was necessary to r e p l e n i s h surface ponds to an a t t r a c t i v e l e v e l . I t i s i n t e r e s t i n g that a nega-t i v e c o r r e l a t i o n was found between the numbers of b i r d s on the " A i r p o r t " zone and minutes a f t e r s u n r i s e (r= -0.4233) and the previous t i d e extreme (-0.3211). This suggests that fewer b i r d s occurred i n the " A i r p o r t " zone when counts were made l a t e r a f t e r s u n r i s e and when the previous t i d e extreme was higher. Both c a l c u l a t i o n s are c o n s i s t e n t w i t h general impressions of a c t i v i t y . A lower negative c o r r e l a t i o n i s recorded between the num-bers of b i r d s i n the " A i r p o r t " zone and the f o l l o w i n g maximum daytime temperature ( r = -0.2983). However t h i s r e s u l t i s rea-sonable when one considers that increased temperatures at t h i s time of year are g e n e r a l l y associated w i t h c l e a r e r weather, which i n t u r n tends to dry up surface ponds which are a t t r a c -t i v e to the b i r d s . A negative c o r r e l a t i o n between the numbers of b i r d s i n the "study area" and the previous nighttime tempera-ture i n d i c a t e s that c o o l e r weather tended to increase the numbers of b i r d s i n the study area at that time. Hazard to a i r c r a f t : M a l l a r d s were a hazard to a i r c r a f t from mid August u n t i l May because of t h e i r d a i l y h a b i t of f l y i n g t o , from and 67 between s u i t a b l e water areas a v a i l a b l e i n the " A i r p o r t " zone. This a c t i v i t y f r e q u e n t l y caused i n d i v i d u a l s or l a r g e f l o c k s to cross over runways. There were two " s t r i k e s " i n v o l v i n g t h i s species during the study p e r i o d . Food: The a n a l y s i s of food items taken from stomachs of t h i s species c o l l e c t e d during the study period i n d i c a t e d a con-s i d e r a b l e seasonal change i n food h a b i t s (Appendix 10.3.1). B i r d s c o l l e c t e d i n August were found to have eaten la r g e amounts of pond weed (Potemageton sp.) while b i r d s c o l l e c t e d during the e a r l y w i n t e r months showed a preference f o r Smartweed (Poly-gonum s p . ) . Between December and March earthworms and various i n s e c t l a r v a e were taken i n l a r g e amounts. I t should be men-ti o n e d that through the f a l l , w i n t e r and s p r i n g months M a l l a r d s a l s o consumed l a r g e amounts.of Isopods, Amphipods, Scirpus sp. seed, and Carex lyngbyei seed, which they obtained from the various marsh areas. C o n t r o l : The M a l l a r d can be e f f e c t i v e l y c o n t r o l l e d using various s c a r i n g devices a v a i l a b l e . However these c o n t r o l measures are somewhat l i m i t e d i n that they r e q u i r e someone on guard con-s t a n t l y during periods when the b i r d s are a problem. The w r i t e r considers t h a t a more l a s t i n g and perhaps economical c o n t r o l measure would be to improve drainage i n the low l y i n g areas and where p o s s i b l e to e l i m i n a t e open d i t c h e s . MALLARD 69 b. P i n t a i l (Anas acuta Linnaeus) Seasonal occurrence: F a l l migrants, spring migrants and winter v i s i t a n t s (Figure 4). Early f a l l migrants occur i n the "study area"'between nid August and mid September i n numbers less than +200. These birds do not occur i n the "Airport" zone u n t i l early September when r a i n f a l l provides surface ponds i n various f i e l d s . These general observations were supported by correlations between b i r d numbers i n the "Airport" zone and the t o t a l previous 24 hour p r e c i p i t a t i o n (r = +0.9420) and the t o t a l previous 48 hour pre-c i p i t a t i o n (r = +0.9958). However, only eleven observations of many for t h i s period could be used. There were also correlations between the numbers of birds on the "Airport" zone and the pre-vious nighttime minimum temperature (r = +0.6379) and the following daytime maximum temperature (r = -0.9170). This suggests that the birds were more abundant when previous mini 1-mum nighttime temperatures were high and were less abundant when the following daytime maximum temperatures were high. The r i s e i n minimum temperatures i s generally a result of stormy weather while an increase i n maximum daytime temperature, i n -dicates bright clear days at t h i s time of year. Tides also had an effect on the numbers of birds i n the "Airport" zone as was indicated by the po s i t i v e c o r r e l a t i o n with the previous tide ex-treme (r = +0.3735) and the negative co r r e l a t i o n with the current t i d e l e v e l (r = -0.3215). These l a t t e r correlations, i n l i g h t of general observational data, suggest that the numbers of birds i n the "Airport" zone are dependent on the previous tide extreme 7 0 and that the current tide l e v e l may be related to one or more additional factors not considered i n t h i s program. Bird numbers in the "study area" are also correlated with the number of min-utes aft e r sunrise (r = +0.3197), the previous nighttime minimum temperature (r = +0.4270), the wind speed (r = +0,6332) and the previous tide extreme (r = -0.3892). The correlation with min-utes a f t e r sunrise may be a res u l t of the greater numbers of birds occurring i n the area during d u l l stormy days. The cor r e l a t i o n between b i r d numbers i n the area and the previous minimum nighttime temperature and the wind speed also suggest a r e l a t i o n s h i p since storms generally cause a r i s e i n minimum temperature and i n wind speed at t h i s time of year. The previous t i d e extreme as one might expect, has a negative effect on the numbers of birds i n the "study area" and i t supports the i n t e r -pretation of tid e effect on the numbers of birds i n the "Airport" zone. F a l l migrants begin to occur i n large numbers by early September (+1500) and appear to migrate through the rea i n waves u n t i l December with a gradual decline i n birds i n the area through January, During t h i s time birds frequent the surface ponds of the "Airport" zone during stormy weather. An analysis of the data collected between September and October indicated a strong co r r e l a t i o n between wind speed and the numbers of birds i n the "Airport" zone (r = -0.6674). In addition hunting pres-sure tended to force the birds to feed l a t e r i n the evening and e a r l i e r i n the morning. Bird numbers i n the "study area" during t h i s time were 71 correlated with the previous nighttime minimum temperature (r = +0.4340) and the following daytime maximum temperature (r = +0.6903). This indicated that more birds were i n the "study area" during warm, moist, stormy weather. I t i s noteworthy that b i r d numbers i n the "Airport" zone were not correlated with numbers of birds i n the "Environs" zone. Perhaps there are one or more factors involved i n t h i s instance which were not included i n t h i s programme. Between October and January, P i n t a i l occurred i n the "Airport" zone during stormy weather and were more abundant during high t i d e s . These observations are supported by cor r e l a -tions between the numbers of birds i n the "Airport" zone and wind speed (r = +0,3090), the t o t a l previous 24 hour p r e c i p i t a t i o n (r = +0.4122), the t o t a l previous 48 hour p r e c i p i t a t i o n (r = +0.3381), the previous tid e extreme (r = +0.2240) and the current t i d e l e v e l (r = +0.3129). In addition the numbers of birds i n the "Airport" zone were correlated with numbers of birds i n the "study area" (r = +0.5728). The numbers of birds i n the "study area" were s i g n i f i c a n t l y correlated with the previous tide extreme (r = +0,4870) during t h i s period. Spring migrants occurred i n "study area" between Feb-ruary and May with the maximum number at one time being +1500 b i r d s . Observations indicated that the numbers of birds i n the "a i r p o r t " zone were s t i l l related to stormy weather but that several days of continuous r a i n were required before a r e a l increase i n numbers occurred. Surface pools i n the area were 7 2 gradually receding as a resu l t of below normal r a i n f a l l f o r the period; i t required a prolonged r a i n f a l l to replenish them. An analysis of the data collected at t h i s time supported these ob-servations i n that the numbers of birds i n the "Airport" zone were found to be correlated with the t o t a l previous 4 8 hour p r e c i p i -t a t i o n (r = + 0 . 4 9 2 5 ) but not with the t o t a l previous 24 hour p r e c i p i t a t i o n (r = -0.0174). The bi r d numbers i n the "Airport" zone were also correlated with the numbers of birds i n the "study area" (r = + O . 3 8 6 8 ) and the wind speed (r = +0.3102). The l a t t e r i s related to the occurrence of inclement weather. The numbers of birds i n the "study area", at t h i s time, were negatively correlated with the previous nighttime minimum temperature (r .= -0.3980), i n d i c a t i n g that fewer birds are seen following warm nights. Hazards to a i r c r a f t : When P i n t a i l occurred i n the "Airport" zone they were attracted to surface pond where they fed and/or lounged. While in t h i s zone they frequently flew i n small groups or i n large flocks to, from and between pond areas, crossing the runways. Fortunately there were no st r i k e s involving t h i s species recorded during the study period. Food: Food of t h i s species varied considerably throughout t h e i r occurrence i n the "study area". Generally the items consumed on the i n f i e l d were related to the location of the pond areas and the abundance of associated food (Appendix 10.3.1). The 13 Figure 4. 7 4 most common and abundant food item i n f a l l and early winter was Lady's thumb Polygonum p e r s i c a r i a . During the late winter and early spring birds feeding i n the various marsh areas consumed large amounts of Carex lyngbyei seed, Scirpus sp. seed and various Crustaceae (Amphipoda and Isopoda). One b i r d collected on March 1967 was found to have seeds of marsh and i n f i e l d plants as well as two earthworms. Control: The P i n t a i l can be controlled e f f e c t i v e l y using the various scaring devices av a i l a b l e . However, the writer considers that long term control might be more economical and e f f e c t i v e if drainage of surface ponds i n winter were undertaken and where possible open ditches were eliminated, c. American Widgeon (Mareca americana Gmelin) Seasonal occurrence: spring and f a l l transient and abun-dant winter v i s i t a n t (Figure 5 ) . The Widgeon f i r s t arrived i n the study area i n late August i n small numbers (+300) but rapidly increased i n early September (+2,000). However, birds do not occur on inland areas u n t i l l a t e September or October. An analysis of the data collected at t h i s time indicates that the numbers of birds i n the "study area" were correlated with the number of minutes after sunrise (r = +0.4335) and the wind speed (r = +0,3183). These correla-tions are consistent with observations which indicated that more 7 5 birds were i n the area l a t e r i n the day and that when winds were high birds sought the shelter of the dyke and marsh areas. Be-tween September .and l a t e November migrating widgeon pass through the area i n waves with as many as + 5 , 0 0 0 occuring at one time. These birds frequently fed i n the " a i r p o r t " zone, par-t i c u l a r l y beside surface ponds. Observations indicated that birds are i n i t i a l l y attracted to water areas beside a short green t u r f . However, once the birds landed they often l e f t the water areas and wandered on foot as f a r as 5 0 0 f e e t. When s l i g h t l y s t a r t l e d they would f l y back to the pond, but, when greatly alarmed they would take f l i g h t . Hunting pressure i n October and November tended to force the birds to feed at dusk and early dawn with birds lounging during the daylight hours i n the open water of the foreshore. From November u n t i l March the population remained at approximately + 4 , 5 0 0 b i r d s . In A p r i l t h i s number increased to + 5 , 0 0 0 and then gradually dropped off to n i l i n early May, During t h i s time birds i n the "study area" appeared to develop a stronger inland feeding habit with less time spent on the foreshore areas. The larger number of birds i n the "environs" zone indicated i n Figure 5 were mostly found lounging and feed-ing beside pools i n c a t t l e grazed f i e l d s on the Northwest of Sea Island. The only co r r e l a t i o n with b i r d numbers i n the "Airport" zone at t h i s time was with the numbers of birds i n the "study area". The l a t t e r were correlated with previous nighttime minimum temperatures (r = -0.3304). The numbers of birds i n the "study area" were weakly correlated with the t o t a l previous 76 48 hours p r e c i p i t a t i o n (r = -0.2888) and the current tide l e v e l (r = -0 .2447); t h i s indicates that fewer birds were i n the "study area" during wet stormy weather and when current tide l e v e l s were high. It i s i n t e r e s t i n g to note here that at th i s time large numbers of widgeon (+10,000) were observed $0 miles east of the study area near Chilliwack, B.C. Perhaps at t h i s time of year t h i s species feeds further inland when tides are high and r a i n i s heavy. Hazards to a i r c r a f t : When widgeon occur on the flooded t u r f areas, par-t i c u l a r l y i n the "Intensive" zone, they frequently f l y over runways. General observations indicate that much of th i s ac-t i v i t y occurs at night when a i r c r a f t movements are few. How-ever on d u l l and rainy days birds have become a problem to a i r -c r a f t landing and taking o f f . No b i r d s t r i k e s involving t h i s species occurred during the study period. Food: The food analysis of stomachs collected from Widgeon i n the "Airport" zone indicate that they are l a r g e l y graziers. In a l l cases the leaves of plants eaten were r e l a t i v e l y new shoots which were available near bodies of water. Therefore the plants eaten were la r g e l y taken from "wet" and "moist" sub-zones, A few c o l l e c t i o n s from various marsh areas made during the winter indicated that birds were also consuming seeds of several Scirpus species and Carex lyngbyei, AMERICAN WIDGEON 78 C o n t r o l : The Widgeon can be c o n t r o l l e d e f f e c t i v e l y i n the " A i r p o r t " zone us i n g various s c a r i n g devices a v a i l a b l e . However, because of t h e i r n o c t u r n a l f e e d i n g h a b i t s during a considerable part of t h e i r stay i n the area t h i s type of c o n t r o l becomes some-what i m p r a c t i c a l . Long term c o n t r o l might be more economical and more e f f e c t i v e through p r o v i d i n g adequate drainage i n a l l areas where surface ponds occur and where p o s s i b l e by e l i m i n a t i n g open d i t c h e s . d. Green-winged Teal (Anas c a r o l i n e n s i s Gmelin) Seasonal occurrence: S p r i n g and f a l l t r a n s i e n t and winter v i s i t a n t (Figure 6 ) . The Green-winged Teal f i r s t a r r i v e d i n the "study area" i n l a t e August i n numbers of +1000. B i r d s continued to migrate through the area i n waves w i t h as many as +3500 at one time u n t i l e a r l y December when the population s t a b a l i z e d at +1000. The f i r s t migrants i n August occurred i n di t c h e s i n the " A i r p o r t " zone p a r t i c u l a r l y i n e a r l y morning when t i d e s were hi g h . In September when r a i n i n t e n s i f i e d and f l o o d i n g occured In low l y i n g areas i n the " A i r p o r t " zone, Green-winged Teal begain to feed i n the pools formed. An a n a l y s i s of the data gathered at t h i s time i n d i c a t e d that the numbers of b i r d s i n the " A i r p o r t " zone were c o r r e l a t e d w i t h the number of minutes a f t e r s u n r i s e (r = -0.3192), the previous nighttime minimum temperature (r = -0.4124), the t o t a l previous 24 hour p r e c i p i t a t i o n ( r = +0.7295) 79 and the t o t a l previous 48 hour p r e c i p i t a t i o n ( r = +0.7527). These c o r r e l a t i o n s support the observations made e a r l i e r i n the area. B i r d numbers i n the "study area" were found to be c o r r e l a t e d w i t h the previous nighttime minimum temperature ( r = +0.3067). Between December and February when the population was considered to be " w i n t e r i n g b i r d s " , the numbers of b i r d s i n the " A i r p o r t " zone continued to f l u c t u a t e w i t h the occurrence of p r e c i p i t a t i o n . This observation i s supported by the c o r r e l a -t i o n c o e f f i c i e n t c a l c u l a t e d from data c o l l e c t e d at t h i s time. The numbers of b i r d s i n the " A i r p o r t " zone were c o r r e l a t e d w i t h the t o t a l previous 24 hour p r e c i p i t a t i o n ( r = +0.3419) and the ! t o t a l previous 48 hour p r e c i p i t a t i o n ( r = +0.3323). Information 'supporting t h i s observation i s also a v a i l a b l e from lower c o r r e l a -t i o n c o e f f i c i e n t s between the numbers of b i r d s i n the " A i r p o r t " zone and the previous nighttime minimum temperature ( r = +0.2683) and the f o l l o w i n g daytime maximum temperature ( r = +0.2746). When storms occur i n the area at t h i s time temperatures r i s e . Good c o r r e l a t i o n s were not obtained between the numbers of b i r d s i n the " A i r p o r t " zone and the previous t i d e extreme (r = +0.1112) and the current t i d e l e v e l (r = +0.1592). General observations i n d i c a t e d that when t i d e s were very high many more b i r d s occurred i n the i n l a n d areas i n c l u d i n g the " A i r p o r t " zone. On the other hand, the numbers of b i r d s i n the "study area" were n e g a t i v e l y c o r r e l a t e d w i t h the current t i d e l e v e l (r = -0.6617) and l e s s s i g n i f i c a n t l y w i t h the previous t i d e extreme (r = -0.2475), the t o t a l previous t i d e extreme (r = -0.2475), the t o t a l previous 48 hour p r e c i p i t a t i o n ( r = -0.1995). 80 These c o r r e l a t i o n s support the e a r l i e r genera l o b s e r v a t i o n s . S p r i n g migrants were cons idered to occur i n the "s tudy area" between mid February and e a r l y A p r i l w i t h a peak of +4 ,000 b i r d s o c c u r i n g i n mid May. The d a i l y a c t i v i t y of these b i r d s was not cons idered to d i f f e r markedly from that of w i n t e r v i s i t a n t s . An-•analysis of data c o l l e c t e d at tha t t ime supported t h i s o b s e r v a t i o n . The numbers of b i r d s i n the " A i r p o r t " zone were found to be weakly c o r r e l a t e d w i t h the p rev ious n igh t t ime minimum temperature ( r = +O .2765) . The numbers of b i r d s o c c u r r i n g the "s tudy area" were found to be c o r r e l a t e d w i t h the f o l l o w i n g daytime maximum temperature ( r = + 0 . 3 9 3 9 ) . Th is i n d i c a t e s tha t warmer days d u r i n g the s p r i n g , encouraged l a r g e r numbers of b i r d s i n the "s tudy a rea" . Hazard to a i r c r a f t : The Green-winged Tea l are a t t r a c t e d to the d i t ches and surface ponds i n the " A i r p o r t " zone to feed and to lounge. Whi le i n t h i s zone they f r e q u e n t l y f l y i n s m a l l groups or i n l a r g e f l o c k s t o , from and between a t t r a c t i v e a reas , c r o s s i n g the runways... However, there were no b i r d s t r i k e s dur ing the s tudy p e r i o d . Food: The Green-winged Tea l was found to vary i t s d i e t du r ing :the study p e r i o d . In the " A i r p o r t " zone i n the f a l l and e a r l y w i n t e r sma l l seeds, p a r t i c u l a r l y P s i l o c a r p u s e l a t i o r , were taken I n l a r g e amounts when a v a i l a b l e . In marsh areas at t h i s time GREEN-WINGED TEAL 82 seeds of v a r i o u s sedges, p a r t i c u l a r l y S c i r p u s a m e r i c a n u s, were e a t e n a l o n g w i t h l a r g e amounts of a n i m a l m a t t e r I n c l u d i n g v a r i o u s amphipods and I s o p o d s . Throughout t h e w i n t e r f o o d consumed i n t h e " A i r p o r t " zone c o n s i s t e d m a i n l y o f Smartweed Polygonum sp. Food h a b i t s d i d n o t change i n t h e marsh areas, except perhaps t h e r e was a g r e a t e r f r e q u e n c y and abundance of Carex l y n g b y e i s e e d s . D u r i n g t h e e a r l y s p r i n g b i r d s f e e d i n g i n the " A i r p o r t " zone were found t o eat g r e a t e r amounts of a n i m a l s p e c i e s i n c l u d i n g earthworms and f l y l a r v a e . However, seeds were s t i l l consumed i n l a r g e amounts. Specimens were not c o l l e c t e d f rom t h e marsh a r e a s at t h i s t i m e . C o n t r o l : The Green-winged T e a l can be c o n t r o l l e d e f f e c t i v e l y u s i n g t h e v a r i o u s s c a r i n g d e v i c e s a v a i l a b l e . However, t h e w r i t e r c o n s i d e r s t h a t l o n g term c o n t r o l c o u l d be more economical and more e f f e c t i v e t h r o u g h i m p r o v i n g d r a i n a g e where s u r f a c e ponds o c c u r i n w i n t e r .and, 'where p o s s i b l e , by e l i m i n a t i n g open d i t c h e s . e. Marsh Hawk ( C i r c u s cyaneus L i n n a e u s ) S e a s o n a l o c c u r r e n c e : Summer v i s i t a n t , abundant f a l l t r a n s i e n t and w i n t e r v i s i t a n t ( F i g u r e 7 ) . L u r i n g t h e summer months t h e r e a r e u s u a l l y o n l y one o r two r e s i d e n t b i r d s i n t h e " s t u d y a r e a " . A l t h o u g h no n e s t s were found i t was b e l i e v e d t h a t one p a i r may have n e s t e d i n t h e " s t u d y a r e a " . F a l l m i g r a n t s a re n o t i c e a b l e i n t h e " s t u d y a r e a " between 83 early August and late November with as many as twelve birds occuring at one time. Wide fluctuations i n numbers during the f u l l migrations are common. General observations indicated that the majority of birds i n the "study area" -at t h i s time were immature. Adult females were common and adult males were rare. D a i l y a c t i v i t y of the birds at t h i s time consisted of hunting along hedgerows, over marshes and over t a l l "grassy" f i e l d s with frequent landings on various perches including shurbbery^ poles, clumps of d i r t and the ground. On a number of occasions immature birds were observed "playing" with pieces of sod and/or clumps of d i r t . These birds would f l y up to twenty feet i n the a i r with such objects and drop them to the ground. They would then immediately swoop down and grasp the object again and repeat the procedure. This a c t i v i t y has also been observed i n other birds of prey (see Section 2.2.3). However the problem arises when these birds have completed t h i s "play" a c t i v i t y and drop the object. On two occasions clumps of d i r t , twice the size of a golf b a l l , were dropped on taxiway X. Objects of t h i s size can be e a s i l y sucked into airscopes of jet engines as the a i r -c r a f t t a x i past and can r e s u l t ' i n damage. General observations indicate that these birds covered a large area i n a short period of time when hunting. On a number of occasions i n d i v i d u a l birds were noticed to cover sys-tematically most of the a t t r a c t i v e areas i n the "Airport" zone within one hour. The attractiveness of the "Airport" zone to t h i s species i s shown by Its r e l a t i v e abundance i n the "Airport" and "Environs" zones i n Figure 7. 84 Between November and e a r l y February b i r d numbers were below f i v e and by mid February the number dropped to one i n the "study area". However i n March the number of b i r d s i n the "study area" again increased to f o u r . In e a r l y A p r i l the population again returned to one r e s i d e n t p a i r . Winter v i s i t a n t s and Spring migrants were not found to d i f f e r from f a l l t r a n s i e n t s i n t h e i r d a i l y h a b i t s . Hazard to a i r c r a f t : The Marsh Hawk i s a t t r a c t e d to the favourable "hunting" h a b i t a t i n the " A i r p o r t " zone. B i r d s a c t i v e l y hunt over a t t r a c -t i v e areas w i t h a c h a r a c t e r i s t i c slow, low f l i g h t and f r e q u e n t l y pass over runways. There was one " s t r i k e " i n v o l v i n g t h i s species d u r i n g the study p e r i o d . Food: Although c o l l e c t i o n s of t h i s species were not made during the study p e r i o d , general observations i n d i c a t e d that i t s food was p r i n c i p a l l y Microtus townsendii. C o n t r o l : The Marsh Hawk cannot be c o n t r o l l e d e f f e c t i v e l y using a v a i l a b l e s c a r i n g devices. Frightened b i r d s simply take " f l i g h t " f o r a short distance and then resume normal a c t i v i t y . Long term c o n t r o l by removing a t t r a c t i v e features i n the " A i r p o r t " zone may be p o s s i b l e but i t should a l s o be supported by s i m i l a r e f f o r t s i n the "Environs" zone. Generally a t t r a c t i v e f e a t u r e s are those which encourage i t s c h i e f prey s p e c i e s , Microtus 3,5 Figure 7 . MARSH HAWK I 86 townsendii and other rodents. These features include "grassy" t u r f areas above three inches i n height and hedgerows. Cutting rough areas to 6 inches i s not s u f f i c i e n t , because rodents are s t i l l able to t h r i v e . f . Rough-legged Hawk (Buteo lagopus Pontoppidan) Seasonal occurrence: Winter v i s i t a n t (Figure 8) . Munro and Cowan (1947) considered the Rough-legged Hawk to be an occasional winter v i s i t a n t i n the Puget Sound Lowlands. However the records of Hughes (1966) and those of the writer would support the view that t h i s species i s a regular winter v i s i t a n t which p e r i o d i c a l l y becomes abundant. Each year birds arrive i n the "study area" i n October and remain u n t i l March or A p r i l . Records taken prior to the study period indicate that numbers i n the "Airport" zone did not exceed four, but, during the present study as many as twelve were recorded at one time i n the "Airport" zone out of a population of fourteen i n the "study area". This species was found to ac t i v e l y hunt over a l l "grassy" areas above two inches i n the "Airport" zone. Observations indicated that t a l l "grassy" areas, p a r t i c u l a r l y those near a perching area such as a hedgerow, fence or telephone pole were a t t r a c t i v e to the bird s . On number of occasions birds hunting i n "grassy" areas, where there were no perches ava i l a b l e , landed on or beside the s l i g h t l y elevated runways and taxiways. General observations indicated that regular d a i l y 87 movements occurred between the t a l l "grassy" areas and hedgerows west of runway 1 2 : 3 0 and the ex tens ive hedgerows east of Shannon Road and nor th of the new a i r p o r t t e r m i n a l . However, b i r d s were a l s o observed hun t ing i n o ther s u i t a b l e areas south of Taxiway " A " and no r th and south of Taxiway " N " . " Observat ions i n l a t e evening and at n igh t i n d i c a t e d tha t the m a j o r i t y of the b i r d s i n the "s tudy a rea" roos ted on the t a l l hedgerows North of the new a i r p o r t t e r -m i n a l (Appendix 1 0 . l ) . Each day s h o r t l y before sun r i s e b i r d s l e f t t h e i r r oos t s to hunt i n s u i t a b l e areas and re turned s h o r t l y a f t e r sunse t . Hazards to a i r c r a f t : The Rough-legged Hawk was a frequent hazard to a i r c r a f t when i t f l ew over runways between feed ing areas and pe rch ing a reas . In a d d i t i o n a hazard was crea ted when b i r d s s i t on or bes ide the runway. There was one " s t r i k e " i n v o l v i n g t h i s spec ies d u r i n g the study p e r i o d . Food: C o l l e c t i o n s were not made of the Rough-legged Hawk du r ing the s tudy p e r i o d but genera l observa t ions i n d i c a t e tha t i t s main prey spec ies was M i c r o t u s t o w n s e n d i i . C o n t r o l : The Rough-legged Hawk cannot be c o n t r o l l e d e f f e c t i v e l y u s i n g a v a i l a b l e s c a r i n g d e v i c e s . B i r d s when f r i g h t e n e d move away from the d i s tu rbance and resume a c t i v i t y i n a nearby secure a r ea . Long term c o n t r o l might be e f f e c t i v e by removing such a t t r a c t i v e f ea tu res as hedgerows and t a l l "g rassy" a reas . ROUGH-LEGGED HAWK 89 g. Ring-necked Pheasant (Phasianus colchicus Linnaeus) Seasonal occurrence: Year around resident (Figure 9 ) . The Ring-necked Pheasant was found to begin nesting i n the "study area" i n May. Records of f i r s t eggs and f i r s t young are as follows (*Hughes 1966); *July 2, 1963 (42 young), *June 24, 1964 (21 young), May 30, 1966 (6 young), May 17, 1967 (9 eggs) and June 4, 1967 (6 young). General observations indicate that there were at least f i f t e e n setting hens and seven crowing cocks i n the "study area" i n the spring of 1966. E a r l i e r records indicate that through the summer the numbers of birds i n the " A i r port" zone gradually increase u n t i l a peak i s reached between July and September. As many as 70 birds have been counted i n the "Airport" zone during t h i s peak but, during the study period, the maximum count was 25 b i r d s . Following t h i s peak there was a gradual decline i n b i r d numbers i n the "Airport" zone to a low of f i v e i n December and January. At that time larger numbers of birds were found to occur i n the more exten-sive hedgerow areas north of the new terminal i n the "Environs" zone. In late January and early February the numbers of birds i n the "Airport" zone gradually increased to a maximum of +25 i n March. This was followed'hy another decline i n numbers which i s believed to be the res u l t of hens setting eggs. The gradual i n -crease i n numbers throughout the summer i s a res u l t of hens show-ing up with t h e i r broods. The loss of the large numbers of birds between late summer and spring must be assumed to be the result of mortality, since the birds have l i t t l e opportunity to disperse 9 0 i n t o unoccupied areas. D a i l y a c t i v i t y of the Ring-necked Pheasant during s p r i n g , summer and f a l l months was found to c o n s i s t l a r g e l y of feeding beside hedgerows, along f i e l d borders and i n "weed" areas. Ob-s e r v a t i o n s i n d i c a t e d two feeding peaks; one two hours a f t e r sun-r i s e and the second one hour before sunset. B i r d s , before be-g i n n i n g f e e d i n g i n the e a r l y morning s h o r t l y a f t e r sunrise were found to lounge and when p o s s i b l e sun themselves. "Sunning" a c t i v i t y was p a r t i c u l a r l y n o t i c e a b l e on sunny mornings f o l l o w i n g a heavy dew or r a i n f a l l . In s e v e r a l instances b i r d s were observed "sunning" themselves on the r e l a t i v e l y dry edges of the runways and taxiways. When b i r d s were at t h e i r peak abundance i n f a l l many small groups were observed f e e d i n g one hour before sunrise i n the short t u r f of the " I n t e n s i v e " zone. Several b i r d s at t h i s time were a l s o seen walking or f l y i n g across the main run-way between t a l l "grassy" areas. Hazard to a i r c r a f t : The Pheasant i s a hazard to a i c r a f t whenever i t occurs on or beside runways. Generally t h i s occurs when b i r d s are feed-i n g , "sunning" or c r o s s i n g between two areas. There was one " s t r i k e " i n v o l v i n g t h i s species during the study period. Food: A n a l y s i s of stomach contents taken from b i r d s during the study period i n d i c a t e d that the Ring-necked Pheasant v a r i e d i t s d i e t considerably throughout the year (Appendix 1 0 . 3 . 1 ) . Generally b i r d s appeared to consume "what was a v a i l a b l e " . In 91 spring food l a r g e l y consisted of buds, green shoots, and a v a i l -able insects, but i n summer seed consumption gradually rose u n t i l i t amounted to l / 2 of the d i e t . During the f a l l and winter seeds were the most frequent and abundant food item. However several birds collected at t h i s time were found to have eaten nothing but larvae of Bibionidae. Control: The Ring-necked Pheasant has been successfully reduced i n the "Airport" zone by shooting and habitat modification. The removal of hedgerows and t a l l "grassy" areas reduces the amount of winter and breeding habitat respectively. The present popula-t i o n i n the "Airport" zone i s l a r g e l y a result of untidy farming and f i e l d management practices. Each winter patches of shrubby growth along ditches, fences and dykes and t a l l "grassy" areas along f i e l d borders, dyke shoulders and i n rough areas are a v a i l -able as cover f o r Pheasants (Figure 1 0 ) . In addition these areas, provided i d e a l s i t e s f o r nesting i n the spring. Long term con-t r o l must be directed towards a reduction of t h i s habitat. However, even i f t h i s habitat were removed during the winter and spring months a population could s t i l l p e rsist i n the area i f f i e l d s were l e f t to be taken as hay or l e f t f o r too long a period between cuttings using a "rotary-type" mower. General observations indicate that there i s a considerable movement of birds into the "Airport" zone from the "Environs" zone during spring. Therefore long term control should consist of 1. removing t a l l shrubby areas i n the "study area" and 2 . maintaining the ground cover i n a l l areas as a short tur f the year around. RING-NECKED PHEASANT 93 Figure 1 0 . T y p i c a l f i e l d border and hedgerow i n the " A i r p o r t " zone. Note the extensive shrubby growth beside ditc h e s and the broad uncut f i e l d borders. : 94 h. Great-blue Heron (Ardea herodias Linnaeus) Seasonal occurrence: Year around resident and abundant winter v i s i t a n t (Figure 11 ) . During the study period the Great-blue Heron remained abundant i n the area (+25). Throughout the summer of 1966 only a few birds occurred i n the "Airport" zone. An analysis of data co l l e c t e d at t h i s time indicated that the numbers of birds on ,the "Airport" zone were correlated with the numbers of birds i n the "study area" (r = +0.4239), the following daytime maximum temperature (r = - 0 . 3 8 5 0 ) , and the previous tid e extreme (r = - 0 . 4 0 5 9 ) . This suggests that birds were more abundant i n the "Airport" zone when there were more birds i n the "study area" on cooler days and when previous tides were lower. There were low correlations between the numbers of birds i n the "Airport" zone and the number of minutes afte r sunrise (r = -0.2842) and the wind speed (r = +0.2400). This at best suggests that more birds occurred i n the "Airport" zone e a r l i e r i n the morning and during high winds. Each of these correlations support general obser-vations during the study period. The numbers of birds i n the "study area" were negatively correlated with the previous tide l e v e l (r = - 0 . 4 8 9 4 ) . This i s quite consistent with observations which indicated that more birds occurred i n the area during and following lower t i d e s . However birds did not begin frequenting ditches and f i e l d s of the "Airport" zone i n greater numbers u n t i l early September, This a c t i v i t y gradually increased u n t i l mid October when there was a sudden increase i n the t o t a l population. 95 Between mid October and the end of February wintering birds made f l i g h t s each day to s p e c i f i c ditches and large, t a l l "grassy" areas i n the "Airport" zone to feed and/or lounge. On a number of occasions as many as 50 birds occurred i n t a l l "grassy" f i e l d s beside the main runways. In a few instances l a t e a r r i v i n g birds landed i n the middle of the main runway. An analysis of the data collected at t h i s time showed correla-tions between the numbers of birds i n the "Airport" zone and the numbers of birds i n the "study area" (r = +0.3009), the wind speed (r = +0.3410), the t o t a l previous 48 hours p r e c i p i t a t i o n (r = +0.3272) and the current tide l e v e l (r = +0.4286). This again supports the observation that birds were more abundant i n the ^"Airport" zone when tides were high and the weather inclement and when there were more birds i n the "study area". The number of birds occurring i n the "study area" at t h i s time, were negatively correlated with the following maximum daytime temperature (r = -0.3755) and weakly correlated with the current tide l e v e l (r = +0.2723). This suggests birds were more abundant on cool days and when current tide l e v e l s were high. Between March and May the Herons i n the "study area" began d i r e c t i n g a considerable part of t h e i r d a i l y a c t i v i t y to nesting a c t i v i t i e s at the heronry near Point Gray i n the University Endowment Lands. Large numbers of birds occurred less frequently i n the "Airport" zone as tides gradually became less r e s t r i c t i n g during the day throughout l a t e March and A p r i l . As a r e s u l t birds tended to occur i n the "Airport" zone only during inclement weather. These observations are supported by correlations calculated from data collected at 9 6 t h i s time. For example, the numbers of birds i n the "Airport" zone were found to be correlated with the following daytime maximum temperature (r = - 0 . 3 5 5 4 ) , the wind speed (r = + 0 . 3 6 2 3 ) and the t o t a l previous 4 8 hours p r e c i p i t a t i o n (r = + 0 . 4 1 1 9 ) . As one might expect during the breeding season the numbers of birds i n the "study area" were not found to be correlated with any weather fa c t o r . Hazard to a i r c r a f t : Herons occurring i n the "Airport" zone were attracted to t a l l "grassy" f i e l d s and ditches. When feeding areas were not available elsewhere these birds would migrate from roosting areas to a t t r a c t i v e areas i n the "Airport" zone twice daily; approxi-mately one hour before sunrise and one hour after sunset. There were three " s t r i k e s " involving this species during the study period. Food: During the study period only one Heron was collected. Numerous observations indicated that birds using the "Airport" zone were large l y feeding on Microtus sp. i n f i e l d s and, to a lesser extent, on various animal food occurring i n ditches. Control: The Great-blue Heron was not controlled e f f e c t i v e l y using the available scaring devices. When attempts were made to scare them out of the "Airport" zone using cracker she l l s and "zon guns" the birds simply flew back and forth between GREAT BLUE HERON 98 a t t r a c t i v e areas. Long term control might be possible i f t a l l "grassy" areas were kept short, drainage of these areas were made more e f f e c t i v e and where possible ditches covered. i . K i l l d e e r Plover (Charadrius vociferus Linnaeus) Seasonal occurrence: Year around resident and abundant spring and f a l l transient (Figure 12). This species i s a year around resident i n the "study area" but there i s a tendency f o r the population to move from the "Airport" zone i n late December and early January. Nesting begins i n the area i n early February when birds return to set up t e r r i t o r i e s , to carry out courtship, and to bui l d nests. Records of the K i l l d e e r s f i r s t nest, f i r s t eggs and f i r s t young i n the "Airport" zone are given below (*From Hughes 1966). F i r s t nests -*March 13, 1964; *March 20, 1965; *March 19, 1966; February 26, 1967. F i r s t eggs -*March 30, 1966 (3 eggs) March 26 & 27, 1967 (3 & 4 eggs r e s p e c t i v e l y ) . F i r s t young - - A p r i l 7, 1964; - A p r i l 14, 1965; - A p r i l 13, 1966; A p r i l 6 and 21, 1967. Throughout the summer months, from May to July, there was a gradual increase i n the numbers of birds with a maximum of +50 occurring by late June and early July. When nesting was i n progress birds were most commonly found on or near graveled areas such as dykes, the j e t t y , roads, around runway and taxiway l i g h t s and i n some cases on open sand deposits. Feeding a c t i v i t y at t h i s time l a r g e l y consisted of searching f o r food i n the short 99 t u r f of the "Intensive" zone and when tides were low i t was ex-tended to ditch banks, marshes and mud f l a t s . As young matured the birds began occurring i n small flocks feeding as a group. An analysis of data collected during t h i s time indicated that the numbers of K i l l d e e r i n the "Airport" zone were correlated with the t o t a l previous 24 hour p r e c i p i t a t i o n (r = +0.4195) and to a lesser extent with the previous tide l e v e l (r = +0.2875) and the numbers of birds i n the "study area" (r = -O.2965). This indicated that there were more birds i n the "Airport" zone when r a i n f a l l increased, when previous tid e l e v e l s were higher and when the numbers of birds i n the study area decreased. However the l a t t e r factor i s somewhat biased by the effect of late breed-ing a c t i v i t y during the months of May and June. F a l l migrants occur i n the study area between late July and late September, General observations indicated that the numbers of birds i n the "Airport" zone increased during f a i r weather. An analysis of data collected at t h i s time supports t h i s conclusion. Important correlations occurred between the numbers of birds i n the "Airport" zone and the wind speed (r = -0.4057). The numbers of birds i n the "study area" were cor r e l a -ted with minutes a f t e r sunrise (r = +0.3227), the following day-time maximum temperature (r = +0.7753), the t o t a l previous 24 hours p r e c i p i t a t i o n (r = -0.3784) and the t o t a l previous 4$ hour p r e c i p i t a t i o n (r = -0.3978). These correlations also support general observational data, i n that they indicate that birds tended to be more numerous i n the area l a t e r In the day when the maximum temperatures were higher and when r a i n f a l l was lower. 100 Birds occurring i n the "Airport" zone between October and January were importantly correlated with the numbers of birds i n the "study area" (r = +0.4757). Observations at th i s time i n -dicated that more birds occurred i n the "Airport" zone during high t i d e s . However, an analysis of the data did not-support these observations i n that the previous tide l e v e l (r = -0.2430) and the current tide l e v e l (r = -0.2388) both correlated poorly with the numbers of birds i n the "Airport" zone. Birds occurring i n the "study area" were found to be correlated with minutes af t e r sunrise (r = -0.3790), the previous nighttime minimum temperature (r = +0.4109), the following daytime maximum temper-ature (r = +0.6467), the previous-tide l e v e l (r = -0.4246) and the current t i d e l e v e l (r = -O.5814). That i s , birds were more numerous i n the "study area" at sunrise when temperatures were higher, and when the previous t i d e l e v e l and the current tide l e v e l were lower. However, these correlations are biased by the coincident occurrence of tide l e v e l s , minutes after sunrise and maximum and minimum temperatures. Hazard to a i r c r a f t : K i l l d e e r p e r i o d i c a l l y occur i n large numbers i n the "Intensive" zone feeding i n the short grass t u r f . Birds found i n the area frequently f l y to, from or between a t t r a c t i v e areas and cross.runways. There were two " s t r i k e s " involving t h i s species during the study period. Food: The food of the K i l l d e e r iPlover varied somewhat during the study period. Throughout the summer months food consisted 1'P.I Figure 12. -200 KILLDEER 102 of a variety of Coleoptera, Hymenoptera, Lepidoptera and Orthop-t e r a . During the winter and early spring months between October and A p r i l earthworms were the most abundant food item; Curcu l i o n i -dae and various other insects were also consumed..(Appendix 1 0 . 3 . 1 ) . Control: K i l l d e e r cannot be controlled e f f e c t i v e l y using the available scaring devices. When frightened birds f l y away from the disturbance and land i n another a t t r a c t i v e area i n the "Airport" Zone. General observations indicate that short t u r f i s a pre-ferred habitat of K i l l d e e r ; i t i s not very a t t r a c t i v e to many other species. I t would appear that K i l l d e e r warrant further Study i f short tur f i s to p r e v a i l over most of the a i r p o r t . j . S h o r t - b i l l e d Dowitcher .(Limnodromus griseus Gmelin) Seasonal occurrence: F a l l and spring transient (Figure 1 3 ) . In the f a l l migration between July and November, the Dowitcher migrates through"' the "study area" i n two d i s t i n c t peaks. The f i r s t migration peak occurs i n l a t e July with as tfiany as +900 birds at one time. Collections and observations at t h i s time showed that a l l birds were adults i n f u l l breeding plumage. The second migration peak i s more extended with a b u i l d up i n numbers before the birds are l a s t seen i n the area, During t h i s period numbers averaged less than +200 with the 103 f i n a l peak reaching +600 bi r d s . I l l of these birds were i n winter plumage and c o l l e c t i o n s indicated they were immature. General observations during t h i s time seemed to indicate that high tides caused more birds to frequent ditches and surface pools with rainy weather having an additive e f f e c t . The low correla-tions obtained between the numbers of birds i n the "Airport" zone and the t o t a l previous 24 hour p r e c i p i t a t i o n (r = +0.1959), the t o t a l previous 48 hour p r e c i t i p a t i o n (r = +0.2638) and the previous tide extreme (r = -0.1779), are not e a s i l y explained. It may be that one or more factors were involved which were not included i n t h i s program. The numbers of birds i n the "study area" were found to be correlated with the previous nighttime minimum temperature (r = -0.3657) and the following daytime maximum temperature (r = -0.3877), which indicates that fewer birds occurred i n the "study area" when temperatures were higher. Perhaps t h i s condition encouraged the birds to migrate. In addition the numbers of birds i n the "study area" were found to be negatively correlated with the previous tide l e v e l (r = -0.3024). This suggests that there were more birds i n the area when previous tide extremes were lower. However, because the migration occurred over a period of f i v e months i t i s possible t h i s r e s u l t has been biased by the coincident changes of minimum tides and the abundance of migrating bir d s . A re-assessment of the natural seasons used for t h i s analysis may .provide more meaningful r e s u l t s . Spring migrants occurred i n the "study area" between early A p r i l and early June and t h e i r numbers were less than +100 104 at any one time.- General observations suggest that the numbers of birds occurring i n the "Airport" zone increased when there were more birds i n the area and during high t i d e s . Analysis supported these observations; the numbers of birds i n the " A i r -port" zone were correlated with the numbers of birds i n the "stu area" (r = +0.5179) and the current t i d e l e v e l (r = + 0 . 3 3 2 5 ) . It i s i n t e r e s t i n g to note that the numbers of birds i n the "study area" were correlated with the previous night-time minimum temperature (r = +0.7227) and the following daytime maximum temperature (r = + 0 . 3 9 2 9 ) . These correlations suggest that more birds occurred i n the "study area" during warmer weather but i t may be biased by the coincident seasonal occur-rence of higher temperatures and migrating birds. Low negative correlations between birds i n the "study area" and wind speed (r = - 0 . 2 9 0 3 ) and the t o t a l previous 48 hour p r e c i p i t a t i o n (r = - 0 . 2 4 5 9 ) also support these r e s u l t s . Increased wind speed and p r e c i p i t a t i o n and lower maximum and minimum temperatures are usually associated with inclement weather at t h i s time of year. A negative c o r r e l a t i o n occurred between the numbers of birds i n the "study area" and the previous tide l e v e l (r = - 0 . 2 1 0 3 ) . The mean ti d e during t h i s time was 12.99 feet, therefore, i t i s quite reasonable that higher l e v e l s should reduce the popula-t i o n by eliminating access to the l i t t o r a l zone and for c i n g the birds to high ground. Hazard to a i r c r a f t : The Dowitcher i s serious hazard to a i r c r a f t whenever i t occurs i n the "Airport" zone because of i t s tendency to make SHORT-BILLED DOWITCHER 106 frequent f l i g h t s to, from and between a t t r a c t i v e surface pools. This a c t i v i t y causes small groups or large flocks to cross over runways. However, there were no " s t r i k e s " involving t h i s species during the study period. Food: The analysis of food items taken from stomachs of t h i s species collected during the study period indicated a preference f o r earthworms. Other food items included larvae of 'Lepidoptera and Diptera (Appendix 1 0 . 3 . 2 ) . Control: The Dowitcher cannot be controlled e f f e c t i v e l y using available scaring devices. Birds when frightened simply move away from the disturbances to other a t t r a c t i v e areas i n the ''Airport" zone. The writer considers that the attractiveness of the "Airport" zone could be reduced by improving drainage i n low l y i n g areas and where possible by eliminating open ditches. This action may render that available scaring devices more ef f e c t i v e by eliminating alternative a t t r a c t i v e areas for the birds to f l y to. k. Dunlin ( E r o l i a alpina Linnaeus) Seasonal occurrence: Winter v i s i t a n t and abundant spring and f a l l migrant (Figure 1 4 ) . The Dunlin occurs i n the "study area" each year between l a t e September and early May. Numbers increase gradually during October to a f a l l maximum i n November (+7000). Following t h i s 1 0 7 peak the numbers decline i n December to the winter population of +2000 - + 3000 which remains r e l a t i v e l y stable u n t i l l a t e January, Between late January and early May spring migrants increase the population to + 5 0 0 0 , Collections of t h i s species during the study period indicated that spring and early f a l l migrants were adults and that the wintering birds were immature. During t h e i r occurrence i n the "study area" the Dunlin were found to prefer surface pools and recently disturbed s o i l areas. Numbers of birds i n the "Airport" zone were found to vary with tid e l e v e l s during spring and f a l l migrations. How-ever during the months of December and January birds tended to frequent the "Airport" zone at night. Wintering birds were frequently observed lounging along the Iona, and Sea Island j e t t y s and beside surface ponds i n the "sandpile" during the daylight hours. An analysis of data collected during the "study period" indicated that the numbers of birds i n the "Airport" zone were correlated i n a minor way with the numbers of birds i n the "study area" (r = +0.1082). Perhaps there were one or more additional factors not considered i n the computer program which caused these r e s u l t s to d i f f e r from general observational data. The numbers of birds i n the "study area" were found to have low negative correlations with the previous nighttime minimum temperature (r = -0.2948) and the following daytime maximum temperature (r = -0.2493); t h i s may indicate that the 108 birds tended to leave the area during inclement weather. How-ever, the writer believes that these correlations are a result of the seasonal coincidence of inclement weather and the low winter population. Further analysis i s required using shorter periods of time to l i m i t seasonal e f f e c t s . Hazard to a i r c r a f t : Dunlin frequently become a hazard to a i r c r a f t during t h e i r migration periods but the wintering population i s generally not a problem. During f a l l and spring migration high tides cause birds to frequent the "Airport" zone and to land i n a t t r a c t i v e areas to lounge and feed. The greatest hazard occurs when small groups or large flocks f l y to, from and between a t t r a c t i v e areas crossing runways. Food: Birds collected while feeding i n the "Airport" zone were found to have eaten various seeds and invertebrates (Appendix 10.3.2). The seeds were mostly of two types; Scirpus sp. and Polygonum p e r s i c a r i a . Invertebrates consumed were large l y i n s e c t s , including various Carabidae, Staphylinidae and Diptera, Several birds collected i n the "Airport" zone had not fed i n the area and as a r e s u l t l i t t l e or no i n d e n t i f i a b l e food material was recovered from t h e i r stomachs. Control: The Dunlin cannot be controlled e f f e c t i v e l y using available scaring devices. When frightened the birds simply f l y to another a t t r a c t i v e area i n the "Airport" zone. General DUNLIN 110 observations indicate that drainage of surface ponds the the planting of a tu r f on bare s o i l areas may decrease attractions fo r t h i s species. However, t h i s measure cannot be considered the f i n a l answer to the problem. Large flocks w i l l continue to f l y between the foreshore and various "Environs" areas during the l a s t stages of r i s i n g tides and the early stages of f a l l i n g t i d e s . It i s conceivable that the modification of the nearby t i d a l areas might reduce the birds i n the "study area", but even t h i s measure may f a i l to provide good control since t i d a l areas would s t i l l exist elsewhere. 1. Western Sandpiper (Ereunetes mauri Cabanis) Seasonal occurrence: Spring and f a l l migrant (Figure 15). In the "study area" the f a l l migration of the Western Sandpiper occurs between July and September as two d i s t i n c t peaks. The f i r s t peak occurs i n July and, i n l i g h t of c o l l e c -tions made during the study period, i t consists of adult birds. The maximum numbers are usually less than +3000. The second '.. migration peak occurs i n la t e August and early September with a maximum of +3000 recorded at one time. Collections indicate that these birds were l a r g e l y immature. General observations indicated that high tides were the main factor causing birds to frequent the "Airport" zone during the f a l l migration. Wind speed was also considered important p a r t i c u l a r l y when the winds were from the west during clearing weather. An analysis of the data collected at t h i s time supported these observations i n that the I l l numbers of birds i n the "Airport" zone were correlated with wind speed (r = +0.4977) and the current tid e l e v e l (r = +0.3726). Correlations also occurred between the numbers of birds i n the " A i r p o r t " zone and the previous nighttime minimum temperature (r = +0.2434) and the following daytime maximum temperature (r = +O.316O). This indicates that birds were more abundant i n the 1 " A i r p o r t " zone on warmer days. At t h i s time of year warmer temperatures are associated with clear weather. Low correlations occurred between the numbers of birds i n the "Airport" zone and the t o t a l previous 24 hour p r e c i p i t a t i o n (r = -0.1403), the t o t a l previous 48 hour p r e c i p i t a t i o n (r = -0.1412) and the pre-vious tide extreme (r = +O .II65). This information further supports the general observations above i n that birds were more abundant i n the "Airport" zone during previous high tide and when r a i n f a l l was low (clear weather). The numbers of birds i n the "study area" were found to be negatively correlated with the previous tid e extreme (r = -0.3109). This again supports general observations since one expects to have fewer birds i n the "study area" when the t i d a l f l a t s are inaccessible. Spring migration i n the "study area" occurs between mid A p r i l and mid May with as many as +16,000 birds occurring at one time. General observations indicate that these birds respond i n the same way as f a l l migrants to t i d e , wind and p r e c i p i t a t i o n . However, tide l e v e l s were considered the most .significant factor a f f e c t i n g the numbers of birds i n the "Airport" 112 zone because high winds were uncommon and p r e c i p i t a t i o n was below 'normal. Analysis indicated that the numbers of birds i n the "Airport" zone were correlated with the numbers of birds i n the "study area" (r = +0.3714), the number of minutes a f t e r sunrise (r = -0.5454), the previous tide extreme (r = +0.2934) and the current tide l e v e l (r = +0.7078). This indicates that the numbers of birds i n the "Airport" zone were greater e a r l i e r i n the morning when birds were more abundant i n the "study area" and when tides were high. However, i t i s of Interest to note that minutes after sunrise were importantly correlated with the current tide l e v e l (r = -0.6991), but only eleven observa-tions of many f o r t h i s period could be used. Low correlations were obtained between the numbers of birds i n the "Airport" zone and the wind speed (r = -0.0775), the t o t a l previous 24 hour p r e c i p i t a t i o n (r = -0.2204) and the t o t a l previous 48 hour p r e c i p i t a t i o n (r = -0.1699). The numbers of birds i n the "study area" were cor-related with the following daytime maximum temperature (r = +0,5325), the t o t a l previous 24 hour -precipitation (r = -0.6795), the t o t a l 48 hour p r e c i p i t a t i o n (r = -0.8396) and the previous tide extreme (r = +0.6262). This suggests that birds were more abundant i n the area on d r i e r warmer days when previous tide extremes were higher. Hazard to a i r c r a f t : When the Western Sandpiper occurred i n the "Airport" zone i t a c t i v e l y fed and lounged around surface pools, ditches, 113 bare s o i l areas, and on paved areas, i n p a r t i c u l a r runways. Small and large flocks of birds frequently flew to, from and between a t t r a c t i v e areas crossing runways. In addition general observations indicated that regular and often large f l i g h t s occurred between the Sea Island foreshore and "Environs" area with the main body of the movement passing through the " A i r -port" zone (Figure 1 6). There were two " s t r i k e s " involving t h i s species during the study period. Food: Generally the food taken from birds collected during the study period indicated an insectivorous diet (Appendix 1 0 . 3 . 2 ) . However, various small seeds and other invertebrate animals were also taken. Control: The Western Sandpiper cannot be controlled e f f e c t i v e l y using available scaring devices. Birds, when frightened, flew to another a t t r a c t i v e area i n the "Airport" zone. The writer considers that an improvement of drainage i n low areas and where possible, the elimination of open ditches, might reduce the attractiveness of the area to t h i s species. In addition, t h i s action may render the available scaring devices more ef f e c t i v e by eliminating alternative a t t r a c t i v e areas f o r birds to f l y to. 1 1 4 Figure 1 5 . 1967 . • A^y^. 1966 , , M\A . , Ji\ 196if I , , , I , 1 , A ~i r 1963 M M ' j ' s ' N 000 WESTERN SANDPIPER 115 Figure 16. Large f l o c k of Western Sandpiper (+2000) which has j u s t a r r i v e d on the Sea I s l a n d foreshore a f t e r f l y i n g through the " A i r p o r t " zone. 116 m. Glaucous-winged Gull (Larus glaucescens Naumann) Seasonal occurrence: Winter v i s i t a n t (Figure 17). The Glaucous-winged Gull occurs i n the "study area" between August and May. In recent years numbers gradually i n -creased between August and early October with a rapid increase to a wintering peak of +4500, i n October-November, This peak was usually sustained u n t i l early A p r i l after which there was a rapid decline of the population to a few stragglers i n May, However, during the study period the numbers recorded from t h i s species were markedly lower than those recorded i n e a r l i e r periods. The population s t i l l showed the cha r a c t e r i s t i c seasonal fluctuations but t o t a l numbers did not exceed +1500. This re-duction i n the numbers of birds using the "study area" i s be-lie v e d to be a result of the moving of Vancouver City dump from South-east Vancouver to Burns bog i n Delta municipality 8 miles south of the previous s i t e . In e a r l i e r years" birds would pass through the "Airport" zone each morning and evening on short period migrations between t h e i r night roost near Steveston V i l l a g e and the Vancouver City dump (Harris, personal communica-tio n May 1966). General observations indicate that during the study period larger numbers of birds occur i n the "Airport" zone., during high t i d e s , r a i n storms, and early morning. An analysis of data collected during t h i s time indicates that the numbers of birds i n the "Airport" zone are correlated with the current tide l e v e l (r = +0.3450). Lower correlations also occurred between 117 the numbers of birds i n the "Airport" zone and the numbers of birds i n the "study area" (r = +0.2655), the following daytime maximum temperature (r = +0.2301), the t o t a l previous 24 hour p r e c i p i t a t i o n (r =. +0.2198), the t o t a l previous 48 hour p r e c i p i -t a t i o n and the previous tid e extreme (r = +0.1104). However, i t i s believed that these r e s u l t s are biased by the coincident change i n bird numbers, temperatures, t i d e l e v e l s , and p r e c i p i -t a t i o n with the seasons. The numbers of birds i n the "study area" were found to be correlated with the previous nighttime minimum temperature (r = -0.5930), the following daytime maximum temperature (r = -0.6371) and the current t i d e l e v e l (r = +0.3809). These results suggest that birds were more abundant i n the area when tempera-tures were lower and current tide l e v e l s were higher. However these correlations are also biased by the fact that b i r d numbers, temperatures and tid e l e v e l s vary coincidently with the season. Further analysis i s needed to remove some of the seasonal e f f e c t . It i s i n t e r e s t i n g to note that of the twenty birds co l l e c t e d and examined during f i v e d i f f e r e n t months of the study period, only one was a male, and i t was immature. This may suggest that a segregation of adult sexes i n the Glaucous-Winged Gull during winter months. Similar sex ra t i o s were also detected i n the other g u l l species collected during the study period. Hazard to a i r c r a f t : The Glaucous-winged Gull perhaps represents the greatest hazard to a i r c r a f t of any b i r d species i n the "study area", 118 except, f o r the other g u l l species. The habits of t h i s species cause i t to occur i n the "Airport" zone i n the most hazardous locations and i n peak numbers when v i s i b i l i t y i s poorest and the number of a i r c r a f t movements i s high. General observations indicate that the Glaucous-winged Gull was attracted to the short tur f of the "Intensive" zone, p a r t i c u l a r l y when earth-worms are abundantly available (Figure 1$). Water trap c o l l e c t i o n s (see Figure 2) and an examina-t i o n of sod samples taken throughout the "study area" indicate that earthworms are most abundant i n moist and wet subzones and that they occur on the top of the t u r f during early hours of the morning and during rainy weather. When the f i r s t few birds occur i n the area they a c t i v e l y search f o r food and act as decoys for other g u l l s passing by. Once the f i r s t birds have been fed to s a t i a t i o n they lounge in large groups often occurring on or beside runways. Passing a i r c r a f t do not frighten the birds u n t i l they are too close for the birds to f l y out of t h e i r path. Observations also indicate that various b i r d sized white objects, p a r t i c u l a r l y waste paper serve as decoys f o r t h i s and other g u l l species. There were thirteen " s t r i k e s " involving t h i s species during the study period. Food: The Glaucous-winged Gull did not a l t e r i t s choice of food i n the "Airport" zone throughout the study period. A l l birds collected i n the "Airport" zone and i n p a r t i c u l a r the 119 120 Figure 18. S t r a g g l e r s from a f l o c k of +300 Glaucous-winged G u l l s feeding on earthworms beside surface pools near the east approach of the main runway. 1 2 1 "Intensive" zone were found to have eaten large numbers of earthworms (Appendix 1 0 . 3 . 1 ) . Control: Fortunately the Glaucous-winged Gull can be controlled e f f e c t i v e l y using available scaring devices (see Section 4.4). However, the writer believes that long term e f f o r t s may also reduce the hazard to a i r c r a f t associated with t h i s species. General observations indicate that increased surface drainage and the removal of scattered waste paper from f i e l d areas i n the "Airport" zone may greatly decrease attractions for t h i s species. n. Herring Gull (Larus argentatus Pontoppidan) Seasonal occurrence: Winter v i s i t a n t (Figure 1 9 ) . Each f a l l the Herring Gull arrives i n the "study area" in l a t e September or early October. Their numbers gradually increase to as many as + 2 0 0 0 by mid October and remain r e l a t i v e l y ,constant throughout the winter u n t i l t h e i r departure from the area i n A p r i l . During the study period d a i l y fluctuations i n numbers were quite marked. In one instance as many as + 3 , 7 0 0 were recorded on the north-east section of Sea Island i n the "Environs" zone but on the following day there were only + 1 5 0 . General observations indicated that the majority of the birds designated as Herring Gulls were i n fact Thayer's 1 2 2 Gulls Larus thayeri Brooks. However, since d i f f e r e n t i a l counts were not possible these species w i l l be grouped as Herring Gulls throughout t h i s discussion. This i s a reasonable approach i n view of the d i f f i c u l t y of d i f f e r e n t i a t i n g these two species p a r t i c u l a r l y when immature birds are involved (Godfrey, 19'66). Collections made during the study period indicated that the birds occuring i n the "Airport" zone were predominantly females. Of a t o t a l of eleven birds collected during the months of October, November and December only one b i r d was a male and it was immature. These results are the same as was found f o r the other g u l l species frequenting the "Airport" zone and i t suggests these birds segregate by sex i n the winter months. General observations indicated that the Herring Gull occurred i n greater numbers i n the "Airport" zone i n the early morning and during or following periods of r i n f a l l . An analysis of data collected during the study period indicated that the numbers of birds i n the "Airport" zone correlated poorly with the previous nighttime minimum temperatures (r = -0.1335), the following daytime maximum temperatures (= -0,1360), the wind speeds ( r = + 0 . 1 7 1 8 ) , the t o t a l previous 2 4 hour pre c i p i t a t i o n s (r = +O . I46I) and the t o t a l previous 4 8 hour pr e c i p i t a t i o n s (r = +0.1268). In addition, the numbers of birds i n the "study area" correlated with the previous nighttime minimum tempera-ture (r = -0.5995), the following daytime maximum temperature ( r = - 0 . 6 9 2 4 ) , the previous tid e l e v e l (r = + 0 . 2 7 1 8 ) and the current t i d e l e v e l (r = +0.3602). However, because of the coincident seasonal change between b i r d numbers, tide l e v e l s 123 and weather these correlations must be considered spurious for short period a c t i v i t y . Further analysis using shorter time periods might improve the re l a t i o n s h i p . The low correlations between the numbers of birds in the "Airport" zone and the numbers of birds i n the "study area" (r = +0,1395) a n d between the numbers of birds i n the "study area" and the numbers of minutes after sunrise (r = +O.O676) do not appear to be coincident with seasonal change and therefore can be considered representative of short period responses. This suggests that birds i n the "Airport" zone increase as the numbers of birds In the "study area" increase and that birds i n "study area" are more abundant e a r l i e r i n the morning. These r e s u l t s support e a r l i e r observations. Hazard to a i r c r a f t : Herring Gulls a c t i v e l y feed i n short tur f and surface pool areas. Early a r r i v a l s and "bird-sized" white objects, p a r t i c u l a r l y waste paper, tend to "decoy" additional..' birds including other g u l l species. Herring Gulls a c t i v e l y fed u n t i l satiated and then lounged beside or on paved areas, including runways. Approaching a i r c r a f t usually did not frighten the birds u n t i l they were too close for the birds to f l y out of th e i r path. There were two " s t r i k e s " involving t h i s species during the study period. Food: Earthworms were the most frequent and abundant food item consumed by Herring Gulls i n the "study area". However, HERRING GULL 125 other invertebrates were consumed including one species of slug and several beetles (Appendix 10.3.1) . Control: Fortunately the Herring Gull can be controlled e f f e c t i v e l y using the available scaring devices (see Section 4 . 4 ) . However, the writer believes that long term effo r t s may also reduce the hazard to a i r c r a f t associated with t h i s species. General observations indicate that increased surface drainage and a removal of scattered waste paper from f i e l d areas i n :.the "Air p o r t " zone may greatly decrease attractions for t h i s species. o. C a l i f o r n i a Gull (Larus c a l i f o r n i c u s Lawrence) Seasonal occurrence: Spring and f a l l migrant (Figure 20), Each year f a l l migrants occur i n the "study area" between mid July and early October with numbers reaching +400 i n the "Airport" zone. During the study period as many as +2000 occurred i n the "study area". General observations indicated that the numbers of birds feeding and/or lounging i n the " A i r -port" zone increased when tides were high. On bright dry days b i r d s l a r g e l y lounged or, when possible, fed on voles by following the "rotary mowers" cutting t a l l grass areas. Following such feeding periods birds would frequently lounge on paved g r i t . During September and October b i r d numbers increased i n the "Airport" zone during storms. They a c t i v e l y fed on various invertebrates available i n the short t u r f . An analysis of data 1 2 6 . c o l l e c t e d at t h i s time i n d i c a t e d low c o r r e l a t i o n s between the numbers of b i r d s i n the " A i r p o r t " zone and the wind speed ( r = +0.2171), the t o t a l previous 24 hour p r e c i p i t a t i o n ( r = +0.1270), and the t o t a l previous 48 hour p r e c i p i t a t i o n (r = +0.1290). However, there were higher c o r r e l a t i o n s between the numbers of b i r d s i n the "study area" and the numbers of minutes a f t e r sun-r i s e (r = +0.3066) and the f o l l o w i n g daytime maximum temperature (r = +0.4347). The w r i t e r b e l i e v e s that the low c o r r e l a t i o n s between the numbers of b i r d s i n the " A i r p o r t " zone and the previous t i d e extreme .(r = +0.0718) and the current t i d e l e v e l ( r = -0,0468) may be a r e s u l t of the seasonal coincidence between the numbers of b i r d s i n the "study area" and the change i n t i d e s . Further a n a l y s i s might e l i m i n a t e t h i s seasonal a f f e c t . B i r d s c o l l e c t e d during t h i s time were found to be mostly female; there were a few immature males as w e l l . Of a t o t a l of twelve b i r d s c o l l e c t e d only three were males (immature). Spring migrants occur i n the "study area" between mid March and e a r l y May w i t h as many as +4000 o c c u r r i n g at one time. However, during the study p e r i o d l e s s than +50 occurred i n the "study area" and only two b i r d s were recorded i n the " A i r p o r t " zone. Perhaps, changing the l o c a t i o n of the Vancouver C i t y dump e f f e c t e d t h i s r e d u c t i o n . Normally these b i r d s occur i n the " A i r p o r t " zone at t h i s time t o feed behind farm implements used f o r t i l l i n g the s o i l (Hughes 1966, personal communication). 127 haza rd t o a i r c r a f t : The C a l i f o r n i a G u l l was t h e l e a s t h a z a r d o u s t o a i r -c r a f t o f t h e g u l l s p e c i e s d u r i n g t h e s t u d y p e r i o d . However , t h e i r h a b i t o f l a n d i n g on and f e e d i n g b e s i d e runways d i d c r e a t e p r o b l e m s . I n a d d i t i o n t h e i r i n f r e q u e n t h a b i t o f r e g u r g i t a t i n g " p e l l e t s " on paved a r e a s such as runways and t a x i w a y s c r e a t e d a m a i n t e n a n c e p rob lem b e c a u s e s u c h " r e f u s e " can cause damage t o j e t e n g i n e s i f i n g e s t e d by them. There was. one " s t r i k e " i n v o l v i n g t h i s s p e c i e s d u r i n g t h e s t u d y p e r i o d . F o o d : C o l l e c t i o n s and e x a m i n a t i o n s o f s tomach c o n t e n t s o f b i r d s d u r i n g t h e f a l l m i g r a t i o n i n d i c a t e d t h a t t h i s s p e c i e s i s an " o p p o r t u n i s t " f e e d e r . M a j o r f o o d i t e m s i n c l u d e d ea r t hwo rms , i n s e c t s and s l u g s . I n a d d i t i o n g e n e r a l o b s e r v a t i o n s and exam-i n a t i o n s o f r e g u r g i t a t e d " p e l l e t s " i n d i c a t e d t h e y consumed M i c r o t u s -sp. w h i c h were made a v a i l a b l e by " r o t a r y " c u t t i n g o f t a l l g r a s s a r e a s . C o n t r o l : The C a l i f o r n i a G u l l can be c o n t r o l l e d e f f e c t i v e l y u s i n g a v a i l a b l e s c a r i n g d e v i c e s (see S e c t i o n 4 . 4 ) . However , l o n g t e rm c o n t r o l by r e m o v i n g a t t r a c t i v e f e a t u r e s i n t h e " A i r p o r t " zone ;may be p o s s i b l e . F o r e x a m p l e , by m a i n t a i n i n g a l l " g r a s s y " a r e a s as a s h o r t t u r f one removes t he f o o d a t t r a c t i o n a s s o c i a t e d w i t h " r o t a r y " c u t t i n g . I n a d d i t i o n by m a i n t a i n i n g a permanent s h o r t t u r f one e l i m i n a t e s t h e s e a s o n a l a t t r a c t i o n o f t i l l i n g . When b i r d s p e r i o d i c a l l y l i n g e r i n t he " s t u d y a r e a " u n t i l O c t o b e r , 128 CALIFORNIA GULL 1 2 9 a s t h e y d i d d u r i n g t h e s t u d y p e r i o d , t h e y m igh t be l e s s a t t r a c t e d t o t h e " A i r p o r t " zone i f more adequa te d r a i n a g e were p r o v i d e d i n f i e l d a r e a s . p . Mew G u l l ( L a r u s c a n i s S e a s o n a l o c c u r r e n c e : W i n t e r v i s i t a n t ( F i g u r e 2 1 ) . T h e Mew G u l l o c c u r s i n t h e " s t u d y a r e a " between September and l a t e A p r i l each y e a r . Between 1 9 6 3 and 1 9 6 5 t h i s s p e c i e s o c c u r r e d i n numbers be low + 7 0 0 i n t he " s t u d y a r e a " a n d d u r i n g J a n u a r y o f 1 9 6 6 , Hughes ( 1 9 6 6 ) r e c o r d e d a t o t a l o f + 7 0 0 0 i n t h e " A i r p o r t " z o n e . However d u r i n g t h e s t u d y p e r i o d t h e p o p u l a t i o n rema ined r e l a t i v e l y s t a b l e a t 2 0 0 0 - 3 0 0 0 . G e n e r a l o b s e r v a t i o n s i n d i c a t e d t h a t t h i s s p e c i e s o c c u r r e d i n g r e a t e r numbers i n t h e " A i r p o r t " zone d u r i n g r a i n y w e a t h e r , e a r l i e r i n t h e m o r n i n g , d u r i n g h i g h t i d e s and when t h e r e were more b i r d s i n t he " s t u d y a r e a " . An a n a l y s i s o f d a t a c o l l e c t e d d u r i n g t h i s t i m e i n d i c a t e s t h a t t h e numbers o f b i r d s i n t h e " A i r p o r t " z o n e a r e c o r r e l a t e d w i t h t h e numbers o f b i r d s i n t h e " s t u d y a r e a " ( r = +0,3164). Lower c o r r e l a t i o n s were a l s o I n d i c a t e d be tween t h e numbers o f b i r d s i n t he " A i r p o r t " zone and t h e f o l l o w i n g d a y t i m e maximum t e m p e r a t u r e ( r = -0.1833), t h e w ind speed ( r = + 0 . 2 0 6 5 ) , t h e t o t a l p r e v i o u s 2 4 hou r p r e -c i p i t a t i o n ( r = + 0 . 2 2 7 7 ) and t h e t o t a l p r e v i o u s 4 8 hou r p r e c i p i -t a t i o n ( r = +0 .2356). However , t h e w r i t e r b e l i e v e s t h e l a t t e r 1 3 0 t h r e e c o r r e l a t i o n s t o be b i a s e d by t he c o i n c i d e n t s e a s o n a l change i n t he numbers o f b i r d s i n t h e " s t u d y a r e a " , p r e c i p i t a t i o n , t i d e l e v e l s and t e m p e r a t u r e s . T h i s f a c t o r i s a l s o c o n s i d e r e d t o b i a s t h e c o r r e l a t i o n s between t h e numbers o f b i r d s i n t h e " s t u d y a r e a " and t h e p r e v i o u s n i g h t t i m e minimum t e m p e r a t u r e ( r = -0,5090), t h e f o l l o w i n g day t ime maximum t e m p e r a t u r e ( r = - 0 . 6 2 8 4 ) , t h e p r e v i o u s t i d e ex t reme ( r = + 0 . 3 1 2 2 ) and ' the c u r r e n t t i d e l e v e l ( r = +0.5552). However , t h e i n f l u e n c e o f s e a s o n was no t c o n s i d e r e d t o be i m p o r t a n t i n t h e l o w e r c o r r e l a -t i o n be tween t h e numbers o f b i r d s i n t h e " s t u d y a r e a " and t h e number o f m i n u t e s a f t e r s u n r i s e ( r = +0,2484). T h i s s u g g e s t s more b i r d s were i n t h e a r e a d u r i n g e a r l y m o r n i n g . F u r t h e r a n a l y s i s u s i n g s h o r t e r t i m e p e r i o d s i s r e q u i r e d t o r e d u c e t h e e f f e c t o f s e a s o n . C o l l e c t i o n s o f t h i s s p e c i e s made d u r i g g t h e s t u d y p e r i o d i n d i c a t e d t h a t t h e p o p u l a t i o n c o n s i s t e d l a r g e l y o f f e m a l e s w i t h a few immature m a l e s . There were f i v e immature ma les and t w e n t y - s i x f e m a l e s ( a d u l t and immature) c o l l e c t e d d u r i n g s e v e n months o f t h e s t u d y p e r i o d . The d a i l y a c t i v i t y o f the Mew G u l l i n t h e " A i r p o r t " zone was c o n f i n e d t o t h e " I n t e n s i v e " zone and nore s p e c i f i c a l l y t h e wet and m o i s t subzones f o r f e e d i n g and f o r l o u n g i n g . Haza rd t o a i r c r a f t : T h e Mew G u l l i s a h a z a r d t o a i r c r a f t when i t i s a t t r a c t e d t o t h e " I n t e n s i v e " zone t o f e e d and l o u n g e a round F i g u r e 2 1 . 7131 1967 1966 1965 1961+ 1963 -1 i " r -1 r -i 1 i r -I t 1 I 1 1 ! r -J ~ M ' M J S N MEW GULL 132 runways. This species i s frequently associated with other g u l l species and i t has been observed to serve as a decoy for them, and vice versa. On a number of occasions "bird-sized" white objects, such as waste paper, have also been considered to serve as decoys f o r the Mew Gull and other species of g u l l s . Food: Examination of stomach contents taken from Mew Gulls c o l l e c t e d during the study period indicated that t h i s species was feeding l a r g e l y on earthworms. However, birds collected during the early winter months were also found to have eaten beetles and slugs (Appendix 10.3.1). Control: The Mew Gull can be controlled e f f e c t i v e l y using a v a i l -able scaring devices. However, long term control by removing a t t r a c t i v e features i n the "Airport" zone may be possible by providing adequate drainage i n a l l f i e l d areas. General obser-vations indicated the birds were very much attracted to flooded areas, p a r t i c u l a r l y when such flooding was increasing. Other considerations should include the removal of objects such as waste paper from f i e l d areas where they may attract the Mew Gull and other species of g u l l , q. Short-eared Owl (Asio flammeus Pontoppidan) Seasonal occurrence: Summer resident, f a l l transient and winter v i s i t a n t (Figure 22). The Short-eared Owl i s an abundant summer resident (2-3 pairs) i n the "study area". Nesting and f i r s t young 133 records include the following (from Hughes 1966; A p r i l 9, 1965 (two nests with 6 and 3 eggs) and May 22, 1965 (1 n e s t l i n g banded)). Generally records indicate that there i s a movement of birds i n the "study area" between June and September with a maximum of 25 occurring at one time. However, the migration does not appear to be at the same time or i n the same numbers each year (Figure 22). Following the increase there i s usually a general decline to less than f i v e birds between late December and l a t e January which i s followed by a s l i g h t increase i n late March to the breeding population. During the study period there was a marked change from the general seasonal fluctuations i n numbers between December and A p r i l . The writer, while making "follow up" counts d i s -covered a large winter roost i n the t a l l "grassy" area i n the north section of the "sandpile". As many as 78 birds were counted i n t h i s area at one time. General observations indicated that these birds moved out from t h e i r roost to feed at dawn and dusk but remained i n i t throughout the day. The d a i l y a c t i v i t y of the Short-eared Owl throughout the study period l a r g e l y consisted of hunting over (crepuscular) or lounging i n t a l l "grassy" areas (diurnal). However, during d u l l weather more birds were seen during the day. Hazard to a i r c r a f t : General observations indicate that the Short-eared Owl has a marked preference for t a l l "grassy" areas i n the "Airport" zone. Birds were seldom seen elsewhere except when crossing 1 3 4 between t a l l "grassy" areas. This l a t e r a c t i v i t y frequently caused them to cross runways. There were seven "strikes,." involving t h i s species during the study period. Food: Birds were not collected during the study period f o r analysis of ingested food. However, general observations i n d i -cate that t h i s species feeds almost t o t a l l y on the vole Microtus townsendii. In a number of cases p e l l e t s were re-covered from several known Short-eared Owl perches (small clumps of d i r t or stake) and from l i v e trapped b i r d s . In a l l cases jthe p e l l e t s were found to be the fur and skeletons of Microtus sp Control: The Short-eared Owl cannot be controlled using a v a i l a b l scaring devices. Frightened birds move away from the disturbance and resume normal a c t i v i t y . However, the writer believes control might be effected through removal of a l l a t t r a c t i v e f a l l "grassy" areas from the "Airport" zone. The program of l i v e trapping birds of prey and r e l e a s i n them off the airport was thought to be quite successful as a measure to reduce the numbers of birds occurring i n the "Airport" zone (Hughes personal communication, May 1967). However, the writer believes t h i s e f f o r t to have had a minor effect on re-ducing the numbers of birds i n the "Airport" zone during the study period i n l i g h t of the numbers of birds known to have returned to the "study area" following removal (Hughes 1967). 135 Figure 22. •0 6 •if SHORT-EARED OWL 136 I n a d d i t i o n t h e numbers o f b i r d s removed f r o m t h e a i r p o r t d i d no t cause a n o t i c e a b l e r e d u c t i o n i n t he numbers o f b i r d s i n t h e " s t u d y a r e a " even when t h e p o p u l a t i o n was s m a l l . r . Snowy Owl ( N y c t e a s c a n d i a c a L i n n a e u s ) . S e a s o n a l o c c u r r e n c e : W i n t e r v i s i t a n t ( F i g u r e 23). G e n e r a l l y t h e Snowy Owl i s no t an abundant v i s i t a n t i n t h e " s t u d y a r e a " . There has been a t l e a s t one o r two b i r d s i n t h e a r e a each w i n t e r s i n c e 1963 and d u r i n g t h e p r e s e n t s t u d y t h e y became r e l a t i v e l y abundant (17). T h i s r e c o r d i s c o n s i s t e n t w i t h t h e f i n d i n g s o f Munro and Cowan (1947) who c o n s i d e r e d t h i s s p e c i e s t o be "-^-a w i d e s p r e a d o c c a s i o n a l l y a b u n d a n t , w i n t e r v i s i t a n t " . G e n e r a l o b s e r v a t i o n s i n d i c a t e d t h a t t h e day t ime a i r -p o r t a c t i v i t y o f t h i s s p e c i e s l a r g e l y c o n s i s t e d o f r e s t i n g on s u i t a b l e p e r c h e s . However , on s e v e r a l o c c a s i o n s b i r d s were s e e n a c t i v e l y h u n t i n g v a r i o u s o t h e r b i r d s i n t h e " s t u d y a r e a " . I n d i v i d u a l b i r d s appeared?" t o h o l d l a r g e t e r r i t o r i e s w i t h i n w h i c h t h e y moved f r e e l y . These t e r r i t o r i e s had s e v e r a l t h i n g s i n common i n c l u d i n g t h e f o l l o w i n g ; 1. t h e y were l a r g e and a c t i v e l y d e f e n d e d a g a i n s t o t h e r Snowy O w l s , 2. t h e y had a s u i t a b l e r o o s t ( i e . runway l i g h t , p o l e , f e n c e p o s t , t r a n s m i s s o -m e t e r l o w e r , s tump , e t c . ) and t h e y i n c l u d e d one o r more w a t e r a r e a s f r e q u e n t e d by w a t e r f o w l . These o b s e r v a t i o n s a r e s i m i l a r ^•Munro, J . A . and I. M e T . . Cowan. 1947. A R e v i e w - o f t he B i r d Fauna o f B r i t i s h C o l u m b i a , B . C . P r o v . Museum, D e p t . o f E d u c a t i o n , S p e c i a l P u b . N o . 2. 137 to those of Keith (i960) who reported on Snowy Owls wintering at Delta, Manitoba. Birds occurred during the study period between early November and late A p r i l with a maximum number of 17 i n December. General observations and co l l e c t i o n s indicated that a l l of the birds were immature. Hazard to a i r c r a f t : The Snowy Owls which maintained t e r r i t o r i e s i n the " A i r -port" zone frequently crossed runways and used approach and run-way l i g h t s as perches. This a c t i v i t y placed such birds d i r e c t l y i n an areas where a i r t r a f f i c was maximum. Although generally undisturbed by the noise, smell or "bl a s t " of various a i r c r a f t these birds p e r i o d i c a l l y flew i n to the path of a i r c r a f t landing or taking o f f . There were three " s t r i k e s " involving t h i s species during the study period. Food: There were a t o t a l of eight birds examined during the study period. However a quantitative analysis of th e i r stomach contents was not attempted. These birds were found to have eaten the following items; three with coot, three with duck (t e a l and scaup) and two with r a t . These findings supported general observations. Control: The Snowy Owl cannot be controlled using available scaring devices. Such action can remove birds from an area temporarily but they soon return. Perhaps t h i s i s a response Figure 23 . :138 1967 1966 1965 196*f 1963 -1 r-~i 1— M lAAi 15 10 •5 15 10 5 15 10 5 -1 1 i 1--15 10 5 -15 10 5 T T SNOWY; OWL 139 to t h e i r system of t e r r i t o r i a l i t y . At the present time these birds must be removed by shooting because of the high " s t r i k e " hazard associated with them. The writer believes t h i s species could be controlled by removing the i n i t i a l a t t r a c t i o n , namely the waterfowl. s. Barn Swallow (Hirundo r u s t i c a Linnaeus). Seasonal occurrence: Summer resident (Figure 24). The Barn swallow arrives i n the "study area" i n the t h i r d week of A p r i l each year and remains u n t i l i t s departure i n the second week of October. On June 15, 1967 nests were being b u i l t i n the "Airport" zone on and i n various man made structures; no records were available for e a r l i e r years. In the summer of 1966 birds gradually increased from the i n i t i a l 150 breeding pairs i n the "study area" to more than +1000 by August. Collections indicate that t h i s change i n abundance was a r e s u l t of the occurrence of young birds . Hazard to a i r c r a f t : The Barn swallow a c t i v e l y feeds on insects which i t encounters when f l y i n g over "grassy" f i e l d s , marshes, ditches and hedgerows. The numbers of feeding birds i n given areas appears to be dependent on the abundance of available food. When food i s available throughout the "study area" the birds are evenly d i s t r i b u t e d and when food i s abundant i n a confined area 140 the b i r d s concentrate. During the study period concentrations of f e e d i n g b i r d s p e r i o d i c a l l y occurred over oat f i e l d s , marsh areas, along hedgerows and behind machines c u t t i n g grass. On s e v e r a l occasions b i r d s would concentrate on the runways or taxiways to r e s t . Pavement i s a favourable r e s t i n g area because i t does not have ground o b s t r u c t i o n s which normally hamper such a short legged b i r d . Both feeding and r e s t i n g a c t i v i t y cause t h i s b i r d to occur i n f r o n t of a i r c r a f t . There were three " s t r i k e s " i n v o l v i n g t h i s species during the study period. Food: Barn swallows a c t i v e l y consume l a r g e numbers of a i r -borne i n v e r t e b r a t e s , the most common of which are i n s e c t s . Throughout t h e i r stay i n the "study area" they were found to consume various D i p t e r a , Hymenoptera, Homoptera and Coleoptera (Appendix 10.3.2). C o n t r o l : Up to the time of the present study breeding Barn swallows were c o n t r o l l e d by keeping doors of b u i l d i n g s closed and by e l i m i n a t i n g n e s t i n g areas found on the outside of many b u i l d i n g s by covering s u i t a b l e s i t e s w i t h chicken w i r e . This technique has been very s u c c e s s f u l but i t has not e f f e c t e d a re d u c t i o n i n the t o t a l number of b i r d s using the area from August t o October. B i r d s are s t i l l able to breed s u c c e s s f u l l y i n the "Environs" zone. Observations i n d i c a t e that i f a l l vegetation were 141 Figure 24. 2k ° 1 1 r 1 t 1 ' 1 0 O ooo 17 ^ _ _ y j ( j _ ^ ^ 21 1 9 1 i r i i i > I I 2k i Ik 1 8 . j , j j , , 1 j 1 t i '00 6 3 M M N BARN SWALLOW 142 maintained as a short well drained t u r f , the birds might greatly reduce there a c t i v i t y i n the "Airport" zone. Birds were most frequently seen feeding over vegetation which was t a l l e r than over the t u r f i n the "Intensive" zone. The r e s t i n g of birds on runways was believed to be a result of birds f i r s t being attracted to the area for food. t. Water P i p i t (Anthus spinoletta Linnaeus). Seasonal occurrence: Spring and f a l l transient (Figure 25). Each f a l l , between early September and the end of October, and, each spring between early A p r i l and mid May, P i p i t s migrate through the study area. During t h e i r stay they are frequently found i n a l l short t u r f or sparsely vegetated areas including marshes, feeding a c t i v e l y on various insects. In the f a l l t h e i r numbers have reached +5000 i n the "Airport" zone, but during the spring migration less than +500 have been recorded at one time. Observations indicate that tide and the time of day are s i g n i f i c a n t factors a f f e c t i n g t h e i r d a i l y a c t i v i t y . Although correlations were not attempted, the consistent observations indicated that birds were more abun-dant on the airport during high tides and between one hour afte r sunrise and one hour before sunset. When on the "Intensive" zone p i p i t s tended to prefer moist and wet subzones. Collections indicated that a l l the migrants i n f a l l were immature with more males than females (7 males to 3 females) and that spring migrants were adults with more males than females (3 males to 143 1 female). However, i t i s d i f f i c u l t to base a conclusion on such li m i t e d information. Further information i s needed to confirm that males are the most abundant sex in the population :or that the f a l l migrants are a l l immature. Hazard to a i r c r a f t : When i n the intensive zone p i p i t s fed i n small flocks and frequently flew to, from and between suitable feeding areas. This a c t i v i t y often caused flocks to f l y over runways. There were two "b i r d s t r i k e s " involving t h i s species during the study period. Food: Water p i p i t s were found to be t o t a l l y insectivorous auring the study period. The most frequent and abundant food Items found i n stomachs of collected birds were Curculionidae and i n pa r t i c u l a r the root weevil S i t o n i a hispidus. Root weevils were found i n the stomach contents of every b i r d c o l l e c t e d . Control: The Water p i p i t was not controlled e f f e c t i v e l y using available scaring devices. When frightened the birds would simply f l y a short distance away from the disturbance and land. Con-tinued harrassment did not a l t e r t h i s response. Control, therefore, seems lim i t e d to removing i t s source of food i n the "Airport" zone (insects) and/or eliminating nearby t i d a l marshes. Since the l a t t e r , at present i s quite impractical, the former stands as the only control measure at t h i s time. 144 Figure 25. 1967 1966 1965 196*f 1963 AvA 1 1 1 / K / i / v \ / v w f 1 1 1 1 1 1 1 \ ' / 1 , , , T ; 1 i I ' ! . . . . . . •, ' •00 ko 10 5 4-0 10 5 ho 10 5 IfO 10 5 IfO 10 5 M M N WATER PIPIT 1 4 5 u . Common S t a r l i n g ( S t u r n u s v u l g a r i s L i n n a u e s ) S e a s o n a l o c c u r r e n c e : R e s i d e n t and abundant w i n t e r v i s i t a n t ( F i g u r e 2 6 ) . D u r i n g t h e s t u d y p e r i o d l e s s t h a n l o p a i r s o f s t a r l i n g s n e s t e d i n t h e s t u d y a r e a . The f i r s t young were o b s e r v e d b e i n g f e d on A p r i l 1 3 , 1 9 6 7 . As summer advanced s m a l l f l o c k s o f young b i r d s w i t h one o r two a d u l t s began f e e d i n g i n " g r a s s y " a r e a s . The a c t i v i t y o f t h e s e f l o c k s was c o n f i n e d t o a r e a s o u t -s i d e t h e " I n t e n s i v e " zone most o f t h e t i m e and t h e y were no t c o n -s i d e r e d a " b i r d s t r i k e " h a z a r d . By l a t e Augus t and e a r l y S e p -tember l a r g e numbers o f w i n t e r i n g b i r d s . a r r i v e d i n t h e g r e a t e r V a n c o u v e r a r e a and r e m a i n e d u n t i l e a r l y A p r i l . Throughout t h i s t i m e b i r d s moved f r o m r o o s t i n g a r e a s out o v e r a g r i c u l t u r a l l a n d s each day t o f e e d . Many b i r d s u t i l i z e d s u i t a b l e f e e d i n g a r e a s f o u n d i n t h e " s t u d y a r e a " . U s u a l l y t h e i r numbers do no t exceed + 5 , 0 0 0 (Hughes 1 9 6 6 ) bu t d u r i n g t h e s t u d y p e r i o d as many as + 1 5 , 0 0 0 were r e c o r d e d a t one t i m e b e s i d e r u n w a y s . These l a r g e f l o c k s p r e f e r r e d t o f e e d on s h o r t t u r f such as i s f ound i n t h e " I n t e n s i v e " z o n e , bu t on many o c c a s i o n s t h e y a l s o f e d i n t a l l " g r a s s y " f i e l d s , a l o n g d i t c h e s and i n " w e e d " a r e a s . I n t h e " I n t e n s i v e " zone b i r d s were o b s e r v e d f e e d i n g i n " m o i s t " and " w e t " s u b z o n e s more f r e q u e n t l y t h a n i n t h e " d r y " s u b z o n e s . On a number o f o c c a s i o n s , when r a i n f a l l had been h e a v y , f l o c k s were o b s e r v e d f e e d i n g a l o n g t he edges o f v a r i o u s s u r f a c e p o o l s . When t i d e s were l o w f l i g h t s i n v o l v i n g t h r e e t o f o u r t h o u s a n d b i r d s were common between t h e f a r m i n g a r e a on t h e n o r t h s i d e o f Sea I s l a n d and t h e Sea I s l a n d f o r e s h o r e . I n a d d i t i o n such f l i g h t s 146 were often made over the "Intensive" zone between Vancouver c i t y or the north side of Sea Island and the d e l t a i c deposits south of Sea Island. On one occasion a large flock of birds (+800) was observed "hawking" f o r insects, somewhat l i k e swallows, on a warm day 100 feet above a t a l l "grassy" f i e l d beside runway 12:30. Food: Examination of stomach contents of birds collected i n the "Airport" zone indicated that the diet of the S t a r l i n g was l a r g e l y the same f o r each month during the study period (Appen-dix 10,3.1). However, between December and March earthworms were more frequently taken than i n e a r l i e r months when other invertebrates, p a r t i c u l a r l y insects, were the most abundant and frequent food items. Vegetable food was recorded when birds arrived i n the "Airport" zone afte r having fed on f r u i t s a v a i l -able i n "shrubby" areas of the "Environs" zone. A few birds c o l l e c t e d while they were feeding on the foreshore were found to have eaten isopods, amphipods and a few small molluscs. Hazard to a i r c r a f t : Starlings are p a r t i c u l a r l y hazardous to a i r c r a f t when feeding beside or f l y i n g over runways because when frightened they ha b i t u a l l y f l y upward and form dense f l o c k s . Fortunately many of the large f l o c k s , which occurred during thesstudy period, were successfully frightened from the area before 1 4 7 148 any damage occurred. Only one "bird s t r i k e " involving t h i s species was recorded during the study period. Control: the S t a r l i n g can be controlled e f f e c t i v e l y by using the available scaring devices. This species was frightened from the "Airport" zone by using recorded d i s t r e s s c a l l s , "very" f l a r e s , a shotgun and "cracker s h e l l s " (see Section 4.4). How-ever, the writer believes that several farm areas i n the "En-virons" zone on Sea Island served as a reservoir for birds which used the "Airport" zone. Large flocks of s t a r l i n g s were f r e -quently associated with c a t t l e i n f i e l d s or at feed l o t s par-t i c u l a r l y north-east and east of the "sandpile". When the winter rains begin the s o i l becomes soft and p l i a b l e and c a t t l e e a s i l y break up the t u r f making invertebrates more available to b i r d s . Starlings scared from the airport would often f l y to these areas to rest and/or resume feeding. This area may be made less a t t r a c t i v e i f c a t t l e were not allowed i n f i e l d s when the ground i s soft or to be fed from open feed bins. v. House Finch (Carpodacus mexicanus Muller). Seasonal occurrence: Year around resident (Figure 27). The House f i n c h i s a common breeding and wintering b i r d i n the study area. In summer i t occurs i n very small numbers i n the "Airport" zone because of a lack of suitable nesting s i t e s . By August and September the immature and adult birds begin to 1 4 9 form large flocks (+700) which move into the "Airport" zone from the "Environs" zone to feed on seeds. Food: This species shows a marked preference for the seeds of Wild Radish.Raphanus raphanistrum and Bird Rape, Brassica  campestris. The seeds of Corn Spurry, Spurgula arvensis. and Lady's Thumb, Polygonum p e r s i c a r i a . were also taken i n con-siderable amounts (Appendix 10.3.2). Hazard to a i r c r a f t : Plants, the seeds of which were found to be eaten by the birds during the study period were confined to construction or t i l l e d areas. Dormant seeds when brought to the surface were germinated (Figure 28). Large flocks of birds throughout the f a l l and winter fed i n these areas and frequently moved between them crossing runways. There was on£"bird s t r i k e " i nvolving t h i s species during the study period. Control: This species cannot be controlled e f f e c t i v e l y using conventional scaring devices. However, observations of move-ments and analysis of feeding habits indicate that control might be effected by removing plants used as food. This would re-quire cutting or spraying plants with herbicides to prevent seed production. Ideally a l l areas should be maintained as a short grass t u r f to prevent the occurrence of plants and seeds which attract b i r d s . 1 5 0 Figure 27. '00 HOUSE FINCH Figure 28 . P l a n t s of B r a s s i c a campestris and Rhaphanus raphanistrum growing i n r e c e n t l y d i s t u r b e d areas. (Light areas from mid l e f t to upper r i g h t of p i c t u r e ) . 152 w. American Goldfinch (Spinus t r i s t i s Linnaeus) Seasonal occurrence: Summer resident and abundant f a l l transient (Figure 29). Birds arrived i n the study area i n late A p r i l to breed (+100 b i r d s ) , and increase i n abundance throughout the summer. However, they do not occur i n the "Airport" zone i n large numbers u n t i l mid August. By t h i s time most nesting has ceased and large flocks begin to occur i n suitable. ;'f eeding areas during the day. At night the birds roost i n trees and shrubs; some on the north side of Sea Island outside the "Airport" zone. Hazard to a i r c r a f t : No "bi r d s t r i k e s " involving t h i s species were known to have occurred during the study period. However, when the gold-f i n c h was abundant, from mid August to early October, large f l o c k s frequently fed on seeding plants i n the west half of the "Air p o r t " zone beside or at the end of both runways. In one area, northwest of the "button" of 12, where seeds of various forbs were abundant, these birds exceeded +1000 i n number (Figure 30). Passing a i r c r a f t often caused the birds to take " f l i g h t " upward en masse and i n a few instances they barely missed c o l l i d i n g . Pood: The food from birds collected i n the "Airport" zone l a r g e l y r e f l e c t e d the a v a i l a b i l i t y of each food item (Appendix 10.3.2). In areas beside and at the end of both runways food 153 154 Figure 30. "Weed" areas northwest of the "button" of 12 w i t h l a r g e numbers of Cirsium arvense and Sonchus ar-vense s e t t i n g seed. 155 was m a i n l y seeds o f H a i r y - c a t ' s ea r H y p o c h a e r i s r a d i c a t a . I n o t h e r a r e a s seeds o f S t o r k s b i l l E r o d i u m c i r c u t a r i u m ? Canada t h i s t l e C i r s i u m a r v e n s e and P e r e n n i a l Sow t h i s t l e Sonchus a r v e n s e were t a k e n i n l a r g e amounts . C o n t r o l : T h i s s p e c i e s canno t be c o n t r o l l e d e f f e c t i v e l y u s i n g a v a i l a b l e s c a r i n g d e v i c e s . The wr i te r b e l i e v e s t h a t when t h i s s p e c i e s i s h a z a r d o u s i t i s t h e l o c a t i o n and abundance o f f o o d w h i c h l a r g e l y gove rns i t s a c t i v i t y . I t i s b e l i e v e d t h a t by r e m o v i n g o r l i m i t i n g f o o d , p a r t i c u l a r l y i n c r i t i c a l a r e a s i n t h e " I n t e n s i v e " z o n e , t h i s s p e c i e s can be c o n t r o l l e d . T h i s w o u l d r e q u i r e mowing o f seed p r o d u c i n g p l a n t s f o u n d b e s i d e r u n w a y s , s u c h as H a i r y c a t ' s e a r , b e f o r e f l o w e r heads a r e a b l e t o f o r m and " r o t a r y " c u t t i n g o r H p r a y i n g w i t h h e r b i c i d e s o f o t h e r a t t r a c t i n g p l a n t s f o u n d i n rough a r e a s . k.k C o n t r o l M e a s u r e s Methods used t o c o n t r o l b i r d s on Vancouve r A i r p o r t r e p r e s e n t t h e s a f e s t , most e f f e c t i v e and l e a s t c o s t l y r emed ies so f a r d e v i s e d f o r b i r d c o n t r o l i n t h e w o r l d . T h r o u g h ' p r o p e r use i t i s b e l i e v e d t h a t t h e y can e f f e c t i v e l y l i m i t t h e a c t i v i t y o f most p r o b l e m b i r d s o v e r and on t h e a i r p o r t t o a m i n i m a l l e v e l . However , i t must be r e a l i z e d t h a t t h i s p r o p e r use p r e s u p p o s e s some b a s i c knowledge o f t h e b i r d s t h e m s e l v e s ( h a b i t a t s , h a b i t s and r e a c t i o n s t o s c a r i n g d e v i c e s ) and t h e s c a r i n g d e v i c e s ( range 156 l i m i t a t i o n ) . Currently some of the improper uses of these de-vices arise out of ignorance of the aforementioned points. The writer during the course of t h i s study was able to observe the use of a l l of these control measures and the reactions of various birds to them. The control device and something of t h e i r uses and effectiveness are given i n Table 4. Birds considered to be problem species, but shorebirds incl u d i n plovers, owls, and passerines. With these birds the i n -effectiveness of the control devices i s due to the li m i t e d response a b i l i t y of the birds themselves. A l l of these species can be frightened by the pyrotechniques but they l i m i t t h e i r " f l i g h t " by simply seeking an undisturbed (secure) location i n the same general area. It may be possible to t r a i n them to respond favorably by i n t e n s i f y i n g e f f o r t s to make them wary of the whole airport area but t h i s would e n t a i l much time and cost Fortunately a l l of these species may eventually be controlled i n the area by l i m i t i n g those factors which provide security and a t t r a c t i o n f o r them. As has been indicated, under the discussion of each species i n the previous section, those factors which concern the greatest number i n t h i s group are: food, cover and "lounging" areas. Therefore, t h e i r e f f e c t i v e control i s dependent l a r g e l y on the maintenance of the physical and b i o l o g i c a l environment. T a b l e 4. O b s e r v a t i o n s on c o n t r o l measures u s e d by t h e Depar tmen t o f T r a n s p o r t d u r i n g t h e s t u d y p e r i o d . E f f e c t i v e C o n t r o l M e a s u r e Range i n F e e t B i r d s A f f e c t e d Comments on Use and L i m i t a t i o n s . S t a r l i n g d i s t r e s s 200-500 S t a r l i n g c a l l ( c o n t i n u o u s t a p e ) T h i s c a l l , most o f t e n , a t t r a c t s b i r d s i n i t i a l l y t o t h e s o u r c e and t h e n h a v i n g i n s p e c t e d i t t h e y d e p a r t f r o m t h e a r e a r a p i d l y . I t i s much l e s s e f f e c t i v e on e x t r e m e l y l a r g e f l o c k s t h a n s m a l l ones b e c a u s e f r i g h t e n e d b i r d s t e n d t o be d e c o y e d by b i r d s r e s p o n d i n g i n a s e c u r e manner o u t s i d e t h e r a n g e l i m i t . However , t h i s d e v i c e i s 100% e f f e c t i v e i f o t h e r s c a r i n g d e v i c e s , p a r t i c u l a r l y c r a c k e r s h e l l s , a r e u s e d a t t h e same t i m e . F o r e x a m p l e , b i r d s up t o 1/2 m i l e away can be d i s t u r b e d by en masse p a n i c o f t h e f l o c k d i r e c t e d o v e r t h e m . The e f f e c t i v e r ange i n d i c a t e d i s a r e s u l t o f t h e d i s r u p t i o n by p r e v a i l i n g w i n d . G l a u c o u s - w i n g e d 200-500 G l a u c o u s - w i n g e d T h i s c a l l most o f t e n a t t r a c t s t h e g u l l s t o G u l l d i s t r e s s c a l l G u l l H e r r i n g G u l l , t h e s o u r c e and t h e n h a v i n g i n v e s t i g a t e d i t ( c o n t i n u o u s t a p e ) Mew G u l l t h e y s l o w l y c i r c l e away f r o m t h e a r e a . The s i n g l e and c o m b i n a t i o n t e c h n i q u e s d e s c r i b e d unde r s t a r l i n g d i s t r e s s c a l l i m m e d i a t e l y above have t h e same e f f e c t h e r e . The c a l l i s much l e s s e f f e c t i v e and t h e r e s u l t s l e s s c o n -s i s t e n t on i n d i v i d u a l f l o c k s o f H e r r i n g and Mew G u l l when G l a u c o u s - w i n g e d G u l l s a r e no t p r e s e n t . C a l i f o r n i a G u l l s m a i n l y f r e q u e n t t h e a i r p o r t when o t h e r g u l l s p e c i e s a r e no t a b u n d a n t . T h i s l i m i t s t h e e f f e c t i v e n e s s o f t h i s c a l l w i t h t h i s s p e c i e s b e c a u s e i t does M n o t a p p e a r t o r e s p o n d u n l e s s r e i n f o r c e m e n t vn i s a v a i l a b l e f r o m o t h e r s p e c i e s . T a b l e 4. C o n t i n u e d . E f f e c t i v e C o n t r o l Measu re Range i n F e e t B i r d s A f f e c t e d R i n g - b i l l e d G u l l 200-500 R i n g - b i l l e d G u l l d i s t r e s s c a l l C a l i f o r n i a G u l l F l o o d l i g h t s on 500 + .Wate r fow l V e h i c l e s Zon-Gun 0-1000 A l l w a t e r f o w l , ( A c e t y l e n e G r e a t b l u e Heron cannon) S t a r l i n g and a l l Sea G u l l s Comments on Use and L i m i t a t i o n s . T h i s c a l l has l i m i t e d a p p l i c a t i o n on V a n -c o u v e r A i r p o r t excep t i n t h e case o f C a l i f o r -n i a G u l l s . The r e s p o n s e i s t h e same as i s d e s c r i b e d f o r G l a u c o u s - w i n g e d G u l l and t he -c o m b i n a t i o n t e c h n i q u e s d e s c r i b e d unde r S t a r l i n g d i s t r e s s c a l l can be a p p l i e d h e r e . R i n g - b i l l e d g u l l s o c c u r r a r e l y on Vancouve r a i r p o r t a l t h o u g h t h e y a r e seen s e a s o n a l l y i n s m a l l numbers i n t h e " e n v i r o n s " z o n e . T h i s d e v i c e i s u s e f u l o n l y a t n i g h t and i n d i c a t i o n s a r e t h a t t h e r e s p o n s e i s l i m i t e d and t h a t f r i g h t e n e d b i r d s most o f t e n a l i g h t a g a i n on o t h e r n e a r b y a r e a s . C r a c k e r s h e l l s and s h o t gun b l a s t s add t o i t s e f f e c t . T h i s d e v i c e i s p a r t i c u l a r l y u s e f u l d u r i n g t h e e a r l y p a r t o f h u n t i n g s e a s o n when b i r d s a re wary o f any l o u d n o i s e s i m i l a r t o a s h o t - g u n b l a s t . P r l o n g e d use i n any a r e a i n v a r i a b l y r e d u c e s i t s e f f e c t i v e n e s s due t o b i r d h a b i t u a t i o n (see s e c t i o n 2.2,3). I t has the a d v a n t a g e s o f b e i n g a u t o m a t i c bu t has t he d i s a d v a n t a g e s o f b e i n g r e l a t i v e l y i m m o b i l e . H vn 00-T a b l e 4. C o n t i n u e d . E f f e c t i v e C o n t r o l Measu re Range I n F e e t B i r d s A f f e c t e d V e r y f l a r e $00 + A l l w a t e r f o w l , G rea t B l u e H e r o n , S t a r l i n g , a l l Sea G u l l s C r a c k e r s h e l l s 1000 + A l l w a t e r f o w l , G rea t B l u e H e r o n , S t a r l i n g , a l l Sea G u l l s Comments on Use and L i m i t a t i o n s T h i s d e v i c e i s most e f f e c t i v e f o r l a r g e f l o c k s o f b i r d s a t c l o s e range bu t one canno t d i r e c t t h e i r d e p a r t u r e . I t i s most e f f e c t i v e w i t h t h G l a u c o u s - w i n g e d G u l l s and t h e S t a r l i n g s when r e c o r d e d d i s t r e s s c a l l s f o r t h e s e b i r d s a r e p l a y e d a t t he same t i m e . T h i s c o m b i n a t i o n r e i n f o r c e s t h e i r i n s e c u r i t y . P r a c t i c a l s h o r t comings a r e t h e i r c o m p a r a t i v e l y h i g h c o s t ( 1.00 e a c h ) , t h e n e c e s s i t y o f g e t t i n g p e r -m i s s i o n t o f i r e f r om t h e a i r p o r t c o n t r o l t ower and t h e i n c o n v e n i e n c e o f h a v i n g t o p i c k up wads o f f t h e f i e l d a f t e r d i s c h a r g e . I t does have t h e advan tage o f p r o d u c i n g smoke w h i c h s c a r e s t h e b i r d s . C r a c k e r s h e l l s a r e by f a r t h e most e f f e c t i v e , v e r s a t i l e and e a s i l y u s e d o f a l l c o n t r o l d e -v i c e s . An e x p e r i e n c e d p e r s o n can c o n t r o l t he d e p a r t u r e , speed and d i r e c t i o n o f l a r g e num-b e r s o f p r o b l e m b i r d s i n a v e r y s h o r t t i m e ; t h e e x p l o s i o n i n t h e a i r t e r r i f i e s a l l b i r d s and t h e y f l e e f r o m i t . One p r a c t i c a l p r o b -lem i s t h a t p e r i o d i c a l l y a p rema tu re i g n i t i o n o f t he p r o j e c t i l e o c c u r s i n t h e f i r i n g cham-b e r o f b a r r e l o f t he g u n . Such " b a c k f i r e s " have been known t o b u r s t t h e gun and t h e r e f o r e a r e a p o t e n t i a l danger t o p e r s o n n e l , a more " b a c k f i r e " ' p r o o f gun i s needed a l o n g w i t h a more r e l i a b l e s h e l l . T a b l e Uc; C o n t i n u e d . E f f e c t i v e C o n t r o l Measure Range i n F e e t B i r d s A f f e c t e d S h o t - G u n 500 + A l l w a t e r f o w l , G rea t B l u e H e r o n , S t a r l i n g , a l l Sea G u l l s . S c r e e n i n g n e s t i n g a r e a s S w a l l o w s , S p a r -on b u i l d i n g s and k e e p i n g r o w s , S t a r l i n g s l a r g e d o o r s c l o s e d as much and r o b i n s as p o s s i b l e Comments on Use and L i m i t a t i o n s T h i s weapon can be used t o s c a r e b i r d s o r k i l l t hem. I t i s as v e r s a t i l e as c r a c k e r s h e l l s but i t does no t have the same r a n g e . The k i l l i n g o f a b i r d r e i n f o r c e s t h e i n -s e c u r i t y r e s p o n s e but i t i s u n d e s i r a b l e b e -cause i t i s a was te o f l i f e and n e c e s s i t a t e s r e m o v a l and' d i s p o s a l o f t he c a r c a s s . I t i s e x t r e m e l y u s e f u l f o r r emov ing i n d i v i d u a l b i r d s w h i c h a r e a p e r s i s t e n t p r o b l e m and canno t be c o n t r o l l e d i n a n o t h e r way , bu t i n a l l c a s e s i t s use r e q u i r e s good j u d g e -ment . These measures have been v e r y s u c c e s s f u l i n l i m i t i n g t h e numbers o f b i r d s u s i n g man made s t r u c t u r e s f o r n e s t s i t e s . However some s t r u c t u r e s s u c h as r a d a r t o w e r s and l a r g e b u i l d i n g s do no t l e n d t h e m s e l v e s t o t h i s t y p e o f c o n t r o l and as a r e s u l t a few members o f each s p e c i e s a r e s t i l l a b l e t o f i n d accommoda t ion . ON o T a b l e 4. C o n t i n u e d . E f f e c t i v e C o n t r o l Measu re Range i n Fe C u t t i n g rough " g r a s s y " a r e a s t o s i x i n c h e s Remov ing " s h r u b b y " v e g e t a t i o n ( p h y s i c a l l y o r c h e m i c a l l y ) Comments on Use and L i m i t a t i o n s The c u t t i n g o f " g r a s s y " a r e a s i s most e f f e c t i v e i n r e d u c i n g n e s t i n g h a b i t a t and c o v e r . However , t o be s u c c e s s f u l i t must be c a r r i e d out i n a d i l l i g e n t manner so t h a t t h e a r e a s a f f e c t e d do no t have t h e o p p o r t u n i t y t o grow above t e n i n c h e s i n h e i g h t . By p e r m i t t i n g t h e c o v e r t o e x -ceed t e n i n c h e s one may a f f o r d t h e b i r d s i n t he a r e a ample o p p o r t u n i t y t o n e s t and h a t c h young a n d / o r t h e a t t r a c t i o n o f • a d d i t i o n a l b i r d s f r om s u r r o u n d i n g a r e a s . The e l i m i n a t i o n o f s h r u b b y v e g e t a t i o n i s most i m p o r t a n t t o t h e e f f e c t i v e c o n t r o l o f b i r d a c t i v i t y i n t h e a r e a . I t e l i m i n a t e s c o v e r , n e s t i n g s i t e s , r o o s t -i n g a r e a s and p r o v i d e s a b e t t e r o p p o r -t u n i t y f o r t h e b i r d c o n t r o l l e r t o d e t e c t b i r d s and e f f e c t t h e i r r e m o v a l . 162 4.5 Grazing by c a p t i v e widgeon 4.5.1 General statement American Widgeon, Mareca americana, have been con s i d e r e d to be a "problem s p e c i e s " on Vancouver I n t e r n a t i o n a l A i r p o r t since i n v e s t i g a t i o n s i n t o the b i r d hazard began i n 1963. In November of t h a t year on two separate occasions, a t o t a l of s i x t e e n widgeon were i n v o l v e d i n c o l l i s i o n s w i t h a i r -c r a f t causing a t o t a l of $1200.00 damage (Hughes 1966). At t h a t time as many as 4700+ b i r d s were recorded on the a i r p o r t . Each winter these b i r d s make evening f l i g h t s from the f o r e -shore areas to flooded short grass f i e l d s to feed. Large numbers, i f undisturbed, remain a l l night g r a z i n g i n areas near ponds. However when b i r d s graze beside the runways they are e a s i l y s t a r t l e d by a i r c r a f t l a n d i n g or t a k i n g o f f and as a r e s u l t are a " s t r i k e " hazard. Since i t was found that the main a t t r a c t i o n i n the area was the short green grass, i t was decided that an i n v e s -t i g a t i o n i n t o the g r a z i n g s e l e c t i v i t y of penned widgeon might be i n f o r m a t i v e . In l i g h t of f i e l d observations i t was hypothe-s i z e d that although the b i r d s p r e f e r to eat short young grass, they might show preferences f o r s p e c i f i c grass species. A i r -f i e l d s could be seeded to unpalatable s p e c i e s . To t e s t t h i s hypothesis the f o l l o w i n g experiments were planned: 1. To t e s t the g r a z i n g preferences of l i v e widgeon on the n a t i v e grass sward i n s i t u at Vancouver A i r p o r t by using po r t a b l e open bottom pens and a crop and a crop f l u s h i n g device to recover Ingested m a t e r i a l s . 1 6 3 2 . In addition, several experimental ground cover species were grown i n greenhouse f l a t s so that they could be presented to penned widgeon to determine, by observation and recovery of crop contents, what species were not preferred as food. 4 . 5 . 2 Methods In preparation for these experiments a large "main" pen was constructed to accommodate a dozen birds (Figure 3 1 ) . This structure was located i n an open f i e l d near the west dyke of Sea Island where, because of the extremely high water table, water was obtained by digging an open p i t two feet deep. At one end of t h i s pen there was a "drive" funnel f o r t r a n s f e r r i n g birds into a "transporting" pen. The "transporting" pen had a s l i d e gate to permit passage of birds between i t and the "main" pen or the "portable grazing" pens and a top f l a p door (Figure 3 2 ) . The top f l a p door enabled recovery of birds from the "trans-porting" pen for crop f l u s h i n g when birds were removed from "portable grazing" pens. Two "portable grazing" pens, with open bottoms to permit birds to graze i n areas on which they were placed, were also constructed (Figure 3 3 ) . Each of these pens had a s l i d e gate to permit easy passage of birds between i t and the "transporting" pen. The purpose of these various pens was to l i m i t the amount of direct handling of the birds between the "main pen" and the grazing s i t e i n the f i e l d . A l l pens were made of heavy gauge chicken wire woven together by heavy copper wire Figure 3 1 . "Main pen" 1 6 4 Fish net Chicken wire funnel trap (slide door removed) X(9 x 1 0 " 3 ) Figure 3 2 . "Transport Pen" ( a l l sides chicken wire) Trap door Slide door X(9 x IO" 3) Figure 3 3 . "Grazing Pen" Slide door chicken wire X(9 x 1 0 3 ) Bottom open 165 except f o r the "main pen" which was a 2 x 3" wood frame struc-ture with l / 2 " mesh nylon covered f o r three feet from the bottom 'with heavy guage one inch chicken wire to prevent predation. Birds were supplied with an abundance of water and g r i t throughout the experiment. Unfortunately t h i s work suffered a number of severe setbacks. E f f o r t s to trap widgeon through the winter of 1966-1967 on Sea Island and at other locations throughout the Lower Fraser Delta were plagued with f a i l u r e . Methods used f o r trapping birds included; baited funnel traps, cannon net, padded #2 jaw traps, mist nets and Balchatri snare traps. Trapped birds were held by L. Fisher of Coquitlam Municipality, B.G. on a 1/4 acre area with other ducks and geese u n t i l the experiment was to begin. However, by February 1967 the t o t a l catch was only three birds (one male ("M"-j_) found wounded during the hunting season, one female ("F-^ ") caught i n a Balchatri snare trap and one female ("F^") caught i n a padded #2 jaw tr a p ) . In A p r i l of 1967 b i r d "M-^" died as a res u l t of wounds i n f l i c t e d by a Canada goose i n the holding area, leaving only the two females f o r the experiment. It was found that the extreme wariness of these birds was the main reason for the lack of success. Also, i f the writer were more experienced and, i n some cases, i f the equipment were more serviceable the results of trapping might have been more impressive. Another unforeseen misfortune was the ineffectiveness of the crop flusher i n recovering grass shoots from l i v e widgeon. This device was o r i g i n a l l y described by Vogtman, 1945, who used i t f o r recovering crop contents from 166 gallinaceous game bi r d s . Later i t was discovered that grass ingested by widgeon copiously covered with s a l i v a causing the grass blades to s t i c k together i n "package-like" clumps i n the eosophagus. These "packages" of grass blades could not be flushed out through the tube and there was no way of dissolving the s a l i v a without doing harm to the birds. As a result of these setbacks i t was decided that the experiment would be limited to observing the reaction of the birds to the diff e r e n t experimental cover plants. Prior to the actual experiment both "F-^" and "F^" were pladed i n one "modified portable grazing" pen so as to enable ad-justment to the confined conditions. However, the birds remained extremely wary of people and would run about i n the pen t r y i n g to get out when someone approached. Even afte r one week of adjust-ment to the pen and to the mixed feed (cracked corn, wheat, oats, barley, m i l l e t , canary seed and an abundance of assorted g r i t ) the birds were e a s i l y disturbed. Therefore, to l i m i t the amount of stress on the birds observations were made by comparing the condition of the plants i n the f l a t s before and after grazing. D e t a i l s of t h i s procedure are given i n section 4.5. A l l experi-ments were conducted outdoors with the "modified portable grazing" pen located on top of a carport roof i n the c i t y of New Westmin-st e r . This location enabled the writer to provide fresh water d a i l y and to maintain an adequate food supply. Domestic animals such as cats and dogs were not a problem because the locations was inaccessable to them. 167 The presenting of a single f l a t to the birds for a 21+ hour period was considered to be a " t r i a l " . When a l l f l a t s were presented once during consecutive 21+ hour periods they were c o l l e c t i v e l y termed a "cycle". Three "cycles" using the same f l a t s , but i n varied orders, were considered to represent a " s e r i e s " . In thi s experiment there were two "series"; "A", a l l f l a t s with plants cut to two inches; and, "B", a l l f l a t s with plants grown to 6-10 inches. Series "A" was to be carried out f i r s t and series "B" was to follow when the plants had grown to s u f f i c i e n t height. 4.5.3 Observation Observations were made immediately after each t r i a l to assess the use of the plants by the birds . Plants were checked f o r signs of shoots removed and the pen was checked for discarded f o l i a g e and green faeces (which indicate plant use). In th i s way i t was possible to estimate, i n a r e l a t i v e way, what use had been made of the plants. To quantify these obser-vations the following scale was used: Colour of Use Rating Description Faeces 1 No shoots eaten, chewed or discarded normal 2 No shoots eaten but some chewed and discarded normal 3 Same shoots eaten and some chewed and discarded green 4 Many shoots eaten and some chewed and discarded green 5 Nearly a l l shoots eaten and none discarded green 168 4 . 5 . 4 E x p e r i m e n t a l p l a n t s E x p e r i m e n t a l p l a n t s used were chosen because t h e y were t h o u g h t t o have some f e a t u r e w h i c h m igh t r e n d e r them u n p a l a t a b l e t o w idgeon ( T a b l e 5 ) . These p l a n t s a l s o p o s s e s s f e a t u r e s w h i c h q u a l i f y them as g e n e r a l g r o u n d c o v e r s f o r Vancouve r A i r p o r t (see S e c t i o n 5 . 2 . 1 ) . Not i n c l u d e d i n T a b l e 5 i s t h e c o n t r o l s p e c i e s f o r t he e x p e r i m e n t , Ben t g r a s s , A g r o s t i s s t o l o n i f e r a , w h i c h i s known t o be p a l a t a b l e t o w i d g e o n . A l l p l a n t s , i n c l u d i n g t h e c o n t r o l s p e c i e s , were grown f r o m seed i n s e p a r a t e g reenhouse f l a t s 2 / 3 f u l l o f s t r a i n e d t o p -s o i l . I n a d d i t i o n , one f l a t was seeded t o c o n t a i n a s i n g l e row o f each p l a n t . When t h e p l a n t s had grown t o 6 i n c h e s i n h e i g h t t h e y were cu t back t o two i n c h e s u s i n g hand c l i p p e r s and a l l o w e d t ime t o p roduce an abundance o f new s h o o t s . When new s h o o t s were f o r m e d , and t h e p l a n t s were g r o w i n g v i g o r o u s l y , t h e e x p e r i m e n t was b e g u n . 4 . 5 . 5 Results I n i t i a l l y " s e r i e s A " , was begun on May 8 , 1 9 6 7 w i t h b i r d s " F ^ " and " F ^ " v i g o r o u s and i n a p p a r e n t good h e a l t h . B e f o r e the f i r s t c y c l e o f t h i s s e r i e s was comp le ted b i r d "F2" d i e d f r om what a p p e a r e d t o be a head i n j u r y ( T a b l e 8 ) . I n a d d i t i o n , " F 2 " appea red t o have r e d u c e d v i g o r . T h i s n e c e s s i t a t e d t h e t e r m i n a t i o n o f t h i s s e r i e s . The l i m i t e d i n f o r m a t i o n g a t h e r e d a t t h i s t i m e i n d i -c a t e d t h a t t h e b i r d s were show ing a l e s s v i g o r o u s r e s p o n s e as T a b l e Common name 5. E x p e r i m e n t a l p l a n t s u s e d i n w idgeon g r a z i n g t r i a l s . P l a n t S p e c i e s S c i e n t i f i c name P l a n t Form U n p a l a t a b l e f e a t u r e C r e s t e d d o g s t a i l Sweet v e r n a l g r a s s V e l v e t g r a s s Y a r r o w Tansey C y n o s u r o s c r i s t a t u m g r a s s Anthoxanthum odora tum g r a s s H o l c u s . l a n a t u s g r a s s A c h i l l e a m i l l i f o l i u m f o r b T a n a c e t i u m v a l g a r e f o r b C o a r s e l e a v e s , w h i c h may be r e j e c t e d on g rounds of t e x t u r e H i g h i n c o u m a r i n * , w h i c h may be r e j e c t e d t h r o u g h t a s t e V e r y p u b e s c e n t , r e l a t i v e l y u n -p a l a t a b l e t o c a t t l e Pungent f r a g r a n c e and t a s t e Pungent f r a g r a n c e and t a s t e 5 , i An a r o m a t i c h y d r o x y a c i d w h i c h i s t h e l a c t o n e o f o - H y d r o x y c i n n a m i c a c i d . I t i s an i m p o r t a n t f l a v o r i n g and per fume p r i n c i p l e ( B r e w s t e r and McEwen 1959). H ON NO 170 the experiment progressed (Table 6 ) . This i s i n d i c a t e d q u i t e c l e a r l y by t h e i r response to the c o n t r o l (Bent grass) which was used l e s s than any of the species i n the preceding t r i a l s . There-f o r e use r a t i n g s probably r e f l e c t the d e c l i n i n g v i g o r of the b i r d s up u n t i l the t e r m i n a t i o n of the c y c l e . With the l o s s of one experimental animal i t was de-cided that " s e r i e s A" would be rerun once the s u r v i v i n g b i r d ("F ") regained i t s v i g o r . A two week p e r i o d was allowed f o r the recovery of the s u r v i v i n g b i r d a f t e r which the experiment was resumed. In a d d i t i o n , to permit s u f f i c i e n t time f o r grazing and to enable d e t e c t i o n of i t s response, the t r i a l p e riod was ex-tended to 48 hours. This f u r t h e r decreased the s t r e s s on the b i r d . The r e s u l t s of " s e r i e s Ag" are given i n Table 7. Again i t was not p o s s i b l e to complete the f i r s t c y c l e before the experiC ment b i r d d i e d . The cause of death was unknown (Table 8) but i t was b e l i e v e d to be a r e s u l t of the general poor v i g o r of the b i r d p o s s i b l y brought on by s t r e s s i n the experiment, 4.5.6 D i s c u s s i o n There i s l i t t l e t hat can be concluded i n t h i s e x p e r i -ment other than that the s e n s i t i v i t y and s t r e s s on the widgeon appears to be the main f a c t o r l i m i t i n g success. The w r i t e r i s q u i t e sure that the i n f o r m a t i o n gathered i n both " s e r i e s A]_" and "A2" i s of T i t t l e use f o r i n d i c a t i n g the g r a z i n g preferences of the b i r d s . " S e r i es A^" must be discarded because of the many f a c t o r s of u n c e r t a i n t y . "Series A2" o f f e r s l i m i t e d i n f o r m a t i o n because " t r i a l 1" i n c l u d e d a l l the experimental cover species as w e l l as the c o n t r o l species but, again the t r i a l s were so T a b l e 6. R e s u l t s o f g r a z i n g " S e r i e s A " , u s i n g two l i v e w i d g e o n . T r i a l Use Da te T r i a l D u r a t i o n P l a n t S p e c i e s R a t i n g May 8/67 May 9/67 May 10/67 May 11/67 May 12/67 May 13/67 May 14/67 1 24 h r s . Sweet v e r n a l g r a s s 3 2 24 h r s . C r e s t e d d o g s t a i l 3 3 24 h r s . Ya r row 2 4 24 h r s . Tansey 2 24 h r s . Bent, g r a s s 1 6 24 h r s . V e l v e t g r a s s 1 Comment On ly s h o o t s c l o s e s t t o pond u s e d On ly s h o o t s c l o s e s t t o pond used On ly s h o o t s c l o s e s t t o pond used On ly s h o o t s c l o s e s t t o pond u s e d B i r d s l o o s i n g v i g o r B i r d s l o o s i n g v i g o r B i r d d i e d f r om head i n j u r i e s s u s t a i n e d by h i t i n g t h e t o p o f t he c a g e . T a b l e 7- R e s u l t s o f g r a z i n g " s e r i e s A 2 " , u s i n g one l i v e w i d g e o n . T r i a l Da te T r i a l • D u r a t i o n P l a n t S p e c i e s Use R a t i n g Comment 1 May 27-29 2 3 4 5 May 29-31 May 31 -June 2 June 2-4 June 4-6 June 7 48 h r s . M i x e d f l a t a) Y a r r o w b) Tansey c) Sweet v e r n a l g r a s s d) V e l v e t g r a s s e) C r e s t e d d o g s t a i l f ) Bent g r a s s 48 h r s . Y a r r o w 48 h r s . Sweet v e r n a l g r a s s 48 h r s . C r e s t e d - d o g s t a i l 48 h r s . V e l v e t g r a s s 2 2 4 4 4 4 3 4 2 2 S h o o t s c l o s e s t t o pond used Shoo ts c l o s e s t t o pond used Shoo ts c l o s e s t t o pond u s e d S h o o t s c l o s e s t t o pond used S h o o t s c l o s e s t t o pond u s e d S h o o t s c l o s e s t t o pond u s e d S h o o t s c l o s e s t t o pond used S h o o t s c l o s e s t t o pond u s e d Shoo ts c l o s e s t to pond u s e d S h o o t s c l o s e s t t o pond u s e d B i r d d i e d ; cause unknown 173 Table 8. Dissections of casualties which occurred during widgeon grazing "Series A" and "A^". Bird Autopsy findings F^ Large blood clot on top of head; pectoral muscles degenerated to l/2 normal size; digestive track normal, organs and skin normal. Cause of death probably from head injury (may have h i t top of pen when frightened). Fg No bruises or cuts; digestive t r a c t normal; organs and skin normal; pec-t o r a l muscles degenerated to l/2 normal s i z e . Cause of death unknown. 174 l i m i t e d that l i t t l e dependence can be placed on the preferences shown by the widgeon. In " T r i a l 1", "Series A^" the three grasses were used e x t e n s i v e l y but the two forbs were u t i l i z e d to a minor extent. The e a r l i e s t observation that the p o s i t i o n s of the plant w i t h respect to the water source i n f l u e n c e d use d i d not apply here because the forbs were nearer to the water. The t r i a l may i n d i -cate t h a t the experiment b i r d , p r e f e r s grasses to f o r b s , the grasses used by the b i r d were p r e f e r r e d to the forbs used or the b i r d shows no preference f o r s p e c i f i c grasses i n t h i s experiment. Further experiments using wild-caught widgeon should f i r s t of a l l be designed to l i m i t the amount of s t r e s s e x p e r i -enced by the b i r d s b e f o r e , during and a f t e r periods of observa-t i o n . The w r i t e r b e l i e v e s t h i s to be the paramount f a c t o r -pre-v e n t i n g success i n the present work. Further changes, i n l i g h t of the present work, might i n c l u d e the f o l l o w i n g : -Design pen so as to l i m i t e r r o r due to p o s i t i o n i n g of water and p l a n t s . -Have water f l u s h i n g continuously r a t h e r than once a day to l i m i t disturbance to the b i r d s . -Extend the t r i a l p e r i o d so as to permit a more accurate deter-mination of p l a n t use. -Have b i r d s under observation from a b l i n d to a i d judgement on the extent and g r a z i n g s e l e c t i o n . -Use as many-birds as p o s s i b l e to l i m i t e r r o r due to i n d i v i d u a l .preferences, V 175 F i n a l l y , one might f i n d some success i n recovering the s a l i v a covered clumps of fol i a g e by using long blunt forceps which could be placed down the birds eosophagus. This technique was not attempted by the writer but i t does seem to off e r a p o s s i b i l i t y . The recovery of ingested materials i n an experiment of t h i s type would provide invaluable information. 176 5. VEGETATION OBSERVATIONS AND TRIALS 5.1 Survey of Sea Island A survey of the vegetation i n the study area was of p a r t i c u l a r importance f o r determining the d i s t r i b u t i o n and a c t i v i t y of b i r d s . As was stated i n section 2.2.2, vegetation i s the ultimate factor determining any animal population i n a given area, i n the great majority of cases, because i f deter-mines the primary production. The following survey was made throughout the study period and i t represents the general vegetation of the study area. More detailed information was found necessary for the "Airport" zone and more s p e c i f i c a l l y the "intensive" zone. Nomenclature used follows Hitchcock et a l (1955), "Vascular plants of the p a c i f i c Northwest", except for members of the family Gramineae, which were taken from Hitchcock (1950), "Manual of the grasses of the United States", second edition, 1950. 5.1.1 Methods (a) "Study Area" A general survey of the vegetation i n the study area was made during the summer of 1966 and winter of 1966-1967. This survey consisted of a general ground and a e r i a l recon-naissance of the area to determine major vegetation types ( i e ; crops, shrubbery, t a l l grass, lawn, weedy growth, e t c . ) . 177 Spe c i f i c locations, abundance and vigor are not given f o r i n d i v i d u a l species but the d i s t r i b u t i o n of the major types of vegetation are indicated on the "cover map" (Appendix 10.1); the major species i n each type are given i n Table 9 , The "cover map" represents the combined information of several Department of Transport u t i l i t y maps and the work of the writer ( a e r i a l photographs and ground reconnaissance). '(b) "Airport" zone A more intensive analysis of the vegetation was attempted i n the " a i r p o r t " zone. In addition to the general survey described under the preceding section, the vegetation of the " a i r p o r t " zone was analyzed by using permanent photo-stations. These stations were established at points along the dykes and at observation stations 3, 4, 7, 8, and 9 (See Figure 34 for loca-t i o n s ) . Photographs were taken from these stations during each seasion. (c) "Intensive" zone The most detailed survey of the vegetation was carried out i n the "intensive" zone and the p r i n c i p l e means of analysis was by using a point-transect frame. By t h i s method, metal pins were inserted through holes, spaced three centimeters apart along a meter s t i c k which was supported one foot o f f the ground. Pins were inserted through the holes u n t i l the ground was reached and then " s t r i k e s " (each time a pin contacted a plant) were recorded. A l l " s t r i k e s " were recorded separately for each species i n prepared tables so as to enable c a l c u l a t i o n of frequency of 178 Table \9, Major plants found i n the vegetation groupings depicted i n appendix 10.1. Vegetation Grouping Common Name S c i e n t i f i c Name Form Lawn ("cut to Bent grass Agrostis s t o l o n i f e r a L. Grass 1 i n . by Sheep fescue Festuca ovina L. Grass D.O.T.) Velvet grass Holcus lanatus L. Grass Kentucky bluegrass Poa pratensis L. Grass Coach grass Agropyron repens L. Grass Hairy Cats' ear Hypochaeris radicata L. Forb Common dandelion Taraxacum o f f i c i n a l e Weber Forb F a l l dandelion Leontidon autumnalis L. Forb Ryegrass Lolium sp. Forb Timothy Phleum pratense L. Forb Hop clover Trif o l i u m dubium Sibth. Forb White clover Trifolium repens L. Forb Water f o x t a i l Alopecurus geniculatus L. Grass Mouse-eared chickweed Cerastium vulgatum L. Grass Lawn Bent grass Agrostis sp. Grass (private) Kentucky bluegrass Poa pratensis L. Grass Livestock Bent grass Agrostis s t o l o n i f e r a L. Grass (zero Kentucky bluegrass Poa pratensis L. Grass grazing) Rye grass Lolium sp. Grass Velvet grass Holcus lanatus L. Grass White clover Trif o l i u m repens L. Forb Couch grass Agropyron repens L. Grass Timothy Phleum pratense L. Grass Couch grass Agropyron repens L. Grass Velvet grass Holcus lanatus L. Grass Rye/grass Lolium sp. Grass Bent grass Agrostis s t o l o n i f e r a L. Grass Sedge Carex lynghyei Hornem Forb White top Agrostis alba L. Grass White clover Tri f o l i u m repens L. Forb Red clover T. pratense L. Forb Rush Juncus sp. Forb Hay (zero Velvet grass Holcus lanatus L. Grass grazing) Couch grass Agropyron repens L. Grass Rye grass Lolium sp. Grass Timothy Phleum pratense L. Grass Red clover Trif o l i u m pratense L. Forb Alsike clover T r i f o l i u m hybridium L. Forb White clover Trifolium repens L. Forb Rough areas (periodic-a l l y cut to 6 i n . by D.O.T. ) 179 T a b l e 9. C o n t i n u e d . V e g e t a t i o n G r o u p i n g Common Name S c i e n t i f i c Name Form Rough a r e a s Couch g r a s s Agropyron repens L. Grass ( u n c u t ) V e l v e t g r a s s H o l c u s l a n a t u s L. Grass Bent g r a s s A g r o s t i s s t o l o n i f e r a L. Grass Rye g r a s s L o l i u m sp. Grass Canada t h i s t l e C i r s i u m arvense L. Forb B u l l t h i s t l e C i r s i u m v u l g a r e ( S a x i ) Airy-Shaw Forb V e t c h L a t h y r u s sp. Forb Sedge Carex l y n g h y e i Hornem Forb G i a n t w i l d r y e Elymus condensatus P r e s l . Rel.Haenk Grass Seashore g r a s s D i s t i c h l i s s p i c a t a (L.) Greene Grass Rush Juncus s p. Forb Oats C u l t i v a t e d o a t s Avena s a t i v a L. Grass Smart weed Polygonum p e r s i c a r i a L. Forb B r o a d - l e a v e d p l a n t a i n P l a n t a g o major L. Forb Common chickweed S t e l l a r i a media (L.) C y r i l l o Forb B a r n y a r d g r a s s E c h i n o c h l o a c r u s g a l l i (L.) Beauv. Grass I n t e r t i l l e d P o t a t o e s Solanum tuberosum Forb c r o p s S t r a w b e r r i e s F r a g a r i a sp. Forb Cabbage B r a s s i c a sp... Forb Common chickweed S t e l l a r i a media(L.) C y r i l l o Forb Smartweed Polygonum p e r s i c a r i a L. Forb W i l d buckwheat Polygonum c o n v o l v u l u s L. Forb Knot weed Polygonum a v i c u l a r e Forb Marsh Arrow g r a s s T r i g l o c h i n m a r i t i m a L. Forb S c i r p u s s p. (Dominant) Three-square b u l l -r u s h P r a i r i e b u l l r u s h American g r e a t S c i r p u s americanus P e r s . S c i r p u s p a l u d o s u s A. Ne l s o n Forb Forb b u l l r u s h S. v a l i d u s V a h l . Forb V i s c i d b u l l r u s h S. a c u t u s Muhl. Forb Carex s p. Lyngbye's sedge Carex l y n g b y e i Hornem. Forb (Dominant) S i l v e r weed P o t e n t i l l a p a c i f i c a Howell Forb Arrow g r a s s T r i g l o c h i n m a r i t i m a L. Forb Typha sp. CDominant) C a t t a i l Typha l a t i f o l i a L. Forb 180 Table 9. Cont inued . Vege ta t ion Grouping Common Name S c i e n t i f i c Name Form P i c e a s i t c h e n s i s (Bong.) C a r r . Tree Populus t r i c h o c a r p a T o r r . & Gray Tree S a l i x s c o u l e r i a n a B a r r a t t Tree S a l i x s i t c h e n s i s Sanson Tree B e t u l a p a p y r i f e r a V a r . commutata (Regal) F e r n . Tree Alnus rubra Bong. Tree Malus fusca (Raf . ) Schneider Tree Crataegus d o u g l a s i i Lindl . Tree C_, oxyacantha L . Tree Prunus emarginata(Dougl . ) Tree Rhamnus purshiana DC. Tree Sp i r aea d o u g l a s i i Hook. Shrub Sambucus pubens Shrub Symphoriacarpos a lbus ( L . ) B l a k e . Shrub L o n i c e r a i n v o l u c r a t a (Richards) Banks Shrub Osmaronia c e r a s i f o r m i s ( T o r r . & Gray) Greene Shrub Rubus s p e c t a b i l i s Pursh . Shrub C y t i s u s scopar ius ( L . ) L i n k , Shrub Rosa nutkana P r e s l . Shrub Rubus l a c i n i a t u s W i l l d . Shrub Rubus procerus M u e l l . Shrub U r t i c a l y a l l i i Forb Shrubby growth (3 to 20 fee t h igh) S i t k a spruce Black cottonwood Scou le r w i l l o w Northwest w i l l o w Western whi te b i r c h Red a l d e r P a c i f i c c rab-apple Black hawthorn E n g l i s h hawthorn B i t t e r che r ry Cascara Hard hack Red-berry a l d e r Was b e r r y B lack t w i n b e r r y Indian-plum Salmonberry Scotch broom Common w i l d r o s e Evergreen b l a c k -b e r r y Himalayan b l a c k -b e r r y S t i n g i n g n e t t l e Weed area (mixed forbs dominate) Corn spur ry B i r d rape W i l d r a d i s h Canada t h i s t l e P e r e n n i a l sow t h i s t l e Broad- leaved p l a n t a i n Common chickweed Knot weed Smartweed Buckwheat Spurgula a rvens i s L . Forb B r a s s i c a campestr is L , Forb Raphanus raphanis t rum L . Forb C i r s i u m vu lgare (Savi ) Airy-Shaw Forb Sonchus arvense L . Forb Plantago major L . Forb S t e l l a r i a media ( L . ) C y r i l l o . Forb Polygonum a v i c u l a r e Forb Polygonum p e r s i c a r i a L . Forb Polygonum convolvulus L . Forb Ps i l oca rphus e l a t i o r Gray Forb 181 Figure 34. T y p i c a l "Wet" subzone where bent grass and water f o x t a i l dominate. The t a l l grass on e i t h e r s ide i s i n the " M o i s t " subzone. F i g u r e 35. D r i e d pond area where Ps i l oca rphus  e l a t i o r i s ge rmina t ing . T a l l grass areas mark the edge of the " M o i s t " subzone. 182 occurrence. From t h i s data i t was possible to calculate the percent composition of the plant cover. A l l short grass areas i n the intensive zone were analyzed by t h i s method. To place the point-transect frame at random, and thereby l i m i t bias, a two foot long pointed sti c k was thrown backwards over the shoulder and the frame was then placed l y i n g i n the same d i r e c t i o n , immediately i n front of the pointed end. 'Each separate area was sampled i n t h i s manner u n t i l approximately 1 0 0 0 " s t r i k e s " had been recorded. Areas of r e l a t i v e l y uniform topography, drainage and s o i l s were sampled as a unit while areas which d i f f e r e d notice-ably by one or more of these factors were sampled separately. A t o t a l of 4 2 areas were sampled i n the intensive zone and from these three general types of t u r f were discernable; 1. mature or climax, 2, successional of farming o r i g i n and 3. successional of construction o r i g i n . In turn each of these types had zonal variations due to differences i n s o i l s and drainage. A more complete discussion on each type and t h e i r zonal variations i s given i n section 5 . 1 . 2 . I d e n t i f i c a t i o n of grasses by t h e i r f o l i a g e was possible through using vegetative keys applicable to the area from the works of Pechenac ( 1 9 3 6 ) , Ward ( 1 9 0 8 ) , and Hitchcock and Chase (1950). Forbs were r e a d i l y i d e n t i f i e d by using the f i e l d guides of Lyons ( 1 9 6 2 ) , Jaques ( 1 9 5 9 ) , and Frankton ( 1 9 6 3 ) and the i l l u s t r a t e d work of Hitchcock et a l (1955). 183 5.1.2 Results The r e s u l t s of the general vegetation analysis i n the "study area" are depicted as a cover map i n appendix 10.1. The groupings indicated were chosen because they were found to be the most obvious and s i g n i f i c a n t i n so f a r as b i r d a c t i v i t y i n the area was concerned. Many birds completely r e s t r i c t e d t h e i r a c t i v i t i e s to one or more of these groups. However, as a r e s u l t of t h i s generalization an abundance of minor species were i g -nored and the boundaries indicated only approximate the actual plant d i s t r i b u t i o n . The species of major occurrence are i n -cluded i n the comparative l i s t of species given f o r each group i n Table . The information i s also l i m i t e d i n that i t assumes the d i s t r i b u t i o n of the major plant species for each group to be uniform i n a l l areas; such i s not 1 the case. Several species had quite r e s t r i c t e d d i s t r i b u t i o n . Most ornamental plants such as English Hawthorn, Cratageus oxyacantha. Sitka Spruce, Picea s i t c h e n s i s , etc. only occurred as part of shrubby areas along Ferguson, McDonald and Grauer Roads. Areas i n the air p o r t zone which were grouped as "hay" were mostly a mixture of the grasses and legumes indicated i n Table 9 . How-ever, two exceptions did occur i n the f i e l d s immediately west of runway 12:30 and north of runway 08:26. In the f i e l d immediately southwest of the "button" (end of a runway) of 12, Red Clover was the dominant species and i n the f i e l d immediately north of taxiway-L, ryegrass, Lolium sp., was dominant. Generally, such s p e c i f i c d i s t r i b u t i o n s within vegetation groups were not considered to influence b i r d a c t i v i t y to any degree 184 except i n one or two cases. These exceptions are considered i n the discussions of the b i r d species concerned i n section 4 . 3 . 3 . The d i s t r i b u t i o n and extent of vegetation groups i s by no means s t a t i c . The cover map i s only a single view of an area which i s constantly changing due to the a c t i v i t y of man (see section 3 . 3 ) . Each year changes i n farming practices a l t e r the d i s t r i b u t i o n and extent of hay, oats and livestock areas over much of Sea Island. Many of the f i e l d areas i n the " a i r p o r t " zone change status each year as farming concessions and airport u t i l i t i e s adjust and expand respectively. As a r e s u l t of t h i s constant change the vegetation generally has l i t t l e chance to s t a b i l i z e and remains i n a continuous state of succession. The most stable vegetation type i n the "intensive" zone was found to be that of t u r f cut by the Department of Transport (D.O.T.) immediately north of the old terminal. It was estimated by various Department of Transport personnel that much of t h i s area has remained unchanged for 15 to 20 years. For t h i s reason i t was considered by the writer to be representa-t i v e of the near "climax t u r f " f o r the area under a scheme of zero grazing using lawn mowers. Where c u l t i v a t i o n or construction occurred i n an area within the l a s t f i v e years, the vegetation r e f l e c t e d to a marked degree t h i s e a r l i e r influence. In the "intensive" zone these influences were detected quite s p e c i f i c a l l y to given areas. Since I 9 6 0 , construction i n t h i s zone has been 1 8 5 m a i n l y i n t h e f o r m o f new runways and t a x i w a y s (Tax iways A , R, L, V , T , X , P , Q , N, W2, and F , and runways 0 3 : 2 6 wes t o f T -B a n d Runway 1 2 : 3 0 ) ; t h i s r e s u l t e d i n t h e r e m o v a l a n d / o r e x t e n -s i v e d i s t u r b a n c e o f t h e p r e v i o u s t u r f . F a r m i n g o f hay and o a t s o c c u r r e d o v e r t he West (be tween t a x i w a y A and runway 08:26 west o f Tax iway C , N o r t h (Between t a x i w a y X and runway 1 2 : 3 0 n o r t h o f runway 08:26), and E a s t ( a l l o f t h e i n t e n s i v e zone e a s t o f B u t t o n 2 6 ) p o r t i o n s o f t h i s a r e a p r i o r t o 1 9 6 5 . A l l o f t h i s zone i s now cu t as a l awn by t he Depar tment o f T r a n s p o r t . The i n f l u e n c e o f t h e s e two f a c t o r s i s e x e m p l i f i e d i n T a b l e 1 0 Where two sample a r e a s o f v a r i a b l e h i s t o r y a r e compared t o t h e " c l i m a x t u r f " . T h e s e . s a m p l e a r e a s were o t h e r w i s e c o n s i d e r e d t o b e comparab le t o t h e " c l i m a x t u r f " i n t h a t t h e r e s o i l s ( m a i n l y s i l t y l o a m ) , d r a i n a g e ( p o o r - f a i r ) and exposu re ( f l a t t o s l i g h t l y r o l l i n g ) were g e n e r a l l y t h e same. I n T a b l e 1 0 each s p e c i e s i s r e p r e s e n t e d as a p e r c e n t a g e of t h e t u r f s a m p l e d . 5 . 1 . 3 D i s c u s s i o n T h e most n o t i c e a b l e d i f f e r e n c e s between t h e " c l i m a x t u r f " and a r e a s a f f e c t e d by p r e v i o u s c o n s t r u c t i o n o r p r e v i o u s f a r m i n g were i n t he numbers and abundance o f a n n u a l f o r b s and p e r e n n i a l f o r a g e g r a s s e s r e s p e c t i v e l y . I n t h e a r e a i n d i c a t e d a s r e p r e s e n t a t i v e o f r e c e n t c o n s t r u c t i o n i n T a b l e 1 0 t h e p r e v i o u s t u r f was c o m p l e t e l y d i s r u p t e d by m a c h i n e r y so t h a t t h e r e s u l t i n g v e g e t a t i o n was s p a r s e . V a r i o u s p e r e n n i a l f o r b s a n d g r a s s e s o c c u r r e d I n p a t c h e s g e r m i n a t i n g o r r e j u v e n a t i n g fr;om s e e d , r h i z o m e s , s t o l o n s , o r r o o t s t o c k s w h i l e a n n u a l T a b l e 1 0 . P e r c e n t c o v e r a g e by p l a n t s i n compared t o t h e " c l i m a x t u r f " two t u r f a r e a s o f d i f f e r e n t o r i g i n E s t a b l i s h e d t u r f 15-20 y r s . o l d N o r t h o f t he o l d t e r m i n a l t u r f " ) ( " C l i m a x T u r f e s t a b l i s h e d f o l l o w i n g hay f a r m i n g l e s s t h a n 2 y r s . p r i o r t o t h e p r e s e n t s t u d y l o c a t e d West o f t a x i w a y C . T u r f between runway 1 2 : 3 0 and t a x i w a y X , N o r t h of runway 0 8 : 2 6 . E s t a b l i s h e d d u r i n g t h e summer o f 1 9 6 6 , f o l l o w i n g c o n -s t r u c t i o n B e n t g r a s s ( A g r o s t i s s t o l o n i f e r a L.) K e n t u c k y b l u e g r a s s (Poa p r a t e n s i s L, A n n u a l b l u e g r a s s (Poa annua L . ) Couch g r a s s ( A g r o p y r o n r e p e n s L . ) V e l v e t g r a s s ( H o l c u s l a n a t u s L . ) R y e g r a s s ( L o l i u m s p . ) B r o a d l e a v e d p l a n t a i n ( P l a n t a g o ma jo r L . ) Red c l o v e r ( T r i f o l i u m p r a t e n s e L"D W h i t e c l o v e r ( T r i f o l i u m r e p e n s L . ) Smartweed (P lygonum s p . ) Common c h i c k w e e d ( C e r a s t i u m v u l g a t u m L . ) Mouse e a r e d c h i c k w e e d ( S t e l l a r i a med ia ( L . ) Cyr i l l o , Common d a n d e l i o n (Taraxacum o f f i c i n a l e W e b e r . ) H a i r y C a t s ' e a r - ( H y p o c h a e r i s r a d i c a t a L . ) B a r e s o i l Sheep s o r r e l (Rumex a c e t o s e l l a ) C o r n s p u r r y ( S p u r g u l a a r v e n s i s L . ) Lambs q u a r t e r s (Chenepodium a lbum L . ) Canada t h i s t l e ( C i r s i u m a r v e n s e L.) Y e l l o w r o c k e t ( B r a s s i c a c a m p e s t r i s L . ) Buckwheat (Po lygonum c o n v o l v u l u s L . ) T imo thy (Ph leum p a r t e n s e L . ) Sheep fescue ( F e s t u c a o v i n a L . ) W a t e r f o x t a i l ( A l o p e c u r i s g e n i c u l a t u s L . ) 8 6 . 6 0 9 .85 0.32 0.54 2.67 18.95 8.97 4.76 33.15 3 .35 0.47 15.99 0.23 I . 6 5 •2.96 "1.41 7.10 1.01 0.43 22.32 4.38 0.85 2.62 2.06 0 . 0 7 •37.15 3 .82 23.11 0 .50 1.42 1 .27 0 . 0 7 T o t a l s p e c i e s 13 14 187 s p e c i e s had a more g e n e r a l d i s t r i b u t i o n . The most abundant s p e c i e s i n t he l a t t e r c a s e were Co rn s p u r r y , S p u r g u l a a r v e n s i s (23.11%), Smar tweed, Po lygonum s p t (2.62%), w i t h m i n o r o c c u r -r e n c e s o f Y e l l o w r o c k e t , B r a s s i c a c a m p e s t r i s (1.27%), and Lambs q u a r t e r s , Chenepodium a lbum (0.50%). A n n u a l s p e c i e s o c c u p i e d 27.44% and p e r e n n i a l s p e c i e s o c c u p i e d 30.81% o f t he t o t a l a r e a . Seeds f r o m a l l t h e s e p l a n t s and f o l i a g e f r o m Red C l o v e r and Sheep s o r r e l were f o u n d t o be t a k e n as f o o d by v a r i o u s b i r d s d u r i n g t h e s t u d y p e r i o d . P e r e n n i a l s p e c i e s i n c l u d e d Canada T h i s t l e , C i r s i u m a r v e n s e (1.42%), Couch g r a s s , A g r o p y r o n  r e p e h s (22.32%), V e l v e t g r a s s , H o l c u s l a n a t u s (4.30%), Sheep s o r r e l , Rumex a c e t o s e l l a (3 .82%), B r o a d - l e a v e d p l a n t a i n , P l a n t a g o  m a j o r (0.85%) and H a i r y c a t s e a r , H y p o c h a e r i s r a d i c a t a (0.07%). Bare s o i l " o c c u p i e d t h e g r e a t e s t a r e a s (37.15%). The a r e a f a rmed f o r hay p r e v i o u s t o t h e p r e s e n t s t u d y had an abundance o f p e r e n n i a l f o r a g e s p e c i e s i n c l u d i n g V e l v e t g r a s s , H o l c u s l a n a t u s (33.15%), r y e g r a s s , L o l i u m s p . (3.35%), T i m o t h y , Phleum p r a t e n s e (7.10%) and w h i t e c l o v e r , T r i f o l i u m  f e p e n s (15.99%); t o g e t h e r t h e y made up a t o t a l o f 59.59% o f t h e t u r f . Bent g r a s s , A g r o s t i s s t o l o n i f e r a , w h i c h was t h e ma jo r s p e c i e s i n t h e c l i m a x t u r f , made up o n l y 18.95% o f t h e p r e v i o u s l y fa rmed t u r f . I n t h i s a r e a a n n u a l s were l i m i t e d t o two s p e c i e s - common c h i c k w e e d , S t e l l a r i a med ia (1.65%) and M o u s e - e a r e d c h i c k w e e d , C e r a s t i u m v u l g a t u m (0.23%). I n a d d i t i o n t o t h e marked i n f l u e n c e s o f man, t h e s e a s o n a l v a r i a t i o n s i n t h e a v a i l a b i l i t y and d u r a t i o n o f s o i l m o i s t u r e was b e l i e v e d t o e f f e c t t h e l o c a l d i f f e r e n c e s i n 188 v e g e t a t i o n d i s t r i b u t i o n and abundance i n t he " s t u d y a r e a " . T h i s v a r i a t i o n was l a r g e l y c o n s i d e r e d t o be d e t e r m i n e d by t he no rma l w e a t h e r c y c l e f o r t h e a r e a (see s e c t i o n 3 . 2 ) , b u t , i t was r e a l i z e d t h a t o t h e r f a c t o r s such as s o i l t e x t u r e , s o i l f e r -t i l i t y , t o p o g r a p h y and e l e v a t i o n w i t h r e s p e c t t o t h e w a t e r t a b l e were a l s o i m p o r t a n t . As a r e s u l t o f t h i s i n f l u e n c e i t was p o s s i b l e t o d e t e c t t h r e e ma jo r " v e g e t a t i o n s u b z o n e s " i n t h e " s t u d y a r e a " . These subzones were d e s i g n a t e d a s ' " w e t " , " m o i s t " , and " d r y ' ' . E a c h subzone t e n d e d t o have one o r more m a j o r p l a n t s p e c i e s w h i c h were p r e s e n t o r a b s e n t i n g r e a t e r o r l e s s e r d e g r e e s w i t h r e s p e c t t o t h e o t h e r two s u b z o n e s . The m a j o r d i f f e r e n c e s be tween subzones i n t h e " i n t e n s i v e " zone a r e d i s c u s s e d be low and i t i s c o n s i d e r e d t h a t t h e y g e n e r a l l y r e p r e s e n t s i m i l a r subzones i n t h e " s t u d y a r e a " . To f u r t h e r i l l u s t r a t e t h e d i f f e r e n c e s be tween subzones t r a n s e c t r e c o r d s a r e p r e s e n t e d i n T a b l e 11 w i t h each s p e c i e s r e p r e s e n t e d as a p e r c e n t a g e o f t h e t o t a l a r e a s a m p l e d . I n t h e " i n t e n s i v e " z o n e , t h e " w e t " subzone o c c u r r e d i n a r e a s where poo r d r a i n a g e e x i s t e d and s u r f a c e w a t e r rema ined t h r o u g h o u t t h e l a t e f a l l , w i n t e r , and e a r l y s p r i n g mon ths . S o i l s i n t h e s e a r e a s t e n d e d t o be heavy i n t e x t u r e ( s i l t loam t o c l a y l o a m ) , s t r o n g l y a c i d (pH 4.5-5 .0) and t o have a h i g h f l u c t u a t i n g w a t e r t a b l e as was i n d i c a t e d by a " m o t t l e d " appea rance ( a l t e r n a t e s t r e a k s o f o x i d i z e d and r e d u c e d i r o n and manganese, Buchman and B r a d y I 9 6 0 ) . The v e g e t a t i o n c o n s i s t e d a l m o s t e x c l u s i v e l y o f two s p e c i e s o f w a t e r t o l e r a n t g r a s s e s Ben t g r a s s , A g r o s t i s s t o l o n i f e r a L . ( p e r e n n i a l ) and Wate r T a b l e 1 1 . R e s u l t s o f p o i n t t r a n s e c t s made i n t h e " I n t e n s i v e " zone on " D r y " , " M o i s t " and " W e t " s u b z o n e s . F i g u r e s r g i v e n a r e p e r -c e n t a g e s o f t h e t o t a l a r e a s a m p l e d . Common Name S c i e n t i f i c Name Dry M o i s t Wet 7 . 2 1 6 3 . 5 9 4 7 . 9 7 - • - 4 0 . 3 7 1 . 4 0 0 . 8 2 1 . 0 5 - - 1 . 2 9 1 4 . 1 9 - 0 . 7 0 0 . 2 5 1 . 6 5 0 . 4 7 4 2 . 5 0 - -- ' 3 . 9 2 -0 . 2 5 -- 1 . 9 8 -1 4 . 3 2 8 . 9 5 8 . 1 6 0 . 6 8 - -8 . 5 5 3 . 2 5 -2 . 6 3 4 . 2 8 -- 3 . 0 7 -- 0 . 5 9 -Bent g r a s s ( A g r o s t i s s t o l o n i f e r a L . ) Water f o x t a i l ( A l o p e c u r u s g e n i c a l a t u s L . ) V e l v e t g r a s s ( H o l c u s l a n a t u s L . ) K e n t u c k y b l u e g r a s s (Poa p r a t e n s i s ) A n n u a l b l u e g r a s s (Poa annua) T imo thy (Ph leum p r a t e n s e L . ) Sheep f e s c u e ( F e s t u c a o v i n a L . ) R y e g r a s s ( L o l i u m s p . ) M o u s e f e a r e d c h i c k w e e d ( C e r a s t i u m v u l g a t u m L . ) B r o a d - l e a v e d p l a n t a i n ( P l a n t a g o ma jo r L . ) W h i t e c l o v e r ( T r i f o l i u m r e p e n s L . ) R e d c l o v e r ( T r i f o l i u m p r a t e n s e L . ) S m a l l hop c l o v e r ( T r i f o l i u m dubium L . ) H a i r y c a t ' s ea r ( H y p o c h a e r i s r a d i c a t a ) F a l l d a n d e l i o n ( L e o n t i d o n a u t u m i n a l i s L . ) Common d a n d e l i o n (Taraxacum o f f i c i n a l e L . ) B a r e s o i l 8 . 1 2 'I—1 00-1 9 0 f o x t a i l , Alopecurus geniculatus (annual), (Figure 3 4 ). In areas where the water was extremely deep even these tolerant species were absent. Such conditions suppress aerobic de-composition and accommodate anaerobic decomposition of organic materials and thus i t r e s u l t s i n the accumulation of organic endproducts such as acids i n quantities toxic to most plants, (Buchman and Brady i960). However, during the summer when the ponds dried up annual species such as Psilocarphus e l a t i o r Gray, Water f o x t a i l , Alopecurus geniculatus L., Annual blue grass, Poa annua L. and Lady's Thumb, Polygonum p e r s i c a r i a L., take advantage of the available growing area (Figure 3 5 ). Ward (1908) considers Alopecurus geniculatus L. to be i n d i c a t i v e of "sour" s o i l s containing vegetable remains. In t h i s subzone enough water remains available f o r good growing conditions be-cause of the high water table during the period of r e l a t i v e drought i n July and August. The moist subzone i s the most extensive i n the study area. It includes areas where water i s neither excessive i n winter nor i n short supply i n summer. So i l s tended to be heavy i n texture, (more broadly based than they were i n the wet sub-zone i e . loam to clay loam), moderately acid (pH 5 - 6 ) and to have a f l u c t u a t i n g water table. The vegetation l a r g e l y re-f l e c t e d the previous influence of man (Agriculture; Construc-tion) but generally i t consisted of a mixture of grasses and forbs similar to that described i n Table 9 under the heading "Lawn (cut to 1 i n . by D.O.T.:)'", Because of the short cutting of the t u r f , those species which were low 191 growing and reproduced vegetatively tended to be better adapted for s u r v i v a l . For example, the most abundant species was Bent grass, Agrostis s t o l o n i f e r a L., which thrives under close cutting and reproduces by stolons. As the t u r f matures this species becomes more abundant and eventually dominates (See "Climax t u r f " , Table 10). The "dry" subzones occupies a f a i r l y r e s t r i c t e d dis t r i b u t i o n i n the "intensive" zone. It occurs most commonly on the shoulders of roads, runways and taxiways. Its d i s -t r i b u t i o n i s primarily coincident with the d i s t r i b u t i o n of •transported sand and gravel f i l l used f o r construction i n the area. As a r e s u l t , s o i l s tended to be r e l a t i v e l y coarse tex-tured (loamy sand - loam), strongly to s l i g h t l y acid (pH 4 . 5 -6 . 5 ) and unaffected by a f l u c t u a t i n g water table at the surface. Because of the s o i l texture and the elevated position of most of t h i s subzone with respect to the surrounding areas the dry months of July and August created a condition of drought and as a r e s u l t most of the vegetation "browned o f f " (Figure 36 ). Throughout the f a l l , winter and spring months moisture i s not l i m i t i n g and the t u r f becomes green. However, during the winter months low temperatures tend to suppress any appreciable growth. Thus, t h i s zone i s most productive i n the spring and f a l l months. Generally the plant species i n the subzone r e f l e c t the importance of the seasonal drought. For example, the most abundant species i s Sheep fescue, Festuca ovina L., which i s drought resistant (Ward 1908). This adaptation i s so c h a r a c t e r i s t i c of t h i s species that Ward 192 Figure 36. View of "Dry" ( l e f t ) and "Moist" ( r i g h t ) subzones i n mid August. The vegetation i n the "Dry" sub-zone has "browned o f f " . 193 (1908) considered i t an i n d i c a t o r of sandy s o i l . Other abun-dant species adapted to s u r v i v i n g or a v o i d i n g the drought i n t h i s subzone in c l u d e d annual bluegrass, Poa annua L., Hop c l o v e r , T r i f o l i u m dubiurn L., Hairy c a t s ' ear, Hypochaeris  r a d i c a t a L., and White c l o v e r , T r i f o l i u m repens L. (as s o c i a t e d w i t h the loam s o i l s ) . 5.2 Experimental ground covers 5.2.1 General Statement E a r l y i n 1965 when members of the "Associate Committee on B i r d Hazards to A i r c r a f t " began d i r e c t i n g t h e i r a t t e n t i o n to long term e c o l o g i c a l s o l u t i o n s to b i r d s t r i k e problems on a i r p o r t s i n Canada, i t was f e l t that to minimize the problem there must be a l t e r a t i o n s i n the ground covers many of which a t t r a c t b i r d s . This approach sparked i n t e r e s t i n the search f o r n o n - a t t r a c t i n g ground covers f o r major a i r p o r t s i n Canada, and a s p e c i a l Sub-committee on ground cover was formed. Mem-bers of t h i s sub-committee included b i o l o g i s t s , a g r i c u l t u r a l i s t s and Department of Transport Personnel ( B i r d 1965). Since the m a j o r i t y of a i r p o r t s were already e s t a b l i s h e d to graminoid s p e c i e s , the search f o r n o n - a t t r a c t i n g cover p l a n t s l e d towards f o r b s . Dr. V. Solman of the Canadian W i l d l i f e S e r v i c e , who i s a s p e c i a l i s t on m i g r a t i n g b i r d s p e c i e s , suggested the f o l l o w i n g p o i n t s f o r c o n s i d e r a t i o n when s e l e c t i n g such ground cover p l a n t s (personal communication w i t h R.D. H a r r i s of the Canadian W i l d l i f e 1 9 4 Service, A p r i l 1 9 6 5 ) ; 1. Plants should be propagated by means other than seed, 2. Plants should have an inconspicuous inflorescence 3 . F r u i t i f any should be unattractive to birds . 4. Plants should be adapted to open areas and should spread ra p i d l y . 5. Plants should be dominant i n s o i l and climate conditions i n which they are used. 6. Plants should be of short stature ( 6 - 8 inches or l e s s ) . 7. Plants should not attra c t insects which i n turn a t t r a c t b i r d s . In addition, R.D. Harris of the Canadian W i l d l i f e Service (personal communication A p r i l 1 9 6 5 ) , suggested that plants should not be deciduous, suffer from trampling by people or vehicles and have a tendency to burn or dislodge when sub-jected to the direct blast of a i r c r a f t exhaust ( p a r t i c u l a r l y jet types). These q u a l i f i c a t i o n s greatly reduced the range of species from which airport ground covers could be selected. All plants chosen as experimental ground covers for t r i a l s on Vancouver Airport met these requirements. The writer under the di r e c t i o n of R.D. Harris of the Canadian W i l d l i f e Service, selected seven plant species, purchased them from a l o c a l nur-sery and planted them on Vancouver Airport i n May, 1965. The resu l t s of t h i s experimental planting are given i n section 5.2.3. Members of the Sub-committee on ground cover soon r e a l i z e d that there were certain p r a c t i c a l problems involved if one i s to replace the ground cover on an areas as large as an airport; such as, a. the high cost of removing the old t u r f , b. the high cost of purchasing and planting a new ground cover ( i e . some rooted cuttings can be planted using a mechanical 195 lettuce planted but many must be planted by hand) and c. the uncertainty of the adaptability of replacement ground covers to the variety of growing conditions found i n a larger areas. As a resu l t of these problems the sub-committee broadened i t s scope on ground covers to include various graminoid species which met the necessary requirements. Grasses could be seeded ea s i l y to es-t a b l i s h a turf and yet be cut short enough to prevent subsequent seed production and met the condition of dominance better than most ground covers. Experimental plots using two grass species were planted on Vancouver Airport i n May of 1966. It was e a r l i e r intended that f i v e grasses and four forb species would be planted at t h i s time, but, unfortunately seed could not be obtained i n s u f f i c i e n t quantity i n time f o r the growing season for other than two grasses. 5.2.2 Methods In establishing experimental plots on Vancouver A i r -port, locations were chosen which were representative of the general habitat available i n the area but which were well out of the way of normal airport operations. In May of 1965 i t was decided to locate the i n i t i a l plots on the r i c h s i l t y loam immediately south of the Department of Transport S o i l s Labora-tory . (here-in-after referred to as " s o i l s " plots) (Figure 37 ). The area was rough and covered with an extensive grass-forb sward, a remnant of e a r l i e r farming. In t h i s area a two acre section was graded and t i l l e d and a "T" shaped "mock dyke" was constructed at one corner of i t (Figure 38). F i g u r e .".T - E x p e r i m e n t a l Ground Cove r P l o t L o c a t i o n s on Vancouve r A i r p o r t 197 I n d e x F i g u r e 3 8 . P l o t P l a n o f t h e " S o i l s P l o t s " \ To? h > > " T A »" A £2 " M o c k d y k e " p l o t s I* 4 4 A V T -1 -.N: R •» 4 * . > A . j u g a r e p t a n s  C y t i s u s p r a e c o x C y t i s u s p r o c u m b e n s  H e d e r a h e l i x H y p e r i c u m c a l y c i n u m  P a c h y s a n d r a t e r m i n a l i s V i n c a m i n o r m S c a l e - 1 i n c h = 10 f e e t " F l a t ? 1 p l o t s Av <x v t- »• v 1 v r%<uYffi^tt'<g > * . < *» U J \ r ^ 4 * r„ v T * < < r- < V v 1 < -i. > . 4 . V ^ T S c a l e - 1 i n c h = 40 f e e t F i g u r e 3 9 . P l o t P l a n o f t h e " B a r n " P l o t s a n d " D i n s m o r e " P l o t s . B a r n p l o t s (j) D i n s m o r e p l o t s I n d e x O y n o s u r u s c r i s t a t u s H o l c u s l a n a t u s 198 Plants i n a l l cases were planted i n staggered rows six inches apart; plants i n each row were s i x inches apart. This method of planting was recommended by l o c a l nurserymen and i t was said to enable adequate room for good plant growth and the maximum rate of coverage of a given area. One exception to t h i s procedure was where Japanese spurge, Pachysandra  terminalis, was planted as rhizomes on the f l a t ground. In t h i s gase rhizomes were l a i d end to end i n rows f i v e inches apart. A l l other plants were rooted as cuttings f i r s t established either i n " j i f f y pots" (small peat flower pots f i l l e d with peat and sand) or i n greenhouse f l a t s ( f i l l e d with peat and sand). I n i t i a l l y i t was decided that these plots should be given some physical assistance through weeding and regular watering to enable them to establish themselves. This decision was based on two factors judged to be contrary to what would be normal procedure f o r establishing ground covers of thi s type on Vancouver Airport; 1. the planting time was too late i n the spring for the area, causing plants to suffer immediately from drought and 2. the newly ploughed plot area should have been t i l l e d at least twice, prior to planting to afford e f f e c t i v e control of germinating or rejuvenating old sod species. This "assistance" was given from the date of planting (May 21-29, 1965) u n t i l August 15, 1965 when the ground covers were fi r m l y established and further weeding was considered to be causing in j u r y to t h e i r root systems. Once weeding and watering were stopped the ground covers l e f t to compete with old sod species which were developing. 1 9 9 In May 1 9 6 6 additional plots were established using the seed of two grass species. It was hoped that the two grasses would not be a t t r a c t i v e . These plots were located i n two separate areas with two rep l i c a t e s for each grass species i n each area; v i z , the f l a t area immediately west of the barn which i s west of the button of 1 2 ("barn" plots) and the sloping area on the edge of a recently removed sand dyke between Dins-more Island and Sea Island ("Dinsmore" plots) (See Figure 3 7 , f o r t h e i r l o c a t i o n ) . These areas were chosen because they were thought to have s o i l s and drainage s i m i l a r to the three subzones described i n section 5 . 1 . 3 f or the "intensive" zone (Dry, moist and wet). The "barn" plots had s o i l s which were s i l t loam to s i l t y - c l a y loam, and were under the influence of a f l u c t u a t i n g water table. The previous cover was clover and grass which had been farmed f o r hay, A three acre section of t h i s area was ploughed and disced three weeks p r i o r to planting on May 2 5 , 1 9 6 6 . The "Dinsmore" plots were established on sandy loam to s i l t loam and were well drained. The previous grass cover was completely removed, except on the lower edges of the slope, where the old dyke was pa r t l y "flattened back" on to Dinsmore Island. These plots were planted on May 3 0 , 1 9 6 6 following discing. The plot plans for the "barn" and "Dinsmore" plots are given i n Figure 3 9 . A l l experimental ground covers planted on Vancouver Airport were rated f o r competitive a b i l i t y and vigour. 200 Competition was rated throughout the experiment by successive estimates of estimated percent ground covered by experimental plants on each pl o t . For example, i f a given experimental cover species i n i t i a l l y occupied 50% of the plot area and l a t e r occupied only 30%, while old sod plants increased t h e i r coverage the species was considered to be more competitive i n the airport environment. Percent cover was estimated by taking the average area of each plant species, multiplying i t by the t o t a l number of plants per plot and taking the product as a percent of the t o t a l plot area. Plant vigour was rated objectively by using a scale from one to four as follows: 1 = Dying ( w i l t i n g , dropping leaves, etc,) 2 = Poor vigour ( c h l o r o t i c , crowding from other plants, etc.) 3 = F a i r vigour (no new growth) 4 = Vigorous (considerable new growth) Records were kept for each plot on a seasonal basis u n t i l August 1967 when the experiment was concluded. 5.2.3 Results Following the establishment of the " s o i l s " plots i n August, 1965 the experimental ground covers were l e f t to compete with old sod plants. Observations made i n the late f a l l of 1965 (Table 12) indicated that the only t r i a l species increasing were Periwinkle, Vinca minor. Carpet bugle, Ajuga reptans and (to a lesser extent) Aaron's beard (St. John's wort Hypericum  calycinum. Other experimental species had barely maintained Table 1 2 . Results of "Soils Plots" T r i a l s , the estimated percent cover and vigour given for the dates indicated. Plot Type Plant Species Flat Hedera h e l i x Ajuga reptans Hypericum c a l -ycinum Pachysandra ter minalis Vinca minor "Mock Hedera h e l i x dyke" A.iuga reptans Hypericum caly-cinum Pachysandra ter-minalis Vinca minor Cytisus decum-bens Cytisus preacox Method of Propagation at the i n -i t i a t i o n of the experiment M a y , 1 9 6 5 Cover-age Vigour S e p t . , 1 9 6 5 Cover- % age Vigour M a r c h , 1 9 6 6 % Vigour Cover-age M a y , 1 9 6 6 % Vigour Cover-age Rooted cut-tings Rhizomes Rooted cut-tings . ti it tt tt tt tr tt rr 1 3 1 3 1 3 1 .3 1 3 2 5 4 2 5 4 2 5 : 3 1 3 2 4 3 _ 4 3 3 n i l " 3 n i l " 2 n i l " 2 n i l * 2 1 2 . 5 3 2 5 4 2 5 4 2 5 3 1 3 1 3 1 3 1 2 1 3 2 5 4 2 5 4 1 3 1 3 3 4 3 4 2 2 1 2 . 5 3 1 2 . 5 3 1 2 . 5 3 1 2 . 5 3 1 2 . 5 3 2 5 4 2 5 4 2 5 3 5 0 3 2 5 1 1 5 1 5 1 5 0 3 2 5 1 1 5 1 5 1 * N i l - where percent coverage was^below one but the plant was s t i l l present. ro o Table 12. Continued. P l o t Type Plant Species Method of Propagation at the i n -i t i a t i o n of the experiment Oct. ,1966 Jan. ,1966 April,1 9 6 7 Aug.,1967 % % % Cover- % Cover- % Cover- % Cover-age Vigour age Vigour age Vigour age Vig< n i l ' 2 n i 1''" 3 n i l " 3 30 4 30 3 50 4 60 4 1 3 1 3 1 4 nil''" 2 20 3 20 3 15 4 15 4 nil''" 3 n i l " " 3 nil''" 4 nil''" 1 1 3 1 3 2 4 n i l * 2 '1 3 1 3 1 4 1 1 12.5 3 12.5 3 15 4 15 2 25 3 25 3 25 4 30 4 F l a t "Mock dyke" Hedera h e l i x A.juga reptans  Hypericum c a l y -cinum Pachysandra t e r -m i n a l i s  Vinca minor Hedera h e l i x ..A.juga reptans Hypericum c a l y -13 pinum  Pachysandra t e r -m i n a l i s  Vinca minor  C y t i s u s decum-b ens-Rooted cut-t i n g s it tt tt tr Rhizomes " j i f f y pots" Rooted cut-t i n g s rr rt tt tt " j i f f y pots" tt tt tr tt rr tr * n i l -Cy t i s u s preacox where percent coverage was below one but the plant was s t i l l present. o 203 themselves and o l d sod grasses and forbs t h r i v e d . Throughout the w i n t e r of 1965-1966 experimental ground covers and o l d sod species maintained t h e i r r e l a t i v e r a t i n g s . The f i r s t signs of appreciable growth i n the s p r i n g of 1966 were n o t i c e d i n March w i t h Vinca minor and A.juga reptans s t a r t i n g as e a r l y as o l d sod grasses and f o r b s . Other experimen-t a l ground covers showed l i t t l e i f any signs of growth at that time. By l a t e May 1966, because of t h e i r height advantage, o l d sod grasses and forbs had gained a dominant p o s i t i o n i n a l l p l o t s i n c l u d i n g those of the vigorous Vinca minor and Ajuga reptans (Figure 1+0). A l l ground covers were so obscured that they had to be searched f o r i n the p l o t area. With the exception of the C y t i s u s sp., a l l experimental ground covers were at l e a s t main-t a i n i n g themselves. In June of 1966 i t was decided that the f l a t p l o t s would be cut r e g u l a r l y by the Vancouver A i r p o r t , Department of Transport, personnel using " r o t a r y " and"reel-type"mowers. I t was b e l i e v e d that t h i s procedure was i n keeping w i t h e s t a b l i s h e d maintenance i n the area. Such f l a t areas on the a i r p o r t were cut r e g u l a r l y while the shoulders of dykes were l e f t uncut. By t h i s method the v e g e t a t i o n on f l a t areas was maintained at 2 t o 6 inches by c u t t i n g approximately every three to four weeks. I t was b e l i e v e d that such a t r i a l might modify the competitive r e l a t i o n s h i p s of o l d sod and new cover s p e c i e s . The r e s u l t s of the observations made throughout the study p e r i o d are given i n Table 12 and a short note on the general a d a p t a b i l i t y of 2 0 4 Figure 4 0 . " S o i l s " p l o t s i n l a t e May, 1 9 6 6 showing height and d e n s i t y of sod grasses and f o r b s . Behind the w r i t e r are the "dyke" p l o t s . 205 each experimental cover plant are given i n Table 13. The second set of experimental p l o t s were e s t a b l i s h e d i n May of 1966 u s i n g two species of grass. The p o s s i b i l i t y of these species as u s e f u l ground covers f o r the Vancouver A i r p o r t was i n i t i a l l y pointed out by Dr. V. C. B r i n k , Head of the Depart-ment of P l a n t Science, at the U n i v e r s i t y of B r i t i s h Columbia. Dr. Brink a l s o suggested s e v e r a l other grasses and forbs l i s t e d i n Table 14. In t h i s experiment the emphasis was placed on f i n d i n g a ground cover which was considered to be unpalatable to American Widgeon Mareca americana and yet could be e a s i l y seeded and maintained as a lawn by r e g u l a r mowing. The general growth requirements of these p l a n t s and t h e i r unpalatable f e a -t u r e s are given i n Table 14 . Unfortunately, as was s t a t e d p r e v i o u s l y , seed was only obtained f o r two of these species; Velvet grass Holcus  lanatus and Crested d o g ' s - t a i l Cynosurus c r i s t a t u s . The r e s u l t s of these t r i a l s are given i n Table 15. In t h i s experiment the p l o t s were l e f t to compete wi t h n a t i v e p l a n t s f o l l o w i n g seeding. 5 . 2 . 4 D i s c u s s i o n Ge n e r a l l y , i t can be s a i d that a l l p l a n t s thus f a r used as experimental ground covers on Vancouver A i r p o r t are u n s a t i s f a c t o r y as replacements f o r o l d sod s p e c i e s . The r e s u l t s of the " s o i l s " p l o t s t r i a l s c l e a r l y show that no experimental species was vigorous or competitive enough to become dominant during the study p e r i o d . While i t i s t r u e Table: 13. Comparative information on experimental ground covers chosen f o r " s o i l s p l o t s " * . : Plant S c i e n t i f i c name i Species Common name Growth habit ( A l l perennial) Shade and/or sun tolerances Hardy to **Rate of Ground Cover S o i l Preferen Hedera h e l i x English Ivy Woody stoloniferous grows to 1 f t . high Prefers shade but does well i n sun. seed-zero slow-rapid moist acid A.iuga. reptans Carpet bugle Stoloniferous grows to 4" high Prefers sun t o l e r -ates shade. 3 °F rapid moist r i c h s o i l Hypericum calycinum Aron's beard Rhizomatous grows to 12" high Prefers sun t o l e r -ates shade. 0°F rapid prefers dry s o i l Pachysandra termin-a l i s Japanese spurge Rhizomatous grows to 10" high Prefers f u l l shade tol e r a t e s sun. sub-zero slow-rapid prefers wet acid Vinca minor Periwinkle Stoloniferous grows to 4" high Prefers shade t o l e r -ates sun. sub-zero rapid prefers wet acid Cytisus decumbins Broome Woody, prostrate, shrub 4" high Prefers f u l l sun does poorly i n shade sub-zero slow well drained Cystisus preacox Broome Low shrub, grows to 12" high Prefers f u l l sun does poorly i n shade sub-zero slow well drained o . ON Most o f - t h i s information was gathered from t a l k i n g with nurserymen i n the greater Vancouver area but some was taken from the book, "Lawns and ground covers", by the Sunset E d i o t i r a l s t a f f , under the d i r e c t i o n of J.F. Williamson, 1964. Rapid. = complete coverage within a year under average conditions. Slow= takes two years or more to completely cover. 207 Table 14 . Comparative i n f o r m a t i o n on experimentalground covers chosen f o r the "Barn" p l o t s and "Dinsmore" p l o t s . Plant Species S c i e n t i f i c name Common name Form Duration Unpalatable Feature Holcus lanatus Lagurus ovatus Velvet grass or Y o r k s h i r e fog Hare's t a i l grass Bunch grass P e r e n n i a l Grass Annual M o l i n i a caerulea Purple m o l i n i a Grass or F l y i n g Bent Anthoxanthum  odoratum Cvnosurus c r i s t a t u s A c h i l l e a m i l l e -f o l i u m Tamacetum  vulgare Chi, chorium  intybus Sweet v e r n a l Bunch grass grass Crested-dog's Bunch t a i l grass Mentha p i p e r i t a Peppermint Yarrow Tansy Chicory Forb Forb Forb Forb Pe r e n n i a l P e r e n n i a l Very "Hairy" leaves unpal-atable to c a t t l e Coarse ornamen-t a l grass - Seed head + leaves " h a i r y " Coarse ornamen-t a l grass - Leaves h a i r y High i n coumarin which has a b i t t e r ta&e Pe r e n n i a l coarse grass Pere n n i a l has "minty" odour and b i t t e r t a s t e P e r e n n i a l has pungent odour and b i t t e r t a s t e P e r e n n i a l has pungent odour and b i t t e r t a s t e P e r e n n i a l Leaves very broad and f l a t 208 Table 14. Continued. Reproductive Maintenance Common S c i e n t i f i c name Adaptation Required Habitat Holcus lanatus Seed Lagurus ovatus  M o l i n i a caerulea Anthoxanthum odoratum Cynosurus  c r l s t a t u s Mentha p i p e r i t a A c h i l l e a m i l l e -f o l i u m Tanacetum  vulgare Chichorium  intybus Seed Seed + some-times creep-i n g rhizomes Seed Seed Seed and st o l o n s Seed and rhizomes Seed Seed C u t t i n g r e q u i r e d and may need r e -seeding every f i v e years C u t t i n g r e q u i r e d C u t t i n g r e q u i r e d C u t t i n g required C u t t i n g required C u t t i n g required C u t t i n g required C u t t i n g r e q u i r e d and may need r e -seeding every 5 years C u t t i n g required and may need r e -seeding i n 5 years Open ground meadows and moist places Coastal areas Moist f i e l d s Waste places and poor pas-ture F i e l d s and waste places Was c u l t i v a t e d f o r commercial mint Pastures and waste areas Waste areas and roadsides Waste areas and roadsides 209 Table 14. Continued, S c i e n t i f i c name S o i l Preferences Seeds/lb. (thousands) Seeding Rate lbs/A, Holcus lanatus Lagurus ovatus  M o l i n i a caerulea Anthoxanthum  odoratum Cynosurus c r i s t a t u s Mentha p i p e r i t a 1,200' Sandy s o i l s but al s o on heavy s o i l s Heavier, moist s o i l B e t t e r q u a l i t y sands w i t h some humus Moist s o i l s R ich and moderately a c i d vegetative''" s o i l s which are w e l l drained 730" A c h i l l e a m i l l e f o l i u m Poorer s o i l s wet or dry Tanacetum vulgare Poorer s o i l s w e l l drained Chichorium intybus ''"Fertile w e l l drained loam 420'1 or c l a y loam s o i l s 10-25* 15-25 15-25' greater than 2* Information obtained from " P r i n c i p l e s of f i e l d crop production" by J.H. M a r t i n and W.H. Leonard, Macmillan Co., N.Y., 1961 (eleventh p r i n t i n g ) 1176 pages. Other i n f o r m a t i o n used i n t h i s t a b l e was obtained from various sources i n c l u d i n g the f o l l o w i n g : 1) Dr. V.C. Brink Head of the Department of Plant Science, U n i v e r s i t y of B r i t i s h Columbia 2) Hitchcock, A.S., "Manual of the grasses of the United S t a t e s " Second e d i t i o n , r e v i s e d by Agnes Chase, U.S. Department of A g r i c u l t u r e , Misc. Pub. No. 200, 1950. 3) Ward, H.M. "Grasses", a handbook to use i n the f i e l d and l a b o r a t o r y •Cambridge: at the U n i v e r s i t y Press, 1908, 190 pgs. 4) Frankton, Clarence. "Weeds of Canada". Canada Department of A g r i c u l t u r e , Ottawa, Ontario, 1963, 196 pages (Queen's P r i n t e r ) . 5) Jaques, H.E. "How to know the weeds", Win. C. Brown Co., Dubuque, Iowa, 1959, 230 pages. 210 t h a t these p l o t s s u f f e r e d severely under heavy competition from the time of t h e i r establishment, i t was s t i l l considered that i f a ground cover was to be u s e f u l i t had to show a b i l i t y to overcome such o b s t a c l e s . A.juga reptans on the " f l a t " p l o t s and Vinca minor on the "dyke" p l o t s d i d show some signs of prog r e s s i v e competition. However, t h e i r responses must be considered at best t o be too slow f o r a s u i t a b l e a i r p o r t ground cover. In the " f l a t " p l o t s A.juga reptans was c l e a r l y favoured by mowing, whi l e the more upright and "woody" ground covers such as Hedera h e l i x . Pachysandra t e r m i n a l i s and Hypericum calycinum were s e v e r e l y damaged. Vinca minor tended to s u f f e r from the severe pruning was w e l l ; i t s runners were slow i n s e t t i n g r o o t s , but, i t s vigorous growth was enough to o f f s e t a r a p i d d e c l i n e . I n the "mock" dyke p l o t s competition w i t h other p l a n t s was the greatest as i s c l e a r l y shown i n Figure 40. Ground covers were completely dominated by a v a r i e t y of n a t i v e annual, p e r e n n i a l and b i e n n i a l grasses and f o r b s . Since the experimental ground covers were adapted to a low growth h a b i t , the most n o t i c e a b l e e f f e c t of t h i s competition was through the height advantage. Every experimental ground cover s u f f e r e d from t h i s disadvantage except Pachysandra t e r m i n a l i s which appeared to t o l e r a t e the shading and "dampening" e f f e c t of the dense overgrowth created by o l d sod p l a n t s ; however, the slow, almost " l a b o r i o u s " , growth of t h i s species d i s q u a l i f i e s i t , Vinca minor appears to show some promise under f u l l competition as i s i n d i c a t e d by i t s progress from an i n i t i a l 12.5% coverage to the f i n a l 30% coverage; again t h i s advance 211 i s p r i m a r i l y due to i t s vigorous growth h a b i t . A c t u a l l y there were ne a r l y 30% fewer Vinca minor plan t s at the termin-a t i o n of the experiment as compared wi t h the i n i t i a l number plan t e d . A r e d u c t i o n i n numbers was a l s o experienced by other ground covers i n the "dyke" p l o t s . The most n o t i c e a b l e d e c l i n e was i n the case of the two C y t i s u s spp.., which are shade i n -t o l e r a n t and unfavoured by a heavy wet s o i l ; every plant had died w i t h i n fourteen months. The experimental grass p l o t s , i n i t i a t e d i n May 1966, showed that Holcus lanatus and Cynosurus c r i s t a t u s were u n l i k e l y to become dominant under the p r e v a i l i n g c o n d i t i o n s . In both p l o t areas - "Barn p l o t s " and "Dinsmore p l o t s " - these p l a n t s did.not i n c r e a s e . The increase i n percent coverage i n d i c a t e d i n Table i s a r e s u l t of the increase i n s i z e of i n d i v i d u a l p l a n t s . Holcus lanatus and Cynosurus c r i s t a t u s are both Caespitose and they reproduce by seed. Only a few plants of each species set seed i n the f a l l of 1966 and an increase i n numbers i n e i t h e r p l o t area was not detected i n the s p r i n g of 1967. A comparison of the seeding r a t e used i n t h i s experiment (2.$ lbs./Acre) w i t h those recommended by M a r t i n and Leonard (1961) (Holcus lanatus 10-25 lbs./Acre and Cynosurus c r i s t a t u s 15-25 lbs./Acre) i n d i c a t e s that perhaps too low a seeding r a t e was an important f a c t o r l i m i t i n g the success of the e x p e r i -ment. The low seeding r a t e s allowed "weed" species to become e s t a b l i s h e d . Future experiments should i n c l u d e s e v e r a l r a t e s of seeding on d i f f e r e n t areas to determine optimum ra t e s f o r 212 v a r i o u s s l o p e , s o i l and drainage s i t u a t i o n s . The present t r i a l s i n d i c a t e d that Holcus lanatus may have been favoured by the coarser and b e t t e r drained s o i l s of the "Dinsmore p l o t s " w h i l e Cynosurus c r i s t a t u s may have been favoured by the heavier and wetter s o i l s of the "Barn" p l o t s (Table 15) . These r e s u l t s are c o n s i s t e n t w i t h the comparative i n f o r m a t i o n given f o r both species i n Table 14. G e n e r a l l y , the w r i t e r considers that the experiments on ground covers c a r r i e d out during the course of t h i s study simply serve as a b a s i s f o r f u t u r e experimentation. In each case v a r i o u s questions arose as to what might have been the r e s u l t s under d i f f e r e n t c o n d i t i o n s ? When the " s o i l s " p l o t s were being planted i t was r e a l i z e d that the i n i t i a l vigour of the p l a n t s might depend on whether they were propagated from rhizomes, rooted c u t t i n g s , or as rooted c u t t i n g s i n " j i f f y pots". Each type of propagation was considered to r e q u i r e d i f f e r e n t amounts of time f o r establishment depending on the extent to which p l a n t s had to recover from the d i s t u r -bances of p l a n t i n g . For example, rhizomes had to e s t a b l i s h a new root system and new shoots from the stored resources i n t h e i r t i s s u e s before the photosynthetic process c o n t r i b u t e d energy; rooted from f l a t s c u t t i n g s had to replace t h e i r damaged roots and rooted c u t t i n g s i n " j i f f y pots" had only to begin growing. The present experiment d i d l i t t l e to i n d i c a t e which type of propagation was most advantageous. Factors which were thought to a f f e c t the success of experimental ground covers i n c l u d e d : a, the depth of p l a n t i n g , b, the season when planted, c. the age of planted m a t e r i a l s (seeds, shoots, e t c ) , d. the Table 1$. Readings made of "Barn P l o t s " and "Dinsmore P l o t s " fot dates shown. Date May 1966 J u l y / 6 6 Oct . / 6 6 A p r i l / 6 7 P l o t R e p l i - Seeding r a t e % % % % % Area cate Plant Species Lbs. per Acre Cover Vigour Cover Vigour Cover Vigour "Barn 1 Holcus lanatus 2.5 30 4 40 3 35 4 P l o t s were r e -P l o t s " moved i n May 2 Holcus lanatus - . 2 . 5 30 4 40 3 35 4 1967 to per-20 mit the p l a n t -1 Cynosurus c r i s t a t u s 2.5 20 4 3 25 4 i n g of oats 2 Cynosurus c r i s t a t u s 2.5 20 4 20 3 25 4 Aug ./67 "Dinsmore 1 Holcus lanatus 2.5 40 4 50 3 50 4 50 3 P l o t s " 2 Holcus l a n a t u s 2.5 40 4 50 3 50 4 50 3 1 Cynosurus c r i s t a t u s 2.5 15 4 10 3 15 4 15 2 2 Cynosurus c r i s t a t u s 2.5 15 4 10 3 15 4 15 2 The upper one h a l f of the "Dinsmore P l o t s " were destroyed by Department of Transport maintenance personnel w h i l e working on Dinsmore I s l a n d , August, 1966. The p l o t area was adjusted a c c o r d i n g l y . i 1 214 p e r i o d of time between t i l l i n g the o l d t u r f and p l a n t i n g , e. competition, f . water t a b l e l e v e l , g. slope and h. mowing. A l l of these f a c t o r s are known to a f f e c t the s u r v i v a l and p r o d u c t i v i t y of other p l a n t s (Martin and Leonard 1961, and the U.S. Department of A g r i c u l t u r e , Yearbook of A g r i c u l t u r e , 1938). As was mentioned e a r l i e r , the cost of e s t a b l i s h i n g a new ground cover on l a r g e areas such as a i r p o r t s i s of para-mount i n t e r e s t when c o n s i d e r i n g the f e a s i b i l i t y of the opera-t i o n . However, one must also be aware of the long term costs i n v o l v e d i n m a i n t a i n i n g both the e x i s t i n g ground cover and the proposed replacement ground cover. In a d d i t i o n one must weigh the cost of replacement and maintenance against the o v e r a l l e f f e c t i v e n e s s of the new ground cover i n l i m i t i n g the b i r d hazard problem i n the given area. These problems are: not considered i n the present d i s c u s s i o n but i t i s suggested that they be the o b j e c t i v e s of f u t u r e s t u d i e s . 215 6 . PHYSIOGRAPHIC OBSERVATIONS AND TRIALS 6 . 1 Previous s t u d i e s 6 . 1 . 1 S o i l s An understanding of s o i l s of a given area i s of para-mount i n t e r e s t when attempting to i n t e r p r e t the n a t u r a l d i s t r i -b u t i o n and groupings of p l a n t s ( K r a j i n a 1 9 6 5 ) . S o i l i s of s i n -g u l a r importance to the present study because of i t s r e l a t i o n to drainage. Drainage and vegetation s i n g l y and i n t e r a c t i n g l y a f f e c t the d i s t r i b u t i o n and abundance of various b i r d s (see s e c t i o n 2 . 2 . 2 ) . The most recent s o i l survey of the Lower Fraser V a l l e y which i n c l u d e s Sea I s l a n d i s that of K e l l e y and S p i l s b u r y , 1 9 3 8 . I n t h i s survey the authors group Sea I s l a n d s o i l s under t h e i r axonal Ladner s e r i e s . This s e r i e s i s described as r e c e n t l y de-p o s i t e d sediment l a c k i n g v i s i b l e p r o f i l e development except where the land has been i n permanent pasture and organic matter has accumulated to a depth from four to s i x inches t h i c k and gives the A h o r i z o n a dark c o l o u r . Commonly the upper hori z o n c o n s i s t s of grey-brown to black c l a y , granular and heavy, wh i l e the lower horizons and parent m a t e r i a l (50 inches or more) are grey c l a y w e l l mottled w i t h i r o n s t a i n s . K e l l e y and S p i l s b u r y found the s t r u c t u r e of t h i s s o i l to be massive and tough when wet. When the land i s ploughed the gray mottled parent m a t e r i a l i s often turned to the s u r f a c e . More r e c e n t l y Sprout and Holland (1959) made a s o i l 216 survey of D e l t a m u n i c i p a l i t y f i v e miles south of Sea I s l a n d . They d i v i d e the Ladner s e r i e s i n t o two major t e x t u r a l types; 'the Ladner s i l t loam to s i l t y c l a y loam' and 'the Ladner s i l t y c l a y ' . The former i s the major type f o r the area described and i t s p r o f i l e development v a r i e s from o r t h i c dark gray g l e y s o l i c to degraded dark gray g l e y s o l i c . The w r i t e r b e l i e v e s that 'the Ladner s i l t loam to s i l t y c l a y loam' most c l o s e l y des-c r i b e s Sea I s l a n d s o i l s i n l i g h t of the minor s o i l survey c a r r i e d out d u r i n g the study p e r i o d (see s e c t i o n 6.2). Sprout and Holland (1959) describe the parent m a t e r i a l as a type derived from a combination of f r e s h water and marine sediments. They found i t to have a good content of organic matter in the A6 horizo n and f a i r l y strong g l e y s a t i o n i n the s u b s o i l . A p r o f i l e r e p r e s e n t i n g the o r t h i c dark gray g l e y s o l i c member, described i n t h e i r d i s c u s s i o n , i s reproduced on the next page w i t h the thought that i t g e n e r a l l y represents the s o i l p r o f i l e of Sea I s l a n d . The l o c a t i o n of the o r i g i n a l 'type' p r o f i l e on L u l u I s l a n d described was 150 f e e t south of Lewis road and 1500 f e e t east of i t s j u n c t i o n w i t h Mason Road. A r e p r e s e n t a t i v e c u l t i v a t e d p r o f i l e of the l a t t e r i s al s o described by Sprout and Holland (see page 32, Sprout and Holland 1959). Generally the changes brought about by c u l -t i v a t i o n are the d e f i n i t i o n of two d i s t i n c t B horizons (B2 ; B3~) which are c h a r a c t e r i z e d by a dark l a y e r and coarser o p r i s m a t i c s t r u c t u r e which gives way to a dark yellow-brown l a y e r and a weak coarse s t r u c t u r e . C u l t i v a t i o n , t h e r e f o r e , 2 1 7 Horizon Depth D e s c r i p t i o n Ale 0 - 9 " Gray (10 Yr. 5 / l dry) and very dark gray (10 Yr. 3 / l moist) s i l t y c l a y loam, subangular blocky breaking to f i n e granular s t r u c t u r e . S l i g h t l y hard dry. Many f i n e roots and some f r a g -ments of u n d e r l y i n g Cgl m a t e r i a l p i t 5 . 2 Abrupt change to: C l 9 - 2 1 " Gray ( 5 Yr. 5 / 1 moist) s i l t loam to s i l t y c l a y loam matrix w i t h dark yellow-i s h brown (10 Yr. 4 / 4 moist) common d i s t i n c t m o t t l e s , massive, micaceous f r i a b l e moist and s l i g h t l y s t i c k y and p l a s t i c wet. Moderate number of f i n e r o o t s . Dark organic s t a i n i n g along s i d e s of o c c a s i o n a l v e r t i c a l c r a c k s , pH 4 . 6 Gradual change t o : C2 21" + Gray to dark gray ( 5 Yr. 4 . 5 / 1 moist) s i l t loam matrix w i t h many d i s t i n c t dark y e l l o w i s h brown (10 Yr. 4 / 4 moist) m o t t l e s , massive, micaceous, f r i a b l e moist. Occasional f i n e root i n upper p a r t . Becomes courser t e x t u r e d w i t h depth. pH 5 . 5 . mixes the A l h o r i z o n and i t s organic m a t e r i a l w i t h the upper gleyed C l h o r i z o n and u s u a l l y improves s o i l s t r u c t u r e at l e a s t to c u l t i v a t e d depth. As a r e s u l t a true Clg horizon does not develop above a depth of 1 9 inches and may reach the 3 0 i n c h depth on the p r o f i l e . Sprout and Holland ( 1 9 5 9 ) note a l s o t h a t , according to the index r a t i n g of s o i l p r o p e r t i e s , "the Ladner s i l t loam to s i l t y c l a y loam" i s a c l a s s I I I s o i l of f a i r s u i t a b i l i t y f o r a g r i c u l t u r e . I t has a medium t e x t u r e , a f r i a b l e s u r f a c e , and a moderately high exchange and moisture h o l d i n g c a p a c i t y . 218 They consider n u t r i e n t l e v e l s f a i r l y good throughout except f o r calcium which i s low. In a d d i t i o n , other s t u d i e s have i n d i c a t e d the moisture h o l d i n g capacity of t h i s s o i l , even w i t h i t s high water t a b l e , to be i n s u f f i c i e n t f o r f u l l pro-d u c t i v i t y of a g r i c u l t u r a l crops due to an inadequate summer r a i n f a l l (Stewart and van Ryswyk 1950 and Stewart 1953). Stewart (1953) examined the Thornthwaite curve of p o t e n t i a l e v a p o t r a n s p i r a t i o n f o r the Fraser River D e l t a s o i l s and found that a moisture d e f i c i e n c y e x i s t s from the l a t t e r part of June u n t i l September. This d e f i c i e n c y was considered to exceed s i x inches during an average year. Of i n t e r e s t to the present study i s the d i s c u s s i o n by Sprout and Holland (1959) on the anthropic phases of the Ladner s i l t loam to s i l t y c l a y loam t e x t u r e types, o c c u r r i n g in a confined area three miles east of Ladner V i l l a g e , on which was, o r i g i n a l l y , the Boundary Bay A i r p o r t . The s o i l d e s c r i p t i o n s f o r t h i s area were thought to be a p p l i c a b l e to the s o i l s of Vancouver I n t e r n a t i o n a l A i r p o r t i n that disturbances adjacent to runways and taxiways were s i m i l a r . During c o n s t r u c t i o n of runways at Boundary Bay A i r p o r t the s o i l was bulldozed f o r distances of up to 200 f e e t to the edge of the runways and dumped on the runway s t r i p area. De-pressions were thus formed on e i t h e r s ide of the runways from 50 to 200 f e e t i n width and from one to two fee t i n depth. These depressions are po o r l y drained. S i m i l a r l y on Vancouver I n t e r n a t i o n a l A i r p o r t p o o r l y drained depressions on the edges 219 of or between runways and taxiways were created when founda-t i o n m a t e r i a l (dredged r i v e r sand mostly w i t h some g r a v e l ob-ta i n e d from l o c a l g r a v e l p i t s ) was deposited i n a p r e v i o u s l y b u l l d o z e d shallow earth trench on the runway or taxiway s i t e , to a depth which brought the l e v e l above the surrounding ground. Concrete (14 inches t h i c k ) was then layed on top of the l e v e l e d sand foundation and the s o i l which was e a r l i e r d i s p l a c e d from the earth trench was then mixed wi t h foundation m a t e r i a l and banked up to the runway or taxiway edge. This type of con-s t r u c t i o n creates elevated areas from 0 to 200 f e e t wide on both side s of the runways and taxiways f o r most of t h e i r l e n g t h . Thus a low area w i t h respect to the runway or taxiway was created l a t e r a l l y $0 to 500 f e e t i n width and from one to two f e e t i n depth. These areas are often poorly drained and remain p a r t l y f i l l e d w i t h surface' water f o r months at a time. The elevated shoulders, tend to be f a i r l y w e l l drained at a l l times, due to t h e i r slope and sandy t e x t u r e . In addi -t i o n , there are t i l e d r ains immediately beside a l l runways and taxiways. In mid summer most shoulder areas s u f f e r from drought. Other areas on Sea I s l a n d where anthropic s o i l s occur i n c l u d e the deposits of dredged sand, (from the adjacent r i v e r bed) up to 20 f e e t deep, over n a t i v e s o i l s on Dinsmore I s l a n d , Pheasant I s l a n d , south-east and south-west of the button of 30 f o l d s a n d p i l e " ) , North of the button of 12 ("sandpile), and confined s t r i p s used as c o n s t r u c t i o n roads between the " s a n d p i l e " and taxiway-L and the "s a n d p i l e " and the new a i r p o r t t e r m i n a l (see A p p e n d i x D l f o r l o c a t i o n s ) . In 220 a d d i t i o n a l l dykes i n the " a i r p o r t " zone, the a i r p o r t j e t t y , the Iona j e t t y and isthmus, and various access roads i n the " a i r p o r t " zone are covered w i t h g r a v e l obtained from l o c a l g r a v e l p i t s . A l l these s o i l s are w e l l drained and vo i d of any vege t a t i o n except f o r p o r t i o n s of the " o l d s a n d p i l e " and the "s a n d p i l e " . 6.1 .2 Drainage The w r i t e r was unable to f i n d any s p e c i f i c reference to the drainage of Sea I s l a n d i n the l i t e r a t u r e reviewed, K e l l e y and S p i l s b u r y (1939) b r i e f l y d i s c u s s the drainage of the Lower Fraser V a l l e y . They s t a t e d that l o c a l drainage c o n d i t i o n s vary throughout the area. The d e l t a i c deposits when undyked i n e a r l i e r times were covered w i t h cotton woods, grass vegeta-t i o n and extensive bogs of sphagnum peat. When dyking occurred, the lowland area was drained by a system of canals (open, d i t c h e s ) and pumping u n i t s of s u f f i c i e n t c a p a c i t y to cope w i t h p r e c i p i t a t i o n and high water. More s p e c i f i c treatment of d r a i n -age on Sea I s l a n d has r e c e n t l y been developed by the Department of Transport Engineers at Vancouver A i r p o r t who have maps which i n d i c a t e the present l o c a t i o n s and extent of d i t c h e s , pipes, t i l e , f l a p - t y p e f l o o d gates, pump houses and ground e l e v a t i o n s at 100 foot i n t e r v a l s (personnel communication w i t h M. Barber, Department of Transport engineer, at Vancouver A i r p o r t , February, 1 9 6 s ) . However, there i s s t i l l no formal report covering the drainage of the area. 221 At the present time, the Department of Transport i s c a r r y i n g out a study of drainage on Sea I s l a n d w i t h the.thought t h a t the whole system w i l l g r a d u a l l y be renovated and expanded. The general p r i n c i p l e s i n v o l v e d when con s i d e r i n g drainage i n any area are described i n the d i s c u s s i o n s of P i c k e l s (1941), Haswell (1938), and Thorn (1959). 6.2 Survey of the study area 6.2.1 Methods a) S o i l s Composite s o i l samples were taken at random i n various areas of the " a i r p o r t " zone i n order to determine the general d i s t r i b u t i o n of and changes i n s o i l s . The m a j o r i t y of these samples were.taken i n the " i n t e n s i v e " zone. The sampling method i n a l l cases c o n s i s t e d of throwing a two foo t long wood stake at random i n the sample area and t a k i n g a one inch core sample s i x inches deep at the point where the s t i c k landed. In each area a t o t a l of ten core samples were taken and placed i n a l a b e l e d paper bag f o r l a t e r determinations. By t h i s method i t was b e l i e v e d t h a t a reasonably random sample was ob-t a i n e d . In each area one core three f e e t deep, was examined i n s i t u f o r " m o t t l i n g " and moisture content. This examination f a c i l i t a t e d determination of the p o s i t i o n of the water t a b l e w i t h respect to the s o i l s u r f a c e . The s o i l samples were prepared f o r a n a l y s i s by hand mixing core samples taken from a given area. The mixtures were then analysed f o r pH, s a l i n i t y and t e x t u r e . These f a c t o r s were considered to be of primary importance f o r t h i s general 222 survey because they are e a s i l y determined and they a f f o r d considerable i n f o r m a t i o n about general ecology i n the area. The pH values reported f o r the s o i l s were obtained from a saturated s o i l paste by means of a glass electrode pH meter (potentiometer - Beckman Model M). S i m i l a r l y , s o i l s a l i n i t y was roughly determined con-, d u c t o m e t r i c a l l y by measuring the e l e c t r i c a l r e s i s t a n c e of the s o i l paste. This approximate measurement of the s a l t content by s o i l paste r e s i s t a n c e i s simple and r a p i d , and i t has been found very u s e f u l f o r s o i l surveys where s o i l s a l t content v a r i e s over short distances (Jackson 1958). The temperature and consistency of the paste was held constant i n accordance w i t h the recommendations of the manufactures of the machine used (Bouyoucos moisture meter, I n d u s t r i a l Instruments, Model BN-2A). Measurements were read i n 1000 ohms and l a t e r converted to millimhos per centimeter by s t a n d a r d i z i n g the moisture meter s c a l e w i t h a l a b o r a t o r y c o n d u c t i v i t y meter using s o l u t i o n s of potassium c h l o r i d e . The percent s a l t was deter-mined by reading d i r e c t l y from a graph prepared by Stewart and van Ryswyk (1950) showing the e l e c t r i c a l c o n d u c t i v i t y i n millimhos per centimeter p l o t t e d against parts per m i l l i o n d i s s o l v e d s a l t s f o r i r r i g a t i o n waters of the Lower Fraser D e l t a . This method was considered acceptable by Dr. C.A, Rowles of the Department of S o i l Science at the U n i v e r s i t y of B r i t i s h Columbia (Personal communication August 1966). A l l composite samples were hand te x t u r e d by 223 Dr. J . de V r i e s , of the Department of S o i l Science, at the U n i v e r s i t y of B r i t i s h Columbia, who has had considerable ex-perience w i t h t h i s a r t . b) Drainage A e r i a l photographs ( w i n t e r ) , ground reconnaissance and permanent photo-stations were used to achieve a c l e a r understanding of the extent and e f f i c i e n c y of drainage i n the study area. Of prime importance t o various b i r d s i n the area were the l o c a t i o n s , extent and seasonal occurrence of drainage d i t c h e s , p e r s i s t e n t ponds and temporary surface pools. For t h i s reason s p e c i f i c a t t e n t i o n was given to these various bodies of water w i t h the i n t e n t i o n of being able to e x p l a i n t h e i r occurrence and the b i r d a c t i v i t y r e l a t e d to them. Related i n f o r m a t i o n on t i d e s and p r e c i p i t a t i o n was obtained from the published records of the Canadian Hydrographic S e r v i c e and the M e t e o r o l o g i c a l Branch, Canada Department of Transport at Vancouver A i r p o r t , r e s p e c t i v e l y . 6.2.2 Results a) S o i l s The r e s u l t s of the s o i l survey made during the study p e r i o d are presented i n the form of a general d i s c u s s i o n . The o r i g i n a l l o c a t i o n s of s o i l samples taken and the determinations made on them are on f i l e i n the o f f i c e s of the Canadian W i l d l i f e S e r v i c e , on Campus, at the U n i v e r s i t y of B r i t i s h Columbia. 2 2 4 Generally the s o i l s i n the " a i r p o r t " zone were found to be f i n e t e x t u r e d , non-saline and moderately a c i d . However, there was considerable v a r i a t i o n i n some areas. This v a r i a -b i l i t y appeared to c o r r e l a t e w i t h drainage v a r i a b i l i t y and/or anthropic e f f e c t s . S o i l s beside runways and taxiways, from zero to 1 0 0 f e e t , were g e n e r a l l y b e t t e r drained and of a more d i v e r s e composition than those of low l y i n g areas (Table 1 6 ) . This v a r i a b i l i t y i s a r e s u l t of the mixing of transported (construc-t i o n ) m a t e r i a l s w i t h n a t i v e s o i l s . Samples of f i n e r t e x t u r e , higher s a l t content and more a c i d r e a c t i o n occurred i n t h i s area probably as a r e s u l t of c o n s t r u c t i o n a c t i v i t y b r i n g i n g s u b s o i l to the s u r f a c e . The high s a l t content i n s e v e r a l l o c a t i o n s west of runway 1 2 : 3 0 appeared to prevent the e s t a b l i s h -ment of a permanent t u r f . These s o i l s had poor s t r u c t u r e and during the summer drought a white s a l t crust formed on the su r f a c e . When heavy r a i n s occurred during the f a l l and wi n t e r these areas appeared as "glossy patches", s i m i l a t i n g puddles, and o f t e n a t t r a c t e d shorebirds and waterfowl i n l a r g e numbers. Samples of a more coarse t e x t u r e , lower s a l t l e v e l and more moderate a c i d r e a c t i o n were a s s o c i a t e d w i t h the transported (dredged sand) m a t e r i a l s . The highest pH value (7.31) was recorded i n t h i s area and was considered to be the r e s u l t of the e a r l i e r mixing of n a t i v e s o i l s , c o n s t r u c t i o n m a t e r i a l s ( g r a v e l and sand) and ash from a l a r g e f i r e . R e l a t i v e l y undisturbed n a t i v e s o i l s were by f a r the most common type i n the " a i r p o r t " zone. These s o i l s were 225 Table 16. The averages and extremes of pH, s a l i n i t y and te x t u r e determinations f o r anthropic and n a t i v e s o i l s . Anthropic Native S o i l s Determination Value S o i l s Moist Wet pH Average 5.18 5.41 4.69 Maximum 7.31 5.80 5.38 Minimum 3.30 4.24 3.72 S a l i n i t y Average ".250 ".250 "250 (ppm s a l t ) Maximum 1050 675 375 Minimum 0 0 0 Texture Average f i n e sandy loam s i l t loam to loam loam Maximum s i l t loam s i l t y - c l a y loam c l a y loam Minimum g r a v e l i n sandy loam loamy sand s i l t loam s t r o n g l y to moderately a c i d , f i n e t extured and non s a l i n e (Table 16). Minor d i f f e r e n c e s appeared to be r e l a t e d to the p e r s i s -tance of the high water t a b l e found throughout the area. Where the water t a b l e remained at or near the surface throughout the year the s o i l s tended to be of a f i n e r t e x t u r e and more s t r o n g l y a c i d i c . On areas where the water t a b l e dropped considerably during the summer drought, the s o i l s tended to be r e l a t i v e l y coarse textured and of more moderate a c i d r e a c t i o n (Table 16). The f i n e r t e x t u r e and more a c i d r e a c t i o n of the poorly drained s o i l s i s l i k e l y r e l a t e d to the la c k of l e a c h i n g and accummulation of organic residues r e s p e c t i v e l y . b) Drainage The r e s u l t s of the observations on drainage i n the study area are presented i n the form of a map (Appendix 10.T2). 226 However, s e v e r a l r e l a t e d f a c t o r s r e q u i r e d i s c u s s i o n . The pre-sent drainage of Sea I s l a n d i s f o r the most part an open d i t c h grouping system which i s c o n t r o l l e d by automatic pumps and f l a p -type drainage p i p e s . I t s e f f e c t i v e n e s s i s l a r g e l y r e f l e c t e d by the amount of temporary surface water depicted i n Appendix .10,.2. As winter approaches p r e c i p i t a t i o n i n c r e a s e s , s a t u r a t i n g the s o i l and, during storms, f l o o d i n g poorly drained areas. In a d d i t i o n , because of our l a t i t u d e , t i d e l e v e l s tend to be higher i n w i n t e r w i t h fewer low t i d e s o c c u r r i n g d u r i n g the d a y l i g h t hours. As summer approaches these c o n d i t i o n s reverse. I t i s the high p r e c i p i t a t i o n and the p e r i o d i c i n t e r a c t i o n w i t h high t i d e which causes the poor drainage s i t u a t i o n . Flap-gates, which are the common type of drainage o u t l e t i n the'area, are non func-t i o n a l when t i d e s are h i g h . Even automatic pumps are l i m i t e d i n t h e i r a b i l i t i e s to d r a i n a given area because of a " l a g e f f e c t " created i n the di t c h e s and f i e l d s . The f i v e pumps on the i s l a n d , which have c a p a c i t i e s of between 5,000 and 12,000 g a l l o n s per minute, stop pumping p e r i o d i c a l l y even when t i d e s are high and r a i n f a l l i s heavy because water cannot be drained r a p i d l y enough to the pumping b a s i n . The high water t a b l e , heavy s o i l , f l a t ground, clogged ditches', and i n many areas inadequate access between low areas and drainage d i t c h e s , creates t h i s delay. 6.2,3 D i s c u s s i o n S o i l s and drainage r e l a t e d i r e c t l y and i n d i r e c t l y to the cover and to the avifauna of Sea I s l a n d . Both f a c t o r s i n t e r a c t to create h a b i t a t s f o r various b i r d species which occur 227 i n the study area. S o i l s impede or e f f e c t drainage or v i c e  versa and they together i n f l u e n c e the v e g e t a t i o n , the a v a i l a -b i l i t y of water h a b i t a t , and the a v a i l a b i l i t y of food (plant and animal). At the present time s e v e r a l such i n t e r a c t i o n s may w e l l be near optimum f o r many b i r d s p e c i e s . The f e r t i l e s o i l s which are w e l l drained f o r most of the growing season, produce a l u x u r i o u s vegetative cover which i n t u r n encourages an abun-dance of animal l i f e . When such areas are e x t e n s i v e l y flooded d u r i n g the e a r l y f a l l , w i n t e r and e a r l y s p r i n g , they o f t e n a t t r a c t b i r d s i n l a r g e numbers. • The f i r s t step towards reducing t h i s i n t e r a c t i o n i s to provide e f f e c t i v e drainage. By e l i m i n a t i n g v a r i o u s water areas one removes much of the i n i t i a l a t t r a c t i o n f o r many b i r d s i n the area. I n a d d i t i o n , b e t t e r drainage may w e l l l i m i t the a t t r a c t i o n of b i r d s which occur as opportunists f e e d i n g on i n v e r t e b r a t e s p e r i o d i c a l l y flooded to the surface d u r i n g and f o l l o w i n g r a i n . I d e a l l y a l l water areas should be e l i m i n a t e d . Poorly drained s o i l s should be t i l e d , depressions f i l l e d w i t h sand, d i t c h e s replaced by pipe and f l a t - g a t e s replaced by pumps.. This system would be c o s t l y to i n s t a l l but on a long term b a s i s i t may a c t u a l l y be more economical. Adequate drainage u s i n g t i l e and pipe provides a) e f f e c t i v e c o n t r o l of water areas a t t r a c t i v e to problem b i r d s p e c i e s , b) greater access between adjacent f i e l d areas and c) lower ground cover maintenance by e l i m i n a t i n g awkward d i t c h s ide vegetation ( e l i m i n a t e s spraying 228 w i t h h e r b i c i d e s ) and f a c i l i t a t i n g l a r g e r f i e l d areas f o r more e f f e c t i v e use of machine time. In a d d i t i o n drainage pipes and t i l e s are g e n e r a l l y more e f f i c i e n t means of removing water from a given area i n a given p e r i o d of time and they have lower maintenance requirements than open di t c h e s because of reduced er o s i o n and e l i m i n a t i o n of aquatic p l a n t s ( P i c k e l s 1941). The only advantage of the open d i t c h i s low i n i t i a l c o s t . The extensive bare areas west of 12:30 found to a t t r a c t b i r d s during heavy r a i n s might be el i m i n a t e d by covering them w i t h s e v e r a l inches of sand or by p r o v i d i n g more adequate d r a i n -age to f a c i l i t a t e l e a c h i n g of s a l t s . In any case attempts should be made to l i m i t t h i s a t t r a c t i o n to b i r d s because of i t s close p r o x i m i t y to runway 12:30. 229 7. GENERAL DISCUSSION The problem of b i r d c o n t r o l at Vancouver I n t e r n a t i o n a l A i r p o r t i s complex. Because of the a i r p o r t ' s l o c a t i o n , c l i m a t e , e l e v a t i o n , s o i l s , water t a b l e and vegetation i t serves as a breeding, m i g r a t i o n and w i n t e r i n g area f o r a wide v a r i e t y of b i r d s . This d i v e r s i t y of b i r d species n e c e s s i t a t e s a general approach to the study of avian ecology on the a i r p o r t and sur-rounding areas i n order that an i n t e r p r e t a t i o n of the i n t e r r e l a -t i o n s h i p s between each species and i t s environment can be made. I t i s the d i v e r s i t y of b i r d species in the "study area" which creates the general problem of c o n t r o l . I f there were j u s t one or two species i n v o l v e d i t might be p o s s i b l e to make a few e c o l o g i c a l adjustments and m a t e r i a l l y reduce the problem. When more than one hundred species are i n v o l v e d the s o l u t i o n becomes complex. A c o n t r o l measure f o r one species can encourage the incr e a s e of one or more other species which may or may not have been a problem p r e v i o u s l y . Therefore, a p r e l i m i n a r y a n a l y s i s such as the present study must take i n t o account the problem and non-problem b i r d species and as o b j e c t i v e l y as p o s s i b l e , the f a c t o r s a f f e c t i n g t h e i r occurrence i n the study area. In the f i n a l a n a l y s i s one can hope to achieve a r e -duction i n the t o t a l number of b i r d s i n the area to a;Tow prac-t i c a l l e v e l but, i t i s h i g h l y d o u b t f u l that there should ever be complete c o n t r o l . I f i t were p r a c t i c a l to. create a s t e r i l e s i t u a t i o n , where the area i s made v o i d of b i o l o g i c a l a t t r a c t i o n s such as cover, food, water, e t c . many b i r d s would s t i l l be a t t r a c t e d to the area to lounge or r e s t . 2 3 0 In l i g h t of general observations and c o l l e c t i o n s made during the study p e r i o d i t was p o s s i b l e to suggest s e v e r a l long term c o n t r o l measures f o r most of the problem b i r d species (Sec-t i o n 4 . 3 . 2 ) . F o r t u n a t e l y the c o n t r o l measures were s i m i l a r f o r s e v e r a l s p e c i e s . More adequate drainage of f i e l d areas, p a r t i c u l a r l y where temporary surface pools occur during w i n t e r , was considered the most obvious way of reducing the main a t t r a c -t i o n s f o r waterfowl, sea g u l l s and s e v e r a l species of shore-b i r d s . Drainage was an acute problem throughout the "study :area" during the f a l l , w i n t e r and s p r i n g months when p r e c i p i t a -t i o n was high (Appendix 1 0 . 2 ) . In many areas where adequate f i e l d drainage was only p o s s i b l e during low t i d e s , the water •table f r e q u e n t l y rose w e l l above the surface (Figure 4 1 ) . Other long term c o n t r o l measures which were thought to reduce a t t r a c -t i o n s f o r more than one b i r d species i n the "study area" were the removal of "shrubby" vegetation,. t a l l "grassy" areas, "weed" areas and open d i t c h e s . The present b i r d problem i s encouraged by the s e c u r i t y and food resources r e s u l t i n g from untidy and i n some cases i r r e s p o n s i b l e farming of f i e l d areas and inadequate f i e l d management by the Department of Transport. Each year l o c a l farmers have been permitted to take crops of oats, and fodder from l a r g e areas of the " A i r p o r t " zone w i t h the under-standing that they would maintain t i d y , border f r e e , farming p r a c t i c e s . However, during the study period farmers l e f t l a r g e border areas i n a l l f i e l d s cropped and i n many cases f a i l e d to take crops at a l l . Perhaps these r e s u l t s were r e l a t e d to inadequate understanding between the farmers and the Department 231 of Transport on the o b j e c t i v e s of "zero g r a z i n g " . In any case t h i s p r a c t i c e afforded areas of i d e a l h a b i t a t f o r l a r g e numbers of breeding, m i g r a t i n g and w i n t e r i n g b i r d s . In s e v e r a l areas t h i s h a b i t a t e x i s t e d beside the main runway and i t d o u b t l e s s l y was the primary cause of s e v e r a l " b i r d s t r i k e s " (see s e c t i o n 4.3.2) . Several areas, found to be a t t r a c t i v e to many b i r d s , p a r t i c u l a r l y "weed" areas, were the d i r e c t r e s u l t s of inadequate f i e l d management by the Department of Transport (Figure 42). During the study period-there were extensive areas of t a l l grass and "weedy" growth l e f t uncut and "shrubby" vegetation l e f t unsprayed. The w r i t e r b e l i e v e s that the u l t i m a t e management scheme would be to maintain the whole "study area" as a w e l l drained short t u r f f r e e of open d i t c h e s . Under such a management scheme s c a r i n g devices would s t i l l play a major r o l e i n maintaining con-t r o l . Lounging b i r d s or b i r d s feeding i n short t u r f areas would be scared away when ever;they occurred. F o r t u n a t e l y most b i r d s a t t r a c t e d to the short t u r f area, p a r t i c u l a r l y various g u l l s and S t a r l i n g s , can be c o n t r o l l e d e f f e c t i v e l y using s c a r i n g devices (see s e c t i o n 4.4). However various shorebird species would continue to be a problem. Sea I s l a n d , being l o c a t e d at the mouth of the Fraser R i v e r bordering on Georgia S t r a i t , i s adjacent to an extensive t i d a l f l a t area (Figure 43) which i s a major mig r a t i o n route and w i n t e r i n g area f o r many species of s h o r e b i r d s . The d a i l y - a c t i v i t y of these b i r d s i s l a r g e l y governed by the a v a i l a b i l i t y of t h e i r major f e e d i n g h a b i t a t , the t i d a l mud f l a t s , which i n t u r n i s dependent on t i d e . When the t i d a l mud f l a t s are not a v a i l -231a Figure 41. I n f i e l d f l o o d i n g west of observation tower #3 during high t i d e and immediately a f t e r a heavy r a i n f a l l . The lar g e pool to the l e f t i s a c t u a l l y a d i t c h which has more than 8 f e e t of water. Figure 42. T y p i c a l weed area beside a r e c e n t l y constructed taxiway. Note the f l o w e r i n g B r a s s i c a campestris i n the foreground and the extensive carpet of Spurgula arvensis f i l l i n g most of the p i c t u r e . 232 able the b i r d s t u r n to f l a t open areas on higher ground p r e f e r -ably w i t h surface water, to feed and/or lounge. Large f l o c k s of shorebirds d i s p l a c e d by high t i d e s p e r i o d i c a l l y landed i n the " A i r p o r t " zone but, more f r e q u e n t l y , passed through i t to more s u i t a b l e areas i n the "Environs" zone. I n a l l cases s c a r i n g devices were found to be r e l a t i v e l y i n e f f e c t i v e f o r removing landed or t r a n s i e n t b i r d s from the " A i r p o r t " zone. General observations i n d i c a t e that even the removal of the " t i d a l f l a t s " west of Sea I s l a n d may not prevent shorebirds from o c c u r r i n g i n the " A i r p o r t " zone since more extensive t i d a l areas also e x i s t west of Iona, Swishwash and Lu l u I s l a n d s , However, i t i s b e l i e v e d that the e l i m i n a t i o n of t h i s primary a t t r a c t i o n may g r e a t l y reduce the numbers of and frequencies of very l a r g e f l o c k s i n the "study area". The removal of the marsh areas i n the t i d a l f l a t s , perhaps by covering w i t h dredged sand, may g r e a t l y reduce the occurrence of waterfowl i n the "study area". This assumption i s supported by observations made i n the area of the extensive t i d a l f l a t s west of Iona I s l a n d where no emergent aquatic vegetation e x i s t s . Waterfowl were uncommon i n t h i s area and i n most cases those which d i d occur were species c o n f i n i n g t h e i r a c t i v i t y to i t . With the expansion of the a i r p o r t f a c i l i t i e s to the north s e c t i o n of Sea I s l a n d and p o s s i b l y to the west i n t o the " t i d a l f l a t " areas, covering of marsh areas w i t h dredged sand may assume a more p r a c t i c a l r o l e . For example, the Snow Goose, Chen  hyperborea ( P a l l a s ) , whose numbers p e r i o d i c a l l y exceed +12,000, i s p r e s e n t l y considered a non-problem species because i t r e s t r i c t s 232a 43. A e r i a l view (2500 1) of the Sea I s l a n d t i d a l f l a t s l o o k i n g south. Note: a i r p o r t on l e f t and middle arm of Fraser R i v e r i n upper p i c t u r e . 233 i t s a c t i v i t y to foreshore areas north of the main runways west approach. However, i t may become a problem when a new runway i s constructed near Ferguson' road. General observations and the few c o l l e c t i o n s of t h i s species made during the study p e r i o d , i n d i c a t e that i t i s p r i m a r i l y a t t r a c t e d by the marsh ve g e t a t i o n , p a r t i c u l a r l y Scirpus spp. The use of ground covers on Vancouver I n t e r n a t i o n a l A i r p o r t to reduce or e l i m i n a t e a t t r a c t i o n s f o r various b i r d s i s s t i l l a v a l i d approach. The w r i t e r b e l i e v e s the present e x p e r i -ments should be f o l l o w e d by more extensive t r i a l s i n v o l v i n g u n t r i e d s p e c i e s , p a r t i c u l a r l y those which can be seeded to l a r g e areas (Table 14). I t i s d i f f i c u l t to p r e d i c t how economical or how s u c c e s s f u l any ground cover might be when planted i n a sm a l l p l o t . Larger t e s t p l o t s should be attempted p a r t i c u l a r l y i n areas along the edges of new taxiways so.that one may be able to determine not only the competitive vigour but al s o the extent of b i r d use and the abundances of ass o c i a t e d rodents and i n -v e r t e b r a t e s . The r e s u l t s of these experiments would then enable a more accurate i n t e r p r e t a t i o n of the usefulness of a p a r t i c u l a r cover species under p r e v a i l i n g management c o n d i t i o n s . The use of l i v e widgeon as an experimental animal to determine t h e i r g r a z i n g preferences warrants f u r t h e r c o n s i d e r a t i o n . The attempted experiments may i n d i c a t e some of the t e c h n i c a l problems to be overcome but the r e s u l t s are of l i t t l e v a lue. The present study was intended as an i n i t i a l survey and q u a l i t a t i v e a n a l y s i s of the avian ecology on Vancouver I n t e r n a t i o n a l A i r p o r t . I t was not intended to solve the b i r d 234 hazard problem. The importance of t h i s i n i t i a l approach i n any e c o l o g i c a l study was pointed out by Watts (1968). However, i n l i g h t of the in f o r m a t i o n gathered some recommendations f o r b i r d c o n t r o l may be considered and the d i r e c t i o n of f u t u r e study may be i n d i c a t e d . The former has already been discussed and w i l l not be considered f u r t h e r here. In the present study the use of the computer as an a i d to i n t e r p r e t a t i o n of o b s e r v a t i o n a l data was b r i e f l y explored. More d e t a i l e d computer a n a l y s i s of the data gathered would be d e s i r a b l e to increase the understanding of the v a r i a b l e s i n -volved and to reduce the i n f l u e n c e of season. The w r i t e r b e l i e v e s f u t u r e s t u d i e s should i n c l u d e more d e t a i l e d a n a l y s i s of those b i r d s which continue as a hazard. F u r t h e r , these s t u d i e s should p r i m a r i l y consider v a r i a b l e s found important during the present study ( i e . t i d e , time of day, p r e c i p i t a t i o n , e t c . ) ; perhaps i n such a way as to provide quan-t i t a t i v e i n f o r m a t i o n s t u i a b l e f o r computer a n a l y s i s . The p r i n -c i p l e s and methodology i n v o l v e d i n the l a t t e r case are very ably reviewed i n the works of Watts (1966 and 1968). In a d d i t i o n to the b i r d s themselves f u t u r e s t u d i e s c o n s i d e r i n g the c o n t r o l of p e r s i s t a n t food species would be most b e n e f i c i a l . Considerations may in c l u d e bioenvironmental as „Wiell as p h y s i c a l and chemical techniques. * Further research i s needed on the changes i n the numbers of b i r d s using the " A i r p o r t " zone and " b i r d s t r i k e s " r e s u l t i n g from t h i s use. As the a i r p o r t i s g r a d u a l l y changed from a complex to a more simple ecosystem i t i s most c e r t a i n that the 235 avifauna w i l l change a c c o r d i n g l y . Therefore, persons concerned w i t h the b i r d c o n t r o l problem must be aware of such changes to avoid the c r e a t i o n of another and perhaps worse hazard. 236 8. SUMMARY 1. A p r e l i m i n a r y survey and a n a l y s i s of avian ecology as i t r e l a t e s to the hazard t o a i r c r a f t at Vancouver I n t e r n a t i o n a l A i r p o r t was attempted. 2. The d i v e r s i t y of b i r d species o c c u r r i n g i n the "study area" n e c e s s i t a t e d a general approach. As many v a r i a b l e s as p o s s i b l e were considered, so that an i n t e r p r e t a t i o n of the i n t e r r e l a t i o n s h i p s between each species and i t s environment could be made. 3. The methods used to gather i n f o r m a t i o n on the a c t i v i t y of the b i r d s i n c l u d e d r e g u l a r counts, observations and c o l l e c t i o n s . In a d d i t i o n , the seasonal a c t i v i t y of the b i r d s was supported by i n f o r m a t i o n from e a r l i e r s t u d i e s i n the area, 4. In l i g h t of the i n f o r m a t i o n gathered during the present study and i n f o r m a t i o n gathered during the previous work i n the area, i t was p o s s i b l e to designate each b i r d species as e i t h e r a problem or non-problem type. The most outstanding c r i t e r i a i n t h i s regard was the e a r l i e r and present record of " s t r i k e s " i n v o l v i n g each species i n the area. Non-problem b i r d s were not discussed but the food a n a l y s i s of a l l b i r d s c o l l e c t e d i s given i n appendix 10.3.2, Problem b i r d species are discussed i n d i v i d u a l l y i n consider-able, d e t a i l under the headings of Seasonal occurrence, Hazard to a i r c r a f t , Food and C o n t r o l . Under the heading of seasonal occurrence are given the n e s t i n g and f i r s t young records and the sex and age records f o r b i r d s o c c u r r i n g i n the "study "area" d u r i n g the study p e r i o d . 237 The general observations and the a n a l y s i s of food items recovered from b i r d s c o l l e c t e d during the study period i n d i c a t e d the importance of a number of p l a n t s and animals as a t t r a c t i o n s f o r many b i r d s . The most important f e a t u r e s considered to encourage these foods are inadequate drainage, shrubby v e g e t a t i o n , t a l l "grassy" areas, c o n s t r u c t i o n a c t i v i t y , inadequate f i e l d management and improper "zero g r a z i n g " . One problem b i r d s p e c i e s , the American Widgeon, was s t u d i e d to determine i f any of f i v e experimental p l a n t s were un-p a l a t a b l e to them. These experiments, u n f o r t u n a t e l y , were not a success, because of the death of both animals before the t r i a l s were completed. However, there was some i n d i c a -t i o n that grasses were p r e f e r r e d to f o r b s at l e a s t under the experimental c o n d i t i o n s . I t was recommended that f u t u r e experiments using l i v e widgeon should attempt to minimize the s t r e s s f a c t o r . This f a c t o r was considered to be the main cause of f a i l u r e of the present experiments. A survey was made of the b i r d c o n t r o l devices used by the Department of Transport during the study p e r i o d . The r e s u l t s of t h i s survey i n d i c a t e that the use of more than one s c a r i n g device enhances the " f l i g h t " r e a c t i o n of most b i r d s . The most e f f e c t i v e and v e r s a t i l e device was found to be the "cracker s h e l l " . As a r e s u l t of a general survey of the vegetation i n the "study area" a cover map was made. This map serves as a guide f o r the l o c a t i o n of the major vegetation forms described i n the t e x t . A more i n t e n s i v e survey of the vegetation was c a r r i e d out i n the " I n t e n s i v e " zone where i t was p o s s i b l e to describe three q u i t e d i s t i n c t subzones; "dry", "moist", and "wet". These subzones were found to be coincident w i t h the d i s t r i b u t i o n of ant h r o p i c , n a t i v e and poorly drained n a t i v e s o i l s r e s p e c t i v e l y . 0. Several experimental ground covers considered to be un a t t r a c -t i v e to b i r d s were e s t a b l i s h e d i n p l o t s on Vancouver A i r p o r t . i n an attempt t o f i n d a species which was able to become dominant i n the area. A l l experimental p l a n t s used were found to be u n s a t i s f a c t o r y under the experimental c o n d i t i o n s . However, some of the poor response was a t t r i b u t e d to i n -adequate p l o t p r e p a r a t i o n , d i f f e r e n c e s between types of propagation or inadequate seeding r a t e . I t was suggested that i n f u t u r e experiments plant species should be used which can be propagated over l a r g e r areas cheaply. In a d d i t i o n i t was suggested t h a t l a r g e r p l o t areas, i n l o c a t i o n s such as beside taxiways, be used so as to enable more in f o r m a t i o n on p r a c t i c a l aspects such as cos t , a s s o c i a t e d food and b i r d use. 10. Physiographic observations and t r i a l s i n d i c a t e d that the s o i l s and drainage i n the a i r p o r t zone g r e a t l y a f f e c t e d b i r d d i s t r i -b u t i o n and abundance. 11. Generally the problem of b i r d c o n t r o l on Vancouver I n t e r n a t i o n a l A i r p o r t was found to be complex. 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The i n f l u e n c e of climate and weather f a c t o r s upon the numbers of b i r d s on a d e p o s i t i n g creek bank. E c o l . Monogr. 3(4): 535-597. Sowls, L.K. 1955. P r a i r i e ducks: a study of t h e i r behavior, ecology and management. H a r r i s b u r g , Pa., Stockpole Co. 193 P. Spencer, G.J. 1948. Rendering Indian ink l a b e l s permanent i n a l c o h o l . Turtox news V o l . 26(1). Sprout, P.M. and W.D. Holland. 1959. S o i l survey of D e l t a m u n i c i p a l i t y : P r e l i m i n a r y report No. 2 of the Lower Fraser V a l l e y S o i l Survey, B.C. Dept. of A g r i c . Kelowna, B.C. S t a n c h i n s k i i , V.V. 1930. E c o l o g i c a l geography of b i r d s : p r o b l and methods. ( M i s s e n s c h a f t l . M i t t e i l , Univ. Smolensk 3(1): 65-68) In B i o l o g i c a l A b s t r a c t s , 14092. S t e f f e r u d , A, 1966. B i r d s i n our l i v e s . U.S. Bureau of Sport F i s h e r i e s and W i l d l i f e , U.S. Dept. of I n t e r i o r , U.S. P r i n t i n g O f f i c e , Washington, p .561. Stevenson, James, 1933. Experiments on- d i g e s t i o n of food by b i r d s . W ilson B u l l . 45(4): 155-167. Stewart, L. 1953. The use of s a l i n e i r r i g a t i o n water on Fraser R i v e r D e l t a s o i l s . Unpublished M.S.A. Thesis, Department of Agronomy, Univ. of B r i t i s h Columbia. Stewart, J . and A.L. Van Ryswyk. 1950. Q u a l i t y of I r r i g a t i o n waters i n the Fraser V a l l e y D e l t a area. Unpublished Bachelor of Science i n A g r i c u l t u r e Thesis, Department of Agronomy, Univ. of B r i t i s h Columbia. 2 4 6 S t o r e r , Robert ¥. 1 9 5 1 . The seasonal occurrence of shorebirds on Bay Farm I s l a n d , Alameda County, C a l i f o r n i a . Condor 5 3 ( 4 ) : 1 8 6 - 1 9 3 . Thorpe, W.H. 1 9 5 6 . The language of b i r d s . S c i e n t i f i c .American 1 9 5 ( 4 ) : 1 2 8 - 1 3 8 . Learning and i n s t i n c t i n animals. Harvard U n i v e r s i t y Press, Cambridge, Mass. Thorn, R.B. 1 9 5 9 . The design of land drainage works. B u t t e r -worths S c i e n t i f i c P u b l i c a t i o n s , London. T o t h i l l , J.TJ. 1 9 5 8 . Some r e f l e c t i o n s on the cause of i n s e c t outbreaks. Proc. I n t e r n . Congr. Entomol. 1 0 t h . Montreal, 4 , 5 2 5 . U.S. Dept. of A g r i c u l t u r e , " S o i l s and Men". Yearbook of A g r i c u l t u r e . U.S. Gov't P r i n t i n g O f f i c e 1 9 3 8 , pp. 3 2 1 - 3 2 8 ; 4 3 0 , 4 3 5 , 4 6 2 - 4 6 8 . Ward, H.M. 1 9 0 8 . Grasses. Cambridge B i o l o g i c a l S e r i e s , Cambridge at the U n i v e r s i t y Press, Watt, Kenneth, E.F. 1 9 6 6 . Systems A n a l y s i s i n Ecology. Academic Press, New York and London. 2 7 6 p. Watt, Kenneth E.F,. 1 9 6 8 . Ecology and Resource Management. McGraw-Hill Book Company, Toronto, London and New York. 4 5 0 p. W e l l i n g t o n , W.G. 1 9 4 5 . Conditions governing the d i s t r i b u t i o n of i n s e c t s i n the f r e e atmosphere I I I Thermal convection. Canadian Ent. 7 7 ( 3 ) : 4 4 - 4 9 . Welty, J.C. 1 9 6 2 . The l i f e of b i r d s . W.B. Saunders Co., P h i l a d e l p h i a and London. Wils o n , J.E. 1 9 5 9 . The s t a t u s of the Hungarian P a r t r i d g e i n New York. K i n g b i r d , 9 : 5 4 - 5 7 . Yocum, Charles, F. 1 9 5 1 . Waterfowl and t h e i r food p l a n t s i n Washington. Univ. of Wash. Press, S e a t t l e , Wash. Vogtman, Donald B. 1 9 4 5 . F l u s h i n g tube f o r determining food of fame b i r d s . J o u r n a l of W i l d l i f e Management V o l . 9 ( 3 ) : 2 5 5 - 2 5 7 . 249 APPENDIX 10.3 10.3.1 T o t a l Monthly Food A n a l y s i s of 11 Problem B i r d Species Common to the "Intensive" Zone. 250 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during May, 1966. Food Item Pheasant S t a r l i n g # V o l # Vol Animal Matter Annelida -Oligochaeta Allolobophora sp. 1 0.06 Arthropoda -Insecta Lepidoptera -Larvae 3 0.41 Coleoptera -Carabidae Harpalus acneus F. 3 0.22 -Larvae 3 0.03 - U n i d e n t i f i e d 3 0.09 - S t a p h y l i n i d a e 4 0.08 - C u r r u l i o n i d a e - U n i d e n t i f i e d 2 0.02 - S i t o n i a h i s p i d u s F. 2 0.13 Hymenoptera -Formicidae 2 0.09 Plant Matter Angiospermae -Monocotyledoneae -Gramineae -Poa sp. -Leaves 1 T -Dicotyledoneae - C r u c i f e r a e - B r a s s i c a campestris -Seed 1 T -Caryophyllaceae -Cerastium vulgatum -Seed 1 0.10 -Leguminosae - T r i f o l i u m hybridum -Leaves 1 6.97 U n i d e n t i f i e d m a t e r i a l 1 0.04 Sand g r i t 1 3.00 TOTAL 1 10.08 6 1.17 251 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during June, 1966. Food Item Pheasant S t a r l i n g K i l l d e e r # V o l # Vol # Vol Animal Matter Annelida -Oligochaeta Allolobophora sp. 1 0.10 Arthropoda -Arachnida Araneae 3 0.01 Phalangida 3 0.03 -Insecta Homoptera - C i c a d e l l i d a e 3 0.10 Lepidoptera -Larvae 14 6.20 D i p t e r a - Larvae 1 0.80 -Cecidomyidae 2 0.01 -Drosophilidae -Pupae 1 0.05 Coleoptera - C i c i n d e l i d a e - U n i d e n t i f i e d 3 0.02 -Carabidae -Harpalus acneus F. 5 0.10 -Larvae 2 0.01 - U n i d e n t i f i e d 6 6 0.14 1 T -Sta p h y l i n i d a e 6 0.07 1 T -Buprestidae 2 0.01 -Scarabaeidae -Aphodius d i s t i n c t u s ( M u l l . ) 1 T - U n i d e n t i f i e d 3 0.04 -Curculionidae - U n i d e n t i f i e d 7 0.09 1 0.03 -Phytonomus founctatus F. 3 0.03 - S i t o n i a h i s p i d u s gI£y.Y ) . 6 0.14 2 0.01 -Larvae 1 0.05 -Rhizophagidae 1 T - E l a t e r i d a e 1 0.02 -Anthicidae 1 T Hymenoptera -Chalcididae 1 0.01 -Formicidae 1 0.01 Plant Matter Angiospermae -Dicotyledoneae Leguminosae T r i f o l i u m pratense -Leaves 1 0.04 U n i d e n t i f i e d m a t e r i a l 3 0.15 Sand g r i t 1 3.00. 4 0.02 TOTAL 1 3.04 15 7.35 2 0.87 2 5 2 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during J u l y , 1 9 6 6 . Food Item Animal Matter Annelida -Oligochaeta Allolobophora sp. Arthropoda -Arachnida Phalangida -Insecta Hemiptera -Nabiidae Coleoptera -Carabidae - U n i d e n t i f i e d - S t a p h y l i n i d a e -Curculionidae •U n i d e n t i f i e d - S i t o n i a h i s p i d u s F, -Rhizophagidae -Anthicidae P l a n t Matter U n i d e n t i f i e d m a t e r i a l K i l l d e e r # Vol 0 . 1 0 1 1 3 2 3 1 1 1 TOTAL 0 . 0 7 0 . 0 1 0 . 0 9 0 . 0 2 0 . 0 4 0 . 0 1 T 0 . 0 2 0 . 1 5 0 . 5 1 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g August, 1966. Food Item Animal Matter M o l l u s c a -Gastropoda U n i d e n t i f i e d s l u g Annelida -Oligochaeta A l l o l o b o p h o r a sp. Arthropoda -Arachnida Araneae Phalangida - I n s e c t a Orthoptera -Locustidae Hemiptera -Reduviidae - U n i d e n t i f i e d Homoptera -Aphididae T r i c h o p t e r a -Larvae L e p i d o p t e r a -Larvae D i p t e r a -Dolichopodidae Cole o p t e r a -Carabidae - P t e r o s t i c h u s v u l g a r i s L, -Larvae - U n i d e n t i f i e d - S t a p h y l i n i d a e - C u r c u l i o n i d a e - U n i d e n t i f i e d -Phytonomus fOunctatus F, Pheasant S t a r l i n g # V o l # V o l 2 0.10 2 0.92 1 0.01 2 0.01 1 0.05 1 T 1 T 1 T 1 0.06 1 T K i l l d e e r # Vol M a l l a r d # V o l 1 0.15 1 1 0.51 0.01 1 0.04 3 0.06 4 0.51 C a l i f o r n i a G u l l # Vol 4 1 4 1 1 1 16.70 0.05 0.10 1.30 0.10 T 0.01 ro on oo Pood A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g August, 1 9 6 6 . C a l i f o r n i a Food Item Pheasant S t a r l i n g K i l l d e e r M a l l a r d G u l l # V o l # V o l # V o l # Vol # V o l - S i t o n i a h i s p i d u s F. 1 0.02 Hymenoptera Ichneumonidae 2 0.01 P l a n t Matter Angiospermae -Monocotyledoneae -Gramineae Lolium m u l t i f l o r u m -Seed 3 0 . 0 7 -Cyperaceae Scirpus americanus 6 0.05 Scirpus paludosus 1 T -Dicotyledoneae -Polygonaceae Polygonum p e r s i c a r i a -Seed 4 1.31 7 0 . 0 4 3 0 . 0 1 Polygonum convolvulus -Seed 4 0 . 0 7 -Potamogetonaceae Potamogeton p u s i l l u s -Seed 7 1.49 -Leaves 7 15J80 -Caryophyliaceae Cerastium vulgatum -Seed 2 0 . 0 1 -Rosaceae Rubus l a c i n i a t u s -Seed 2 1.75 -Leguminosae T r i f o l i u m sp. -Seed 1 T -Compositae Cir s i u m vulgare -Seed 4 1.27 C i r s i u m a r v e n s i s -Seed 2 0.03 Pieces of l e a d shot I T U n i d e n t i f i e d m a t e r i a l 5 5.67 I T 7 1.55 ro Sand g r i t 7 7 .98 1 T 7 22.83 5 2^07 ^ TOTAL 7 19.28 1 0 . 0 7 4 1.32 7 40.21 7 2 1 . 9 0 255 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during September, 1966. Food Item Animal Matter M o l l u s c a Pheasant S t a r l i n g K i l l d e e r M a l l a r d # Vol # Vol # Vol # Vol Gastropoda - U n i d e n t i f i e d ' 3 0.06 Annelida Oligochaeta > Allolobophora sp. 4 0.25 Arthropoda Crustaceae Isopoda 3 0.58 Amphipoda Gammariidae 3 0.10 Arachnida ; Araneae 1 0.02 5 0.02 1 T In s e c t a ; Orthoptera Locustidae 1 13.39 1 0.32 • S a l t a t o r i a 1 0.02 Hemiptera Nabiidae 1 0.01 Pherhocoridae 1 T U n i d e n t i f i e d 2 0.01 Homoptera C i c a d e l l i d a e 4 0.04 1 T Aphididae 3 T Lepidoptera -Larvae 4 0.28 2 0.36 D i p t e r a -Larvae 2 0.01 Syrphidae 1 T Dros o p h i l i d a e -Pupae 1 T Coleoptera C i c i n d e l i d a e U n i d e n t i f i e d 4 0.04 2 0.01 Carabidae P t e r o s t i c h u s v u l -g a r i s L. 4 0.06 1 0.01 Harpalus acneus F. 2 0.04 Larvae 1 T 1 0.02 U n i d e n t i f i e d 18 0.16 2 0.01 S t a p h y l i n i d a e 27 0.33 4 0.01 C o c c i n e l l i d a e 3 0.03 Scarabaeidae U n i d e n t i f i e d 1 0.01 Curculionidae U n i d e n t i f i e d 25 0.27 5 0.42 Phytonomus foun-ctatus F. 1 0.04 S i t o n i a h i s -pidus F. 25 0.23 3 0.23 Rhizophagidae 1 T U n i d e n t i f i e d 1 T C a l i f o r -n i a G u l l # Vol 2 2 1.20 0.10 1 0.77 2 5 6 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during September, 1 9 6 6 , Food Item Hymenoptera Ichneumonidae Formicidae Plant Matter Angiospermae Monocotyledoneae Gramineae Alopecurus genic-u l a t u s L. -Seed Avena s a t i v a -Seed Lolium m u l t i -florum -Seed Pheasant S t a r l i n g K i l l d e e r M a l l a r d # V o l # Vol # Vol # Vol C a l i f o r -n i a G u l l # Vol 3 3 3 1 10.85 0.53 0 . 2 1 Agropyron repens -Seed 2 Juncaceae Juncus sp. -Seed Cyperaceae Scirpus american-us Scirpus v a l i d u s  Scirpus paludosus  Scirpus sp.-Seeds Carex lyngbyei -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i -c a r i a -Seed 16 2 6 . 7 6 Polygonum a y i -culare -Seed Polygonum convolv vulus -Seeds 4 5.85 Rumex aceto-s e l l a -Seeds 2 T Chenopodiaceae : . --Chenopodium a l -bum -Seed 2 0 . 0 2 Caryophyllaceae Spurgula arven-s i s -Seed 4 3.18 Rosaceae Prunus emar-gi n a t a -Seed Crataegus doug-l a s s i i -Seed Rubus l a c i n i a t u s -Seed 1 7 1 4 0.10 0.97 9.76 0.03 0.02 2 1 1 0 . 1 0 T T 0 . 0 1 1 0.17 1 T 257 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during September, 1966. C a l i f o r -Food Item Pheasant S t a r l i n g K i l l d e e r M a l l a r d n i a G u l l # Vol # Vol # Vol # Vol # Vol Plantaginaceae Plantago major -Seed Leguminosae T r i f o l i u m pratense -Seed 1 0.10 -Leaves. 2 0.44 Lathyrus sp. -Seed 1 0.19 M e l i l o t u s alba -Seed 1 T Compositae Cirsium vulgare -Seed 8 6.84 Hypochaeris r a d i -'cata -Flowers 1 0.21 Psilocarphus e l a -t i o r -Seed U n i d e n t i f i e d Seeds I T Pieces of Lead Shot 5 0.11 2 0.33 U n i d e n t i f i e d M a t e r i a l 15 14.00 8 0.05 1 T 2 1 46 Sand G r i t 20 32 .61 3 0.01 1 0.02 2 1.51 U n i d e n t i f i e d F r u i t 2 1.28 TOTAL 20 127.46 36 2.69 5 1.14 2 4.90 1 0.77 258 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during September, 1966, Glacu.co.us Green Winged Winged Food Item G u l l P i n t a i l Teal Mew G u l l # Vol # Vol # Vol # Vol Animal Matter M o l l u s c a Gastropoda - U n i d e n t i f i e d Annelida Oligochaeta A l l o l o b o p h o r a sp. 1 1.30 2 0.20 Arthropoda Crustaceae Isopoda Amphipoda Gammariidae Arachnida Araneae Insecta Orthoptera Locustidae S a l t a t o r i a Hemiptera Nabiidae Pherhocoridae U n i d e n t i f i e d Homoptera C i c a d e l l i d a e Aphididae Lepidoptera -Larvae 1 T D i p t e r a -Larvae Syrphidae Drosophilidae -pupae Coleoptera C i c i n d e l i d a e U n i d e n t i f i e d Carabidae P t e r o s t i c h u s v u l g a r i s L. 1 0.21 Harpalus acneus F. Larvae 1 0.04 U n i d e n t i f i e d 1 0.04 St a p h y l i n i d a e 1 0.01 1 T C o c c i n e l l i d a e Scarabaeidae U n i d e n t i f i e d C u r c u l i o n i d a e U n i d e n t i f i e d Phytonomus founctatus F. S i t o n i a h i s p i d u s F. Rhizophagidae U n i d e n t i f i e d 1 0.01 Hymenoptera Ichneumonidae Formicidae 259 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during September, 1966. Food Item Glaucous Winged G u l l # Plant Matter Angiospermae Monocotyledoneae Gramineae Alopecurus geniculatus L. -Seed Ayena s a t i v a -Seed Lolium m u l t i f l o r u m -Seed Agropyron repens -Seed Juncaceae Juncus sp. -Seed Cyperaceae Scirpus americanus  Scirpus v a l i d u s  Scirpus paludosus  Scirpus sp. -Seeds 1 Carex lyngbyei -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a -Seed Polygonum a v i c u l a r e -Seed Polygonum,convolvulus '-Seeds Rumex a c e t o s e l l a -Seeds Chenopodiaceae Chenopodium album -Seed Caryophyllaceae Spurgula a r v e n s i s -Seed Rosaceae Prunes emarginata -Seed Crataegus d o u g l a s s i i -Seed Rubus l a c i n i a t u s -Seed Plantaginaceae Plant ago ma.jor -Seed Leguminosae T r i f o l i u m pratense -Seed -Leaves Lathyrus sp. -Seed M e l i l o t u s a l b a -Seed Compositae C i r s i u m vulgare -Seed Hypochaeris r a d i -cata -Flowers Psilocarphus e l a t i o r -Seed Vol P i n t a i l # Vol 5 6.64 1 T Green Winged Teal # Vol 0.10 Mew G u l l # Vol 1 4 0.01 0.04 0.04 5 16.60 2 0.01 0.01 2.40 2 6 0 Food Analysis of Birds Collected on Vancouver Airport during September, 1966. Food Item Unidentified Seeds Pieces of Lead Shot Unidentified Material Sand Grit Unidentified F r u i t Glaucous Winged Gull P i n t a i l Green Winged Teal lew Gull # Vol # Vol # Vol # Vol 1 0 . 1 8 2 1 . 5 1 2 5 0 . 5 0 4 . 3 0 2 1 . 1 0 1 T TOTAL 3 . 0 0 5 2 8 . 0 9 3 . 6 8 2 0 . 4 7 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n Food Item Pheasant S t a r l i n g K i l l d e e r # Vol # V o l •# V o l Animal Matter M o l l u s c a Gastropoda U n i d e n t i f i e d S l u g Annelida Oligochaeta A l l o l o b o p h o r a sp. 3 0.40 1 0.10 Arthropoda Arachnida Araneae 1 T I n s e c t a Orthoptera Locutidae 1 0.26 Hemiptera Nabiidae 1 T Homoptera C i c a d e l l i d a e 1 T 1 T C o r i x i d a e T r i c h o p t e r a Larvae Lepidoptera Larvae 27 2.63 D i p t e r a Larvae 1 0.03 Pupae U n i d e n t i f i e d B i b i o n i d a e -Larvae Coleoptera Carabidae P t e r o s t i c h u s v u l g a r i s L. 4 0.54 Harpalus acneus F. 4 0.10 Larvae 1 0.07 U n i d e n t i f i e d 1 T 12 0.23 October, 1966. Glaucous C a l i f o r n i a Winged M a l l a r d G u l l G u l l # V o l # V o l # Vol 4 18.25 4 7.32 1 0.06 1 T 2 0.78 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n Food Item Pheasant S t a r l i n g K i l l d e e r # Vol # Vol # Vol S t a p h y l i n i d a e 22 0.15 C o c c i n e l l i d a e Buprestidae 1 T Scarabaeidae Aphodius d i s t i n c t u s (Mull) • 9 0.09 C u r c u l i o n i d a e U n i d e n t i f i e d 15 0.04 1 0.02 Phytonomus founc-t a t u s F. 1 0.17 20 1.18 S i t o n i a h i s p i d u s F. 1 T 23 0.72 P l a n t Matter Angiospermae Monocotyledoneae Gramineae Alopecurus g e n i c u l a t u s L. -Seed Poa sp. -Seed Avena s a t i v a -Seed 1 0.65 Echinochloa c r u s g a l l i -Seed Grass sp. -Leaves Juncaceae Juncus sp. -Seed Typhaceae Typha l a t i f o l i a -Seed Cyperaceae Sc i r p u s americanus Sc i r p u s v a l i d u s S c i r p u s sp] -Seedlings Carex l y n g b y e i -Seed Dicotyledoneae Polygonaceae October, 1966. Glaucous C a l i f o r n i a Winged M a l l a r d G u l l G u l l # Vol # V o l # V o l 1 3.70 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g October, 1966. Glaucous C a l i f o r n i a Winged Food Item Pheasant S t a r l i n g K i l l d e e r M a l l a r d G u l l G u l l # Vol # Vol # Vol # V o l # V o l # Vol Polygonum p e r s i c a r i a -Seed 7 16.41 2 0.01 3 4.00 Polygonum a v i c u l a r e -Seed Polygonum convolvulus -Seed 2 0.29 Rumex a c e t o s e l l a -Seed 1 0.02 1 T Potamogetonaceae Potamogeton p u s i l l u s -Seed Chenopodiaceae Chenopodium album -Seed 1 4.50 -Leaves 1 0.12 C r u c i f e r a e B r a s s i c a campestris -Seed 1 0.08 Caryophyliaceae Cerastium vulgatum -Seed 2 0.18 Spurgula a r v e n s i s -Seed 2 0.05 Rosaceae Prunus emarginata -Seed 2 0.24 Rubus l a c i n i a t u s -Seed 1 T Rubus sp. -Seed Malus f u s c a -Seed 11 0.66 Leguminosae T r i f o l i u m sp. -Seed -Leaves 1 O.56 T r i f o l i u m pratense -Seed 1 0.04 Compositae Cirsium vulgare -Seed 1 0.03 ro Hypochaeris r a d i c a t a -Seed ^ P s i l o c a r p h u s e l a t i o r -Seed U n i d e n t i f i e d Seeds Pieces of Lead Shot U n i d e n t i f i e d M a t e r i a l 6 L 1^ ^ n m Sand G r i t 7 A.ll \ ofol 1 0.02 \ I'M 4 ^ 1 °-°2 T O T A L 8 4 1 . 0 8 33 6.90 1 o . H 3 9.76 k 27.01, 4 7 . 3 4 Food A n a l y s i s of B i r d s C o l l e c t Food Item Food Item M o l l u s c a Gastropoda . U n i d e n t i f i e d .slug Annelida Oligochaeta A l l o l o b o p h o r a sp. Arthropoda Arachnida Araneae In s e c t a Orthoptera Locustidae Hemiptera Nabiidae Homoptera C i c a d e l l i d a e C o r i x i d a e T r i c h o p t e r a Larvae Lepidoptera Larvae D i p t e r a Larvae Pupae U n i d e n t i f i e d B i b i o n i d a e -Larvae Coleoptera Carabidae P t e r o s t i c h u s v u l g a r i s L Harpalus acneus F. Larvae U n i d e n t i f i e d er A i r p o r t during October, 1966. Green Winged H e r r i n g P i n t a i l Teal Mew G u l l G u l l Widgeon # V o l # V o l # Vol # V o l # Vol 1 0.22 3 8.80 2 0.03 7 11.52 3 2.97 2 T 1 T 2 0.07 2 T 2 T 1 T Fv> ON 2 0.23 10 0.78 1 0.01 3 0.03 3 0.05 Food A n a l y s i s of B i r d s C o l l e c t e d on Vane Food Item S t a p h y l i n i d a e C o c c i n e l l i d a e Buprestidae Scarabaeidae Aphodius d i s t i n c t u s ( M u l l ) . C u r c u l i o n i d a e . U n i d e n t i f i e d Phytonomus founctatus F. S i t o n i a h i s p i d u s F. P l a n t Matter Angiospermae Monocotyledoneae Gramineae Alopecurus g e n i c u l a t u s L. -Seed Poa sp. -Seed Avena s a t i v a -Seed Echinochloa c r u s g a l l i -Seed Grass sp. -Leaves Juncaceae Juncus sp. -Seed Typhaceae Typha l a t i f o l i a -Seed Cyperaceae Scirpus americanus  Scir p u s v a l i d u s  Scirpus s p l -Seedlings Carex l y n g b y e i -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a -Seed Polygonum a v i c u l a r e -Seed er A i r p o r t d u r i n g October, 1966. Green Winged H e r r i n g P i n t a i l Teal Mew G u l l G u l l Widgeon # V o l # V o l # Vol # Vol # V o l I T 2 T 1 0.01 I T 2 0.22 2 0 .4 6 5 0.02 3 T 3 0.01 5 0.02 7 T 7 0.67 7 0.10 2 0.06 2 T 6 0.03 1 T 11 25.66 12 1.40 2 0.75 6 0.01 1 0.40 ro on Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t . d u r i n g October, 1966. Food Item Polygonum convolvulus -Seed Rumex a c e t o s e l l a -Seed Potamogetonaceae Potamogeton p u s i l l u s -Seed Chenopodiaceae Chenopodium album -Seed -Leaves C r u c i f e r a e B r a s s i c a campestris -Seed Caryophyllaceae Cerastium vulgatum -Seed Spurgula a r v e n s i s -Seed Rosaceae Prunus emarginata -Seed Rubus l a c i n i a t u s -Seed Rubus sp. -Seed Malus f u s c a -Seed Leguminosae T r i f o l i u m sp. -Seed -Leaves T r i f o l i u m pratense -Seed -Leaves Compositae C i r s i u m vulgare -Seed Hypochaeris r a d i c a t a -Seed -Flowers P s i l o c a r p h u s e l a t i o r -Seed U n i d e n t i f i e d Seeds Pieces of Lead Shot U n i d e n t i f i e d M a t e r i a l Sand G r i t TOTAL Green Winged H e r r i n g P i n t a i l Teal Mew G u l l ' G u l l Widgeon # Vol # V o l # V o l # V o l # Vol 3 0.06 3 0.08 1 T 1 0.01 2 T 6 2.94 11 0.25 1 T 2 0.05 1 T 1 0.80 5 0.01 1 11 11 0.81 0.32 12 5.70 12 2.75 4.49 2 8 3 0.01 2.89 0.01 3 3.00 11 37.21 12 10.66 9 15.41 3 15.08 ro O N O N 1 1 1.00 1.40 267 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during November, 1966, Green Winged Herring Food Item P i n t a i l Teal Mew G u l l G u l l Widgeon # V o l # V o l # V o l # Vol # Vol Animal Matter Mollusca Gastropoda-Unidentified 1 2,80 U n i d e n t i f i e d s l u g 5 17.42 • Annelida Oligochaeta Allolobophora sp. 3 2.39 4 51.88 Arthropoda Arachnida Araneae 2 T Insecta Hemiptera Reduviidae Homoptera C i c a d e l l i d a e C o r i x i d a e Lepidoptera 1 0.22 D i p t e r a -Larvae 1 T U n i d e n t i f i e d Dolichopodidae 2 T Muscidae 2 0.10 Coleoptera Carabidae P t e r o s t i c h u s v u l -g a r i s L. 1 0.10 Harpalus acneus F. Larvae U n i d e n t i f i e d 1 0.06 3 0.02 1 0.01 S t a p h y l i n i d a e 3 0.02 Aphodius d i s t i n c -tus ( M u l l ) . 1 0.10 2 0.88 U n i d e n t i f i e d Curculionidae U n i d e n t i f i e d 1 T Phytonomus founc-t a t u s F. 2 0.15 S i t o n i a h i s p i d u s F. .1 0.06 3 1.55 E l a s t e r i d a e Rhysadidae Byrrhidae P l a n t Matter Angiospermae Monocotyledoneae Gramineae A g r o s t i s s t o l o n -i f era -Leaves 1 0.55 Solium sp. -Leaves 1 0.80 Echinochloa c r u s g a l l i -Seed 268 Food' A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during November, 1966. Green Winged H e r r i n g Food Item P i n t a i l Teal Mew G u l l G u l l Widgeon # V o l # V o l # Vol # Vol # Vol Juncaceae Juncus sp. -Seed 1 T Cyperaceae Scirpus ameri-canus -Seed 1 0.03 Scirpus v a l i -dus -Seed 1 0.01 Scirpus p a l u -• dosus -Seed 2 T Scirpus acutus -Seed 1 0.01 Carex lyngbyei -Seed Dicotyledoneae Polygonaceae Polygonum pers-i c a r i a -Seed 2 2.98 1 0.01 Polygonum a v i -culare -Seed Rumex occiden-t a l i s -Seed 1 T Chenopodiaceae A t r i p l e x p a t u l a -Seed 1 T Caryophyllaceae Spurgula arven-s i s -Seed Rosaceae Rubus l a c i n i a t u s -Seed Malus fu s c a -Seed Leguminosae T r i f o l i u m sp. -Seed 1 T U n i d e n t i f i e d Seeds 1 0.01 Pieces of Lead Shot 2 0.01 1 T U n i d e n t i f i e d M a t e r i a l 3 2.36 4 6.10 Sand G r i t 2 2.28 1 0.20 2 T 2 3.01 TOTAL 2 5.36 1 0.28 4 8.00 7 78.37 2 4 .40 269 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during November, 1966. Food Item Pheasant S t a r l i n g -# Vol # Vol Animal Matter Mollusca Gastropoda - U n i d e n t i f i e d - U n i d e n t i f i e d s l u g Annelida Oligochaeta Allolobophora sp. 7 1.39 Arthropoda Arachnida Araneae 12 0.06 Insecta Hemiptera Reduviidae 2 T Homoptera C i c a d e l l i d a e 1 T Cor i x i d a e 1 0.02 Lepidoptera 19 3.93 D i p t e r a -Larvae 9 0.17 U n i d e n t i f i e d 2 T Dolichopodidae Muscidae Coleoptera Carabidae P t e r o s t i c h u s v u l -g a r i s L. 1 0.32 Harpalus acneus F. 3 0.02 Larvae 8 0.15 U n i d e n t i f i e d 9 0.09 S t a p h y l i n i d a e 13 0.58 Scarabaeidae Aphodius d i s t i n c -tus ( M u l l ) . 9 0.06 U n i d e n t i f i e d 2 T Curculionidae U n i d e n t i f i e d 6 0.14 Phytonomus founc-tatu s F. 12 0.69 S i t o n i a h i s p i d u s F. 15 1.27 E l a t e r i d a e 1 T Rhysadidae 1 T Byrrhidae 1 0 01 P l a n t Matter Angiospermae Monocotyledoneae Gramineae A g r o s t i s s t o l o n i f e r a -Leaves Lolium sp, -Leaves Echinochloa c r u s g a l l j -Seed M a l l a r d # V o l Glaucous Winged G u l l # Vol 7 22.05 1 3.29 2(70 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during November, 1966. Food Item Juncaceae Juncus sp.-Seed Cyperaceae Scirpus americanus -Seed Scirpus v a l i d u s -Seed Scirpus paludosus =Seed Scirpus acutus -Seed Carex lyngbyei -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i - c a r i a -Seed Polygonum a v i -cu l a r e -Seed Rumex o c c i d e n t a l i s Pheasant # V o l -Seed Chenopodiaceae A t r i p l e x p a t u l a -Seed Caryophyllaceae Spurgula arven- s i s -Seed Rosaceae Rubus l a c i n i a t u s -Seed Malus fu s c a -Seed Leguminosae T r i f o l i u m sp. -Seed U n i d e n t i f i e d Seeds Pieces of lead shot U n i d e n t i f i e d m a t e r i a l Sand G r i t 1 1 S t a r l i n g # Vol M a l l a r d # Vol Glaucous Winged G u l l # Vol 1 0.30 T 5.60 0.05 1 1.30 T 1.50 16 6 1.54 5.37 0.05 1 1 0.01 0.35 4 2 0.93 0.01 TOTAL 1 2.11 22 15.91 1 9.30 7 12.99 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g December, 1966. Food Item Animal Matter Annelida Oligochaeta A l l o l o b o p h o r a sp. Arthropoda Arachnida Araneae I n s e c t a Hemiptera Coreidae Reduviidae Lepidoptera Larvae D i p t e r a Pupae U n i d e n t i f i e d B i b i o n i d a e -Larvae Coleoptera Carabidae Larvae U n i d e n t i f i e d S t a p h y l i n i d a e C u r c u l i o n i d a e Phytonomus founctatus F. S i t o n i a h i s p i d u s F. U n i d e n t i f i e d i n s e c t eggs w i t h l a r v a e P l a n t Matter Angiospermae Monocotyledoneae Gramineae Holcus l a n a t u s -Seed Pheasant # Vol 0.01 15.11 S t a r l i n g M a l l a r d # Vol # V o l 4 1 4 7 6 7 1> Glaucous Winged G u l l # Vol Green Winged Teal # Vol Mew G u l l # V o l H e r r i n g G u l l # V o l 7 1.51 1 0.21 3 103.98 3 15.90 1 14.10 0.02 0.01 7 0.24 0.08 0.04 0.02 0.12 0.45 0.02 1 ro I—1 0.04 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g December, 1966, continued. Pheasant S t a r l i n g M a l l a r d # V o l # V o l # V o l Avena s a t i v a -Seed Lolium m u l t i f l o r u m 1 -Seed Agropyron repens -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a -Seed 2 Polygonum a v i c u l a r e -Seed Polygonum convol-v u l u s -Seed 2 Caryophyllaceae Spurgula a r v e n s i s -Seed 2 Leguminosae T r i f o l i u m pratense -Seed 1 T r i f o l i u m hybridum -Leaves T r i f o l i u m repens -Seed Gentianaceae Menyanthes t r i f o l i a t a -Seed U n i d e n t i f i e d Seed Pieces of Lead Shot U n i d e n t i f i e d M a t e r i a l Sand G r i t TOTAL Glaucous Winged G u l l # V o l 6.40 T 2.60 0.37 3.23 T 2 3 0.01 0.02 2.84 7 2.88 0.01 2.75 Green Winged Teal # V o l 1 0.01 1 0.06 1 T 1 1 1 1 1 2 33 .48 7 5.38 1 0.21 3 103.98 1 Mew G u l l # V o l 0.10 0.02 0.02 1 0.01 0.17 3 0.34 H e r r i n g G u l l # Vol 1.00 0.77 3 16.90 1 14.10^ Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g January, 1967. Food Item Pheasant S t a r l i n g K i l l d e e r M a l l a r d P i n t a i l Mew G u l l Widgeon # Vol # Vol # V o l # . V o l # V o l # V o l # Vol Animal Matter M o l l u s c a Gastropoda - u n i d e n t i f i e d (Marsh) 1 T -eggs 1 T Annelida Oligochaeta A l l o l o b o p h o r a S p . 11 4.71 1 0.11 4 6.54 6 44.00 Arthropoda Crustaceae Isopoda 2 0.61 Amphipoda, ' Gammariidae 2 0.48 Arachnida Araneae 8 0.01 1 T I n s e c t a Hemiptera Reduviidae 1 0.01 Homoptera Cercopidae 1 T L e p i d o p t e r a -Larvae 14 1.98 D i p t e r a -Larvae 1 0.42 1 0.01 1 0.01 -Pupae 12 0.03 2 0.01 - U n i d e n t i f i e d 7 0.01 1 T B i b i o n i d a e -Larvae 1 8.51 Coleoptera C i c i n d e l i d a e - U n i d e n t i f i e d 1 T Carabidae P t e r o s t i c h u s v u l g a r i s L. 1 0 .05 ro Larvae 1 0.01 ^ U n i d e n t i f i e d 10 0.08 1 T S t a p h y l i n i d a e 7 0.03 Scarabaeidae Aphodius d i s t i n c t u s ( M u l l ) . 7 0.01 1 T U n i d e n t i f i e d 1 T Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g January, 1967. Pheasant S t a r l i n g K i l l d e e r M a l l a r d P i n t a i l Mew G u l l Widgeon # V o l # V o l # V o l # Vol # Vol # V o l # V o l C u r c u l i o n i d a e U n i d e n t i f i e d 10 0.09 Phytonomus founctatus F. 3 0.09 S i t o n i a h i s p i d u s F. 14 0.31 2 0.01 1 T -Larvae 3 0.07 U n i d e n t i f i e d i n s e c t eggs w i t h l a r v a e 7 0.02 P l a n t Matter Angiospermae Monocotyledoneae Gramineae -Grass seed 2 0.03 Poa sp. -Leaves 1 0.01 Avena s a t i v a -Seed 1 0.07 A g r o s t i s s t o l o n i -f e r a -Leaves 1 0.20 Agropyron repens -Leaves 1 0.01 Juncaceae Juncus sp. -Seed 1 T Juncaginaceae T r i g l o c h i n maritima -Seed 3 1.20 Cyperceae E l e o c h a r i s p a l u s t r i s -Seed I T S c i r p u s americanus -Seed 2 0.86 3 0.50 1 T S c i r p u s v a l i d u s -Seed 2 0.03 1 0.04 S c i r p u s paludosus -Seed • 2 8 . 8 l S c i r p u s acutus -Seed 1 0.03 1 0.01 ro Carex l y n g b y e i -Seed I T . 2 0.34 4 5.18 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during January, 1967. Pheasant S t a r l i n g K i l l d e e r M a l l a r d P i n t a i l Mew G u l l Widgeon # Vol # Vol # V o l # Vol # V o l # V o l # V o l Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a -Seed 1 0.55 2 T 1 0.01 3 0.05 Polygonum a v i c u l a r e -Seed I T I T Polygonum convolvulus -Seed 1 15.80 1 T Rumex a c e t o s e l l a -Seed 1 T Chenopodiaceae A t r i p l e x p a t u l a -Seed 3 0.26 Caryophyllaceae S t e l l a r i a media -Seed 2 T Spurgula a r v e n s i s -Seed 1 1.25 1 T Rosaceae P o t e n t i l l a p a c i f i c a -Seed 3 1.41 Rubus l a c i n i a t u s -Seed 1 T Leguminosae T r i f o l i u m sp. -Seed 2 0.02 -Leaves 1 0.04 T r i f o l i u m pratense -Seed 3 T T r i f o l i u m repens -Seed 2 T M e l i l o t u s a l b a -Seed 5 0.01 U m b e l l i f e r a e Sium sauve -Seed 1 0.02 Gentianaceae Menyanthes t r i f o l i a t a -Seed 1 0.01 Compositae C i r s i u m v u l g a r e -Seed I T f^ Aster sp. -Seed 1 T U n i d e n t i f i e d Seeds 2 0.04 U n i d e n t i f i e d M a t e r i a l 1 0.05 16 8.63 2 0.02 2 0.79 4 1.37 6 2.10 1 0.32 Sand G r i t 1 1.28 9 0.06 2 0.03 2 2.00 2 1.54 1 1.80 TOTAL l 27.51 16 17.27 2 0.19 4 10.59 5 22.14 6 46.10 1 2.39 on Food A n a l y s i s of B i r d s C o l l e c t e d on Vane Food Item K i l l d e e r # Vol Animal Matter Annelida -Oligochaeta A l l o l o b o p h o r a sp. 2 0.32 Arthropoda - I n s e c t a T r i c h o p t e r a -Larvae Coleoptera - S t a p h y l i n i d a e 1 T -Scarabacidae -Aphodius d i s t i n c t u s ( M u l l ) . 1 OCQl -C u r c u l i o n i d a e -Phytonomus founctatus F. -Larvae 2 0.06 Pl a n t Matter Angiospermae -Monocotyledoneae Graminese -Alopecurus geniculatus -Leaves -Poa sp. -Leaves - A g r o s t i s s t o l o n i f e r a -Leaves -Agropyron repens -Seed -Leaves \rer A i r p o r t during February, 1967. Glaucous Mew M a l l a r d Winged G u l l Widgeon G u l l # Vol # V o l # Vol # Vol 3 9.56 4 51.63 2 0.22 2 0 .45 1 0.01 1 1.55 2 0.38 ro 1 0.01 o^  4 0.28 0.21 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g February, 1967. Food Item Dicotyledoneae -Polygonaceae Rumex a c e t o s e l l a -Leaves -Caryophyllaceae Spurgula a r v e n s i s -Seed -Leguminosae T r i f o l i u m sp. -Leaves -Compositae Hypochaeris r a d i c a t a -Leaves U n i d e n t i f i e d seeds U n i d e n t i f i e d m a t e r i a l Sand g r i t TOTAL K i l l d e e r # V o l M a l l a r d # V o l 0.01 0.11 1 0.02 Glaucous Winged G u l l # V o l Mew G u l l Widgeon # V o l # V o l 1 0.89 3 0.70 3 1.12 0.06 1 0.41 3 0.07 0.51 3 10.05 4 51.63 3 20Q4 4 3.85 ro Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g March, 1967. Food Item Pheasant # Vol Animal Matter M o l l u s c a -Gastropoda - U n i d e n t i f i e d Annelida -Oligochaeta A l l o l o b o p h o r a sp. Arthropoda -Crustaceae -Isopoda -Arachnida -Araneae - I n s e c t a -Homoptera C i c a d e l l i d a e - T r i c h o p t e r a -Larvae -Lepidoptera -Larvae - D i p t e r a -Larvae -Pupae -D r o s o p h i l i d a e -Pupae -Dolichopodidae -Coleoptera -Carabidae - U n i d e n t i f i e d - S t a p h y l i n i d a e -Scarabacidae -Aphodius d i s t i n c t u s ( M u l l ) . - C u r c u l i o n i d a e - U n i d e n t i f i e d Glaucous Winged Mew-S t a r l i n g M a l l a r d P i n t a i l Teal G u l l Widgeon # V o l # V o l # V o l # Vol # V o l # V o l 3 0.01 1 0.20 • 5 1.99 5 8.12 1 0.55 1 1.36 4 31.87 3 0.39 8 0.02 1 T 0.01 6 2 2 2 0.17 0.04 0.01 0.01 2 1.77 1 2 1 0.01 0.14 T 2 1 0.03 T 4 3 2 2 0.09 0.03 0.02 0.09 ro oa Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g March, 1967. Glaucous Winged Mew-Food Item Pheasant S t a r l i n g M a l l a r d P i n t a i l Teal G u l l Widgeon # Vol # V o l # V o l # V o l # V o l # V o l # V o l -Phytonomus founctatus F. 1 0.04 - S i t o n i a h i s p i d u s F. 8 0.22 1 0.01 1 T -Larvae 3 0.05 -Larvae 1 T - U n i d e n t i f i e d 1 T U n i d e n t i f i e d i n s e c t eggs w i t h l a r v a e 1 T P l a n t Matter Angiospermae -Monocotyledoneae -Gramineae - Grass Seed 1 T -Alopecurus ge n i c u l a t u s -.•Leaves I T 1 2.18 -Poa sp. -Seed 1 T -Typhaceae -Typha l a t i f o l i a -Seed 2 T -Cyperaceae -Sci r p u s americanus 6 0.03 2 0.02 - S c i r p u s v a l i d u s 1 0.04 2 "0.14 -Carex l y n g b y e i -Seed 5 0.28 1 0.03 2 0.05 -Dicotyledoneae -Polygonaceae -Polygonum p e r s i c a r i a -Seed 3 3.62 5 1.25 1 0.04 1 0.08 -Rumex c r i s p u s -Seed 1 T -Caryophyllaceae S t e l l a r i a media -Seed I T I T Cerastium vulgatum -Seed 2 T Spurgula a r v e n s i s -Seed 2 T 2 0.57 \o Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t d u r i n g March, 1967. Glaucous Winged Mew Food Item Pheasant S t a r l i n g M a l l a r d P i n t a i l Teal G u l l Widgeon # Vol # V o l # V o l # V o l # V o l # V o l # Vol » -Rosaceae P o t e n t i l l a p a c i f i c a -Seed 1 T Prunus emarginta -Seed 1 0.02 Rosa nutkana -Seed 2 0.08 Malus f u s c a -Seed 1 0.03 -Leguminosae T r i f o l i u m sp. Seed 1 T T r i f o l i u m repens -Seed 3 T Lathyrus sp. -Seed 2 0.47 V i c i a sp. - Seed 1 T -Compositae Sonochus a r v e n s i s -Seed 1 T -Equisetaceae Equisetum arvense -Buds U n i d e n t i f i e d m a t e r i a l Sand g r i t 3 4.65 3 0.01 9 5.84 1 1.70 3 0.46 1 0.02 1 14.00 2 0.68 8 0.10 7 4.99 1 1.04 3 0.30 4 0.50  .65  .01  .84  .70  .46  3 24.07 8 3.32 9 22.76 1 3.40 3 2.47 4 32.37 1 TOTAL  .   .  .  1  .40 2.20 ro 03. O 281 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during A p r i l , 1967. Food Item Pheasant K i l l d e e r # V o l # V o l Animal Matter Annelida -Oligochaeta Allolobophora sp. 3 0.52 Arthropoda -Insecta -Lepidoptera -Larvae 3 0.31 -Diptera -Larvae 1 T • -Pupae Muscidae 1 0.01 -Coleoptera Carabidae -Larvae 1 0.05 - U n i d e n t i f i e d 1 0.03 3 0.01 S t a p h y l i n i d a e 3 0.03 Scarabaeidae Aphodius d i s t i n c t u s ( M u l l ) . 1 0.01 Curculionidae - U n i d e n t i f i e d 4 0.02 Phytonomus founctatus F. 1 T S i t o n i a h i s p i d u s F. 4 0.02 . Larvae 2 0.07 -Hymenoptera - U n i d e n t i f i e d 1 0.04 Plant Matter Angiospermae -Monocotyledoneae -Gramineae Alopecurus geniculatus -leaves Poa -sp. -leaves 1 A g r o s t i s s t o l o n i f e r a -leaves 2 Echinochloa c r u s g a l l i -Seed -Cyperaceae Scirpus americanus -Seed Carex lyngbyei -Seed'' -Dicotyledoneae -Polygonaceae Polygonum p e r s i c a r i a -Seed 3 Polygonum a v i c u l a r e -Seed 4.16 0.79 3.21 M a l l a r d # Vol 1 O.Oi Widgeon # Vol 1 0.01 2 2 3 1 1 1.76 0.02 0.13 0.05 1.11 T 282 Food A n a l y s i s of B i r d s C o l l e c t e d on Vancouver A i r p o r t during A p r i l , 1967, continued. Food Item Pheasant K i l l d e e r M a l l a r d Widgeon # V o l # Vol # Vol # V o l Caryophyllaceae Cerastium vulgatum -Seed 1 16.40 Rosaceae Prunus emarginata -Seed 1 0.09 1 0.01 Leguminosae T r i f o l i u m sp.-Seed 2 T -leaves 1 0.05 T r i f o l i u m pratense -leaves 1 2.50 T r i f o l i u m repens -seed 1 T Pieces of lead shot 1 0.01 U n i d e n t i f i e d m a t e r i a l 4 0.10 2 0.07 Sand g r i t 3 4.33 1 T 3 3.43 1 0.01 TOTAL 3 31.57 4 1.22 3 4.93 1 1.77 283 Food A n a l y s i s of B i r d s C o l l e c t e d i n Vancouver A i r p o r t during May, 1967. Pheasant S t a r l i n g Food Item # Vol # V o l Animal Matter Mollusca Gastropoda .Un i d e n t i f i e d .slug 1 0.10 1 0.54 Arthropoda Crustacea -Isopoda 1 0.02 Insecta -Lepidoptera Larvae 2 0.29 Coleoptera -Carabidae Harpalus acneus F. 1 0.01 -Chrysomelidae 1 0.10 -Curculionidae - U n i d e n t i f i e d 1 0.03 - U n i d e n t i f i e d 1 0.06 Plant Matter Angiospermae -Monocotyledoneae -Gramineae Poa sp. - seed 1 6.10 - leaves 1 0.02 A g r o s t i s s t o l o n i f e r a - leaves 1 0.01 -Dicotyledoneae -Polygonaceae Polygonum p e r s i c a r i a - seed 2 0 . 0 5 -Caryophyllaceae Cerastium vulgatum - seed 1 0.03 Spurgula a r v e n s i s - seed 1 0.90 -Leguminosae -Lathyrus sp. - seed 1 0.09 -Compositae Hypochaeris r a d i c a t a - flowers 1 0 . 1 5 U n i d e n t i f i e d M a t e r i a l 1 T Sand G r i t 2 •6.24 1 T TOTAL 2 18.02 2 1.07 284 10.3.2 T o t a l Food A n a l y s i s of A l l Non-Problem and Some Problem B i r d Species, Food Item Animal M a t t e r M o l l u s c a Gastropoda Pelecypoda A n n e l i d a Oligochaeta A l l o l o b o p h o r a sp. Arthropoda Arachnida Araneae I n s e c t a Collembola Hemiptera Pentatomidae U n i d e n t i f i e d Homoptera C i c a d e l l i d a e Aphididae Le p i d o p t e r a Larvae D i p t e r a Chironomidae -Larvae Nematocera U n i d e n t i f i e d -Adult -Larvae -Pupae Fragments of Hymenoptera and D i p t e r a C o l e o p t e r a C i c i n d e l i d a e C i n c i n d e l a oregona Le Carabidae P t e r o s t i c h u s v u l g a r i s B l a c k - b e l l i e d P e c t o r a l B a i r d ' s Pl o v e r Sandpiper Sandpiper # V o l # V o l # V o l 1.02 1 0.02 2 2 T T 1 1 3 0.07 1 1 0.H 0.12 1 0.08 1 0.03 1 0.04 3 0.17 1 T Food Item Harpalus acneus F, U n i d e n t i f i e d Larvae S t a p h y l i n i d a e Chrysomelidae C u r c u l i o n i d a e Phytonomus founctatus F. S i t o n i a h i s p i d u s F. U n i d e n t i f i e d Rhizophagidae H a l i p l i d a e Hymenoptera Icheumonidae Braconidae C h a l c i d i d a e P l a n t M a t t e r Angiospermae Monocotyledoneae Gramineae Alopecurus ge n i c u l a t u s -Seed Phleum pratense -Seed Cyperaceae S c i r p u s paludosus -Seed S c i r p u s v a l i d u s -Seed S c i r p u s americanus -Seed Carex l y n g b y e i -Seed Typhaceae Typha l a t i f o l i a -Seed B l a c k - b e l l i e d P e c t o r a l B a i r d ' s Plover Sandpiper Sandpiper # V o l # V o l # V o l 1. 0 . 0 1 1 T 1 T 3 0 . 0 4 2 0 . 0 1 3 0.35 3 0.28 7 0.53 6 0.03 1 0.08 1 0 . 0 1 2 0.13 5 0 . 0 4 5 0 . 0 4 1 T Food Item Dicotyledoneae Polygonaceae Polygonum a v i c u l a r e -Seed Polygonum p e r s i c a r i a -Seed Rumex a c e t o s e l l a -Seed Chenopodiaceae Chenepodium album -Seed C r u c i f e r a e Raphanus raphanistrum -Seed Caryophyllaceae Spurgula a r v e n s i s -Seed Leguminoseae T r i f o l i u m repens -Seed U n i d e n t i f i e d Seeds Pieces of Lead Shot U n i d e n t i f i e d M a t e r i a l Sand G r i t TOTAL B l a c k - b e l l i e d P e c t o r a l B a i r d f s P l o v e r Sandpiper Sandpiper # V o l # V o l # V o l 1 T 2 0.01 T 1 T 4 0.01 1 T 3 0.02 5 0.08 3 1.33 7 0.48 10 1.28 Food Item Animal Matter M o l l u s c a Gastropoda Pelecypoda Annelida CTigochaeta A l l o l o b o p h o r a sp. Arthropoda Arachnida Araneae I n s e c t a Collembola Hemiptera Pentatomidae U n i d e n t i f i e d Homoptera C i c a d e l l i d a e Aphididae Lepidoptera -Larvae D i p t e r a Chironomidae -Larvae Nematocera U n i d e n t i f i e d -Adult -Larvae -Pupae Fragments of Hymenoptera and D i p t e r a Coleoptera C i c i n d e l i d a e C i n c i n d e l a oregona Lec Western Dunlin Dowitcher Sandpiper # Vol # V o l # Vol 1 0.01 1 0.03 7 1.40 1 0.03 7 0.10 2 0.06 2 0.16 1 0.01 1 O.i 1 T 3 0.06 6 0.22 6 0.45 1 T Least Food Item Sandpiper # V o l Carabidae P t e r o s t i c h u s v u l g a r i s L. Harpalus acneus F. U n i d e n t i f i e d 2 0.01 Larvae 7 0.53 S t a p h y l i n i d a e 2 T Chrysomelidae C u r c u l i o n i d a e Phytonomus founctatus F. S i t o n i a h i s p i d u s F. U n i d e n t i f i e d 4 0.06 Rhizophagidae H a l i p l i d a e Hymenoptera Icheumonidae Braconidae C h a l c i d i d a e 1 T P l a n t M a t t e r Angiospermae Monocotyledoneae Gramineae Alopecurus geniculatus -Seed Phleum pratense -Seed Cyperaceae Scir p u s paludosus -Seed S c i r p u s v a l i d u s -Seed S c i r p u s americanus -Seed Carex l y n g b y e i -Seed Typhaceae Typha l a t i f o l i a -Seed Western D u n l i n Dowitcher Sandpiper # V o l # V o l # V o l 1 T 2 T 1 0.04 1 0.01 1 0.01 2 T 2 0.01 1 T 1 0.01 2 T 4 0.01 2 0.01 1 T 1 T 1 T 4 0.02 5 0.01 6 0.09 8 0.15 5 0.06 1 T 1 T Food Item Dicotyledoneae Polygonaceae Polygonum a v i c u l a r e -Seed - Polygonum p e r s i c a r i a -Seed Rumex a c e t o s e l l a -Seed Chenopodiaceae Chenopodium album -Seed C r u c i f e r a e Raphanus raphanistrum -Seed Caryophyllaceae Spurgula a r v e n s i s -Seed Leguminoseae T r i f o l i u m repens -Seed U n i d e n t i f i e d Seeds Pieces of Lead Shot U n i d e n t i f i e d M a t e r i a l Sand G r i t TOTAL Western Dunlin Dowitcher Sandpiper # V o l # V o l # V o l 6 0.02 4 1 T 1 1 1 T 5 1 1 T 1 0.01 4 7 0.07 6 18 0.97 11 10 1.32 13 0.01 T 0.01 0.01 T 0.07 0.52 0.37 1 13 28 T 0.02 0.16 3.81 30 1.06 1 Animal Matter Annelida Oligochaeta A l l o l o b o p h o r a sp. Arthropoda Crustacea Isopoda Ampnipoda Gammariidae Arachnida Araneae I n s e c t a Orthoptera Locustidae Hemiptera Homoptera C i c a d e l l i d a e Lepidoptera Larvae D i p t e r a Adult Larvae Pupae D r o s o p h i l i d a e Coleoptera Carabidae Larvae A d u l t s C i n c i n d e l i d a e Larvae Adult C i n c i n d e l a oregona Lec. S t a p h y l i n i d a e Scarabaeidae Semi-Greater Wilson's Lesser palmated Yellowlegs Snipe Yellowlegs Plover # V o l # V o l # V o l # V o l Semi-palmated SSndpiper # Vol 1 0.75 1 0.20 1 T 1 0.03 1 0.01 1 Western Meadow Lark # V o l 1 0.03 3 0.58 1 0.01 8 2.94 1 T 1 T 1 7 1 1 2 4 2 0.05 0.27 0.03 0.04 0.01 0.03 T American Coot # Vol 1 0.01 1 0.22 1 0.01 ro vO I-1 C u r c u l i o n i d a e Phytonomus founctatus F. Adult S i t o n i a h i s p i d u s F. Rhizophagidae Larvae Hymenoptera Formicidae P l a n t Matter Antiospermae Monocotyledonae Gramineae A g r o s t i s s t o l o n i f e r a -Leaves J uncaceae Juncus sp. -Seed Capsules & stems Cyperaceae Sci r p u s acutus -Seed Polygonaceae Polygonum p e r s i c a r i a Caryophyllaceae Spurgula a r v e n s i s -Seed Leguminosae T r i f o l i u m repens -Seed M e l i l o t u s a l b a -Flower Sand G r i t U n i d e n t i f i e d M a t e r i a l TOTAL Semi-Greater Wilson's Lesser palmated Yellowlegs Snipe Yellowlegs Plover # V o l # V o l # V o l # V o l 1 0.01 1 T 1 0.01 1 0.40 Semi-palmated Sandpiper # V o l 0.01 Western Meadow Lark # V o l 1 8 1 1 0.01 0.06 0.05 T 1 0.01 American Coot # Vol 1 1.00 1 0.41 1 T 1 T 1 T 1 0.01 4 0.03 1 0.01 1 T 4 0.14 1 0.45 1 T 3 0.04 1 0.02 1 0.79 4 0.07 1 0.40 1 0.21 2 0.02 12 4.35 1 2.12 T o t a l Food A n a l y s i s of Nonproblem B i r d Species C o l l e c t e d on Vancouver A i r p o r t throughout the Study P e r i o d (May 1966 - May 1 9 6 7 ) . American Horned Barn Water House Gold- Savannah Morning Food Item Lark Swallow Robin P i p i t F i n c h F i n c h Sparrow Dove # Vol # Vol # Vol # V o l # V o l # Vol # V o l # V o l Animal Matter Annelida Oligochaeta 9 5.53 Arthropoda Arachnida Araneae I T I T I T I T I T A c a r i n a 2 T I n s e c t a Collembola 1 T Orthoptera Locutidae 2 0.02 1 0.01 Dermoptera 1 0.03 Ephemeroptera 1 T Hemiptera Nabiidae I T Pentatomidae 1 0.01 U n i d e n t i f i e d 3 T 3 0.01 2 0.02 Homoptera C i c a d e l l i d a e 5 0.03 2 0.10 3 0.01 4 0.04 Aphididae Lepidoptera -Larvae I T 4 0.74 6 0.17 3 0 , 1 5 D i p t e r a Chironomidae -Larvae 2 T Cecidomyidae 3 T 3 T M y c e t o p h i l i d a e 1 0.04 S i m u l i i d a e 1 T A s i l i d a e 2 0.20 Syrphidae 1 0.02 T o t a l Food A n a l y s i s of Nonproblem B i r d Species C o l l e c t e d on Vancouver A i r p o r t throughout the Study P e r i o d (May 1966 - May 1967) continued. Horned Lark # Vol D r o s o p h i l i d a e 1 T Muscidae Dolichopodidae Metopidae Phocidae B i b i o n i d a e -Larvae U n i d e n t i f i e d -Larvae Fragments of Hymenop-t e r a and D i p t e r a Coleoptera C i c i n d e l i d a e C i n c i n d e l a oregona Lec. Carabidae P t e r o s t i b h u s v u l g a r i s L. Harpalus acneus F. U n i d e n t i f i e d Larvae 2 0.10 S t a p h y l i n i d a e C o c c i n e l l i d a e Buprestidae Scarabaeidae Chrysomelidae C u r c u l i o n i d a e Phytonomus founctatus F. S i t o n i a h i s -pidus F. 5 0 .04 U n i d e n t i f i e d 4 0.03 Rhizophagidae Barn Swallow Robin # V o l # V o l 8 0.03 3 0.07 3 0.01 1 0 .01 2 T 4 0.26 3 0.22 6 0.28 1 0.01 1 0 . 0 s 2 0.07 2 0.03 3 0.02 6 0.64 3 0.06 3 0.05 1 T • 2 0.01 2 0 .01 1 0 .01 1 0 .01 3 0 .01 3 0 .06 Water P i p i t # V o l 5 0.01 1 4 4 4 9 2 0.01 0.43 0.01 0.04 0.14 0.12 o;oi House Fi n c h # V o l American Gold-F i n c h # V o l Savannah Sparrow # Vol Morning Dove # V o l 1 0.15 2 T 1 T 8 0 .04 10 0.07 T o t a l Food A n a l y s i s of Nonproblem B i r d Species C o l l e c t e d on Vancouver A i r p o r t throughout the Study P e r i o d (May 1966 - May 1967) Continued. Horned Lark # Vol H i s t e r i d a e Hymenoptera S i r i c i d a e Tenthredinidae Ichneumonidae Braconidae Eurytomidae Chilopoda P l a n t Matter Angiospermae Monocotyledonae Gramineae Alopecurus genic-u l a t u s L. -Seed 1 0.05 Phleum pratense -Seed Holcus l a n a t u s -Seed Poa annua -Seed Avena s a t i v a -Seed A g r o s t i s a l b a -Seed A g r o s t i s sp. -Seed 1 0.03 Juncaceae Juncus sp. -Seed Polygonaceae Polygonum a v i c u l a r e -Seed Polygonum convolvulus  Polygonum p e r s i -c a r i a -Seed 3 0.06 Rumex a c e t o s e l l a -Seed 1 T Barn Swallow # • Vol 2 T 1 T 1 0.01 1 0.05 Robin I Vol Wat er P i p i t # V o l 1 T 1 T House Finch American Gold-F i n c h # Vol # V o l k 0.18 5 0?01 5 0.02 5 0.02 23 2.23 2 T Savannah Sparrow # V o l 1 1 T T 2 T 10 0.21 1 T 3 0.01 Morning Dove # V o l 2 0.01 T 5 0.06 T o t a l Food A n a l y s i s of Nonproblem B i r d Species C o l l e c t e d on Vancouver A i r p o r t throughout the Study P e r i o d (May 1966 - May 1967) Continued. 1 T Horned Lark # Vol Dicotyledonae Chenepodiaceae Chenopodium  album -Seed C r u c i f e r a e Raphanus raphanistrum -Seed B r a s s i c a campestris -Seed Caryophyllaceae S t e l l a r i a media -Seed Cerastium vulgatum -Seed 3 0.02 Spurgula arven-s i s -Seed 4 0.16 Rosaceae Rubus s p e c t a b i l i s -Seed Rubus l a c i n i a t u s -Seed Malus f u s c a -Seed + f r u i t -Leguminosae T r i f o l i u m sp. -Seed T r i f o l i u m repens -Seed Geraminaceae Erodium c i r c u t a r i u m -Seed Barn Swallow # Vol Robin # Vol Water P i p i t # V o l •1 T 1 0.01 1 0.96 House Finc h # Vol 8 0.01 21 7 9 1 1 American Gold-F i n c h # Vol 0.78 0.86 0.64 0.16 T Savannah Morning Sparrow Dove # V o l # V o l 2 10 1 0.01 0.09 T 10 7.( 4 0.14 % 0.37 2 0.07 T o t a l Food A n a l y s i s of Nonproblem B i r d Species C o l l e c t e d on Vancouver A i r p o r t throughout the Study P e r i o d (May 1966 - May 1967) Continued. Horned Barn Water House American Gold-Lark Swallow Robin P i p i t F i n c h Finch Sparrow Dove # Vol # V o l # V o l V o l # Vol # Vol # Vol # Vol C a p r i f o l i a c e a e Sambucus pubens -Seed 6 0.26 Compositae Sonchus a r v e n s i s -Seed 3 0.21 2 T Ci r s i u m sp. 3 0.07 Ci r s i u m vulgare -Seed 4 0.08 3 11.55 Hypochaeris r a d i -cata -Seed 1 T 5 0.07 6 0.63 U n i d e n t i f i e d Seeds 5 0.05 4 0.04 1 T Pieces of Lead Shot 1 0.01 U n i d e n t i f i e d M a t e r i a l 2 T 8 0.15 1 T 6 0.12 Sand G r i t 10 0.20 6 0.03 13 0.04 26 0.34 8 0.04 22 0.37 7 0.77 TOTAL 12 0.77 11 0.79 IS 9.13 13 1.03 36 5.77 11 1.10 29 1.42 10 20.51 Red Winged House B l a c k b i r d Sparrow # V o l # V o l Animal Matter M o l l u s c a Gastropoda M y t i l u s sp. Arthropoda Crustaceae Isopoda Amphipoda Gammariidae Arachnida Araneae ""nsecta Lepidoptera Larvae 1 0 . 0 7 D i p t e r a Larvae 3 0 . 0 7 Pupae 1 0 . 0 1 Nematocera 1 T Coleoptera Carabidae -Larvae 1 T C i n c i n d e l i d a e -Adult 2 T C u r c u l i o n i d a e U n i d e n t i f i e d pupae Chordata P i s c e s F i s h remains P l a n t Matter Angiospermae Monocotyledonae Gramineae Holcus l a n a t u s -Leaves White Snow Crowned Lapland Canada Old Bunting Sparrow Longspur Goose Squaw # V o l # Vol # V o l # V o l # V o l 1 0 . 0 5 1 T I T 1 0 . 0 3 1 0 . 0 2 2 0 . 0 1 1 T 1 0 . 0 1 1 0 . 0 9 1 0 . 3 1 1 0 . 0 1 1 0 . 6 5 Red Winged House B l a c k b i r d Sparrow # V o l # Vol Avena s a t i v a -Seed 1 0.02 A g r o s t i s a l b a f l o r e t s & seeds A g r o s t i s s t o l o n i f e r a Leaves Lolium sp. -Seed Agropyron repens -Seed 1 0.01 Typhaceae Typha l a t i f o l i u m -Seed 3 T Cyperacae S c i r p u s americanus -Seed Carex l y n g b y e i -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a -Seed Polygonum sp. -Seed Caryophyllaceae S t e l l a r i a media -Seed Spurgula a r v e n s i s -Seed Leguminosae T r i f o l i u m pratense -Leaves Sand G r i t 1 0.01 1 0.01 U n i d e n t i f i e d M a t e r i a l 4 0.04 TOTAL 5 0.22 1 0.03 White Snow Crowned Lapland Canada Old Bunting Sparrow Longspur Goose Squaw # V o l # V o l # Vol # V o l # Vol 3 0.06 2 0.03 1 6.37 1 1.35 1 0.05 1 0.32 3 0.02 1 T 1 T 1 T 1 0.01 4 0.01 1 1.60 1 0.08 4 0.29 5 0.20 1 0.30 1 0.05 3 0.05 3 0.02 1 0.55 1 0.15 4 0.36 5 0.36 1 10.00 1 1.68 Long B i l l e d Marsh Cowbird Wren # Vol ' # Vol Arachnida 1 T Homoptera C i c a d e l l i d a e 1 0.08 1 T Lepidoptera Larvae D i p t e r a Larvae D r o s o p h i l i d a e Fragments of Hymenoptera and D i p t e r a Coleoptera Carabidae -Adults C i n c i n d e l i d a e -Adult C i n c i n d e l a oregona Lec. S t a p h y l i n i d a e S i l p h i d a e Buprestidae Scarabaeidae Aphodius d i s t i n c t u s ( M u l l ) . Chrysomelidae C u r c u l i o n i d a e Adult S i t o n i a h i s p i d u s F. Rhizophagidae S c o l y t i d a e 1 T Cerambycidae Song. Brewer's C l i f f Snow Sparrow B l a c k b i r d Crow Swallow Goose # V o l # V o l # Vol # Vol # V o l 1 0.01 1 0.33 1 0.01 1 T T 1 0.03 1 0.07 1 0.01 0.07 1 0.05 1 0.12 T 2 0.02 2 0.03 1 0.01 1 0.01 1 T 1 T 1 T 0.0Z, o o Cowbird # V o l Hymenoptera Chneumonidae Tenthredinidae C h a l c i d i d a e 1 T Chordata Mammalia Mi c r o t u s sp. Pl a n t Matter Angiospermae Monocotyledonae .:Sramineae Holcus l a n a t u s -Seed 3 0.. 28 Avena s a t i v a -Seed 3 0.02 Lolium sp. -Seed Dactylus glomerata -Seed 1 T Cyperacae S c i r p u s americanus -Seed -Roots Carex l y n g b y e i -Seed Dicotyledoneae Polygonaceae Polygonum p e r s i c a r i a 1 T Polygonum convolvulus -Seed Chenopodiaceae Chenopodium album -Seed Sand G r i t 4 0.05 U n i d e n t i f i e d M a t e r i a l 3 0.30 Long B i l l e d Marsh Wren # V o l Song Sparrow # V o l 1 0.01 1 0.01 2 1 3 3 2 0.03 T 0.11 0.14 0.03 Brewer's B l a c k b i r d # V o l 1 0.01 1 TOTAL 4 0.74 1 0.01 4 0.35 1 2 Crow # V o l T C l i f f Snow Swallow Goose # V o l # V o l 1 0.01 1 2.00 0.01 2 0.47 2 0.06 2.32 2 2 13.50 3.37 0.13 2 16.87 VO O M Pi FASF P F TI IR N Tfl THP r.DMPIlTTNG f.FNTftF STAFF S P A U S E M O U N T S C R A T C H T A P E ON U 0 4 J O B N U M B E R 8 1 0 1 8 C A T E G O R Y F U S E R ' S N A M E - D . R A Y H A L L A D A Y U S E R ' S P R O J E C T -* » * » « T H F C O M P U T I N G C . F N T R F W T1. L R F C L 0 S F D F R T . . S A T . . S U N . . A N D M Q N . . - A P R 11 1 2 . 1 3 . 1 4 A N D 1 5 * » * H A P P Y F A S T E R * * * * J O B S T A R T 1 2 H R S 2 1 M I N 4 3 . 4 S E C V 9 M 0 1 1 O F F - L I N E W G 9 5 1 D A T E 0 4 / 0 9 / 6 8 $JOB 8 1 0 1 8 R O N H A L L F O R R H A L L A D A Y * T E S T - R U N * $T I MF LQ , -S P A C E 1 0 0 * F I L E ' F T C 0 4 . » , U 0 4 , N O N E , B L 0 C K = 8 9 5 , L R L = 0 7 4 , R C T = 1 0 0 0 , J $ F I L E . . ... * F T C O A . . ' » U 0 4 , i N O N E , B_L0CK = 8 9 5 . i L R L = 0.74_».RCT = 1 00 .0 » $ETC T Y P E 3 » R E E L t D O U B L E » E R R = R E R R X . $ I 8 L D R P R E P 0 3 / 2 9 / 6 8 P R E P 0 0 0 1 SENTRY  TIME 1 2 H R S 2 1 M I N 5 0 . 5 S E C RON HAUL FOR R HAL LA DAY * T E S I B L D R — J O B OOOOOO 0 4 / 0 9 / 6 8 PAGE 1 M E M O R Y M A P • . J S Y S T E M , I N C L U D I N G I O C S 0 0 0 0 0 THRU 1 4 4 3 3 F I L E B L O C K O R I G I N 1 4 4 4 2 — NUMBER OF F I L E S - 3 1 . F T C 0 4 . 1 4 4 4 2 2 . S . F B I N 1 4 4 6 5 3 . S . F B O U 1 4 5 1 0 O B J E C T PROGRAM 1 4 5 3 3 THRU 2 1 3 7 0 1 . DECK • / F I L E S ' 0 0 0 0 0 2 . DECK ' P R E P » 1 4 5 3 3 3 . SUBR ' I N S Y F B • 1 4 7 1 0 4 . SUBR • O U S Y F B ' 1 4 7 4 7 5 . SUBR • P O S T X » 1 5 0 0 0 6 . SUBR • C N S T N T ' 1 5 1 2 6 7 . SUBR • F PR 1 1 5 1 3 5 8 . SUBR * F 0 4 . • .. . 1 5 1 3 6 9 . SUBR • F 0 5 • 1 5 1 3 7 1 0 . SUBR « I O S • 1 5 1 4 0 1 1 . SUBR • RWB • 1 5 4 3 0 1 2 . SUBR • RWD • 1 6 0 4 1 1 3 . SUBR • E C V • 1 6 5 6 1 i « . . SUBR • F C V J 1 7 0 2 7 i s . SUBR ' GCV • 1 7 1 2 5 1 6 . SUBR • HCV » 1 7 1 5 0 1 7 . SUBR • I C V ' 1 7 2 5 3 1 8 . SUBR • XCV « 1 7 2 7 7 1 9 . SUBR • I N T J • 1 7 3 1 5 2 0 . SUBR • FF.C • . 2 0 0 1 6 2 1 . SUBR • TMTARR• 2 0 4 3 7 2 2 . SUBR 1 E F T • 2 0 6 1 0 2 3 . SUBR ' R WT * 2 0 6 4 3 2 4 . SUBR » F P T • 2 0 6 6 2 2 5 . SUBR ' X EM • * 2 1 0 7 2 2 6 . SUBR . • X I T . • 2 1 3 1 1 2 7 . SUBR • U . E O F R ' 2 1 3 1 3 < * - I N S E R T I O N S OR D E L E T I O N S MADE I N T H I S D E C K ) I N P U T - OUTPUT B U F F E R S 7 3 4 6 5 T H R U 7 7 7 7 6 UNUSED CORE 2 1 3 7 1 THRU 7 3 4 5 5 O B J E C T PROGRAM I S B E I N G E N T E R E D INTO S T O R A G E . T I M E 1 2 H R S 2 2 M I N 0 6 . 7 S E C TIME 12HRS 22MIN 15.5SEC . . ; K SIBSYS $ F I L E •FTC 04. •-,U04,, NONE ,BL0CK = 895,LRL=074,RCT = 1 000, • __$FILE .. '.FTC04.. 1 >T U.04.» NONE ,_BL0.CK-8„93_,_L.R.L.= 07A_, R.CT= 1.0.00., $ETC TYPE3,RE EL,DOUBLE,ERR = RERRX. $ IBLDR TDATA 04/05/68 TDAT0001 - ... ._ . -$ IBLDR U.TR09 04/03/68 t i . T R n n n i $ I BLDR U.TR15 04/03/68 U.TR0001 $ I BLDR U.TR06 03/08/68 U.TROOOl $IBLDR U.TR17 03/21/68 T R n n n i SIBLDR U.TR13 03/20/68 U.TROOOl SI BLDR U.TR07 03/20/68 U.TR0001 • .. STB1 nR U.TR OR 03/20/68 i i . T R n n n i $ I BLDR U.TROl 01/29/68 U.TROOOl $ IBLDR U.TR02 01/19/68 U.TROOOl „ _ _„...__ • - ~ -$TBi DR U,TRQ3 01 /OR/68 i i . T R n n n i $ I BLDR U.TR04 01/09/68 U.TROOOl $ I BLDR U.TR05 01/19/68 U.TROOOl _ - _ .. . $ IBLDR U.TRIO 02/17/68 i t . T R n n n i $ IBLDR U . T R l l 01/08/68 U.TR0001 $ IBLDR U.TR12 01/12/68 U.TROOOl & i RI ng_ U.TR14 01/l9 / 6 R n . T R n n n i $ I BLDR U.TR16 01/08/68 U.TROOOl $IBLD;R U.TRL8 01/08/68 U.TROOOl 4 T R I U.TRIQ m /l 1 /6R n.TRnnni R O N H A L L F O R R H A L L A D A Y * T E S PAGE 2 $IBLDR U . T R 2 0 0 1 / 0 8 / 6 8 U . T R 0 0 0 1 $I8LDR U . T R 2 1 0 1 / 0 8 / 6 8 U . T R 0 0 0 1 $ I BLDR F.IL30. 0 1 / 0 8 / 6 8 . . .. F I L 3 0 0 0 1 $ IBLDR E X T 0 2 / 1 2 / 6 8 E X T 0 0 0 1 $ IBLDR AGTRP 0 2 / 2 3 / 6 5 ] A G T R 0 0 0 1 SENTRY . . .. . A.GJRP . TIME 12HRS 2 2 M I N 5 4 . 9 S E C R O N H A L L F O R R H A L L A D A Y * T E S I B L D R — J O B O O O O O O 0 4 / 0 9 / 6 8 P A G E M E M O R Y M A P SYSTEM, I N C L U D I N G I O C S F I L E B L O C K O R I G I N N I I M R F R O F F T I F S -0 0 0 0 0 T H R U 1 4 4 3 3 1 4 4 4 2 I . 2. 3 . F T C 0 4 . F T C 3 0 . S . F B I N S . F B O U S . F B P P 1 4 4 4 2 14 .4 .65 1 4 5 1 0 1 4 5 3 3 1 4 5 5 6 6 . 7 . 8 . 9 . F T C 0 1 . F T C 0 2 . F T C 1 .1 . R E R E A D 1 4 6 0 1 1 4 6 2 4 1 4 6 4 7 1 4 6 7 2 O B J E C T P R O G R A M 1 4 7 1 5 T H R U 5 4 0 7 6 1 . 2 . 3 . 4 . . 5 ^ D E C K D E C K D E C K D E C K D E C K 6 . 7 . 8 . 9 . 1 0 . 1 1 . D E C K D E C K D E C K D E C K D E C K D E C K 1 2 . 1 3 . 1 4 . 1 5 . 1 6 . 1 7 . D E C K D E C K D E C K D E C K D E C K D E C K 1 8 . 1 9 . 2 0 . 2 1 . 2 2 . 23. D E C K D E C K D E C K D E C K D E C K D E C K 2 4 . 2 5 . 2 6 ^ 2 7 . 2 8 . 2 9 . D E C K D E C K D E C K -S U B R S U B R S U B R 30. 3 1 . _3LZ. 3 3 . 3 4 , S U B R S U B R . S U B R S U B R S U B R / F I L E S T D A T A U . T R 0 9 U . T R 1 5 U > T R 0 6 U . T R 1 7 U . T R 1 3 U . T R 0 7 U . T R 0 8 U . T R 0 1 U . T R 0 2 U . T R 0 3 U . T R 0 4 U . J R - 0 5 U . T R 1 0 U . T R l l U . T R 1 2 U . T R 1 4 U . T R 1 6 U . T R 1 8 U . T R 1 9 U . T R 2 0 U . T R 7 1 F I L 3 0 E X T A G T R . R - . I N S Y F B O U S Y F B P O S T X P P S Y F B C N S T N T F P R F R D F 0 1 * 0 0 0 0 0 1 4 7 1 5 2 0 1 2 4 2 0 7 1 3 2 2 5 3 5 .A * 2 3 7 6 6 2 6 0 0 4 3 0 5 3 6 . 3 1 3 5 5 3 3 1 5 6 3 5 0 1 6 * 3 5 5 4 3 3 5 6 5 7 . 3 6 1 6 6 . 3 6 7 0 1 3 7 7 3 5 4 0 3 7 5 4 1 2 5 4 4 2 1 1 6 . 4 . 5132 . . 4 5 1 5 6 4 5 2 1 5 4 5 3 7 0 4 5 4 6 4 4 5 4 6 5 4 5 5 5 6 4 5 5 5 7 4 5 6 1 6 4 5 6 4 7 4 5 7 7 5 4 6 0 3 3 -4.60.43. . 4 6 0 4 4 4 6 0 4 5 RON HALL FOR R HALLADAY *TES IBLDR — JOB OOOOOO 04/09/68 PAGE 4 35 • SUBR • F02 • 46046 36l SUBR •F04 • 46047 j 37 • SUBR • F05 • 46050 1 3 8 SUBR • F06 • 46051 39 SUBR • F07 • 460.52. . . .. 40 * SUBR • F l l ' 46053 41 • SUBR • F99 • 46054 42 • SUBR ' IOS • 46055 43 • SUBR • R WB • 46345 44 • SUBR • RWD ' 46756 45 • SUBR... LACV _ _ 47476 ... . 46 • SUBR •DCV 1 47526 47 • SUBR • ECV • 47770 48 • SUBR • FCV ' 50236 49 • SUBR •GCV • 50334 50 • SUBR »HCV • 50357 51 • SUBR • ICV • 50462 52 • SUBR •LCV ' 50506 53 • SUBR •ocv • 50543 54 • SUBR •XCV • 50623 55 • SUBR •INTJ » 50641 56 • SUBR »FFC • 51342 57 • SUBR. • TMTARR ' . 5_1J63_ 58 • SUBR •SCA 52134 59 • SUBR »BST • 52434 60 • SUBR * EFT • 52562 1 6 1 # SUBR ' R WT ' 52615 62 • SUBR 'XEM » * 52634 63 • SUBR •XIT • _.. 53053 64 • SUBR ' XP3 • 53055 65 • SUBR •XPN ' 53126 66 • SUBR 'LOG • 53234 67 • SUBR * SQR ' 53401 68 • SUBR •ERF • 53501 69 • SUBR _ LU..DATE*. . 53637 ... 70 • SUBR •U.EOFR' 53710 71 • SUBR 'U.SKIP' 53766 •{* - INSERTIONS OR DELETIONS MADE IN THIS DECK) INPUT -.OUTPUT. ..BUFFERS, _— . . ..67.0.2 4_.Tb.RU. _7J7.Q 5 . — — -BLANK COMMON ORIGIN 77706 UNUSED CORE 54027 THRU 67002 OBJECT PROGRAM IS.BE.ING. EJMTE.RED INTO STORAGE TIME 12HRS 24MIN 09.6SEC — — . . . ._ . .... .. • - - - : ... 0 o 1 6 + • • • • • • 0 • • • 1 • • • 1 • • • 1 • • • 2 • • • 2 • • • 2 • • • 3 • 3 • 4 • 4 • 5 • 5 • 6 6 • 7 • 7 • 8 9 2 5 8 1 4 7 0 5 0 5 0 5 0 5 0 5 0 • • • • • * • • • • • • • * • • • • * • • • * a « * • • * • • • • • C O N i T R O L C A R D S 1. T I T L E _?_J__BFTITL 3, 4. 5-6. 7. I N M S D C INVR p A R C O R R E P E A T END 11 10 11 11111111 40 • • * * • • • * * < ft JI aft* « 9 9 NAME PARTIAL CORRELATIONS 1 2 3 4 5 6 7 8 9 2 -0.0777 -1.0000 —< 3 0.6131 -0.5335 1.0000 4 -0.3881 -0.069.9 .a , 133.9.. ^ 1 . 0 0 0 0 - -5 -0.3087 0.5337 -0.0480 -0.1870 -1.0000 6 -0.1540 0.1959 0.2509 -0.2169 0.0734 -1.OOOO 7 - n . m ^ 9 - n . i i 7 R n . ? r i 4 i - 0 . 1 ? 7 f i n . 1 4 7 6 - n . ? ? ^ 4 - l . n n n n 8 -0.1827 0.2102 0.2871 -0.3240 -0.1953 -0.6156 -0.2150 -1.0000 9 0.0321 0.0823 -0.0702 0.3677 0.1910 -0.0460 0.1617 0.3825 -1.0000 .10 -0.2 L9_8 - - 0...1.844. 0L..L57_0_ _. -0..10A0 -0. 1365 _ - . 0 . 1853_ r 0.2 792. -0.0583 _ 0.0 704 11 -0.1136 -0.3025 -0.2928 -0.3766 0.1212 0.2034 -0.0913 0.2197 -0.0212 _. NAME . PARTIAL. CORRELATIONS 10 11 1 0 - 1 .0000 11 -0.1644 -1.0000 _ _ 660824 - .661102 1 MALLARD - - _. _ •- - - - -• - . . - - - -CONTROI CARD N O - 3 * TNMSnt". * 1 NO. OF OBSERVATIONS 43 - . . .... — 43 OBSERVATIONS 42 DEGREES OF FREEDOM _ . . _ . - . . . ... • - - - - • NAME MEAN S.D. CORRELATION COEFFICIENTS • .. 1 2 3 4 5 _ .—.. 6 - . .. .7 ... . 8 9.. . I 10.26 12.45 1.0000 2 690.7 710.1 -0.0908 1.0000 3 0.3426E - 0 1 0.5582E - 0 1 0 . 8 3 1 3 -0.3463 1.0000 4 42.28 49.24 -0.1808 0.1999 -0.2113 1.0000 5 47.98 5.978 0.1959 0.0157 0.1200 0.0510 1.0000 6 . 61 .09 6. 761 . 0.0 325 0.0354 0.0599 .0 .-26 81-... 0.5880 .1.0000. 7 4.674 4.566 0.0757 -0.1243 0.0589 -0.0053 0.0686 -0. 1564 1.0000 8 13.95 29.51 0.3699 -0.0810 0.0791 -0.0945 -0.0575 -0.3693 0.2383 1.0000 9 2 8 - 9 1 47.88 0.3846 -0.0714 0.1614 - 0 . 1 8 8 9 0.0158 - 0 . 4 5 1 9 0 . 1 1 9 4 0. 7 8 * 5 6 1.nnnn 10 91.23 44.69 0.0210 0.0605 0.0841 -0.0501 0.1245 0.0672 -0.1457 -0.2831 -0.2455 11 96.23 28.10 -0.2131 0.0458 -0.2206 -0.0071 -0.3264 -0.3427 -0.0742 0.0004 - 0 . 0 8 5 9 6 6 0 5 2 4 - 6 6 0 8 1 9 1 M A L L A R D 1 N O . O F O B S E R V A T I O N S 2 4 2 4 O B S E R V A T I O N S 2 3 D E G R E E S O F F R E E D O M N A M E M E A N S . D . C O R R E L A T I O N C O E F F I C I E N T S " I 2 3 4 5 6 7 8 9 1 I . 5 C 0 3 . 0 7 9 I . 0 0 0 0 2 8 2 . 3 3 3 5 . 2 4 - 0 . 3 0 1 3 1 . 0 0 0 0  3 0 . 6 3 5 4 E - 0 1 0 . 1 6 9 0 0 . 6 1 8 5 - 0 . 6 5 3 7 1 . 0 0 0 0 4 1 2 3 . 4 5 9 . 5 3 - 0 . 2 7 4 3 - 0 . 0 8 0 3 0 . 0 4 1 2 1 . 0 0 0 0 5 5 0 . 6 2 . . . 4 . 7 7 1 - 0 . 3 6 2 6 0 _ . J L 6 9 4 j - _ 0 . 5 8 3 5 - 0 . 1 6 4 8 1 . 0 0 0 0 6 6 6 . 5 0 5 . 5 4 0 - 0 . 0 9 6 9 0 . 3 0 6 4 - 0 . 2 5 2 4 - 0 . 2 7 3 2 0 . 4 1 3 6 1 . 0 0 0 0 7 6 . 5 4 2 4 . 3 8 4 0 . 0 2 0 9 0 . 0 4 4 9 0 . 0 4 7 5 - 0 . 0 1 0 6 0 . 1 8 0 6 - 0 . 0 4 2 1 1 . 0 0 0 0 8 5 . 4 5 8 9 . 7 3 1 - 0 . 0 5 1 5 - 0 . 0 1 0 9 0 . 0 6 3 6 - 0 . 0 4 2 1 - 0 . 1 8 0 6 - 0 . 6 0 9 3 - 0 . 1 1 6 2 1 . 0 0 0 0 9 1 4 . 4 2 2 3 . 9 9 - 0 . 2 0 9 6 0 . 1 7 0 4 - 0 . 1 2 0 5 0 . 3 5 7 3 0 . 1 0 8 2 - 0 . 3 5 7 6 0 . 1 1 2 7 0 . 4 2 8 1 1 . 0 0 0 0 1 0 1 2 6 . 8 2 8 . 4 6 - 0 . 0 5 4 3 - 0 . 3 3 2 3 0 . 2 4 5 6 0 . 1 7 5 3 - 0 . 3 7 8 7 - 0 . 3 4 8 7 - 0 . 2 6 2 9 0 . 1 7 4 2 0 . 0 8 1 9 . 1 1 9 9 . 7 5 2 6 . 3 4 0 . 0 2 9 2 - 0 . 0 6 4 6 - J I . J . 6 1 J . . - 0 . . 5 0 2 6 0 . . J . 2 4 . 1 0 . 2 3 . 8 . 6 . - 0 . . 0 7 0 6 . 0 . 0 8 7 8 - 0 . 1 9 0 2 . N A M E M E A N S . D . C O R R E L A T I O N C O E F F I C I E N T S 1 0 1 1 1 0 1 2 6 . 8 2 8 . 4 6 1 . 0 0 0 0 1 1 9 9 . 7 5 2 6 . 6 4 - 0 . 1 8 7 8 1 . 0 0 0 0 C O N T R 0 L C A R D _ N 0 _ , . „ 4 * _ I N V R * C O N T R O L C A R D N O . 5 * P A R C O R * N A M E P A R T I A L C O R R E L A T I O N S . 1 2 3 4. 5 6 . . 7 . _ . _ . 8 .. .. 3 . 1 -l.OGOO NAME MEAN S.D. CORRELATION COEFFICIENTS 10 11 10 91.23 44.69 1.0000 11 96.23 28. 10 0. 1787 1.0000 XO.NTROL.XARD.. N.O... ..A .. .*. J.NV8. CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 2 __3 4 _ 5 6 7 8 9 1 -1.0000 2 -0.0315 -1.0000 JS 0.8908 -0.5632 1 .0000 :  4 -0.1667 0.2000 -0.0001 -1.0000 5 0.0027 0.0581 -0.1182 -0.1015 -1.0000 6 . . 0..X.6X6 -0_..0.6J2.5 -0...0A3J 0...2.5JL8 .0.. 6475. _.„-!..0000... _ . .. .. _ 7 0.0306 -0.1200 0.0567 0.0763 0.2592 -0.2974 -1.0000 8 0.1748 -0.0137 -0.4131 0.0805 -0.1381 0.0957 0.2473 -1.0000 9 0.1733 -0.0121 0.0186 -0.0189 0.3714 -0.5052 -0.2552 0.6816 -1.0000 10 0.1787 0.0331 0.0450 -0.0382 0.2288 -0.1532 -0.1224 -0.1325 -0.1373 11 -0.1322 0.0109 -0.1069 0.0499 -0.0429 -0.2778 -0.1220 0.1714 -0.2103 NAMJE PARTIAL CORRELATIONS _ . .. . _IQ ._• 11 10 -1.0000 11 0.1945 -1.0000 661107 - 670228 1 MALLARD CONTROL CARD NO. 3 ~ ~ " * ~ I N M S D C * 1 NO. OF OBSERVATIONS .44 44 OBSERVATIONS 43 DEGREES QF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS 1 2 , 2 4. 5 6 1 8 9 1 7.614 9.590 1.0000 2 497.7 174.2 -0.0089 1.0000 3 0.» 16.65E-0.1. 0.2.25.3E-0.1 0.. 9.4.88. . _-0.175.2 1...0.00.0 4 96.64 85.84 0.2561 0.0351 0.1708 1.0000 5 36.05 5.582 0.1089 -0.1111 0.0914 0.1752 1.0000 6 46.7 7 3. R 0 9 0.2440 0.0535 0.2390 0 . 01 70 0 . 3790 1 . OOOO  7 6.341 5.207 0.3189 -0.2812 0.4320 0.2237 0.1299 0.3359 1.0000 8 24.00 34.24 0.4641 -0.2887 0.5988 0.2909 0.1315 0.1507 0.4756 1.0000 9 47.39 59.06 0.307.5 -0.3147 .. 0.4232 0.2191 . 0.3218 0.3283 0.4108 0.7561 1.0000 .10 121.6 41.37 0.0340 0.0289 -0.0088 0.2871 0.1663 0.2286 -0.1431 0.0107 0.1331 11 126.1 21.45 -0.0284 0.0393 0.0132 -0.0776 0.3239 0.2964 -0.0507 0.1504 0.2669 NAME MEAN S.D. CORRELATION COEFFICIENTS ! LQ LI 10 121.6 41.37 1.0000 11 126.1 21.45 0.2955 1.0000 CONTROL CARD NO. 4 * INVR . CON.TROI CARD. NO. 5 . _ * .P.ARCOR * -NA|ME PARTIAL. CORRELATIONS 1 2 3 4 5 6 7 8 9 1 - l.nnnn 2 0.1145 -1.0000 -3 0.9664 -0.3999 1 .0000 4 0..08 8.4 0.2161 -0.4233 -1.0000 .... 5 0.0427 -0.1504 -0. 1323 0.2308 -1.OOOO 6 0. 1955 0.2293 -0.0848 -0.2204 0.2568 -1.OOOO 7 0.0474 -0.7488 0 . 3 198 0 . 7 190 - n . n S 7 ^ n.3961 - l.onno 8 0.3656 -0.0817 0.3887 0.1585 -0.1755 -0.1969 0.2104 -1.0000 9 -0.1139 -0.1597 0.0066 -0.0064 0.2000 0.2157 0.0120 0.6757 -1.0000 10 ; ... . 0.0156 —-0.1185 0.034.4 0.3999 -0. 0815 _ - 0, 2442. . - -0.2 808 -0.1052 0.0848 11 -0.1446 0.1335 0.1226 -0.2266 0.2469 0.1332 -0.1083 0.1564 0.0765 N A M E 10 PARTIAL CORRELATIONS 11 10 11 670301 •1.0000 0.2542 6705 09 -1.0000 1 MALLARD CONTROL CARD NO, * INMSDC * NO. OF OBSERVATIONS 29 29 OBSERVATIONS 28 DEGREES OF FREEDOM N A M E MEAN S . D . CORRELATION COEFFICIENTS 1 14.45 13.95 1.0000 2 569.0 308.9 0.0 03 3 1.0000 3 0.3108E-01 0.3686E-01 0.8682 -0.2943 1 .0000 4 140. 7 59. 08 -0.4233 0.0728 -0.3218 1.0000 5 38. 07 _ _ 4.906 -0.0871 -0.3980 0. 1321 0.0561 ... 1.0000 6 50.86 4.518 -0.2983 -0.0147 -0.1205 0.2680 0.5629 1 .OOOO 7 7.000 4.424 -0.0619 0. 1176 -0.1483 0.0424 -0.1267 -0.0232 1.0000 8 9.759 16.48 0.1740 -0.0825 0.2203 -0. 1993 -0.1416 -0.2734 0.3174 1.0000 9 25.03 32.45 0.4133 -0. 1014 0.3691 -0.3318 0.0976 -0.35 79 0.3045 0.5903 1.0000 10 130.8 16.70 -0.3211 0.2035 -0.2998 0.3220 0. 1497 0.1313 -0.1165 -0.3806 -0.1631 11 107.0 . 20.55 0.2316 -0.1940 0 .1546. -0.7734 -0.1287 -0. 3386 ... -0.0051 .. 0. 1736 0.3976 .. N A M E MEAN S.D. CORRELATION COEFFICIENTS . • -10 11 : „« . 10 130.8 16.70 1.0000 11 107.0 20.55 -0.3884 1.0000 . . . - CONTROL CARD NO.. 4 _ * ..INVR * . _ . . . . • . _ • - • • - • CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 _2_ •1.0000 0-0174 -1»QQOQ 3 4 5 6 7 _S_ 0.8894 -0.4623 •0.1634 •0.0481 •0.2420 •0.3332 0.5642 0.2111 -0.52.61 0.2896 0.0390 -0. 1586 1 .0000 0.0551 0.0153. 0.2791 -0.2179 0.7782 •1.0000 -0 ..2451 0.0719 •0.0430 -0. 2814 -1.JO_0.CLQ 0.6650 -0.2310 •0. 2919 -1 . OOOO 0.1917 0-0617 1.0000 Qt QQQ9 •i . oooo 9 10 11 0.4972 -0.4071 .0. 4.43.9.. 0.1948 0. 1634 •0.258.1 -0.0306 0.1243 -.0_._05.05_. 0.2986 -0.1508 -0._7_7_6.0_ 0.52 21 0.0420 _.0._2941. -0. 3687 -0.1131 0.0112 0.3633 •0. 1548 0.. 1412 0.6322 -0.4336 -0.395.4 •1 .0000 0.3236 0.4.90-8 NAME 10 JJ__ 10 -1.0000 -0-3649 PARTIAL CORRELATIONS 11 - 1 -OOOO  660824 - 660913 CONTROL CARD NO. 3 PINTAIL * INMSDC * NO. OF OBSERVATIONS 11 OBSERVATIONS  11 10 DEGREES OF FREEDOM N A M E MFAN S . D . r.DRRFI AT ION CflFF F I f.T FN TS 1 2 3 4 5 6 7 8 9 1 5.818 ...... .13.09... .1 ..OOOO .... . ._ ______ .. ._ . . . . . . . . . . 2 826.4 535.0 0.2015 1.0000 3 0.5636E-02 0. 1315E-01 0.9997 0.1814 1 .0000 4 50.64 51.60 -0.2892 0.3197 -0.3002 1.0000 5 50.82 1.888 0.6379 0.4270 0.6307 -0.1629 1.0000 6 68.09 3.239 -0.9170 -0.1267 -0.9170 0.4352 -0.7166 1.0000 7 . .2.636 _ . 3.139 -0.0407 0.6332.— _ -0 ..0.5.68.. 0-.3522 _____ -0.2148 0.0921 1.0000. 8 5.000 16.58 0.9420 0.1076 0.9422 -0.2162 0.5590 -0.8285 -0. 0672 1 .0000 9 18.18 43.92 0.9958 0. 1333 0.9974 -0.3411 0.6204 -0.9246 -0.0981 0.9276 1.0000 10 96. 82 AI .94 0.3735 -0.3892 0.3879 -0.7175 -0.0787 -0.4739 -0.4797 0.^.099 0. 4 ^ 4 11 80.36 29. 73 -0.3215 -0.2474 -0.3121 -0.1385 -0.4495 0.4680 -0.3102 -0.1826 -0.3124 NAME M E A N S . D . C O R R E L A T I O N C O E F F I C I E N T S 1 0 1 1  10 9 6 . 8 2 4 1 . 9 4 1 . 0 0 0 0 11 8 0 . 3 6 2 9 . 7 3 0 . 3 2 6 8 1 . 0 0 0 0 C O N T R O L C A R D N O . 4 * I N V R * WARNING - D . F . = 0 . I N V E R S I O N D I S C O N T I N U E D . C O N T R O L C A R D N O . 5 N A M E P A R T I A L C O R R E L A T I O N S 1 2 3 4 5 6 7 8 9 1 - 1 . 0 0 0 0 2 _ . 0 . 9 J L 5 2 . - . 1 , 0 0 0 0 3 0 . 0 0 0 0 0 . 0 0 0 0 0 . 0 0 0 0 4 - 0 . 6 1 7 8 0 . 7 6 3 4 0 . 0 0 0 0 - 1 . 0 0 0 0 5 - 0 . 8 5 4 2 0 . 9 8 6 3 0 . 0 0 0 0 - 0 . 7 8 2 4 - 1 . 0 0 0 0 6 - 0 . 8 5 0 2 0 . 9 7 5 1 0 . 0 0 0 0 - 0 . 7 3 4 4 - 0 . 9 8 7 3 - 1 . 0 0 0 0 7 - 0 . 8 3 3 1 0 . 9 8 1 2 0 . 0 0 0 0 - 0 . 7 7 8 9 - 0 . 9 9 4 1 - 0 . 9 8 1 5 - 1 . 0 0 0 0 . 8 ..... 0 . 9 6 4 6 - 0 _ , J U 2 5 _ _ _ 0 . 0 0 0 0 0 . 6 4 2 5 0 . 8 5 6 5 . . 0 . 8 5 7 1 0 . 8 3 9 5 - 1 . 0 0 0 0 9 0 . 9 9 6 7 - 0 . 8 9 2 1 0 . 0 0 0 0 0 . 5 9 7 7 0 . 8 2 6 5 0 . 8 1 6 3 0 . 8 0 3 7 - 0 . 9 4 5 6 - 1 . 0 0 0 0 1 0 - 0 . 8 8 1 5 0 . 9 7 6 9 0 . 0 0 0 0 - 0 . 8 1 8 4 - 0 . 9 8 2 7 - 0 . 9 6 6 0 - 0 . 9 7 5 9 0 . 8 6 9 1 0 . 8 6 1 3 11 - 0 . 8 0 6 8 0 . 8 9 2 2 0 . 0 0 0 0 - 0 . 8 9 9 8 - 0 . 8 8 9 4 - 0 . 8 3 4 5 - 0 . 9 0 1 6 0 . 8 9 4 3 0 . 7 7 6 7 NAME P A R T I A L C O R R E L A T I O N S 1 0 1 1 10 - 1 . 0 0 0 0 11 — _ . - 0 . 8 3 0 6 . _ 1 . 0 0 0 0 . . .. . • - ...... ..... . . • 6 6 0 9 1 4 - 6 6 1 0 1 7 3 P I N T A I L C O N T R O L C A R D N O . 3 * I N M S D C * 3 N O . O F O B S E R V A T I O N S 2 2 2 2 J D B S E R V A T I 0 N . S 2 1 D E G R E E S O F F R E E D O M * P A R C O R * NAME MEAN S.O. CORRELATION COEFFICIENTS 1 2 , 3 4. 5 6 7 8 9 1 1.227 3.161 1.0000 2 531.8 406.4 0.0275 1.0000 3 0.3030E-02 0..9541E-02 0..93.60 -0.103.8 - .L..000.0.. . 4 36.59 33.65 -0.1594 0.0992 -0.0833 1.0000 5 48.59 6.638 0.1408 0.4340 0.1255 0.4956 1.0000 6 60.50 5 . 4 5 f t -0.0759 0.6903 -0.1 3?9 0 . 4 K 1 7 0 . 6 1 3 ? 1 . O O n n  7 5.364 4.766 0.6674 -0.1636 0.7460 0.1352 0.1961 -0.1410 1.0000 8 11.41 30.42 -0.1184 0.0482 -0.1043 0.1128 0.0678 -0.1025 0.1753 1.0000 9 19.95 40.69 .0.0737 . -0.0420 0.. 11.1 I -0.02.20. 0. 1653 . -0. 1688 0.14.79 0.7132 1.0000 10 90.73 46.83 -0.0893 -0.1081 -0.2145 -0.0592 0.0329 -0.1289 -0.2058 -0.2749 -0.3393 11 102.9 28.75 -0.2166 -0.0775 -0.2070 -0.1759 -0.2539 -0.3887 -0.0733 -0.0082 -0.0057 NAME MEAN S.D. ' CORRELATION COEFFICIENTS 10 LI 10 90.73 46.83 1.0000 11 102.9 28.75 0.2169 1.0000 CONTROL CARD NO. 4 * INVR CONTROL CARD NO. 5 _ * PARCGR*. - NAME ... _.. P-ART1 AL -CORR EL AT. IONS 1 2 3 4 5 6 7 8 9 1 J -l .oooo  2 0.3423 -1.0000 3 0.8661 -0.1845 1.0000 4 . -0..20.57. -0.3521. ....-0,122.8 _-1 ..00.0.0. _ 5 -0.0804 0.1999 0.0783 0.2795 -1.0000 6 -0.1266 0.6372 -0.0991 0.3964 0.3535 -1.0000 1 0 - 7 5 9 5 - 0 . 3 0 7 8 0 . 3 3 5 7 0 . 1 9 7 7 0 . 3 7 5 R - n . f ) Q 7 6 - l . f i n n n  8 -0.4698 0.3853 -0.2621 0.1759 -0.2616 -0.1480 0.4427 -1.0000 9 0.3233 -0.2260 0.1082 -0.1359 0.4794 -0.1531 -0.3740 0.7278 -1.0000 10 ........ .0. 1729. -0.1424 -0.3983 -0.0304 0.4161 -0,2047 -0.3386 0.1431 -0.4107 11 -0.3776 0.4257 -0.0165 0.0930 -0.0968 -0.4198 0.2466 -0.2429 0.1516 NAME 10 PARTIAL CORRELATIONS 11 10 11 -1.0000 0.2069 661019 - 670131 -l.GOOO 3 PINTAIL CONTROL CARD NO, * INMSDC * NO. OF OBSERVATIONS 41 41 OBSERVATIONS 40 DEGREES OF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS 1 2 3 4 5 6 7 8 9 1 66.20 174.9 1.0000 2 1146. 347.9 0.5 72 8 1 .0000 :  3 0.4495E-01 0.1049 0.9433 0.4117 1.0000 4 85.32 84.08 -0.0185 0.0678 -0.0009 1.0000 5 38.68 6. 182 0.068.0... 0.0 314 0.0035 -0.2039 1.0000 _ . . . . 6 48.71 5.578 0.1202 0.1295 0.0819 -0.0956 0.6243 1.0000 7 6.585 5.408 0.3090 0.2257 0.3588 0.1410 -0.0048 0.2031 1.0000 8 29.20 3 5.90 0.4122 -0.0210 0.5067 0. 1248 0.0086 0. 0194 0.4996 1 .0000 9 60.37 61.43 0.3381 0.0157 0.3786 0.0660 0.1868 0.1303 0.3543 0.7389 1.0000 10 113.4 45.33 0.2240 0.4870 0.1774 0.2987 0.0324 0.0957 -0.0025 -0.1407 -0.0170 11 118.9 _ 25.57 0.3129 0.1281 __ 0.3434 0.2788 0.0582„ -0.1758 -0.0140. 0.1883 0,2632 NAME MEAN S.D. CORRELATION COEFFICIENTS 10 11 10 113.4 45.33 1.0000 11 118.9 25.57 0.4829 1.0000  CONTROL CARD NO.. 4 * INVR * CONTROL CARD NO. 5 * PARCOR * NAME P A R T I A L C O R R E L A T I O N S 1 2 3 4 5 6 7 8 9 1 -1.0000 2 0-6079 -l.QOQQ 3 0.9263 -0.4323 1.0000 4 -0.2082 0.0400 -0.1055 -1.0000 5 _ ... . . _-0.0909_ 0..05.9.8 -0.2155 _-0.2069. -1..00.0.0 . 6 0.1535 -0.0990 0.0896 0.0733 0.6551 -1.0000 7 -0.0250 0.2139 0.1887 0.1014 -0.1342 0.2254 -1.0000 fl n . ^ 4 6 n - n . ? 7 7 6 0.7180 0.1 443 -0. 0573 -0. 0830 0.3..33 - t . n o n o  9 -0.0394 0.0187 -0.1242 -0.0545 0.1452 0.0614 -0.0149 0.6454 -1.0000 10 -0.1304 0.4507 0.1171 0.1916 -0.1311 0.2420 -0.0527 -0.1527 0.0260 U . . 0.32 71 -0.2704 . .. . 0. 15.75 . 0.2017 .0.2796 -0. 388.3 -0.0641 0.0020 0. 1492 NAME P A R T I A L C O R R E L A T I O N S 10 11 10 -1.0000 1 1 0-5147 -1 .0000 670201 - 670511 3 P I N T A I L C O N T R O L C A R D N O . 3 * I N M S D C * N O . O F O B S E R V A T I O N S 44 44 O B S E R V A T I O N S  43 D E G R E E S O F F R E E D O M NAME MF AN s . n . r.ORRFI A T I ON C O F F F i r . TFNT<. 1 2 3 4 5 6 7 8 9 1 50.89 .270.3 .1.00.00 . . . . . . . . . _ .. 2 831.8 48 3.6 0.3868 1.0000 3 0.3130E-01 0.1350 0.9981 0.3896 1 .0000 4 125.6 73.31 -0.1122 -0.0706 -0.1778 1 .0000 5 36.86 5.192 0.1686 -0.4697 0.1660 0.3429 1.0000 6 49.7 3 4.395 0.0642 -0.5856 0.0588 0.2210 0.5079 1.OOOO 7 __ 6.295 ... 4.333 .0.3102 . 0.1242 . 0.3065 ._ - 0.18.18 0.0845- . 0.. 1106 . 1.0000 8 10.52 18.53 -0.0174 0.0264 -0 .0092 0. 1355 0.0445 -0.1616 0.1768 1.0000 9 22.25 30. 86 0.4925 0.1874 0.5027 0.0563 0.2404 -0.1847 0.2755 0.6992 1.0000 10 , 127.6 26.24 0.0511 0.0164 0.0354 0.467? 0.1879 0.0936 -0. 1071 -0.0954 = 1 11 113.7 20. 31 0.0677 0.0319 0 .0848 -0.7490 -0.3435 -0.4078 -0.1558 -0.0181 0.1061 N A M E M E A N S . D . C O R R E L A T I O N C O E F F I C I E N T S 1 0 l i 1 0 1 2 7 . 6 2 6 . 2 4 1 . 0 0 0 0 1 1 1 1 3 . 7 2 0 . 3 1 - 0 . 4 0 4 4 C O N T R O L C A R D N O . 4 C O N T R O L C A R D _ N 0 . 5 _ _ * P A R C O R * NAME . .... . P A R T I A L C O R R E L A T I O N S 1 2 3 4 5 6 7 8 9 1 - 1 . 0 0 0 0 2 0 . 5 2 8 6 - 1 . 0 0 0 0 3 0 . 9 9 4 6 0 . 2 0 3 5 1 . 0 0 0 0 4 . . - 0 . 1 7 7 0 . - 0 . 0 5 4 7 0 . 0 7 4 9 - 1 . 0 0 0 0 5 0 . 1 2 2 0 - 0 . 4 4 4 2 0 . 0 6 4 2 0 . 0 9 8 4 - 1 . 0 0 0 0 6 0 . 4 6 7 5 - 0 . 6 3 8 0 0 . 1 9 1 5 - 0 . 1 2 1 8 0 . 0 8 6 8 - 1 . 0 0 0 0 7 0 . 1 8 9 9 0 . 0 2 1 4 - 0 . 0 9 1 6 0 . 1 9 1 1 - 0 . 0 9 1 6 0 . 0 9 1 6 - 1 . O O O O 8 - 0 . 4 7 1 1 - 0 . 0 3 7 0 - 0 . 0 4 3 3 - 0 . 0 2 6 8 - 0 . 2 6 7 8 0 . 0 8 8 5 0 . 0 4 0 9 - 1 . 0 0 0 0 9 0 . 5 9 3 7 - 0 . 0 1 7 8 0 . 1 5 4 3 0 . 1 3 1 5 0 . 3 7 1 2 - 0 . 2 6 1 6 0 . 0 5 6 2 0 . 8 1 3 5 - 1 . 0 0 0 0 1 0 0_ ._1340 _ - 0 . 0 5.47 - 0 . J 6 9 9 0 _ . 3 Q 1 4 . - 0 . 0 1 . 6 5 - : 0 . 0 8 5 8 - 0 . 2 4 3 7 - 0 . 1 0 5 4 0 . 0 2 3 9 1 1 0 . 1 .090 - 0 . 4 2 1 4 0 . 2 3 3 2 - 0 . 6 1 0 7 - 0 . 2 4 2 5 - 0 . 4 3 0 8 - 0 . 0 3 8 7 - 0 . 1 7 5 6 6 . 2 1 2 8 N A M E ._ _ - P A R T I A L C O R R E L A T I O N S 1 0 1 1 1 0 - 1 . 0 0 0 0  1 1 - 0 . 1 2 7 2 - 1 . 0 0 0 0 6 6 0 8 2 4 - 6 6 1 0 2 7 5 G R E E N . W I N G E D T E A L C O N T R O L C A R D N O . 3 * I N M S D C * 5 N O . OF O B S E R V A T I O N S 4 1 1 . 0 0 0 0 * I N V R * 4 1 O B S E R V A T I O N S 4 0 D E G R E E S O F F R E E D O M N A M E 1 _2_ M E A N 1 5 . C O 1 783. S . D . 2 1 . 2 9 8 1 4 . A C O R R E L A T I O N C O E F F I C I E N T S 1 . O O O O 0 . 7 0 4 4 1 .oooo 3 4 5 6 7 J3_ 0 . 1 5 8 3 E - 0 1 0 . 2 5 2 4 E - 0 1 3 8 . 4 6 . 4 8 . 5 . 4 6 1 . 4 4 4 . 8 5 4 1 4 . 6 3 3 8 . 7 2 5 . 5 2 3 6 . 7 0 1 4 . 5 9 7 3 0 . 0 7 0 . 6 5 9 5 •0 . 3 1 9 2 -.a. 020o_ •0 . 4 1 2 4 0 . 2 1 1 3 0 . 7 7 9 5 0 . 2 6 5 1 0 . 0 8 5 4 0 . 3 0 6 7 0 . 1 5 6 2 0 . 0 3 1 7 Q . 1 0 1 0 1 . 0 0 0 0 - 0 . 2 5 2 6 : 0 . . . 0 9 6 0 - 0 . 4 7 0 3 0 . 2 6 6 2 0 . 5 8 5 5 1 . 0 0 0 0 0 . 251 .6 0 . 4 0 3 7 0 . 0 4 3 8 - 0 . 0 7 4 6 1...0.0.QO 0 . 5 5 2 8 - 0 . 0 1 2 6 - 0 . 1 1 4 7 1 . O O O O • 0 . 2 1 3 8 0 . 4 0 9 7 1 . 0 0 0 0 0 . 7 2 4 4 1.oooo 9 1 0 1 1 3 0 . 3 2 9 1 . 1 5 9 5 . 0 2 . 4 8 . 6 2 4 3 . 7 1 . 2 8 . 0 5 . 0 . 7 5 2 7 • 0 . 1 6 3 0 . 0 . 0 1 8 6 . 0 . 1 3 0 5 0 . 1 7 5 2 _0.._1513. 0 . 6 6 1 4 -0 . 3 2 1 6 . 0 . 0 9 5 - 0 _ 0 . 1 8 5 4 - 0 . 2 8 9 8 - 0 . . 1.8.0 7 - 0 . 0 4 7 1 0 . 1 3 0 1 :0_. 2 8 2 1 . • 0 . 5 0 4 5 0 . 0 4 3 8 - . 0 . . 3257 . 0 . 0 9 7 8 0 . 1 6 8 9 - . 0 . 0 4 5 9 . 0 . 7 8 2 9 • 0 . 2 9 7 3 0 . 0 2 1.9 1 . 0 0 0 0 - 0 . 2 5 8 3 - 0 . - 0 . 6 1 4 N A M E 1 0 J_l_ M E A N 9 1 . 1 5 9 5 . 0 2 S . D . 4 3 . 7 1 2 8 . 0 5 C O R R E L A T I O N C O E F F I C I E N T S 1 0 1 . 0 0 0 0 0 . 1 5 5 5 1 1 1 . 0 0 0 0 . C O N T R O L C A R D — N O . 4 _*.. I N V R C O N T R O L C A R D N O . 5 * P A R C O R * 1 • , • - ._ _ .. . • N A H E P A R T I A L C O R R E L A T I O N S . 1 2 3 4 - - 5 . 6 7 8 9 . I - 1 . 0 0 0 0 2 0 . 2 0 0 9 - 1 . 0 0 0 0 3 0 . 3 6 7 9 - 0 . S 7 8 7 i .nnnn 4 - 0 . 3 8 1 1 0 . 1 5 8 9 - 0 . 0 9 6 0 - 1 . 0 0 0 0 • 5 0 . 1 0 8 7 0 . 1 0 2 2 0 . 1 8 3 6 0 . 1 3 9 3 - 1 . O O O O 6 . . . . 0 . 0 1 7 8 0 . 1 0 1 2 - 0 . 0 7 2 5 . _ - . 0 . 1 8 0 6 0 . 5 . 4 4 . 8 . - 1 . 0 0 0 0 . .. . . . . . _- ..... _ . . . . . .. 7 0 . 1 5 4 5 0 . 0 3 6 2 0 . 2 2 2 4 0 . 0 9 6 0 0 . 1 7 3 9 - 0 . 3 2 7 7 - 1 . 0 0 0 0 8 0 . 3 6 4 2 - 0 . 0 3 1 4 - 0 . 0 3 0 8 0 . 2 0 8 6 - 0 . 1 8 5 1 0 . 1 0 2 4 0 . 1 7 2 5 - 1 . 0 0 0 0 9 0 . 3 3 5 0 0 . 0 5 9 6 0 . 2 9 8 8 0 . 0 0 1 7 0 . 2 8 4 0 - 0 . 4 7 7 7 - 0 . 3 1 3 7 0 . 5 0 7 6 - i .nnnn 1 0 - 0 . 0 8 2 1 0 . 2 6 6 8 - 0 . 1 9 3 8 - 0 . 3 4 8 0 0 . 2 3 9 2 - 0 . 1 4 9 1 - 0 . 1 4 0 5 - 0 . 0 3 9 2 - 0 . 1 7 0 4 1 1 0 . 0 7 3 7 - 0 . 0 7 4 5 0 . 1 3 4 9 0 . 0 2 2 4 - 0 . 0 2 7 2 - 0 . 2 9 9 9 - 0 . 1 4 4 2 0 . 1 2 1 0 - 0 . 2 5 4 6 N A M E 1 0 .IM-P A R T I A L C O R R E L A T I O N S . _. .. 1 1 - 1 . 0 0 0 0 NAME PARTIAL CORRELATIONS 10 11 11 0.1228 -1.0000 .661101- 6 702 U .5 GREEN. WINGED. TEAL CONTROL CARD NO. 3 * INMSDC * NO. OF OBSERVATIONS 39 39 OBSERVATIONS 38 DEGREES OF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS I ' 2 .3 4 5 ... 6 7 8 9 1 61.36 152.1 1.0000 2 1082. 876.9 -0.0495 1.0000 _3 0. 7009E-01 0. 1543 0.9900 -0.1098 1 .0000  4 100.5 86.64 -0.0629 -0.0936 -0.0522 1.0000 5 36.49 5.610 0.1873 -0.1838 0.1787 0.1154 1.0000 6 .. 47,21 4.293 0.2683 0.1143 0.2772 0.0865 . 0.3727 1.0000 . . .... 7 6.590 5.408 0.2746 -0.0554 0.3013 0.2105 0.0753 0.1862 1.0000 8 23.64 34.52 0.3419 -0.1945 0.4047 0.1631 0.0528 0.0790 0.5212 1.0000 _9 48.79 61.15 0. 3323 -0.2114 0 .4040 0.1100 0. 2583 0.2306 0.4189 0.7479 1.0000 10 123.2 42.23 0.1112 -0.2475 0.1205 0.2795 0.1639 0.2328 -0.1027 -0.0380 0.1062 11 125.3 22.22 0.1592 -0.6617 0.1917 0.0778 0.4122 0.2925 -0.0238 0.2599 0.3570 NAME MEAN S.D. CORRELATION COEFFICIENTS . _ - -10 11 10 123.2 42.23 1.0000 11 125.3 22.22 0.4750 1.0000 CONTROL CARD NO. 4 * INVR CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 2 3 4 5 _ J -1.0000 -0.0253 0.3.9.37 -0.2192 0.1228 -1.0000 : 0.513.5 •0.0862 0.0419 .1...0.0.00 -0.0730 -0.2321 1.0000 0.1543 -1.0000 - 1 . o o o o 7 0.1058 -0.2053 -0.1305 0.1590 0.0459 0.2461 -1.0000 8 0.2057 0.0921 0.1894 0.1928 -0.2626 - 0 . 1811 0.3232 -1.0000 9 0.0056 . -0.0072 0.3944 ...-0.10.23 ._0.. 22.2.1 _._ 0. 1002 0.0573.. 0.65.86- -1.000.0. 10 0.1629 0.0784 0.0696 0.3612 -0.1608 0.0505 -0.0753 -0.2436 0.1188 11 -0.0758 -0.6842 -0.3008 -0.1593 0. 2832 0.3738 -0.2815 0.2520 0.0354 NAME J J L PARTIAL CORRELATIONS _LL 10 11 -1.0000 0.3877 670214 - 670503 -1.0000 5 GREEN WINGED TEAL CONTROL CARD NO. * INMSDC * NO. OF OBSERVATIONS 3 3 _ 33 OBSERVATIONS 32 DBG REES OF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS 1 2 3 4 5 6 7 8 9 1 38.94 60.72 1.0000 2 1252. 611.9 -0.1175 1.0000 3 0.4087E-01 0.8566E-01 0.8828 -0.2403 1 .0000 4 126.3 73.38 0. 1326 -0.0193 0.2688 1.0000 5 36.24. . . 3.937 0..2 76.5 0. 21.00.- 0.2487 0.2432 1.00.00 6 49.36 4.159 -0.1493 0.3939 -0.1720 0.2847 0.4181 1.0000 7 6.455 4.374 0.1906 0.0073 0.1148 0.1656 0 . 1 2 7 7 0.2603 1.0000 8 11.94 2 0.79 0.4687 -0 . 1047 0.2673 0.1 7 0 2 0 . 0 5 7 9 - 0 . 7 4 9 5 n. l 461 i .nnoo 9 26.12 34.42 0.5279 -0.0576 0.2478 0.0394 0.3443 -0.2465 0.2632 0.6953 1.0000 10 125.0 27.51 -0.0275 0.0986 0.0534 0.5164 0 . 2 1 7 8 0.1559 0.0008 -0.0321 0.0468 11 . .112.8 . 21.44. -0. 14.69 . „ -0.2.0J46 . -0...3.2.24 -0.7996 -.0. 1765. - 0 . 35.04 -0.1511 _ . . 0.0277 . 0. 1726 NAME MEAN S.D. CORRELATION COEFFICIENTS 10 11 10 125.0 27.51 1.0000 11 112.8 21.44 -0.5198 1.0000  .„ CONTROL CARD NO. _ 4 _ . * INVR * j CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS .1.. 2 . 3 4 .5 6 7 8 9 1 -1.0000 2 -0.2224 -1.0000 3 0.9253 -0.3613 1.0000 4 -0.2521 -0.4072 0.0974 -1.0000 5 0.2287 0.0585 0.4207 0.1280 -1.0000 ... 6 .; . . -0.1130 0.3290 -0.4765 0. 14.38 0. 494.5 -I.OOOO 7 0.0238 -0.1461 0.0979 -0.0354 -0.2151 0.3858 -1.0000 8 0.1722 0.0422 -0.0810 0.2448 -0.3224 0.0413 -0.1261 -1.0000 9 0.2797 0.1853 -0.5166 0.1226 0.4516 -0.3466 0.3726 0.5912 -I.OOOO 10 -0.2208 -0.0190 -0.0189 0.1257 0.0584 -0.0426 -0.1412 -0. 1755 0.2585 11 -0.4189 -0.4009 -0.2434 -0.7533 0.0623 0.0251 -0.1540 0.0395 0.3614 NAME PARTIAL CORRELATIONS . . _ 10 ._. 11 .. 10 -1.0000 11 -0.2869 -1.0000 660907 - 661019 7 WIDGEON CONTROL CARD NO. 3 * INMSDC * 7 _ NO. OF OBSERVATIONS 2jB. 28 OBSERVATIONS 27 DEGREES OF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS JL 1 2 3 4 5 -0, -0, -0. 63 3.9 39.29 49.04 .-JO ... 510.1 41.16 6. 131 -0.0000 -0.0000 -0. 00.00 -0.0000 -0.0000 1.0000 :.O..O0OO 0.4335 0.1038 -.0,0.00.0. -0.0000 -0 .0000 1.0000 0.3720 1.0000 i.noon 7 5.286 4.512 -0.0000 0.3183 -0.0000 0.1531 0.1000 -0.1320 1.0000 8 14.96 34.33 -0.0000 0.0203 -0.0000 -0.1027 -0.0211 -0.3489 0. 1624 1.0000 9 . 27.75 .49.. 08 . -0.000.0 0...0584 -0 .0000 .. -0.2328 0. 109.6 -0.3426 .. 0.0632 0.7852 1.0000 10 87. 89 46. 34 -0.0000 -0.2607 -0.0000 -0.1680 0.0812 -0.1011 -0.2738 -0.2577 -0.1715 11 95.79 30.43 -0.0000 -0.2402 -0.0000 -0.2228 -0.3175 -0.4915 -0. 0270 0.0526 -0.0499 NAME MEAN S . D . CORRELATION COEFFICIENTS 10 11 10 11 87.89 95.79 46.34 30.43 1.0000 0.1394 1.0000 CONTROL CARD NO. 4 * INVR * VARIABLE EXCLUDED 1 CORRESPONDING DIAGONAL ELEMENT L.T. .0001 CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 2 3 4 5 6 7 8 9 1 0.0000 2 .... . . 0.0000 -1.0000 . ... . ... 3 0.0000 0.0000 0.0000 4 0.0000 0.4354 0.0000 -1.0000 _5 0.0000 -0. 101 1 Q.QQQO 0. 1403 -1 .0000  6 0.0000 -0.0710 0.0000 0.3143 0.6195 -1.0000 7 0.0000 0.2379 0.0000 0.0489 0.3587 -0.3849 -1.0000 8 0.0000 -.0.2028 0.0000 0.2586 -0. 1401 -0.0546. 0. 1536 -1.000.0. 9 0.0000 0.2122 0.0000 -0.2737 0.4513 -0.3342 -0.2678 0.7363 -1.0000 10 0.0000 -0.1113 0.0000 -0.0252 0.3659 -0.3425 -0.3044 -0.1411 -0.1416 U 0.0000 -0.1712 0.0000 0. 1126 0.0977 -0.4494 -0. 1029 0.0762 - 0 . 7 7 0 0 NAME 10 P A R T I A L C O R R E L A T I O N S 11 10 11 - 1 . 0 0 0 0 - 0 . 0 2 5 1 - 1 . 0 0 0 0 6 6 1 0 2 0 - 6 7 0 5 1 1 7 WIDGEON CONTROL CARD N O . * INMSDC * N O . OF O B S E R V A T I O N S 84 8 4 O B S E R V A T I O N S 8 3 D E G R E E S OF FREEDOM NAME MEAN S . D , C O R R E L A T I O N C O E F F I C I E N T S 1 2 3 4 5 6 7 8 9 1 4 4 . 4 5 1 2 4 . 3 1 . 0 0 0 0 2 2 6 3 0 . 1 0 3 5 . 0 . 1 1 1 0 1 . 0 0 0 0 3 0 . 2 0 9 4 E - 0 1 0 . 5 8 0 3 E - 0 1 0 . 7 7 6 3 - 0 . 1 7 9 0 1 . 0 0 0 0 4 1 0 7 . 4 8 0 . 4 3 - 0 . 0 4 8 3 0 . 0 0 2 7 - 0 . 1 0 7 4 1 . 0 0 0 0 ,_.5 3 7 . 6 7 ^ 5 . 7 2 3 - 0 . 0 0 4 6 . - 0 . 3 3 0 4 _._ P . J . 9 6 9 0 . 0 1 . 2 8 . . 1 . 0 0 0 0 6 4 9 . 2 4 5 . 0 2 7 - 0 . 0 3 1 4 - 0 . 1 2 4 3 0 . 0 4 6 4 0 . 0 6 3 1 0 . 5 5 3 5 1 . 0 0 0 0 7 6 . 4 1 7 A . 8 8 0 0 . 0 6 9 5 0 . 0 2 4 5 0 . 1 3 6 4 0 . 1 5 2 5 0 . 0 3 3 1 0 . 16.19 1 . 0 0 0 0 8 1 8 . 4 2 2 7 . 9 6 0 . 0 8 4 8 - 0 . 2 0 9 2 0 . 2 3 2 5 0 . 0 9 1 4 0 . 0 2 9 3 - 0 . 0 6 7 9 0 . 3 9 3 6 1 . 0 0 0 0 9 3 9 . 4 3 5 0 . 5 8 0 . 1 8 1 3 - 0 . 2 8 8 8 0 . 3 0 4 3 - 0 . 0 0 7 7 0 . 2 2 1 6 - 0 . 0 0 4 3 0 . 3 1 0 8 0 . 7 4 8 9 1 . 0 0 0 0 10 1 2 1 . 8 3 6 . 12 0 . 0 8 0 8 - 0 . 0 4 0 2 0 . 1 5 0 1 0 . 3 5 8 8 0 . 0 8 5 7 0 . 1 1 4 1 - 0 . 0 3 2 3 - 0 . 1 0 1 4 - 0 . 0 3 5 0 1 1 . 1 1 6 . 3 2 3 . 1 4 0 . 0 8 7 5 - 0 . 2 4 4 7 . _._Q._2.15i_ - 0 . 1 8 8 5 - 0 . 0 8 6 2 - 0 . 2 7 8 0 - 0 . 0 6 6 7 0 . 1 7 3 0 0 . 2 4 9 9 NAME 1 0 11 MEAN 1 2 1 . 8 1 1 6 . 3 S . D . 3 6 . 12 2 3 . 14 C O R R E L A T I O N C O E F F I C I E N T S 10 1 . 0 0 0 0 0 . 1 5 8 5 11 1 . 0 0 0 0 CONTROL CARD. N O . 4 * . INVR CONTROL CARD N O . 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 2 3 4 5 6 7 8 9 1 -1.0000 2 , 0.1694 -1.0000  3 8107 0 343 1.0000 4 -0.0663 -0.0464 -0.2095 -1.0000 5 -0. 00.26.. . ...-0...25.32. -0.0.109 .-0.0050 .._ ..0..QJ0.0._ 6 -0.0103 -0.0460 0.0777 -0.0663 0.5182 - 1 . oooo 7 0.0300 0.1092 0.1016 0.1174 -0.0879 0. 2136 .-1.0000 8 | -0.062? -0.0688 0.1575 0.1590 -0.1643 - 0 . 01 96 0.7345 - l . n n n n 9 0.1818 -0.1036 -0.0345 -0.0881 0.2788 - 0 . 0861 0.0814 0.6979 -1.0000 10 0.1000 0.0225 0.2030 0.4370 0.0224 0. 1399 -0.0461 -0.1413 0.0283 11 0.039.0. -0.2.40 4 0 . 07.8.4 -0.2759 -0.0677 -0. .2484 . -0.0400 . 0.0253 0.1322 NAM'E PARTIAL CORRELATIONS 10 11 10 -1.0000 n 0.7968 -1.0000 660704 - 661024 9 CALIFORNIA GULL CONTROL CARD NO. 3 * INMSDC * 9 NO. OF OBSERVATIONS 50 .... — • - - - ... . .. . . 50 OBSERVATIONS 49 DEGREES OF FREEDOM NAME MEAN ...... CORRELATION COEFFICIENTS 1 2 3 4 5 6 7 8 9 1 8.900 38.29 . . 1.0 000 2 226.8 312.9 0.1030 1.0000 3 0.2959E-01 0.1225 0.9830 0.0582 1.0000 4 55.90 53.10 -0.0296 0.3066 -0.0739 1.0000 5 49.84 5.560 -0.0484 0.2131 -0.0683 0.3870 1.0000 6 63.60 7.188 -0.0306 0.4347 -0.1027 0.4423 0.6132 1. OOOO 7 5.240 ._ 4.62 7 0.2171 0.0655 0.2205 . 0.1420 0.1499 _.^0. 0437. 1.0000 8 12.42 27.86 0.1270 -0.1314 0.2059 -0.1690 -0.1711 -0. 4694 0.1241 1.oooo 9 26.74 46.17 0.1290 -0.1557 0.1908 -0.12 37 -0.1152 - 0 . 5423 0.0622 0.7712 1.0000 10 94.18 42.33 0.0718 0.1149 0.0500 -0.053? 0. ?3?? 0. 197 8 - n . ? D 4 ^ -n.3r.67 -n.?66R 11 97.42 28.40 -0.0468 -0.0366 -0.0591 -0.1573 -0.1900 - 0 . 1789 -0.0078 0.0034 -0.0821 1 - „ _ — — — .. . . . . . . . — _ — .. .... — " NAME MEAN S . D . C O R R E L A T I O N C O E F F I C I E N T S 10 11 10 9 4 . 1 8 4 2 . 3 3 1 . 0 0 0 0 11 9 7 . 4 2 2 8 . 4 0 0 . 1 9 5 6 1 . 0 0 0 0 CONTROL CARD N O . 4 * INVR * CONTROL CARD N O . 5 , * PARCOR _* _..NA*|i . _P AR LI A L . CO R R E L A T I 0 N S 1 2 3 4 5 6 7 8 9 1 - 1 . 0 0 0 0  2 0 . 0 6 9 9 - 1 . 0 0 0 0 3 0 . 9 8 6 0 - 0 . 0 5 9 2 1 . 0 0 0 0 4 . . - 0 . 0 5 0 3 . 0 . 1518 _ - 0 . 1 0 5 5 - 1 . 0 0 0 0 5 - 0 . 1 7 8 0 - 0 . 1 6 3 6 0 . 1 4 4 3 0 . 1 2 1 7 - 1 . 0 0 0 0 6 0 . 1 1 7 9 0 . 3 6 3 9 - 0 . 2 2 8 1 0 . 2 1 2 8 0 . 6 0 9 8 - 1 . 0 0 0 0 7 0 . 2 7 7 1 0 . 0 9 9 0 - 0 . 0 1 6 6 0 . 1177 0 . 3 1 7 9 - 0 . 2 5 5 4 - 1 . 0 0 0 0  8 0 . 0 3 3 8 0 . 0 2 0 6 0 . 3 0 2 1 - 0 . 1 1 1 6 - 0 . 0 4 9 1 0 . 0 2 5 7 0 . 1 0 0 1 - 1 . 0 0 0 0 9 0 . 1 2 4 1 0 . 0 9 6 9 - 0 . 1 1 8 3 0 . 1 1 4 2 0 . 3 2 3 3 - 0 . 4 8 5 1 - 0 . 1 8 8 0 0 . 6 6 3 2 - 1 . 0 0 0 0 10 _ 0 . 2 0 4 5 _ . 0 . 1 0 9 4 ..0..03O.6_ - 0 , 1 4 1 2 . 0 . 3 3 0 2 - 0 . 1199 - 0 . 2 7 8 3 _ - 0 . 1 5 2 7 - 0 . 0 9 6 9 11 - 0 . 0 8 7 6 0 . 0 4 9 8 - 0 . 1 5 7 9 - 0 . 0 2 3 2 - 0 . 0 9 2 4 - 0 . 1 3 4 7 0 . 0 6 7 2 0 . 1 0 9 1 - 0 . 1 5 8 0 _ NANJE ... . . P A R T I A L C O R R E L A T I O N S 10 11 10 - 1 . 0 0 0 0  T l ' 0 . 2 3 9 7 - 1 . 0 0 0 0 66.05.24. R ._6 6 1 0 0 9 11 G.R EAT . B L U E . HER RON 11 52 O B S E R V A T I O N S 51 D E G R E E S OF FREEDOM N O . OF O B S E R V A T I O N S 52 NAME MEAN S.D. CORRELATION COEFFICIENTS 1 2 3 4 5 6 7 8 9 1 2.058 3.578 1.0000 2 14.06 7.43? 0.4239 1 .OOQO 3 0.1257 0.1994 0.8831 0.2001 1.0000 4 82.12 63.08 -0.2842 -0.5128 -0.2527 1.0000 ..5 - _ 50.83 -4.15.7- .-0.. 01.78 .0..1.0L2 0..019A. . -0.0605 _ 1 . . _ O O . O J O 6 65.58 5.093 -0.3850 -0.2620 -0.3204 0.0734 0.2354 1.0000 7 5.423 4.539 0.2400 -0.0885 0.1624 0.1839 0.1629 -0.1847 1.0000 8 8.404 71 .94 -0.0070 0. 1811 -Q.Q1 90 -0.1097 -0.Q685 -0.451 7 0. 071 5 1 . 0 0 0 0 9 18.85 36.03 -0.1006 0.1858 -0.1099 -0.0718 0.0963 -0.4860 0.0624 0.6762 1.0000 10 105.9 41.26 -0.4059 -0.4894 -0.2903 0.2607 0.0367 0.0387 -0.0575 -0.1417 -0.0698 11 94.56 .. 28 .36 -0.0262 -0.1317 0.0356 -0. 1316 0.0858 0.0902 . 0.0184 ... 0.0460 -0.0872 NAME ' MEAN S.D. CORRELATION COEFFICIENTS 10 11 10 105.9 41.26 1.0000 11 94. 56 78.36 0. 0984 1 .0000 CONTROL CARD NO. _ 4 * INVR CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 2 3 -1.0000 0.1513 0.8659 . 2 -1.0000 -0.4829 3 1 .0000 4 . ... 5 6 7 _ ..8 9 4 -0.1748 -0.3996 -0.1839 -1.0000 5 0.1211 0.2187 0.2004 0.0057 -1.0000 6 . . -0.5020. .. . -0.1871 . _ -0.0735 -0. 1048 .... 0.3982 -1... 0.0 00 7 0.2266 -0.1862 -0.2451 0.1932 0.2495 -0.1361 -1. 0000 8 -0.0832 0.0209 0.0454 -0.0414 -0. 1322 -0.1499 0.0528 -1.0000 9 -0.3485 0.0192 -0.0014 -0.0574 0.3194 -0.4399 -0.0111 0 .5346 - 1 . 0 0 0 0 10 11 -0.3453 0.0149 -0.3668 -0. 1808 -0.0439 0.0168 -0.0251 -0.2220 0.1997 0.1070 -0.3440 0.0218 -0.0947 0.0251 -0.1292 0. 1727 -0.1172 -0.1392 — NAME PARTIAL CORRELATIONS 10 - -1.0000 NAME 1 0 PARTIAL CORRELATIONS 11 11 6 6JL 012 0.0579 -1.0000 67022.6... . 11 CONTROL CARD NO. GREAT BLUE_HERON * INMSDC * 11 NO. OF OBSERVATIONS 58 58 OBSERVATIONS 57 DEGREES OF FREEDOM NAME MEAN S.D. CORRELATION COEFFICIENTS 1 ._ 2 3 4 5 . 6 7 8 9 1 21.05 .14.49 1.0000 2 52. 81 7.273 0.3009 1.0000 3 0.3935 0.2596 0.9815 0. 1456 1 .0000 4 76.90 80. 15 0.1999 0.2389 0.1596 1.0000 5 37.59 "6. 187 0.1092 -0.1835 0.1229 -0.0936 1.0000 6 48.69 5. 103 0.052 2 -0.3755 0.113.5_ -0.1609 0.5365 1 .0000 7 6.034 5. 133 0.3410 0.1557 0.3119 0.2028 0.0695 0. 1866 1.0000 8 21.81 32.60 0.2393 0.1693 0.2106 0.1546 0.0887 0.0087 0.4662 1 .0000 9 44.55 57.33 0.3272 0.1841 0.3029 0.1281 0.2554 0. 1022 0.3647 0.7768 1.0000 10 114 .7 44.56 0.1282 -0.0663 0.1544 0.2940 0.0187 0.0437 -0.1080 -0.1451 -0.0534 11 121.8 22.85 0.4286 0.2723 0.4159 0.1590 -0.0711 -0. 1635 -0. 0834 0.0924 0.1356 ... . . . .. - • — - - . • ••- - - - - - - -----NAME MEAN S.D. CORRELATION COEFFICIENTS .10. . 11 10 114.7 44.56 1.0000 11 121.8 22.85 0.3556 1.0000 * INVR * * PARCOR * NAME PARTIAL CORRELATIONS 1 2 3 4 5 _6_ __1 -1.0000 0.1618 0.9.9.18-0.0540 0.0735 0.0628 -1.0000 -0.-7964 0.1475 -0.0239 •0.3199 .1..0000 -0.0811 -0.2226 0.1125 -1.0000 -0.0144 0.1313 •1.0000 0.4693 •1 .oooo 7 8 9 10 11 0.3148 -0. 1140 0.1617 -0. 0014 0.4087 0.1193 -0.0782 .0_._1_.2SL -0.1740 0.1688 -0.0751 -0.0533 _0_..071S_ 0.0488 0.1369 0.1589 0.0698 -JO ...0.1.53-0.3427 -0.0488 -0.1049 -0.0956 0,24.31 -0.0048 -0.0528 0.2480 -0.0851 .0_._03.88_ 0.0862 -0.0676 •1. 0000 0.3264 •0.0670 •0.0467 •0. 2521 •1 .0000 0.7389 -0. 1646 0.1116 -1.0000. 0.0590 -0.0083 NAME _LQ_ PARTIAL CORRELATIONS LI 10 11 670301 -1.0000 0.3486 670511 -1 .0000 11 GREAT BLUE HERON CONTROL CARD NO. * INMSDC * 11. NO. OF OBSERVATIONS 31 31 OBSERVATIONS 3.0. DEGREES OF FREEDOM N A M E MEAN S.D. CORRELATION COEFFICIENTS 1 2 3 4 5 6 7 8 9 . . . . 1 5.839 6.461 1.0000 2 56.00 0.5705E-02 0.0001 1 .0000 3 0. 1043 0.1154 1.0000 -0.0007 1.0000 4 139.3 59.71 -0.1873 0.0004 -0.187 3 1.0000 . 5 38.29 4.859 .. -.-0.2002 0.0012 _ -0.2002 . -0..001.L .... 1..0.000 6 50.97 A.401 -0.3554 0.0013 -0.3554 0.2209 0.5725 1.0000 7 6.903 4.308 0.3623 0.0002 0.362 3 0.0232 -0.1260 -0.0230 1.0000 8 10.000 15.96 0.2053 0.0001 0.2053 -0.P023 -0.12 42 -0.2630 0.3113 1.0000 9 24.68 31.44 0.4119 0.0001 0.4119 -0.3293 0.0953 -0.3526 0.3106 0.5863 I.0000 10 130.7 16. 14 0.0676 0.0007 0.0676 0.3102 0.1409 0.1275 -0. 1131 -0.3813 -0.1614 .11 . 1.07.6 .20.00 .0.1.855 . .. 0..0.006 . . __Q_._1.85.5_ -0.7584 .. . -0.09 7.9 -0.3183 . -0.0101 0.1798 ... 0.3917 _ _ _ _ _ _ _ NAME MEAN S.D. CORRELATION COEFFICIENTS 10 11 10 130.7 16.14 1.0000 U 107.6 2G.00 -0.3884 1.0000  CONTROL CARD NO. 4 . Z_ JNVR * CONTROL CARD NO. 5 * PARCOR * NAME PARTIAL CORRELATIONS 1 ... . 2 3 4 ... 5 6 7 8 9 . 1 -1.0 000 2 0.0005 -1.0000 _3 0.0000 0.0000 0.0000  4 -0.1169 0.0015 0.0000 -1.0000 5 -0.1034 0.0006 0.0000 -0.1248 -1.0000 6 . -0.1613 0.00.10 0.0000 . 0.0095 0.6349 -1.0000 7 0.3121 0.0001 0.0000 0.0655 -0.2232 0.2760 -1.0000 8 -0.0717 0.0009 0.0000 -0.1230 -0.1800 0.0202 0.0949 -1.0000 _9 0.2271 -0.0005 0.0000 0.0651 0.4744 -0.3685 0. 2250 0.5399 -1.0000 10 0.2001 0.0011 0.0000 0.0187 0.0601 -0.0180 -0.1141 -0.3618 0.1389 11 -0.0179 0.0020 0.0000 -0.6884 -0.1153 -0.0653 -0.0752 -0.2401 0.2879 NAME PARTIAL CO