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The effects of hunting and seral succession upon Vancouver Island black-tailed deer Smith, Ian Donaldson 1968

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THE EFFECTS OF HUNTING AND SERAL SUCCESSION UPON VANCOUVER ISLAND BLACK-TAILED DEER by IAN DONALDSON SMITH B. A . , U n i v e r s i t y of V i c t o r i a , 1961 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department o f Zoology We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o the r e q u i r e d ^standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1968 x i v In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t , o f the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y of B r i t i s h Columbia, I a g r e e 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 agree 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 of t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head of my Depart-ment or by h i s r e p r e s e n t a t i v e . I t i s und e r s t o o d t h a t c o p y i n g or 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 of ZOOLOGY The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 6% Canada i i ABSTRACT THE EFFECTS OF HUNTING AND SERAL SUCCESSION UPON VANCOUVER ISLAND BLACK-TAILED DEER The r o l e of s e r a i s u c c e s s i o n and h u n t i n g i n the r e g u l a t i o n of Vancouver I s l a n d b l a c k - t a i l e d deer p o p u l a t i o n s ( O d o c o i l e u s  hemionus c o l u m b i a n u s , R i c h a r d s o n ) was s t u d i e d from comparison of observed changes i n t h e Northwest Bay h e r d over t h e p e r i o d 1954=1966 w i t h t h o s e p r e d i c t e d from a computer s i m u l a t i o n of p o p u l a t i o n p r o c e s s e s of such a h e r d . Northwest Bay was chosen because t h e r e were a c c u r a t e l o g -g i n g r e c o r d s s i n c e t h e f i r s t c u t was made i n 1939, and a c c u r a t e k i l l r e c o r d s s i n c e h u n t e r s were f i r s t a l l o w e d i n t o t h e a r e a i n a p p r e c i a b l e numbers i n 1954- P r e v i o u s s t u d i e s had shown t h a t d eer p o p u l a t i o n s i n c r e a s e r a p i d l y a f t e r f i r e and l o g g i n g , but tend t o r e t u r n t o fo r m e r l e v e l s 15 t o 20 y e a r s l a t e r . I n d i c e s o f range c o n d i t i o n were c a l c u l a t e d by m u l t i p l y i n g the number of square m i l e s of l a n d i n c e r t a i n s e r a i s t a g e s by t h e number o f deer per square m i l e expected t o occupy each s t a g e (as d e t e r -mined by p r e v i o u s s t u d i e s ) . Over the p e r i o d 1956-1966 t h e Northwest Bay a r e a was i n d e c l i n e as deer h a b i t a t , w h i l e hunt-i n g p r e s s u r e i n c r e a s e d . Two independent i n d i c e s s u g g e s t e d t h a t deer numbers de-c l i n e d o v er t h i s p e r i o d , i n a s s o c i a t i o n w i t h a d e c l i n e i n con-d i t i o n (measured b y w e i g h t i n f a l l ) o f the younger a g e - c l a s s e s of m a l e s . Average w e i g h t s of the lower a g e - c l a s s e s of fe m a l e s f o l l o w e d s i m i l a r p a t t e r n s , but the d e c r e a s e s i n we i g h t were n ot i i i s i g n i f i c a n t — p e r h a p s because of i n a d e q u a t e samples. These changes s u p p o r t e d t h e h y p o t h e s i s t h a t s e r a i s u c c e s s i o n i s t h e most i m p o r t a n t l o n g - r a n g e d e t e r m i n a n t of d e e r numbers, but one e x p e c t e d change ( t h e development of an o l d e r average age) was not f o u n d . The p r o p o r t i o n o f 1 . 5-year=old an i m a l s i n c r e a s e d and d e c r e a s e d i n c y c l i c f a s h i o n over the p e r i o d 1954-1966, but no c o n s i s t e n t t r e n d towards an o l d e r o r younger a g e - c l a s s s t r u c -t u r e was observed when the p e r i o d 1954-1959 was compared w i t h the p e r i o d 1960-1966. The absence o f such a change was a t t r i b u t e d t o the e f f e c t s o f h u n t i n g , which would be e x p e c t e d t o produce a younger average age i f s i g n i f i c a n t numbers o f a n i m a l s were h a r v e s t e d , and thus c o u n t e r a c t the e f f e c t s o f a d e t e r i o r a t i n g h a b i t a t . In the y e a r s of h e a v i e s t h u n t i n g m o r t a l i t y (1962 and 1963 ) h u n t e r s p r o b a b l y accounted f o r 15 per c e n t o f the f a l l p o p u l a t i o n as a whole, and over 20 p e r c e n t o f the f a l 1 male p o p u l a t i o n . These l e v e l s of e x p l o i t a t i o n a p p a r e n t l y r e s u l t e d i n s i g n i f i c a n t d e c l i n e s i n num-b e r s o f a n i m a l s a f t e r both of t h e s e y e a r s , which s u p p o r t e d t h e h y p o t h e s i s t h a t h u n t i n g can s e r v e as a r e g u l a t o r y mechanism to m a i n t a i n numbers w i t h i n the l i m i t s d e t e r m i n e d by s e r a i s u c c e s -s i o n . F u r t h e r s u p p o r t f o r t h i s v i e w p o i n t came from t h e f a c t t h a t y e a r - t o - y e a r f l u c t u a t i o n s i n numbers, w h i c h were a p p a r e n t l y g r e a t i n the p e r i o d 1954-1962, appeared t o be dampened o v e r t h e l a s t f o u r y e a r s o f the s t u d y — a r e s u l t which was p r e d i c t e d by computer s i m u l a t i o n . A second major d i r e c t cause o f m o r t a l i t y o v e r t h e p e r i o d 1954-1966 was b e l i e v e d to be w i n t e r weather. S i g n i f i c a n t i v d e c l i n e s i n b o t h numbers of animals and c o n d i t i o n o f males a f t e r t h e 1955=56 w i n t e r , w h i c h a c c o r d i n g t o t e m p e r a t u r e and s n o w f a l l r e c o r d s was more severe t h a n n o r m a l . There i s r e a s o n t o b e l i e v e t h a t t h i s w i n t e r a l s o r e s u l t e d i n d i s p r o p o r t i o n a t e l y - h i g h mor-t a l i t y among f e m a l e fawns and 1.5-year-olds, but sample s i z e s were t o o s m a l l t o p e r m i t adequate assessment o f t h i s p o i n t . A second w i n t e r , 1964=65, which was b e l i e v e d to have a f f e c t e d many Vancouver I s l a n d deer h e r d s a d v e r s e l y and w h i c h was more severe t h a n n o r m a l a c c o r d i n g -to t e m p e r a t u r e and s n o w f a l l i n d i c e s , had n e g l i g i b l e e f f e c t s upon the Northwest Bay deer. T h i s may have been because, by t h i s t i m e , numbers had been reduced by h u n t i n g t o l e v e l s t h a t the a r e a c o u l d e f f e c t i v e l y support even i n a severe w i n t e r . One paradox was f o u n d , however. Hunting p a t t e r n s r e s u l t e d i n males b e i n g shot i n p r o p o r t i o n a t e l y g r e a t e r numbers than f e -m a les, and i n l a t t e r y e a r s t h i s d i f f e r e n c e was a p p a r e n t l y g r e a t enough to r e d u c e the p r o p o r t i o n of a d u l t males. However, no c o r r e s p o n d i n g s i g n i f i c a n t change i n t h e p a t t e r n of d i f f e r e n c e s i n male and female a g e - c l a s s s t r u c t u r e was o bserved. Computer s i m u l a t i o n o f Northwest Bay p o p u l a t i o n p r o c e s s e s (not i n c l u d i n g fawns d u r i n g t h e f i r s t two months of l i f e ) i n d i -c a t e d t h a t n a t u r a l m o r t a l i t y from a c c i d e n t , p r e d a t i o n , d i s e a s e and o t h e r m i s c e l l a n e o u s causes e x c l u d i n g w i n t e r l o s s a s s o c i a t e d w i t h m a l n u t r i t i o n was a p p r o x i m a t e l y 10 per cent o f t h e h e r d every s i x months. I t was c o n c l u d e d t h a t s e r a i s u c c e s s i o n had been the i n d i r e c t cause of t h e d e c l i n e i n numbers of Northwest Bay deer o v e r t h e V period 1954-1966, but that numbers of animals in any year during the period 1954-1961 were dependent upon the severity of the winter, while following t h i s time year-to-year popula-tion l e v e l s were dependent primarily upon the eff e c t s of hunting. v i TABLE OF CONTENTS Page PART ONE: INTRODUCTION 1 PART TWO: THE STUDY AREA 4 LOCatlOn . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 TOpOgraphV o o o oo o o o • . oo o o o o oo • 4 C l i m a x v e g e t a t i o n . . . . . . a ' . . . . . . . . ' . • 6 S e r a i v e g e t a t i o n o o o o o oo o.oo o . o o o . 7 Logging h i s t o r y . . . . a . - . . . 8 H u n t i n g h i s t o r y . . . . . . . . . . . . . . . . o 10 PART THREE: METHODS 10 P o p u l a t i o n changes: Numbers . . . . . . . . . . 11 P o p u l a t i o n c h a n g e s : Age-Class S t r u c t u r e . . . . 15 P o p u l a t i o n changes: Sex R a t i o s . . . . . . . . 15 P o p u l a t i o n changes: C o n d i t i o n . . o o o o o o . 16 S e r a i changes o oo o o oo oo o.o o. . o o o.o 16 H u n t i n g changes oo . . o o.o o o o o o o o o . 17 W i n t e r weather changes . . . . . o o o o o . . . 19 P o p u l a t i o n model <, . ... .. « o .. o « - . < . o . . o 19 PART FOUR: RESULTS 19 P o p u l a t i o n changes: Numbers v . . . . . . . . . . 19 P o p u l a t i o n changes: A g e - C l a s s S t r u c t u r e . . . . 30 P o p u l a t i o n changes: Sex R a t i o s . . 36 P o p u l a t i o n changes: L i f e T a b l e s . . . 38 P o p u l a t i o n changes: C o n d i t i o n . . . . . . . . . . . . 44 S e r a i changes o o o o o.o o oo.o o o o o o o . 49 H u n t i n g changes . . . . . . . . . . . . . . . . . . 56 W i n t e r weather changes . . . . . . . . . o o . . 63 F a c t o r s a f f e c t i n g the sample . . . . . . . . . . 68 PART FIVE: THE POPULATION MODEL 72 " C a r r y i n g c a p a c i t y " of t h e environment . . . . . 73 Wint e r weather . . oo . . . ... o o o o o o . . 76 Hunt' m g . . . . oo oo o o. . . . . o o . o o 80 Normal m i s c e l l a n e o u s m o r t a l i t y » . . . . . . . . 82 Fawn m o r t a l i t y . o o . o o . « . o . « . . o . e 84 I m m i g r a t i o n and e m i g r a t i o n . . . . . . . . . . . 86 R e p r o d u c t i o n « . o . . . . . . . o . o . . . . . . 87 S t r u c t u r e o f the model o o . . . . . . . . o o o 88 R e s u l t s of computer s i m u l a t i o n . . . . . . . . . . 91 v i i Page PART SIX: DISCUSSION 98 E f f e c t s of s e r a i s u c c e s s i o n . . . . . . . . . 98" E f f e c t s of h u n t i n g . . . . . . . . . . . . . . . . 102 E f f e c t s of w i n t e r weather and o t h e r f a c t o r s . . 109 P o p u l a t i o n r e g u l a t i o n a t Northwest Bay . . . . 110 PART SEVEN: SUMMARY 115 REFERENCES CITED 120 APPENDICES 123 Use of h u n t e r s i g h t i n g s . . . . . . . . . . . 123 P o p u l a t i o n s i m u l a t i o n . . . . . . . . . . . . 12$ VSriOUS t cil^ IL O S a o o o o o o o o o o o o e o o 13 ^  v i i i LIST OF TABLES Page 1 Numbers of antl e r l e s s deer: sighted per hunter i n dif f e r e n t areas of the Northwest Bay logging c 1 c i i rn i n l . ^ 6 6 <> o © o o o o o o o <> © © © © © © o © o 2 3 2 Numbers of hunters per square mile in di f f e r e n t parts of the Northwest Bay study area i n 1 9 6 6 . . . . . . . 2 6 3 S t a t i s t i c s used in ca l c u l a t i o n of Lincoln index for tagging area ( 1 9 5 9 - 1 9 6 2 ) and entire Northwest Bay claim ( 1959°™ ~—9^ 3 ) o . o o o o o o o o o o - o o o . o o o o 2 *J 4 Numbers of sightings or recoveries of tags from tag-ging program, 1 9 5 9 - 1 9 6 3 i n c l u s i v e . . . . . . . . . . 2 9 5 Analysis of age-class structure of Northwest Bay black-t a i l e d deer herd by tre a t i n g i t as a binomial p O p i l l c l i x L O Tl o o o o o o o o o . o o o o o o o o o - o o o 3--6 Comparison of age-class d i s t r i b u t i o n f o r combined years 1 9 5 4 - 1 9 5 9 and 1960-1966 . . . . . . . . . . . . . . . . . 3 3 7 Per cent age-class composition of deer k i l l e d by hunters i n areas 1 and 4 at Northwest Bay i n 1 9 6 6 (both sexes combi ne d) . . . . . . . . . . . . . . . 3 6 8 L i f e tables for Northwest Bay black-tailed deer, based on hunter k i l l from i 9 6 0 to 1 9 6 6 i n c l u s i v e . . . 4 1 9 Life tables f o r Northwest Bay b l a c k - t a i l e d deer, based on hunter k i l l i n 1 9 5 4 and 1 9 5 5 » . . . . . . . 4 2 1 0 L i f e tables for Northwest Bay blac k - t a i l e d deer, based on hunter k i l l in 1 9 o 5 and 1 9 6 6 . . . . . . . . 4 3 1 1 Results of analysis of variance of average weights of d i f f e r e n t age and sex classes of Northwest Bay deer f o r the period 1 9 5 4 to 1 9 6 6 . . . . . . . . . . . 4 5 1 2 Changes i n the amount of land in various successional stages i n the Northwest Bay study area. . . . . . . . 5 0 13 Changes i n the amount of land in various successional stages for area 1 of the Northwest Bay logging d 1 V I S iO Tl o 0 o © o . o 0 0 0 o o 0 -0.00.0 o o o e - « • o 5-~ 14 Changes in the amount of land i n various successional stages for area 2 of the Northwest Bay logging C l l V l S l O T l o o o o o O O 0 0 0 o t o o 0 0 0 0 0 o 0 o o 15 Changes i n the amount of land i n various succes-sional stages for area 3 of the Northwest Bay loggi ng di vi sio n O - o o o o o o o o o o o o o o o o 16 Changes i n the amount of land i n various succes-sional stages for area 4 of the Northwest Bay-logging d i v i s i o n . o o o o o o o o o O O O O O - 9 o 17 Numbers of hunters and reported deer k i l l f o r 1962-1964 a n t l e r l e s s seasons at Northwest Bay o 0 o o .. o 18 Causes of death of a l l tagged deer from which tags were recovered o o o 0 - 0 0 o o o o 0 0 0 o O O • o 19 Winter weather s t a t i s t i c s f o r Nanaimo, B. C , for the period 1954 to 1966 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20 E f f e c t of the 1955-56 winter upon s u r v i v a l of fawns at Northwest Bay 0 0 0 0 0 0 0 0 O O O O O O O O o 21 E f f e c t of the 1955-56 winter upon s u r v i v a l of 1.5-year-old deer at Northwest Bay O O O O O O O O O 22 Effect of the 1964-65 winter upon s u r v i v a l of female fawns and 1.5-year-olds at Northwest Bay 0 0 o o o 23 Changes in weight of males between 1955 and 1956 hunting seasons at Northwest Bay o o 0 0 0 o o 0 0 24 Effects of wet and dry weather upon hunter sight-ings of an t l e r l e s s animals at Northwest Bay in 1966 . . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 25 Changes in deer populations following logging, as indicated by p e l l e t group counts (from Dasmann cind time s ^  3-939 } o o o o o o o . o o o o . o o o o o o 26 Reproduction parameters u t i l i z e d i n the computer simulation of the Northwest Bay bl a c k - t a i l e d deer population o o o O O O O O O O O O O O o o o 27 Mortality patterns derived from computer simulation of a hypothetical b l a c k - t a i l e d deer population . . Appendix 28 Estimated numbers of bucks shot during days in which r e s u l t s were not reported at Northwest Bay 0 o 0 0 29 Per cent success during buck seasons, by month, when known, at Northwest Bay . . . . . . . . . . . . . . 30 Ages and numbers of deer r e c o r d e d d u r i n g buck seasons a t Northwest Bay check s t a t i o n . . . , 31 Ages and numbers o f bucks r e c o r d e d d u r i n g a n t l e r -l e s s seasons a t Northwest Bay check s t a t i o n . . 32 Ages and numbers o f does r e c o r d e d d u r i n g a n t l e r -l e s s seasons a t Northwest Bay check s t a t i o n . . . 33 R e s u l t s of August counts a t Northwest Bay. . , . 34 R e s u l t s of s p r i n g c o u n t s at Northwest Bay. . . . 35 T o t a l numbers of h u n t e r s r e c o r d e d d u r i n g a n t l e r -l e s s seasons at Northwest Bay, 1954-1966 . . . LIST OF FIGURES 1 O u t l i n e map of t h e Northwest Bay s t u d y a r e a , w i t h i n s e t map showing l o c a t i o n o f the study a r e a on Vancouver I s l a n d . o o o , o o o o o , . o o . 2 T y p i c a l mixed s e r a i s t a g e s as a r e s u l t o f p a t c h l o g g i n g a t Northwest Bay , . . . » o . . . . . 3 The r e l a t i o n s h i p between numbers and s e r a i stage 4 Average numbers o f deer seen per s p r i n g count a t Northwest Bay, 1955-1967 . . . . . . . . . . . . 5 Per cent h u n t e r s u c c e s s d u r i n g a n t l e r l e s s season a t Northwest Bay, 1954-1966 . . o o o , . . . 6 The r e l a t i o n s h i p between h u n t e r s u c c e s s i n a n t l e r -l e s s season and average nunibers o f d e e r s i g h t e d per count i n the p r e v i o u s s p r i n g a t Northwest B&y* j --*9 5 5 ™" 19^^ ° o o o o o o o o o o o o o o o 7 Changes i n t h e p r o p o r t i o n o f 1 . 5 - y e a r - o l d deer i n the h u n t e r k i l l a t Northwest Bay, 1954-1966 . 8 Changes i n the p r o p o r t i o n o f males i n the h u n t e r k i l l d u r i n g a n t l e r l e s s season and i n f a l l c o u n t s a t Northwest Bay, 1954-1966 . . o o . . 9 C a t c h c u r v e s f o r Northwest Bay d e e r , 1954-1966 . 10 Average a g e - s p e c i f i c w e i g h t s of male b l a c k - t a i l e d deer at Northwest Bay, 1954-1966 . . . o o o o 11 Average a g e - s p e c i f i c w e i g h t s of female b l a c k -t a i l e d deer a t Northwest Bay, 1954-1966 . . . 12 Average w e i g h t s of 1 . 5 - y e a r - o l d male b l a c k - t a i l e d deer from d i f f e r e n t a r e a s at Northwest Bay, --*9 5 A" 19^^ 0 0 0 0 0 0 0 0 0 0 0 0 o o o o o o 13 Changes i n e s t i m a t e d numbers o f d e e r t h a t c o u l d t h e o r e t i c a l l y be su p p o r t e d a t Northwest Bay because of c h a n g i n g s e r e s . . . . . . o , . . 14 Changes due t o s e r a i s u c c e s s i o n i n numbers o f deer t h a t c o u l d t h e o r e t i c a l l y be support e d i n d i f f e r e n t a r e a s a t Northwest Bay . . . . . . . 15 Known and e s t i m a t e d numbers of d e e r t a k e n d u r i n g h u n t i n g seasona and f o r s c i e n t i f i c p urposes a t Northwest Bay, 1954-1966 . . . . . . . . o » . 16 Changes i n h u n t i n g p r e s s u r e d u r i n g a n t l e r l e s s season a t Northwest Bay, 1954-1966 . . . . . . . 17 Changes i n - s u c c e s s a t s i g h t i n g a n t l e r l e s s d e e r , by month, i n wet and d r y c o n d i t i o n s a t N o r t h -we st^ Bfiy i n 1966 o 0 0 <* o o o o o o © © 0 • * 18 Flow c h a r t r e p r e s e n t i n g computer model f o r popula-t i o n s i m u l a t i o n O O O O O 19 Types of p o p u l a t i o n p a t t e r n s produced by changing l e v e l s o f n a t u r a l m i s c e l l a n e o u s m o r t a l i t y i n a s i m u l a t e d deer p o p u l a t i o n 0 0 0 0 20 Types of p o p u l a t i o n p a t t e r n s produced by cha n g i n g l e v e l s o f e x p l o i t a t i o n i n a s i m u l a t e d deer P 0 p \ l l c i t l 0 r i O O O O O O O O O O O 0 0 0 0 Appendix 21 Number of bucks s i g h t e d and shot per day a t N o r t h -west Bay i n 1966 o o o o o o o « o o o o o o 22 Number of bucks and a n t l e r l e s s a n i m a l s s i g h t e d and shot p e r day at Northwest Bay i n 1966 . 0 0 . A C K N O W L E D G E M E N T S x i i i T h i s s t u d y c o u l d n o t h a v e b e e n c o m p l e t e d w i t h o u t t h e g e n -e r o u s a s s i s t a n c e o f t h e f o l l o w i n g p e r s o n s a n d o r g a n i z a t i o n s . V a l u a b l e c r i t i c i s m w a s p r o v i d e d b y m e m b e r s o f my c o m m i t t e e , w h i c h i n c l u d e d D r „ P . A , L a r k i n , D r . D , H . C h i t t y , D r , I . M c T a g -g a r * t C o w a n , D r , J " . F , B e n d e l l , a n d p a r t i c u l a r l y D r , P . J . B a n d y , w h o d i r e c t e d t h e r e s e a r c h a n d g a v e a s s i s t a n c e t h r o u g h o u t i t s c o u r s e , I am i n d e b t e d t o o f f i c i a l s o f t h e M a c M i l l a n B l o e d e l C o m p a n y w h o g a v e a c c e s s t o l o g g i n g r e c o r d s f o r t h e N o r t h w e s t B a y d i v i s i o n , a n d t o m e m b e r s o f t h e B , C , F i s h a n d W i l d l i f e B r a n c h w h o l e t me u t i l i z e m a t e r i a l c o l l e c t e d b y t h e m i n e a r l i e r y e a r s , M r . D o n a l d B l o o d , M r . G . W . S m i t h , M r . D o n a l d E a s t m a n , M r , R o r y F i n n e g a n , M r , D . J . R o b i n s o n , a n d M r . W. G . S m i t h w e r e e s p e c i a l l y h e l p f u l i n v a r i o u s w a y s . S p e c i a l t h a n k s m u s t a l s o g o t o M r , B r y a n G a t e s a n d M r . D o n a l d T h o m a s , w h o w e r e w o r k i n g o n t h e s e s c o n n e c t e d w i t h t h e s a m e d e e r h e r d a n d w h o g e n e r o u s l y a l l o w e d me t o u s e t h e i r d a t a . M r . G a t e s ' w o r k o n s e r a i s u c c e s s i o n a n d M r . T h o m a s ' s t a -t i s t i c s o n r e p r o d u c t i o n w e r e i n v a l u a b l e i n t h e c o n s t r u c t i o n o f t h e p o p u l a t i o n m o d e l . F i n a l l y , I w o u l d l i k e t o t h a n k M r s , W , A . L o w , w h o p r e p a r e d t h e d i a g r a m s . , m e m b e r s o f my f a m i l y w h o a s s i s t e d i n t h e p r e p -a r a t i o n o f t h e m a n u s c r i p t , a n d M r , S , B o r d e n , w h o g a v e m a n y s u g -g e s t i o n s o n c o m p u t e r p r o g r a m m i n g . PART ONE: INTRODUCTION The Columbian b l a c k - t a i l e d deer (Odocoileus hemionus  co lumbi anus, Richardson) is widely distributed throughout the Vancouver Island f o r e s t , but i t reaches peak densities only i n disturbed habitat. In common with many species, b l a c k - t a i l e d deer tend to reach t h e i r highest d a i s i t i e s where f i r e , logging, or other factors have caused the mature f o r e s t to be replaced by early successional stages of vegetation. Dasmann and Hines (1959) have shown quantitatively how densities of C a l i f o r n i a b l a c k - t a i l e d deer change with altered habitat, and s i m i l a r i n -vestigations have been c a r r i e d out by Gates (Unpub. mat.) on Vancouver Island at Northwest Bay. Much of t he east coast of Vancouver Island has been logged and/or burned within recent times, and i t i s believed that the deer population has changed accordingly (Robinson, 1 9 5 6 ) . How-ever, quantitative estimates of such changes have been lacking, and the current study was designed to attempt to overcome t h i s lack. One of the main objectives of this i n vestigation, there-fore, was to assess effects of changing serai conditions upon numbers, condition, and age-class structure of the Vancouver Island b l a c k - t a i l e d deer herd. In general, i t was hypothesized that numbers would be high-est, condition best, and age-class structure youngest i n favor-able s e r a i conditions, whereas in areas of deteriorating habitat i t was hypothesized that deer numbers and condition would tend 2 to decline, and that average age of the population would tend to increase. The e f f e c t s of changing s e r a i conditions upon deer may be obscured, however, by the effects of hunting. If hunting i s heavy enough, a population w i l l be unable tP increaseidespite any improvement that may occur i n the range i t occupies. And even i f hunting i s not severe enough to cause a decline, any l e v e l of hunting should a l t e r normal population parameters to some extent. Since Vancouver Island b l a c k - t a i l e d deer have undergone considerable hunting, especially i n areas of abund-ance, the e f f e c t s of such exploitation are important. If hunting i s severe enough to cause a decline in popula-ti o n l e v e l s over a number of years, condition of animals may improve owing to lowered competition for a v a i l a b l e environmental resources--a s i t u a t i o n which may have occurred aft e r an exten-sive series of hunts at the Seneca Army Depot i n New York (Hes-selton et a l , 1965). Even i f no response i s noted i n either numbers or condition of animals, i t i s s t i l l probable that s i g -n i f i c a n t levels of hunting could lead to a younger age-class structure, since hunting would presumably upset natural patterns of mortality and n a t a l i t y . Such changes have apparently occurred i n stocks of baleen whales (Laws, 1962), which have been;heavily exploited i n recent years. Young deer are usually believed to suffer the greatest mortality since they represent a "surplus" i n a population which is close to the food c e i l i n g imposed by the environment ( B a r t l e t t , I960; Lassen «_t a l , 1952; Ribinette et a l , 1957; Erickson et a l , 1961). But i f hunting of adults i s 3 great enough, the l i f e expectancy of the older age-classes w i l l be s i g n i f i c a n t l y decreased and young deer that normally would have died may get a chance to l i v e . S i m i l a r l y , i f hunting rates are unequal for the two sexes, hunting may be r e f l e c t e d i n s i g -n i f i c a n t changes i n the sex r a t i o of the population (Kelker, 1943)o For these reasons, investigations were conducted to detect changes i n numbers, condition, age-class structure, and sex ra t i o s which could be a t t r i b u t e d to the effects of hunting. Serai succession and hunting probably temd to interact i n t h e i r effects upon a deer population. For example, while hunting might be expected to lead to a decrease in the ^average age of the hunted population, deteriorating habitat might res u l t in an older average age due to decreased recruitment. But when deer numbers are considered, a deteriorating range and increased hunting would both be expected to lead to reduction i n numbers of animals. Construction of a model for computer simulation of popula-t i o n processes provided a t h e o r e t i c a l basis f o r discussion of the investigations described above. The simulation was based upon the model for white-tailed deer described by Adams ; ( I 9 6 0 ) . The area chosen for the study was the Northwest Bay d i v i -sion of the MacMillan Bloedel Company, near P a r k s v i l l e on Van-couver Island. This area i s t y p i c a l of logged portions of east-ern Vancouver Island in topography, vegetation, and climate, and records of both logging and hunting have been well-maintained. The area i s r e a d i l y accessible to both hunters and researchers, 4 and the deer population was considered to be representative of others on Vancouver Island. PART TWO: THE STUDY AREA The Northwest Bay logging d i v i s i o n of the MacMillan Bloedel Company i s situated on the eastern side of Vancouver Island (Fig. l ) , t o the south of the Alberni-Parksville Highway and to the west of the Trans-Canada Highway. It i s ty p i c a l of many Vancouver Island logging areas i n that the loggers have l e f t a legacy of "patchwork" vegetation, a network of roads, and i n -creased numbers of deer. Since neither deer nor hunters stay s t r i c t l y within the borders of the MacMillan-Bloedel timber grants, the study area actually included lands not controlled by MacMillan Bloedel. In general, the borders of the study area included land up to roughly one mile beyond the d i s t a l ends of the Northwest Bay road system, depending upon topography. For convenience, however, reference is made p e r i o d i c a l l y to the "Northwest Bay logging claim"; i t is understood that this i n -cludes a l l land within the borders of a 135<>8 square mile study area. Topography i s varied, with mountains or high ridges marking the edge of the study area i n most cases, while the central portion tends to be r e l a t i v e l y f l a t . The central area i s bro-ken by a steep r i v e r v a l l e y which forms the main d i v i s i o n between subareas 2 and 3 i n F i g . 1. As is normal on Vancouver .Island's east coast, the land gradually becomes more rugged Mt Amor de Cosmos 6 towards the i n t e r i o r , where Mount Arrowsmith (5 ,962 f t . ) and Mount Moriarty (5,282 f t . ) provide e f f e c t i v e western l i m i t s to the study area. To the south l i e s Mount Amor de Cosmos (4,444 f t . ) and an unnamed ridge that is 3,620 feet above sea l e v e l at i t s highest point. Okay Mountain (2,826 f t . ) and Blackjack Ridge (3,129 f t . ) provide the highest points i n the eastern part of the study area. Most of the study area i s above 800 feet elevation, although near the Trans-Canada Highway elevation may be as low as 200 f e e t . The severity of the climate i s believed to vary generally i n r e l a t i o n to the elevation, although no quantitative descriptions are available for Northwest ;Bay for the winter. It i s believed that the climate f o r the area tends to be more severe to the west. For instance, Cameron Lake ( d i r e c t l y to the north of Mount Arrowsmith, which i s located at the west-ern l i m i t of the study area) receives an average of 57 inches of r a i n per year, whereas Nanaimo (on the east coast of -Vancou-ver Island, and approximately 20 miles south of the study area) receives 41 inches annually. The annual mean temperature i s approximately 49=50 F. at low elevations throughout the Nanaimo-Park s v i l l e - A l b e r n i area, and Northwest Bay probably possesses a s i m i l a r average. Yearly extremes i n this region usually f a l l between 15 and 90 degrees. Vegetation patterns at Northwest Bay r e f l e c t variations i n climate and t e r r a i n within the area and are t y p i c a l of the east side of Vancouver Island. The dominant tree i n the eastern portion of the Northwest Bay logging area i s Douglas f i r 7 (Pseudotsuga menziesii ), whereas western hemlock (Tsuga hetero- phylla ) tends to become more common to the west. Other v a r i e t i e s of conifers may also be found, including red cedar (Thu.ja  p l i c a t a ) , Amabilis f i r (Abies amabilis). grand f i r (Abies  grand i s ), and lodgepole pine (Pinus contorta). The dominant shrub i n the Northwest Bay for e s t i s s a l a l (Gaultheria shal Ion), which grows i n profusion up to 3.000 feet elevation. On higher ridges, s a l a l gives way to copper bush (Cladothamnus pyrolae- f l o r u s ) , f a l s e azalea (Menziesia ferruginea ), and other alpine species. Yellow cedar (Chamaecyparis nootkatensis) and mountain hemlock (Tsuga mertensiana ) are the dominant conifers iri alpine and sub-alpine areas at Northwest Bay. In logged areas (which are commonly burned within one or two years) successional patterns develop which o r d i n a r i l y lead to the o r i g i n a l forest type. The dominant vegetation following burning consists of such forbs as fireweed (Epilobium angust-ifolium ) and pearly everlasting (Anaphalis margaritaceae ), and various grasses and ferns, of which the most common is bracken (Pteridium aquilinum). Shrubs such as s a l a l , salmon berry (Rubus spec t a b i l i s ). thimble berry (Rubus parvif l o r u s ) , black berry (Rubus ursinus ) „ and black cap (Rubus leucodermis ) also become established during t h i s period, usually becoming common approximately nine years a f t e r burning (Gates, Unpub. mat.). The pattern of regeneration i s affected by the eff i c i e n c y of burning , however, and i t i s not uncommon to find areas domi-nated by s a l a l or bracken or other species where other forms of vegetation would be expected. Willows (Salix sp.) and red alder 8 (Alnus rubra) may a l s o become well-established during t h i s period, often forming dense stands that prevent regeneration of coniferso Usually Douglas f i r is dominant 12 years a f t e r burning, however, with a high proportion of the young trees reaching escape height (the height beyond which deer cannot browse the leader) by about 15 years. After 18 years the burned area t y p i c a l l y supports a vigorous stand of young Douglas f i r trees with an average height of 10 feet or more, and by 20 years such stands are so thick that walking i s impeded. The process of regeneration i s abetted by loggers, who usually plant seed-l i n g Douglas f i r s within a few years of logging. This practice may upset natural regeneration patterns in the western part of the study area, sire e i f plantings are successful, hemlock s i t e s w i l l be replaced by Douglas f i r . Logging has changed the area substantially since 1939, when the f i r s t cuts were made. In general, roads have been pushed through the v a l l e y s , f i r s t i n a southerly and then i n a westerly d i r e c t i o n , with spurs leading higher up the mountain slopes u n t i l the area i s at present interlaced with roads, many of which are e a s i l y negotiable by passenger car. The e a r l i e s t logging was c a r r i e d out in area 1 (Fig. 1), with the result that succession i s much more advanced i n this area than in others. Areas 3 and 4 are at present being u t i l i z e d most heavily by loggers, but cuttin g i s s t i l l occurring i n a l l four areas. Logging is of the "patch" type, so that loggers tend to cut r e l a t i v e l y small areas i n scattered parts of the claim each year, rather than cutting large swaths at one loc a t i o n . F i g . 2 FIGURE 2: Typical mixed serai stages as a result of patch logging at Northwest Bay. t Top photographs Area i n foreground logged four years prev-iously j while area across gully burned a f t e r logging 18 years previously. Bottom photograph; Typical Northwest Bay h i l l s i d e , with a crown of timber above a three-year-old logging s i t e , 10 illustrates such patch logging, which results in many succes-sional stages being found in the same vicinity „ In general, logging has not occurred above 39000 feet, so that most ridges s t i l l contain substantial crowns of timber. Hunters were f irs t officially allowed into the area in 1954, although it is known that small numbers of hunters had utilized the area prior to this time . Between 1954 and 1961 inclusive, the area was open only to members of Vancouver Island fish and game clubs or those with Company passes, while in 1962 and thereafter the general public was permitted to hunt „ Be-tween 1954 and 1963 inclusive, the area was open only during weekends and on holidays, but in 1964 and thereafter hunters were allowed into the area after working hours during weekdays as well 0 The Company has always maintained its right to erect permanent or temporary roadblocks to prevent hunters driving into active logging areas, where equipment might be damaged. Prior to 1959 much of the western area of the claim was blocked to hunters, while small areas of active logging have usually been out of bounds since this time. As a result of these chan-ges, both numbers of hunters and numbers of deer killed have varied considerably from year to year. PART THREE: METHODS Objectives of the current study included the measurement of changes in the Northwest Bay black-tailed deer population and the assessment of the relationship of serai succession and exploitation to these changes. Expected types of changes a 11 included variations in numbers, age-class structure, sex r a t i o s , and condition, and the methods described below were designed to assess the extent of such changes and t h e i r causes. While the study was primarily concerned with the e f f e c t s of s e r a i succes-sion and hunting, i t was f e l t that f a i l u r e to consider the pos-sible effects of winter weather would be u n r e a l i s t i c because of the probable influence of weather upon deer populations. Winter weather was therefore included within the scope of the i n v e s t i -gation, as described below. I Changes in the Population and Its Environment To f a c i l i t a t e the assessment of trends over an extended period of time, extensive use was made of data col l e c t e d by others. Since these data were often collected with other pur-poses i n mind, they were in some cases not ide a l f o r the type of analyses attempted i n this study. This situation was un-avoidable, however, i f a long-term analysis was to be attempted. Sources of data included the hunter checking station at North-west Bay, MacMillan Bloedel Company logging records, p e l l e t -group counts conducted by Gates (Unpub, mat.), spring and f a l l deer counts conducted by B. C. Fish and W i l d l i f e Branch person-n e l , a fawn-tagging study, and fe d e r a l government meteorological records. A. Population Changes 1) Numb ers Changes i n numbers were assessed both d i r e c t l y and i n d i r -e c t l y . A direct estimate of changes was provided by spring and 12 f a l l counts by Fish and W i l d l i f e Branch personnel, while i n -dir e c t estimates were provided by hunter success rates over the period 1954 to 1966 and the fawn-tagging program from 1959 to 1964 o In addition, assessment of numbers was made possible by calculations based on sera i succession which w i l l be described in d e t a i l below. None of these methods was i d e a l , but since a l l four approaches were v i r t u a l l y independent i t was f e l t that i n cases where the various methods tended to indicate similar con-clusions, considerable confidence could be placed i n the r e s u l t s . Spring carry-over counts were conducted each year for the purpose of assessing juvenile s u r v i v a l , while f a l l counts were conducted to assess fawn production. Both counts were conducted only to obtain r a t i o s — i n the spring, the r a t i o of yearlings to adult deer; and i n the f a l l , the f awn sdoe :buck r a t i o . No spe-c i a l care was taken to make each count a r e p l i c a t e i n terms of length of counting time, weather, and other factors. Neverthe-l e s s , these counts are roughly comparable i n that they were usually conducted over a s i m i l a r area from approximately 6 p.m. u n t i l dark. Counts were made by car, with or without an obser-ver. The number of deer seen is probably affected by both the presence of an observer and the e f f i c i e n c y of those conducting the count. These factors are of small importance i f the object of the count is to obtain a r a t i o , but they become important i f the count is to be used as a density index as i t was here. Hunter success figures were derived from s t a t i s t i c s gath~ ered by those manning the hunter checking station at Northwest 13 Bay, This s t a t i o n was manned by trained, r e l i a b l e personnel, but in some years during portions of the buck season (when the k i l l i s usually low) s t a t i s t i c s were not kept. For t h i s reason, analyses were based only on the anterless season wherever pos-s i b l e . Those at the checking st a t i o n recorded the number of hunt-ers u t i l i z i n g the Northwest Bay area each day. These figures are not complete, since some hunters who u t i l i z e d area 1 were able to leave via another road (Fig. 1 ) , but v i r t u a l l y a l l those who hunted i n are'as 2 , 3 , and 4 were forced to come through the check point. Numbers of deer were also recorded (along with other s t a t i s t i c s which w i l l be described i n d e t a i l below), and again there were some gaps i n the record f o r area 1 only. In most cases hunters were able to describe the location i n which they had shot t h e i r animals, so that i t was possible to place them within the appropriate area and thus obtain separate sets of s t a t i s t i c s for each area. These descriptions took two forms. If the hunter was able to specify the exact location (such as the mountain upon which the animal was shot), then this loca-t i o n was recorded. I f not, the hunter was asked to name the road upon which he parked his vehicle . In 1 9 6 6 a l l hunters were asked to specify t h e i r hunting spots even i f they did not get a deer, so that per cent success figures were available f o r a l l four areas. Since both weather and deer wariness may affect hunter success (Leopold et a l , 1 9 5 1 ; Robinette, 1 9 6 6 ) , tests were de-vised to estimate the extent of such effects and the way i n 14 which they might bias any population estimates derived from hunter success fi g u r e s . These tests depended heavily upon the use of hunter sightings of deer, since i n most cases the hunter k i l l provided an inadequate sample f o r meaningful analysis. Therefore i n 1 9 6 6 additional data were collected on d a i l y weather and numbers of deer sighted by hunters. Because of climatic differences in various parts of the study area and the p r a c t i c a l impossibility of recording such d i f -ferences, no attempt was made to measure weather changes quanti-t a t i v e l y . Instead, days were categorized simply as either wet or dry. I f any r a i n f e l l at the checking st a t i o n throughout the hunting period, the day was c l a s s i f i e d as wet. If snow f e l l at higher elevations, r e s u l t s f o r these areas were treated separately. Hunter sightings of deer were c l a s s i f i e d as antlered, a n t l e r -less, and un i d e n t i f i e d . No attempt was made to forewarn the hunters that they would be asked to report numbers of deer sighted. The fawn tagging program carried out each year by B. C. Fish and W i l d l i f e Branch personnel from 1 9 5 9 - 1 9 6 4 provided a t o t a l l y d ifferent type of population estimate. Fawns were marked with metal s e l f - p i e r c i n g tags and plastic ear tags to aid i n i d e n t i -f i c a t i o n from a distance. Records were kept of a l l tagged ani-mals sighted and a l l tags returned by hunters k i l l i n g tagged deer, with the r e s u l t that i t was possible to estimate t o t a l population within the tagging area through a Lincoln index c a l -c u l a t i o n . Tagging took place mainly within area 2 . 1 5 2) Age-Class Structure Assessment of changes i n age-class structure was made pos-sible by the c o l l e c t i o n of deer jaws at the hunter checking st a t i o n . Jaws were aged by experienced personnel, using the tooth wear and eruption method, A number of d i f f e r e n t workers determined ages throughout the study period, but since usually more than one person aged the jaws each year to provide a cross-check, i t is f e l t that the recorded ages are as accurate as possible with t h i s method. The only age categories used were . 5 , 1 . 5 , 2 . 5 , 3 » 5 , 4 » 5 , and over 4 o 5 , since the tooth wear and eruption method i s not accurate enough to j u s t i f y the use of older categories. The age composition of the k i l l was analysed f o r o v e r a l l changes between 1 9 5 4 and 1 9 6 6 by analysis of variance i n the manner suggested by L i ( 1 9 6 4 , P « 4 4 3 f f ••).,. the herd being t r e a -ted as a binomial population. The two classes employed were 1 . 5-year-olds and a l l those deer over 1 . 5 years of age. Fawns were ignored because of the p o s s i b i l i t y that the sample was i n -adequate in some years. The two classes were chosen because of the p r o b a b i l i t y that with c a r e f u l aging, no mistake would be made i n the separation of 1 . 5-year-old animals from those over that age. 3 ) Sex Ratios Two sources of data on sex r a t i o s were available over the period 1 9 5 4 to 1 9 6 6 — t h e hunter k i l l , and f a l l counts. These two sources of data are not d i r e c t l y comparable since the i n f l u -ence of the rut i s presumably f e l t only i n the hunter k i l l . 16 N e v e r t h e l e s s they bo th s e r v e as i ndependen t i n d i c e s o f sex r a t i o c h a n g e s . 4 ) C o n d i t i on Changes i n c o n d i t i o n w e r e a s s e s s e d by c o m p a r i s o n o f t h e a v e r a g e d r e s s e d w e i g h t o f each age and s e x c l a s s as r e c o r d e d a t t he h u n t e r c h e c k i n g s t a t i o n . W h i l e t h e r e a r e many o t h e r i n d i -c a t o r s of c o n d i t i o n , i n t h e p r e s e n t s t u d y i t was c o n v e n i e n t to u t i l i z e w e i g h t a s the s o l e c r i t e r i o n . The work o f Tabe r ( 1 9 6 1 ) , Bandy ( 1 9 6 5 ) , and H e s s e l t o n e t a l (1965 ) i n d i c a t e s t h a t w e i g h t i s a v a l i d i n d i c a t o r o f c o n d i t i o n . Weight a t t h e c h e c k i n g s t a t i o n was r e c o r d e d t o the n e a r e s t h a l f - p o u n d , b u t no n o t e was made f o r the p r e s e n c e o r absence o f i n t e r n a l organs such as h e a r t , l i v e r , and l u n g s . The p r e s e n c e o r absence o f i n t e r n a l organs o b v i o u s l y i n c r e a s e s v a r i a b i l i t y i n t h e r e c o r d e d w e i g h t , but no b i a s i s s u s p e c t e d s i n c e no o b v i o u s p a t -t e r n was a p p a r e n t i n t h e manner i n which dee r were g u t t e d by h u n t e r s . V a r i a t i o n f rom t h i s s o u r c e was no t b e l i e v e d t o amount t o more t h a n f i v e p e r c e n t . B . S e r a i Changes S e r a i changes i n the s t u d y a r e a were o f major i m p o r t a n c e , s i n c e a p r imary o b j e c t i v e o f the c u r r e n t i n v e s t i g a t i o n was t h e assessment of e f f e c t s of su ch changes upon t h e d e e r p o p u l a t i o n . M a i n s o u r c e s of d a t a f o r t h e assessment o f s e r a i changes were M a c M i l l a n B l o e d e l Company l o g g i n g r e c o r d s and p e l l e t - g r o u p c o u n t s c o n d u c t e d b y Ga tes (Unpub. m a t . ) . 17 By clearing plots and counting p e l l e t groups within them at the end of each summer and winter from I 9 6 0 to 1 9 6 2 , Gates was able to estimate deer usage of various s e r a i stages i n area 2 over t h i s period. These data are presented i n F i g . 3-> Logging records were u t i l i z e d extensively i n conjunction with Gates's data. From maps of a l l areas cut and burned each year, calculations were made for the age and extent of a l l sat-ai-sf i n a l l years at Northwest Bay. There are s i g n i f i c a n t differences e^«-o.,( sieves i n plant cover i n r,^i .:s from year to year (Gates, Unpub, mat.), and, as indicated by Fig. 3 S deer usage of a burned area changes as s e r a i succession occurs. M u l t i p l i c a t i o n of the estimated number of deer per st&^e. (from F i g . 3 ) by the amount of land i n given s e r a i stages (from logging records) y i e l d s a quantitative estimate of the number of deer that would be found i f serai changes were the only factors influencing deer populations. In e f f e c t , t h i s c a l c u l a t i o n provides a quantitative estimate of the way i n which the range changed over the years as deer "habitat, The r e s u l t s of such a c a l c u l a t i o n are necessarily expressed i n terms of numbers of deer, but i t i s understood that these f i g -ures represent an estimate of the manner in which the habitat has changed in i t s a b i l i t y to support deer. C. Hunting Changes The sole source of hunting information was the hunter check-ing station at Northwest Bay. Since v i r t u a l l y a l l hunters (with the exception of some that hunted in area 1 ) had to pass through the check-point, i t was possible to keep good records of numb era k i l l e d i n the study area. FIGURE 3: The relationship between numbers of deer and serai stage (from unpublished material prepared by Gates). YEARS AFTER BURNING 19 D. Winter Weather Changes Since i t was commonly believed that the winters of 1955-56 and I964-65 had adversely affected Vancouver Island deer popu-l a t i o n s , government weather records for winter snowfall, number of freezing days, and mean temperature from November to March i n c l u s i v e were analyzed for these winters. II The Population Model In order to compare actual r e s u l t s with a t h e o r e t i c a l model, I constructed a model suitable f o r simulation on an I.B.M. 7044 electronic computer. Construction of the model w i l l be discussed in d e t a i l below, since t o a large extent the components of the model are quite subjective. PART FOUR : RESULTS I Deer Population Changes The deer herd at Northwest Bay apparently underwent s i g n i -f i c a n t changes in numbers, condition, age-class structure, and sex ratios over the period 1954 to 1966. These changes are presented i n d e t a i l below. A. Numbers Population size was investigated in two general ways. The f i r s t approach was to determine whether consistent trends occurred from 1954-1966 in spring counts and hunter success. The second approach was an attempt to establish the actual num-bers of deer i n the study area i n various years, from analyses 20 of fawn-tagging data and serai changes. Serai c a l c u l a t i o n s were based upon Fig. 3» 1) Population Trends A s i g n i f i c a n t decline i n numbers of deer at Northwest Bay-apparently occurred over the period 1954 to 1966 (Fig. 4 and 5 ) . For reasons discussed above the spring counts did not represent the most a t t r a c t i v e source of data, but despite expected large varia t i o n s from year to year the decline was s t a t i s t i c a l l y s i g n i -f i c a n t . Probably a more r e l i a b l e source of information for the same period was hunter success. The s i g n i f i c a n t decline in suc-cess was i n d i c a t i v e of a decline i n deer numbers, and tended to corroborate the trend shown i n F i g . 4» As suggested by F i g . 6 , the two indices tended to correlate well from year to year and i t is nevertheless apparently possible to predict hunter success from a count taken i n spring. These results indicated that the var i a t i o n s i n numbers of deer counted and hunter success were not mere a r t i f a c t s of the method used, but instead probably represen-ted r e a l v a r i a t i o n s in the population. I believe that the i n d i -cated variations were exaggerated by the method, however, espe c i a l l y i n the case of spring counts. With these reserva-tions, hunter success and spring counts indicated that the populati on rose from a r e l a t i v e l y low point i n 1956 to a gener-a l l y higher L*vel throughout the late 1950's. It apparently declined sharply between 1962 and 1964, and l a t e r tended to re-main stable. However, the l a t e r l e v e l appeared to be s i g n i f i -cantly lower than that prior to 1957« FIGURE 5: Percent hunter success during antlerless season at Northwest Bay, 1954-1966. FIGURE 4: Average numbers of deer seen per spring count at Northwest Bay, 1955-1967. 1955 1956 1957 1958 1959 I960 1961 1962 1963 r 1964 1965 1966 1967 YEAR FIGURE 6: The r e l a t i o n s h i p between h u n t e r s u c c e s s d u r i n g a n t l e r l e s s s e a s o n and a v e r a g e numbers o f d e e r , s i g h t e d p e r count t h e p r e v i o u s s p r i n g a t N o r t h -west Bay, 1955-1966. Y = 10.06 + 1.002X '1958 r = .701, d. f . = 1 0 • 1966 20 30 40 50 PERCENT SUCCESS 24 Differences in deer density probably occurred among d i f f e r -ent parts of the study area i n 1966 . As indicated by Table 1 , s i g n i f i c a n t differences were noted in hunter success at sighting antlerless animals in that year between areas 1 and 4 . (A d i s -cussion on the use of hunter sightings of deer as a population index i s presented i n Appendix 1 . ) However, the r e s u l t s were contradictory, since s i g n i f i c a n t l y more deer were sighted by the average hunter in area 4 i n September and October, whereas i n November success was greater i n area 1 . These r e s u l t s indicated that deer density changed i n the two areas over the course of the hunting season. However, i f repeated hunter contacts can lead to increased wariness i n deer (Maguire and Severinghaus, 1 9 5 4 ; Leopold et_ al„ 1951) then hunter success at sighting or shooting animals l a t e r i n the season may not accurately r e f l e c t density of animals, when re s u l t s are compared with data c o l l e c -ted e a r l i e r i n the hunting season. In 1966 , area 4 received s i g n i f i c a n t l y more hunting pressure than did area 1 (Table 2 ) . 2 ) Population Size Two types of population estimates were possible from a v a i l -able data--an estimate derived from a tagging program, and an estimate based upon deer usage of serai stages. While fawn-tagging was carried out at Northwest Bay from 1959 to 1963 i n c l u s i v e , r e s u l t s from 1963 were not used in the calculations described below since some hunting s t a t i s t i c s from that year (including the areas i n which animals were shot) were inadvertently l o s t . Table 3 therefore included data only from 1959 to 1 9 6 2 . A Lincoln index c a l c u l a t i o n yielded an estimate Table 1: Numbers of antl e r l e s s deer sighted per hunter i n d i f f e r e n t areas of the Northwest Bay logging claim i n 1966 No. of deer per hunter AREA SEPT.-OCT. NOV. ALL MONTHS COMBINED 1 1.14 .65 .85 4 1.46 .46 1.00 No. of hunters 1 112 156 268 4 2 0 9 178 387 No. of deer seen 1 128 101 2 2 9 4 305 82 367 chi-square for Sept.-Oct, — 5.3791 (.025) chi-square for Nov. — 5 0623 (.025) chi-square for a l l months — 3.5524 (N.S.) 26 Table 2 : Numbers of hunters per square mile i n dif f e r e n t parts of the Northwest Bay study area i n 1966 Area Month No. of Hunters 1 Sept.-Oct. 2 .54 1 Nov. 3 . 4 3 4 Sept.-Oct. 9 . $3 4 Nov. 7 . 9 0 27 Table 3 • S t a t i s t i c s used i n ca l c u l a t i o n of Lincoln index for tagging area (1959-1962) and entire Northwest Bay-claim (1959-1963 ). (Confidence l i m i t s calculated through method described by Chapman, 1948) Sex No. Tagged Male Female Combined No. of Tagged Animals Shot as Fawns Tagging Area (20 square miles) 98 8 86 5 184 13 Total No. of Fawns Shot i n Area 108 71 178 Entire Claim (13 5.8 square miles) Male 118 8 Female 111 10 Combined 229 18 331 254 585 Tagging area (4 years) Entire claim (5 years) Males Females Total Estimated No. of Fawns 557-2709 20 54-9999 393-3132 1319-5300 Estimated Number of Fawns Per Year Tagging area Entire claim 331 976 305 564 Combined 1310-4356 4331-11789 630 1488 28 of 623 fawns fo r the area of tagging i n any given year over this period. Since the tagging area consisted of approximately 20 square miles, these c a l c u l a t i o n s led to an estimate of approxi-mately 31 fawns per square mile per year f o r the tagging area for the period 1959-1962. Due to the small numbers involved, data from these four years were grouped, but t h i s may have introduced errors into the r e s u l t s because of d i f f e r i n g population trends in d i f f e r e n t years over t h i s period. I f population trends did d i f f e r over t h i s period i t did not destroy the value of the c a l -culations completely, for the figures s t i l l represented an average over the four-year period. Given the number of fawns per square mile and the reproduc-t i v e rate, one can derive population estimates. According to calculations based on the work of Thomas (Unpub. Mat.), the fawn component of the population approximated 35 per cent immediately after b i r t h , whereas August counts over this period indicated that there were 18.87 per cent fawns in the population. The differences between these two figures may have been due to sum-mer mortality of fawns, which Brigham (1958) found to be high i n Washington. However, the difference between these two f i g -ures was close to 50 per cent, which was paradoxical i n l i g h t of tagging information. As indicated by Table 4, v i r t u a l l y 50 per cent of the tagged animals were a l i v e by August of the year i n which they were tagged. I f there was a 50 per cent fawn mortality through July, i t would mean that almost every tagged animal that s i r v i v e d the summer was either subsequently sighted or else had i t s tag recovered. 29 Table 4 : Numbers of sightings or recoveries of tags from tagging program, 1 9 5 9 - 1 9 6 3 i n c l u s i v e Sex No. Tagged A B C D E Male 118 18 46 57 60 66 Fema le 111 15 38 52 54 58 Combined 229 33 84 109 114 124 A : No. of animals seen prior to recovery B: No. of tags eventually recovered C: No. of animals d e f i n i t e l y a l i v e a f t e r July (either sighted or recovered) D : C plus those probably sighted a f t e r July E; D plus others seen prior to July but never subsequently sighted or recovered However, the two estimates of 35 and 1 8 . 8 7 per cent repre-sented extremes, and are valuable as such. Presuming that fawns make up 35 per cent of the population at the time of tagging, a density of 91 animals per square mile (including 32 fawns) was indicated for the tagging area. Presuming that fawns make up only 1 8 . 8 7 per cent of the herd at the time of tagging, a dens-i t y of 170 deer per square mile was indicated, of which again 32 were fawns. For the entire Northwest Bay study area, the Lincoln index calculations indicated approximately 11 fawns per square mile, leading to estimates of 31 and 58 deer per square mile r e s p e c t i v e l y . 30 From t h e s e f i g u r e s , t h e f o l l o w i n g p o p u l a t i o n e s t i m a t e s were d e r i v e d : T a g g i n g a r e a (1180 to 2760 a d u l t deer)) E n t i r e c l a i m (2716 t o 6383 a d u l t d e e r ) The t a g g i n g a r e a i n f o r m a t i o n a p p l i e d t o a r e a 2 as a w h o l e y i e l d e d p o p u l a t i o n e s t i m a t e s o f 2006 t o 4692 a d u l t d e e r . C a l c u l a t i o n s ba sed upon the p e l l e t - g r o u p c o u n t s o f Gates ( F i g . 3 ) l e d t o an e s t i m a t e o f a p p r o x i m a t e l y 2700 a d u l t d e e r f o r a r e a 2 and 4000 t o 6900 a d u l t a n i m a l s f o r the e n t i r e s tudy a r e a d u r i n g t h i s p e r i o d , i n summer. These e s t i m a t e s a r e d i s c u s s e d i n g r e a t e r d e t a i l b e l o w . B . A g e - C l a s s S t r u c t u r e S i g n i f i c a n t changes i n a g e - c l a s s s t r u c t u r e a p p a r e n t l y o c c u r r e d i n the N o r t h w e s t Bay d e e r h e r d o v e r t h e p e r i o d 1954 t o 1 9 6 6 , bu t t h e s e changes were s u b t l e . By t r e a t i n g t h e p o p u l a t i o n b i n o m i a l l y - - t h a t i s , b y s p l i t t i n g each sex i n t o 1 . 5 - y e a r - o l d s and t h o s e o v e r 1.5 y e a r s o l d ) , a n a l y s i s o f v a r i a n c e (Tab le 5) i n d i c a t e d t h a t 1 1. M a l e s and f e m a l e s have s i g n i f i c a n t l y d i f f e r e n t a g e -c l a s s s t r u c t u r e . 2 . The a g e - c l a s s s t r u c t u r e (as e x p r e s s e d by p r o p o r t i o n o f 1 . 5 - y e a r - o l d s t o o l d e r d e e r ) underwent s i g n i f i c a n t changes o v e r t h e p e r i o d 1954 t o 1966 . 3 . The d i f f e r e n c e s between male and f ema le a g e - c l a s s s t r u c -t u r e d i d not a l t e r s i g n i f i c a n t l y o v e r the p e r i o d o f the s t u d y . T h i s method o f a n a l y s i s , w h i l e a t t r a c t i v e i n t h a t i t p r e -c l u d e s e r r o r s i n a g i n g o f a n i m a l s , n e c e s s a r i l y a l s o p r e c l u d e d 31 Table 5' Analysis of age-class structure of Northwest Bay black-tailed deer herd treated as a binomial population Tot a Is for 1 .5-year-old animals 1 9 5 4 1955 1 9 5 6 1 9 5 7 1 9 5 8 1 9 5 9 I 9 6 0 Females 1 2 2 4 7 1 4 3 0 18 2 6 Males 2 0 17 1 5 2 3 4 7 3 9 41 Total 3 2 4 1 2 2 3 7 7 7 5 7 6 7 1 9 6 1 1 9 6 2 1 9 6 3 1 9 6 4 1 9 6 5 1 9 6 6 Total Female s 2 4 3 1 3 1 4 2 26 2 4 3 0 9 Males 2 7 6 4 5 3 3 6 3 2 3 5 4 4 9 Total 5 1 9 5 8 4 7 8 5 8 5 9 7 5 8 ".. Totals for a l l ages incl ud ing 1.5-year--olds, but excluding fawns 1 9 5 4 1 9 5 5 1 9 5 6 1957 1958 1 9 5 9 I 9 6 0 Fema les 4 7 81 2 5 4 2 8 3 5 4 7 8 Males 3 8 61 4 1 5 1 8 8 7 6 1 1 0 Total 8 5 1 4 2 6 6 9 3 171 1 3 0 188 1 9 6 1 1 9 6 2 1 9 6 3 1 9 6 4 1 9 6 5 1 9 6 6 Total Female s 8 3 1 5 6 1 1 0 1 0 4 80 6 2 1 0 0 5 Males 9 4 1 3 9 1 1 0 9 3 80 82 1 0 6 3 Total 1 7 7 2 9 5 2 2 0 197 160 1 4 4 2068 Source of Varia tion D. F, — s s MS Sex 1 6 . 8 2 3 2 5 6 . 8 2 3 2 5 2 9 . 3 7 2 5 8 (Si^ at' * .01) Year 12 5 . 0 8 9 1 2 0.42409 l.< 32 561 (Slg at I . 0 5 ) Sex-year 12 4.51442 0.37620 1,( 51946 (not sig interaction E r r o r 2042 463.73762 0.22710 Total 2067 480.16441 0.23230 32 analysis of changes within the age-classes older than 1 . 5 . Since a l l older age-classes of animals are greatly dependent upon the o r i g i n a l proportion of 1 . 5-year-olds in the popula-t i o n , i t i s doubtful i f t h i s objection i s important. Neverthe-l e s s , use of chi-square permitted analysis of such changes, plus the analysis of any p a r t i c u l a r trends which were not immediately apparent from analysis of variance. For example, while analysis of variance indicated that there were s i g n i f i c a n t changes i n the proportion o f 1 . 5-year-olds to older animals throughout the period 1 9 5 4 to 1 9 6 6 , i t did not reveal whether these changes followed any particular pattern or trend. A test for such a trend is d e t a i l e d i n Table 6 . In t h i s case, the test was con-ducted to determine whether the age-class structure tended to become younger i n the l a t t e r years of the study period, and no s i g n i f i c a n t trend was found. Further substantiation of these results was provided by the following a n a l y s i s . I f the 1 1 . 3 per cent that survived age 4 » 5 i n the 1 9 5 4 - 1 9 5 9 group of males died a£ a slower rate than the 9 . 9 per cent that survived age 4 « 5 i n the 1 9 6 0 = 1 9 6 6 group, then the average of the 1 9 5 4 = 1 9 5 9 group should be older than the average age of the 1 9 6 0 - 1 9 6 6 group. To test t h i s , hypothetical age-class structures were constructed based upon the fastest probable rate of death for 1 9 6 0 - 1 9 6 6 group, and the slowest probable rate of death f o r the 1 9 5 4 - 1 9 5 9 group. These data were then combined with data f o r the younger age-classes (from Table 6 ) and the number of animals in each class was multiplied by the 33 Table 6 : Comparison of age-class dist r i b u t i o n s for combined years 1954-1959 and 1960-1966 Males Age 1954-1959 1960-1966 1.5 45.3 39.8 2.5 20.6 22.1 3.5 15.2 17.3 4.5 7.6 10.9 over 4»5 11.3 9.9 100.0$ 100.0$ Female s 1.5 31.6 30.3 2.5 20.5 22.1 3.5 16 .0 16 .5 4.5 11.7 10.7 over 4»5 20.2 20.4 100.0$ 100.0$ Numb er of animals in sample Males 355 724 Females 332 673 34 age of the animals. The r e s u l t i n g figures were summed and divided by the t o t a l number of animals in the sample to provide an average age. The average age f o r the 1954-1959 group of males was 2.856, whereas the average age for the I96O-I966 group of males was 2.830. Since these averages were taken from data purposely made as disparate as possible, the results strongly indicate that no differences in age-class structure occurred be-tween these two periods. Since no general trends towards a younger or older age-class structure were noted over the period 1954 to 1966, data from Table 4 was analysed (Fig. 7) to determine whether any other types of patterns were present. Disregarding sex ra t i o s among 1.5-year-old animals, i t was apparent that the proportion of 1.5-year-old animals in the population varied quite regularly over the period o f the study. Analysis of variance indicated that males and females did not d i f f e r s i g n i f i c a n t l y i n general pattern over the 13-year period of the study, but i n both 1954 and 1962 the 1 .5-year-old males and females showed patterns that d i f f e r e d to a marked degree. A test to determine whether there were differences i n age-class structure o f the deer herd among diff e r e n t parts of the study area in 1966 was inconclusive. As indicated by Table 7, there was a higher proportion of animals 2,5 years old and older in the deer taken from area 1 than in the deer taken from area 4» However, the differences were not significant, possibly because sample sizes were too small or because there was interchange of animals between the two areas. FIGURE 7: Changes in the proportion of 1.5-year-old deer in the hunter k i l l at Northwest Bay, 1954-1966. 1954 1955 1956 1957 1958 1959 I960 1961 1962 1963 1964 1965 1966 YEAR 36 T a b l e 7 : Pe r c e n t a g e - c l a s s c o m p o s i t i o n of d e e r k i l l e d by-h u n t e r s i n a r e a s 1 and 4 a t Nor thwes t Bay i n 1966 (both s e x e s combined) A r e a 1.5 o r l e s s Over 1.5 T o t a l Number 1 42.9 57.1 21 4 59.1 4 0 . 9 66 C h i - s q u a r e not s i g n i f i c a n t C . Sex R a t i o s The p r o p o r t i o n o f males i n the Nor thwes t Bay d e e r p o p u l a t i o n changes s i g n i f i c a n t l y ove r t h e p e r i o d 1954 t o 1966 a c c o r d i n g t o two independen t c r i t e r i a , t h e h u n t e r k i l l i n a n t l e r l e s s s eason and the f a l l c o u n t s . These d a t a a r e p r e s e n t e d i n F i g . $ . B o t h i n d i c e s s u g g e s t e d t h a t the p r o p o r t i o n o f males i n t h e p o p u l a t i o n was a t i t s l o w e s t p o i n t i n 1954 and t h a t i t g e n e r a l l y i n c r e a s e d ( w i t h one p o s s i b l e e x c e p t i o n ) u n t i l I 9 6 0 . T h i s e x c e p t i o n o c c u r r e d i n 1956, when t h e p r o p o r t i o n o f males i n the h u n t e r k i l l was t h e h i g h e s t e v e r r e c o r d e d a t N o r t h w e s t Bay ( i n c o n t r a s t w i t h t h e f a l l coun t o f 1956, w h i c h f i t t e d i n w e l l w i t h the p a t -t e r n o f o the r y e a r s ) . Both i n d i c e s i n d i c a t e d a s h a r p d e c l i n e f rom I960 t o 1962, b u t a f t e r t h i s p o i n t t he two i n d i c e s t ended t o d i f f e r once a g a i n . The p r o p o r t i o n o f ma le s i n t h e h u n t e r k i l l r o s e s l i g h t l y from 1963 t o 1966, w h i l e the f a l l c o u n t s i n d i c a t e d t h a t p r o b a b l y t h e p r o p o r t i o n o f m a l e s i n the p o p u l a -t i o n c o n t i n u e d to d e c l i n e o v e r t h i s p e r i o d . Between 1956 and FIGURE 8: Changes i n the proportion of males i n the hunter k i l l during antlerless season and i n f a l l counts at Northwest Bay, 1954-1966. (Fawns not included.) FALL COUNTS HUNTER KILL 1 • • • • • • • • • * * • 1954 1955 1956 1957 1958 1959 I960 1961 1962 1963 1964 1965 1966 YEAR 38 1961, the proportion of males in the k i l l was consistently over 50 per cent. Since that time, the proportion of males was over 50 per cent only i n 1966, when 51 «5 per cent of the animals were males. Both indices were based only on the adult population. D. L i f e Tables Lif e tables are only as accurate as the samples from which they are constructed, so i t was of interest to determine whether Northwest Bay hunters tended to sample deer randomly over the period of the study. The use of "catch curves" (as described by Ricker, 1958, from Baranov, 1918) provided a convenient method of assessing t h i s point. Providing that s u r v i v a l rate is r e l a -t i v e l y uniform with age, and that there has been no change i n mortality with time, straightness in any part of a catch curve implies random sampling. As may be seen from Fig. 9 , in the years 1954 to 1959 i n c l u s i v e hunters shot proportionately few fawns during the a n t l e r l e s s season. However, from I960 to 1966 i t was possible that fawns were taken i n numbers approaching their actual proportion i n the population, providing that bucks and does were considered separately. In any case, the f a c t that both male and female catch curves tended to straightness through-out the e n t i r e age spectrum indicated that during a n t l e r l e s s season hunters tended to shoot without regard to sex. Since i t i s v i r t u a l l y impossible to d i f f e r e n t i a t e between does of 1 .5 years of age and those that are older, i t may be assumed that hunters were taking adult animals randomly from I 9 6 0 to 1 9 6 6 . FIGURE 9: Catch curves f o r Northwest Bay deer, 1954-1966. 1954-1959 1960-1966 B fx* o Pa 150 100 80 60 50 40 30 .5 1.5 2.5 3.5 4.5 AGE IN YEARS 400 350 300 .'.50 200 w § 150 & Pi 1 100 80 70 MALES FEMALES .5 1.5 2.5 3.5 4.5 AGE IN YEARS ANTLERLESS SEASON 1954-1959 1960-1966 150 100 80 70 I 60 o 50 & 40 | 30 20 250 200 150 oi 100 ^ 80 o =3 25 60 50 40 1.5 2.5 3.5 4.5 AGE IN YEARS BUCK SEASON 1.5 2.5 3.5 4.5 AGE IN YEARS 40 Data from I 960 to 1966 i n c l u s i v e were therefore combined to produce the general Northwest Bay b l a c k - t a i l e d deer l i f e tables presented i n Table 8 . The k i l l was s p l i t into male and female cohorts f o r two reasons: f i r s t , because males and f e -males have considerably different l i f e expectancies; and, second, because the hunter k i l l probably does not r e f l e c t true male to female proportions i n November due to the influence of the r u t . Nevertheless, a combined male and female l i f e table i s presented since data are sometimes a v a i l a b l e without regard to sex. The combined table permits meaningful assessment of such data. The l i f e tables shown in Table 8 provided the best possible estimate of l i f e expectancies under conditions which prevailed at Northwest Bay during the period of the study. However, i t was of interest to determine l i f e expectancies at the beginning of the study period (when hunting was not a major f a c t o r ) and at the end of the study period (by which time hunting might have altered l i f e expectancies of some age-classes). Such l i f e tables are presented in Tables 9 and 1 0 . It was apparent that in both tables fawns were under-represented. Possible explanations for t h i s include biased sampling by hunters or abnormally poor re-production and/or recruitment during these years. Fawns were therefore ignored i n the l i f e - t a b l e c a l c u l a t i o n s . Table 8 : L i f e t a b l e s f o r Northwest Bay b l a c k - t a i l e d d e e r , based on h u n t e r k i l l f r o m I 960 to 1966 i n c l u s i v e Males A g e - C l a s s I x dx £* • Lx Ex 0 . 5 - 1 . 4 1000 270 .270 865 2 . 4 3 6 1 .5 -2 .4 - 730 324 .443 568 2 .152 2 . 5 - 3 . 4 406 89 .219 3 6 1 . 5 2 .224 3 . 5 - 4 . 4 317 117 .369 2 5 8 . 5 1 .708 4 . 5 ^ 5 . 4 200 1 9 1 . 5 1 .415 over 5 . 4 183 9 1 . 5 . 5 0 0 Females 0 . 5 - 1 . 4 1000 346 .346 827 2 .607 1 . 5 - 2 . 4 654 176 .269 566 2 . 7 2 1 2 . 5 - 3 . 4 478 122 .255 417 2 . 5 3 9 3 . 5 - 4 -4 356 125 .351 2 9 3 . 5 2 . 2 3 8 4 . 5 - 5 . 4 231 309.5 2 .179 over 5 .4 388 194 .500 Combined 0 . 5 - 1 . 4 1000 303 .303 848 .5 2 . 4 6 5 1 . 5 - 2 . 4 697 259 .371 5 6 7 . 5 2.323 2 . 5 - 3 . 4 438 104 .237 386 2 .374 3 . 5 - 4 . 4 334 120 .359 274 1 .958 4 . 5 - 5 . 4 214 243.5 1.775 over 5 .4 273 1 3 6 . 5 . 500 42 Table 9 : L i f e t a b l e s f o r Northwest Bay b l a c k - t a i l e d d e e r , based on h u n t e r k i l l i n 1954 and 1955 Males A g e - C l a s s Number Shot l x Lx Ex 0 , 5 - 1 . 4 25 = 1 .5 -2 .4 37 100G 851.5 1.89 2 .5 -3 .4 26 703 554.0 1.90 3 . 5 - 4 . 4 15 405 283.5 1.40 4 . 5 - 5 . 4 6 162 283.5 2.99 over 5»4 15 405 202 .5 .50 Female s 0 . 5 - 1 . 4 23 1 . 5 - 2 . 4 36 1000 958.0 3.06 2 . 5 - 3 . 4 33 916 708 . 0 2.29 3 . 5 - 4 . 4 18 500 4 4 4 . 5 2 . 78 4 . 5 - 5 . 4 14 389 569.5 2.43 over 5>4 27 750 3 7 5 . 0 .50 Combined 0 . 5 - 1 . 4 48 1 . 5 - 2 . 4 73 1000 904.0 2.61 2 . 5 - 3 . 4 59 ' 808 630.0 2.11 3 . 5 - 4 . 4 33 452 3 6 3 . 0 2 .37 4 . 5 - 5 . 4 20 274 4 2 4 . 5 2 .60 over 5 . 4 42 575 287.5 .50 43 Table 10: Life tables for Northwest Bay black-tailed deer, based on hunter k i l l in 1965 and 1966 Males Age-Class Number Shot lx Lx Ex 0 . 5 - 1 . 4 65 , 1 . 5 - 2 . 4 67 1000 753.5 1.92 2 .5 -3 .4 34 507 425.0 2.29 3 . 5 - 4 . 4 2 3 343 320.5 2.15 4 . 5 - 5 . 4 20 298 283 .5 1.40 over 5.4 18 269 134.5 .50 Females 0 . 5 - 1 . 4 40 1 .5 -2 . 4 50 1000 800.0 2.34 2 0 5—3 »4 30 600 500.0 2. 56 3 . 5 - 4 . 4 20 400 310.0 2.60 4 . 5 - 5 . 4 11 220 420.0 3.32 over 5.4 31 620 310.0 .50 Combined 0 . 5 - 1 . 4 105 1 .5 -2 .4 117 1000 773.5 2.10 2 .5 -3 .4 64 547 457.5 2.43 3 . 5 - 4 . 4 43 368 321.5 2.37 4 . 5 - 5 . 4 31 265 342.0 2.08 over 5.4 49 419 209.5 .50 44 E. Condition , Most age and sex classes of Northwest Bay deer apparently underwent s i g n i f i c a n t changes in weight over the period 1954 to 1966, as indicated by Table 11 . But these changes assumed the proportion of s i g n i f i c a n t trends only for the youngest three age classes of males (Fig. 10 and 11) . A l l of these age-classes of males showed a s i g n i f i c a n t decline in weight (indicative of a decline i n condition) over the period 1954 to 1966. While femal fawns and 1 .5-year-olds showed s i m i l a r i t i e s in weight pattern over t h i s time, no s i g n i f i c a n t decline could be demonstrated. Lines of best f i t have been superimposed i n Figure 10 only for age-classes in which a s i g n i f i c a n t decline was found. While weights of 1 .5-year-old males apparently declined over the period 1954 to 1966 f o r Northwest Bay as a whole, there were., apparently ? departures from t h i s pattern i n area 4« As shown by F i g , 12, while area 1 deer exhibited a s i g n i f i c a n t decline in weight, area 4 deer did not—and, i f anything, the weights bf animals from area 4 tended to increase over the study period. The slopes of the two l i n e s in F i g . 12 were s i g n i f i -cantly d i f f e r e n t from each other, i n d i c a t i n g that animals i n area 4 tended to follow weight patterns s i g n i f i c a n t l y different from animals in area 1 . 45 Table 1 1 : R e s u l t s of a n a l y s i s of v a r i a n c e of average w e i g h t s of d i f f e r e n t age and sex c l a s s e s of Northwest Bay deer f o r the p e r i o d 1954 to 1966* (See F i g . 10 and 11 f o r a v e r a g e w e i g h t s . ) Males Age Numb e r F S i g n i f i c a n c e . 5 418 2 .13219 .025 1.5 796 6 .60066 .005 2 .5 389 4. 47105 .005 3 . 5 256 5 .17760 .005 4 .5 144 1.90157 .05 Females . 5 305 1 .60675 N.S. 1.5 285 4 . 30430 .005 2. 5 200 1 .87197 .05 3.5 146 1 .02588 N.S. 4 . 5 94 1 .33088 N.S. FIGURE 10: Average age-specific weights of male black-t a i l e d deer at Northwest Bay,1954-1966. i i i • • • * ' ' • • • ' 1954 1956 1958 I960 1962 1964 1966 YEAR FIGURE 1 1 : Average age-specific weights of female black-t a i l e d deer at Northwest Bay, 1954-1966. FIGURE 12: Average weights of•1.5-year-old male black-tailed deer from different areas at Northwest Bay, 1954-1966. (t-test between slopes = 2.2017, d.f. = 12) II Changes i n Factors Influencing the Deer Herd 49 A. Serai Changes Sign i f i c a n t changes have taken place i n the Northwest Bay-range since logging began i n 1939 (Table 12). These changes are shown in greater d e t a i l i n Tables 13-16. Through the c a l c u l a -t i o n described on page 17, based on Gates' pellet-group counts, t h e o r e t i c a l estimates of numbers of deer i n the study area i n any given year were computed. However, there are certain prob-lems inherent i n t h i s method of c a l c u l a t i o n of deer numbers. For instance, the deer population would be expected to equal the indicated figures for a given year only i f no influence other than serai succession affected the herd, and even in t h i s case response to environmental change would have to be instan-taneous. Neither of these conditions prevailed. In addition, the estimates were based upon pellet-group counts conducted only in a portion of area 2 during a time at which i t was in a highly-favorable stage of regeneration and therefore probably much more densely populated than other parts of the study area. Because of t h i s , i t i s doubtful i f Gates' estimate of upwards of 40 deer per square mile in timber should be applied to other parts of the study area, or even to area 2 i t s e l f in other years. Therefore estimates of deer abundance were made using three separate c r i t e r i a for the number of deer per square mile of timber—one, f i v e , and f o r t y (Fig. 13). I t must not be construed that the deer population was be-lieved to follow the indicated f i g u r e s . While the changes were 50 T a b l e 12: Changes i n the amount o f l a n d i n v a r i o u s s u c c e s s i o n a l s t a g e s i n t h e Northwest Bay study a r e a ( e x p r e s s e d i n per c e n t ) YEARS AFTER BURNING Year Timber 0=4 5-9 1 0 - 1 4 over 14 1939 100.0 0.0 0.0 0.0 0.0 1 9 4 0 99.927 0 . 0 7 3 0.0 0.0 0.0 1 9 4 1 99.927 0.073 0.0 0.0 0.0 1 9 4 2 98.047 1.953 0.0 0.0 0.0 1 9 4 3 9 6 . 1 1 4 3, 886 0.0 0.0 0.0 1944 9 4 . 1 7 1 5. 829 0.0 0.0 0.0 1945 92.545 7 .381 0.073 0.0 0.0 1946 90.883 9 . 0 4 4 0.073 0.0 0.0 1947 89.615 8.433 1.953 0.0 0.0 1 9 4 8 8 6 . 1 1 6 9.998 3. 886 0.0 0.0 1949 84.632 9.539 5 0829 0.0 0.0 1950 81 .175 11.371 7.381 0.073 0.0 1951 790297 11.585 9.044 0.073 0.0 1952 75 o 0 0 7 14 . 6 0 8 8.433 1.953 0.0 1 9 5 3 7 109 0 5 14 .211 9 . 9 9 8 3 . 8 8 6 0.0 1954 67.708 1 6 . 9 2 4 9.539 5.829 0.0 1 9 5 5 6 6 . 2 4 3 14.932 1 1 . 3 7 1 7 . 3 8 1 0.073 1956 65.131 14 . 1 5 4 11.597 9 .044 0 . 0 7 3 1957 63 .726 11.282 1 4 . 6 0 9 8.433 1 . 9 5 3 1958 6 2 . 7 8 6 9.121 14.209 9 . 9 9 8 3.886 1959 6 1 . 8 6 8 6.327 1 6 . 4 3 7 9.539 5.829 I960 6 0 . 6 3 0 6 . 0 1 9 1 4 . 5 2 6 11.371 7 . 4 5 3 1 9 6 1 5 9 .332 6.453 13.513 11.597 9.105 1 9 6 2 5 7 . 6 0 6 6 .591 1 0 . 8 1 2 1 4 . 6 0 9 1 0 . 3 8 3 1 9 6 3 5 7 . 2 1 9 6 . 7 8 7 8 . 5 0 1 1 4 . 2 0 9 1 3 . 2 8 5 1 9 6 4 5 5 . 6 8 9 7.229 5 . 9 5 7 1 6 . 4 3 7 1 4 . 6 8 9 1965 5 3 . 6 7 2 8 .452 5 . 1 9 3 1 4 . 5 2 6 1 8 . 1 5 8 1 9 6 6 5 1 . 3 0 3 9 .295 5 . 8 7 4 1 3 . 5 1 3 2 0 . 0 1 4 51 Table 13: Changes i n the amount o f l a n d i n v a r i o u s s u c c e s s i o n a l s t a g e s f o r a r e a 1 of the Northwest Bay l o g g i n g d i v i -s i o n i ( e x p r e s s e d i n per c ent ) YEARS AFTER BURNING Year Timber 0-4 5 - 9 1 0 - 1 4 over 1 4 1 9 3 9 100 o 0 0.0 0 . 0 0 , 0 0.0 1 9 4 0 9 9 . 7 5 8 0 . 2 4 2 0 . 0 0 . 0 0.0 1941 9 9 . 7 5 8 0 . 2 4 2 0 . 0 0 . 0 0.0 1 9 4 2 93 .546 6 . 4 5 4 0 . 0 0 . 0 0 . 0 1943 87.154 12. 846 0 . 0 0 . 0 0 . 0 1944 8 0 . 7 3 1 1 9 . 2 6 9 0 . 0 0 . 0 0 . 0 1 9 4 5 75 . 3 5 9 2 4 . 3 9 8 0 .242 0 . 0 0 . 0 1 9 4 6 7 2 . 0 4 5 27.712 0 .242 0 . 0 0 . 0 1947 7 0 . 3 1 6 23.229 6 .454 0 . 0 0 . 0 1948 6 7 . 3 3 8 1 9 . 8 1 6 12.846 0 . 0 0 . 0 1 9 4 9 6 6 . 5 6 1 14.170 1 9 . 2 6 9 0.0 0 . 0 1 9 5 0 6 1 . 5 4 9 13 . 8 1 0 2 4 . 3 9 8 0.242 0 . 0 1 9 5 1 5 7 . 3 1 5 14 0 730 2 7 . 7 1 2 0.242 0 . 0 1 9 5 2 5 1 . 1 3 5 1 9 . 1 8 2 2 3 . 2 29 6.454 0 . 0 1953 44.643 2 2 . 6 9 5 1 9 . 8 1 6 12.846 0 . 0 1 9 5 4 42.032 23 .529 1 4 . 1 7 0 19.269 0 . 0 1 9 5 5 4 2 . 0 3 2 1 9 . 5 1 8 1 3 . 8 1 0 24.398 0 . 2 4 2 1956 42.032 1 5 . 2 8 3 1 4 . 7 3 0 27.712 0.242 1957 4 1 . 8 0 8 9 .327 1 9 . 1 8 2 23.229 6.454 1958 4 1 . 8 0 8 2 .835 22.695 1 9 . 8 1 6 12.846 1 9 5 9 41.734 0 .298 24.529 1 4 . 1 7 0 19.269 I960 a.734 0 ,298 19 . 5 1 8 1 3 . 8 1 0 24.641 1961 41.734 0 ,298 15 . 2 8 3 14.730 27 . 955 1962 41.734 0 .075 9 .327 1 9 . 1 8 2 29 . 6 84 1963 a.734 0 ,075 2 . 6 3 5 22,695 3 2 . 6 6 2 1964 a.734 0 . 0 7 5 0 , 2 2 4 24 .529 33.439 1965 4 0 . 6 7 6 1 . 1 3 2 0 , 2 2 4 1 9 . 5 1 8 3 6 . 4 5 1 1 9 6 6 4 0 . 2 9 1 1 . 4 4 3 0 . 2 9 6 1 5 . 283 42 .685 52 Table 14: Changes i n t h e amount o f l a n d i n v a r i o u s s u c c e s s i o n a l s t a g e s f o r a r e a 2 of t h e Northwest Bay l o g g i n g d i v i s i o n ( e x p r e s s e d i n p e r c e n t ) YEARS AFTER BURNING Year Timb e r 0=4 5=9 10=14 over 14 1945 100.0 0.0 0.0 0.0 0.0 1946 98.159 I . 8 4 I 0.0 0.0 0.0 1947 96.082 3.918 0.0 0.0 0.0 1948 88.840 11.160 0.0 0.0 0.0 1949 85.426 14.574 0.0 0.0 0.0 1950 80.014 19.986 0.0 0.0 0.0 1951 7 8 . 6 6 1 19.499 1.841 0.0 0.0 1952 72.645 23.437 3.918 0.0 0.0 1953 69.840 19.000 11.160 0.0 0.0 1954 63.583 21.843 14.574 0.0 0.0 1955 6 1 . 8 1 0 18.203 19.986 0.0 0.0 1956 59 .789 18 .837 19.527 1.841 0.0 1957 58.335 14.315 23.432 3 . 918 0.0 1958 57 .281 12.564 18.995 11 .160 0.0 1959 56.436 7.913 21 ,077 14.574 0.0 I960 54 .119 8.516 17.379 19.986 0.0 1961 52.100 8.657 17.865 19.527 1.841 1962 48.519 10.173 13.958 23.432 3.918 1963 47.150 10.26 2 12.432 18.995 11 .160 1964 45.089 11.452 7.808 21.077 14.574 1965 41.878 13. 560 7 . 198 17.379 19.986 1966 39 .820 12 .726 8.211 17.865 21.378 53 T a b l e 1 5 : Changes i n the amount o f l a n d i n v a r i o u s s u c c e s s i o n a l s t a g e s i n a r e a 3 of the Northwest Bay l o g g i n g d i v i s i o n ( e x p r e s s e d i n per cent ) YEARS AFTER BURNING Year Timber 0-4 5-9 10-14 over 14 1948 100.0 o.o 0.0 0.0 0.0 1949 99.714 0.286 0.0 0.0 0.0 1950 99.714 0.286 0.0 0.0 0.0 1951 98.417 1.583 0.0 0.0 0.0 1952 95 .340 4.660 0.0 0.0 0.0 1953 93 .801 6.199 0.0 0.0 0.0 1954 81.578 18.136 0.286 0.0 0.0 1955 77.863 21.851 0.286 0.0 0.0 1956 76.215 22.203 1.583 0.0 0.0 1957 76.215 19.125 4.660 0.0 0.0 1958 74.434 19.367 6.199 0.0 0.0 1959 72.565 11.497 15.652 0.286 0.0 I960 71.093 7.562 21 .060 0.286 0.0 1961 70.521 7.342 20.554 I.583 0.0 1962 69.224 6.991 19.12 5 4.660 0.0 1963 66.784 8.92 5 18.092 6.199 0.0 1964 62 . 233 11.321 10.508 15.652 0.286 1965 61.50 8 9.585 7.562 21.060 0.286 1966 60.805 9.716 7.342 20.554 1.583 54 Table 16: Changes in the amount of land i n various successional stages for area 4 of the Northwest Bay logging d i v i s i o n (expressed i n per cent ) TEARS AFTER BURNING Year Timb er 0-4 5-9 10-14 over 1953 • 100.0 0.0 0.0 0.0 0.0 1954 99.539 0.461 0.0 0.0 0.0 1955 97.519 2.48I 0 .0 0.0 0.0 1956 96.538 3.462 0 .0 0.0 0.0 1957 93 .329 6.671 0.0 0.0 0 .0 1958 91.710 8.290 0.0 0.0 0.0 1959 90.001 9.538 0.461 0.0 0.0 I960 88.895 8.795 2.310 0.0 0.0 1961 86.822 10.385 2. 793 0.0 0.0 1962 85.515 9.167 5.319 0.0 0.0 1963 84.407 8.973 6.620 0.0 0.0 1964 82.827 8.279 8.432 0.461 0.0 1965 81.151 9.483 7.056 2.310 0.0 1966 75.555 13 .346 8.306 2.793 0.0 FIGURE 13: Changes i n estimated numbers of deer that could theoretically be supported at Northwest Bay because of SGn&f succession» (See text for explanation.) NUMBERS OF DEER PER SQUARE MILE IN TIMBER 1000 . 1948 195.0 1952 1954 "1956 1958 I960 1962 1964 1966 YEAR 56 e x p r e s s e d i n terms of numbers of d e e r , they r e a l l y were more r e p r e s e n t a t i v e of h a b i t a t t h a n d e e r , a s e x p l a i n e d on page 17. The g e n e r a l form of the graphs was t h e most i m p o r t a n t r e s u l t , i n d i c a t i n g t h a t Northwest Bay g e n e r a l l y d e c l i n e d as d e e r h a b i t a t over the p e r i o d of th^e s t u d y . Such graphs may r e p r e s e n t g e n e r a l e s t i m a t e s of p o p u l a t i o n s i z e , however, p r o v i d i n g such f a c t o r s as l a c k of i n s t a n t a n e o u s r e s p o n s e and d i f f e r i n g deer usage o f t i m b e r are t a k e n i n t o account. F i g . 14 shows tfye r e s u l t s o f s i m i l a r c a l c u l a t i o n s (based on an e s t i m a t e of f i v e deer p e r square m i l e i n t i m b e r ) f o r a r e a s 1, 2, 3, and 4 over a s i m i l a r p e r i o d . A g a i n , t h e g e n e r a l shapes o f t h e s l o p e s were i n d i c a t i v e of the manner i n w h i c h t h e a r e a s changed as d e e r h a b i t a t . I t i s a p p a r e n t t h a t much of t h e d e c l i n e i n t he Northwest Bay r a n g e was due to a r e a 1, which d e c r e a s e d s h a r p l y i n i t s a b i l i t y to support deer a f t e r 1954° Areas 2 and 3 changed l i t t l e over t h i s p e r i o d , but a r e a 4 a p p a r e n t l y improved s t e a d i l y a s d e e r h a b i t a t , c ounter to t h e t r e n d of the s t u d y a r e a as a whole. Areas 1 and 4 t h e r e f o r e p r o v i d e d good c o n t r a s t s i n s e r a i c o n d i t i o n s . B. Hunt i n g Changes The numbers of d e e r k i l l e d by h u n t e r s f o r each y e a r between 1954 and 1966 are shown i n F i g . 15. While i t was i m p o s s i b l e t o g i v e e x a c t f i g u r e s f o r t h e k i l l f o r a l l years ( e s p e c i a l l y i n l a t t e r y e a r s , when a f r e e r a c c e s s p o l i c y was i n e f f e c t ) , i t was b e l i e v e d t h a t the a c t u a l k i l l f o l l o w e d c l o s e l y t h e p a t t e r n o f t h e known k i l l . The e s t i m a t e s i n F i g . 15 were made n e c e s s a r y FIGURE 14: Changes due to serai succession i n numbers of deer that could t h e o r e t i c a l l y be supported i n different areas at Northwest Bay. FIGURE 15: Known and estimated numbers of deer taken during hunting seasons and for sc i e n t i f i c purposes at Northwest Bay, 1954-1966. 800 700 600 gj 500 400 300 200 100 CO on D o e s ESTIMATED BUCKS 1954 1955 1956 1957 1958 1959 I960 1961 1962 1963 1964 1965 1966 YEAR 59 because hunter k i l l f i g u res were not recorded f o r a l l days in the bucks-only season in some years. Estimates were based on success on other days i n the year in question and normal success patterns for the missing date. For example, success i s normally low i n October, so i f figures were missing for various days i n October, the normally-low success pattern for October was taken into account in making of estimates. These estimates are presen-ted i n m o re d e t a i l in th e appendices. It i s apparent that both t o t a l numbers of deer and t o t a l numbers of does removed has varied considerably from year to year. Hunting therefor e presum-ably varied considerably i n i t s ef f e c t on the herd within a given year (by reduction of numbers of animals entering t h e winter) and i n i t s ef f e c t in future years (by af f e c t i n g reproduction through removal of varying numbers of does). From a low of under 200 animals i n 1956, the known k i l l reached a high of over 600 animals i n both 1962 and 1963 . In 1963 , the k i l l of 290 does shown i n Fig. 15 includes 77 animals taken over the following winter f o r s c i e n t i f i c purposes. Most of these animals were mature does i n prime reproductive capacity (as opposed to the normal hunting k i l l over this period., which included a high per-centage cf fawns and young a d u l t s ) . The pattern of a general!y-increasing k i l l in l a t t e r years tends to r e f l e c t an increase in numbers of days of l e g a l antler-less hunting. Coincidental with the increase in the length of the hunting season, however, was an increase i n the average num-ber of hunters per day (Fig. 16) as a re s u l t of a relaxation of access poli c y . FIGURE 16: Changes in hunting pressure during antlerless season at Northwest Bayy . 1954-1966. 250 r £ 200 rx, 00 I 150 o ai P=3 ^ 100 1954 1955 1956 1957 1958 1959 I960 1961 1962 1963 1964 1965 1966 YEAR 61 The heavy exploitation of 1962 and 1963 was followed by a decrease in hunter success (Fig. 5) and numbers of deer sighted per spring count (Fig. 4 ) , both of which support the contention that numbers of animals s i m i l a r l y declined over t h i s period. The relati o n s h i p of hunter success to deer k i l l in these years i s explored i n more d e t a i l in Table 17, which indicates that the decline after both 1962 and 1963 was highly s i g n i f i c a n t . An e n t i r e l y d i f f e r e n t c r i t e r i o n for the effect of hunting upon Northwest Bay deer i s provided by results of the tagging program. Causes of death of the tagged animals that were r e -covered are summarized in Table 18. It is un l i k e l y that these figures were representative of actual causes of death for the period 1959=1963 for the population as a whole, however, since the figures are heavily biased by the fac t that tags are much more l i k e l y to be recovered by hunting than from other sources. Nevertheless, these figures may be u t i l i z e d to estimate the per-centage of animals that are l i k e l y to die by hunting. Of the 229 animals tagged, 68 were l a t e r returned as hunter k i l l s = -a 29.7 rate of a t t r i t i o n , and t h i s t o t a l is complete only to the end of the 1966 hunting season. In addition, eight tags were recovered from animals that probably were k i l l e d by hunters but l e f t in the bush. These eight tags (3.5 per cent of the 229 tagged animals) represent the minimum figure for c r i p p l i n g loss and/or i l l e g a l k i l l . Hunters therefore probably k i l l e d a minimum of 33 02 per cent of the animals that were tagged over the period 1959-1963 i n c l u s i v e . Of the hunter-killed tagged deer, 64.7 per cent were bucks. Hunters k i l l e d 28.8 per cent of the 111 tagged 62 Table 1 ? : Numbers of hunters and reported deer k i l l f o r 1962-1964 a n t l e r l e s s seasons at Northwest Bay-Year No, of Hunters Total K i l l Percent Success 1962 1971 544 27.6 1963 2171 452 20 08 1964 2195 303 13 .8 chi-square between 1962 and 1963 19.7- (.005) chi-square between I963 and 1964 — 3.1.4 (.005) Table 18: Causes of death of a l l tagged deer from which tags were recovered (84 animals recovered from a t o t a l of 229 that were tagged) Fema les Males Combined Hunt ing 73 .8 86,9 80.9 Probable hunter wounding 10.5 a,7 9.5 K i l l e d for scienti f i e purposes 10,5 0,0 4.7 Fawn mortality from tagging 2.6 0,0 1.2 Winter death 2.6 4.4 3.6 100,0$ 100.0$ 100.0$ 63 females, whereas they took 37 »3 per cent of the 118 tagged males. With assistance from l i f e tables (Table 8) the average ex-p l o i t a t i o n per year for both males and females was calculated. The average death rate f o r males was 35 .26 per cent, whereas f o r females i t was 3 2 . 18 per cent. For both sexes combined, the death rate was 3 3 . 82 per cent. Assuming that hunters took be-tween 35 and 50 per cent of the animals that died each year (or, to break i t down further, between 30 and 40 per cent of the f e -males and between 40 and 55 per cent of the males), the following per cent yearly rates of exploitation would be l i k e l y : Sex Minimum Maximum i • — — — — — — Male 1 4 . 1 17.6 Female 9 .6 1 2 . 9 Combined 1 1 . 8 1 6 . 9 These ca l c u l a t i o n s are based on the assumption that hunting death rates remained constant from 1959 to 1 9 6 3 . Since they did not, i t i s probable that the above figures over-estimated hunting mor-t a l i t y i n the e a r l i e r years of tagging, and und er-estimated i t in the l a t e r years, C„ Winter Weather Changes Winter weather data were obtained from Nanaimo, since i t i s the closest point for which sa t i s f a c t o r y records have been main-tained. Total winter snowfall, t o t a l number of freezing days, and mean winter temperature for the study period are shown i n Table 1 9 . The winters of 1955-56 and 1964=65 were commonly be-lieved to have adversely affected Vancouver Island deer 64 Table 19: W i n t e r weather s t a t i s t i c s f o r Nanaimo, B o C o , f o r t h e p e r i o d 1954 t o 1966 Year Average Temperature No. o f Days T o t a l W i n t e r (November-March) w i t h F r e e z i n g S n o w f a l l Temperatures 1953 -54 4 0 . 2 6 3 6 2 . 1 1 9 5 4 - 5 5 4 0 o 6 5 9 5 . 4 1 9 5 5 - 5 6 3 6 0 8 7 7 4 3 . 0 1 9 5 6 - 5 7 3 7 . 8 8 0 4 4 . 9 1 9 5 7 - 5 8 4 3 . 0 32 0 . 0 1 9 5 8 - 5 9 4 0 . 6 52 24 . 4 1 9 5 9 - 6 0 4 0 0 2 7 1 7 . 9 1 9 6 0 - 6 1 4 1 . 8 4 1 8 . 0 1 9 6 1 - 6 2 4 0 . 4 5 9 2 8 . 9 1 9 6 2 - 6 3 a . 8 4 3 2 . 3 1 9 6 3 - 6 4 4 1 . 8 6 9 1 . 1 1 9 6 4 - 6 5 3 8 . 6 92 6 3 . 8 1 9 6 5 - 6 6 4 0 . 0 8 0 6 1 . 4 p o p u l a t i o n s but Table 17 i n d i c a t e s t h a t t h e y were by no means un i q u e i n t h e i r s e v e r i t y o v e r t h e p e r i o d of t h e s t u d y . B o t h , however, were c o l d e r t h a n n o r m a l , w i t h a g r e a t e r t o t a l s n o w f a l l , but two o t h e r w i n t e r s (1956-57 and 1965-66) a l s o f e l l i n t o t h i s c a t e g o r y i f t h e s e c r i t e r i a a r e t h e o n l y ones employed. I f t h e 1955-56 and 1964-65 w i n t e r s were u n i q u e l y s e v e r e f o r t h e d e e r herds o f Vancouver I s l a n d , i t i s p r o b a b l e t h a t f a c t o r s other t h a n the ones d e s c r i b e d i n Table 17 were a l s o i m p o r t a n t . The e f f e c t s of the w i n t e r s of 1955-56 and 1964=65 upon the Northwest Bay deer were a p p a r e n t l y d i s s i m i l a r , w i t h t h e 1955-56 w i n t e r being much more s e v e r e i n i t s e f f e c t s . For i n s t a n c e , h u n t e r s u c c e s s ( F i g . 5) d e c l i n e d markedly between 1955 and 1956, 65 but the decline between 1964 and 1965 was not s t a t i s t i c a l l y s i g -nificanto These r e s u l t s indicate that the Northwest Bay deer population declined s i g n i f i c a n t l y as a res u l t of the 1955-56 winter, but not as a r e s u l t of the 1964-65 winter. S i m i l a r l y , r e s u l t s indicated that the 1955-56 winter had much greater e f f e c t s upon age-class structure, sex r a t i o s , and condition of the animals than the 1964 -65 winter d i d . The e f f e c t of 1955=56 winter weather on age-class structure was assessed by chi-square analysis of the hunter k i l l i n 1955 and 1956. This material is summarized in Tables 20 and 21 . In the case of Table 20, the e f f e c t of the 1955-56 winter upon su r v i v a l of fawns was tested by comparing the r a t i o of 1 .5-year-old animals to a l l older age classes but 2.5 i n the hunter k i l l f o r the year preceding and following the severe winter. Table 21 i s si m i l a r , except that i n t h i s case the ratio was between 2 .5-year-olds and a l l older animals to assess the effect of the winter upon 1.5-year-old deer. When males and females were grouped, no s i g -n i f i c a n t differences were noted in the hunter k i l l i n the two years, i n d i c a t i n g that neither fawns nor 1 .5-year-olds were d i s -proportionately affected by the winter of 1955-56. S p l i t t i n g by sex results i n a female sample too small for meaningful analysis, but there are indications that the female fawns and 1.5-year-olds were adversely affected by the winter of 1955-56 disproportionately to other age-classes of animals. Table 22 summarizes the r e s u l t s of similar analyses for the winter of 1964-65, f o r females only. Again, no s i g n i f i c a n t 66 Table 20: E f f e c t of t h e 1955-56 w i n t e r upon s u r v i v a l of fawns a t Northwest Bay-Males Per Cent 1.5 Per Cent Over 2 .5 Number 1955 4 0 . 5 59 .5 42 1956 5 0 . 0 5 0 . 0 30 Females 1955 4 0 . 0 6 0 . 0 • 60 1956 31 .8 6 8 . 2 22 Table 2 1 : E f f e c t of t h e 1955-56 w i n t e r upon s u r v i v a l of 1 . 5 -y e a r - o l d deer a t Northwest Bay Males Per Cent 2.5 Per Cent Over 2.5 Number 1955 4 3 . 2 5 6 . 8 44 1956 4 6 . 4 5 3 . 6 28 Female s 1955 36 . 8 63 .2 57 1956 1 6 . 7 83 .3 18 67 Table 2 2 : Effect of the 1964-65 winter upon survival of female fawns and 1 .5-year-olds at Northwest Bay Survival of fawns Year % 1 .5 % over 1.5 No. 1964 4 0 . 4 5 9 . 6 104 1965 3 2 . 5 67 . 5 80 Survival of 1 .5-year-olds Year % 2.5 % over 2 . 5 No. 1964 3 3 . 9 6 6 . 1 62 1965 42 .6 57 . 4 54 differences were found in the hunter k i l l f o r the year preced-ing and following the reputedly-severe winter. Unlike the 1955-56 analysis, however, there were no clear trends. The data indicated that female fawns may have been adversely affected, but that female 1 .5-year-olds tended to survive better over the 1964-65 winter than over the 1963 -64 winter. Possible effects of winter weather on condition were d i f f i -cult to assess due to the f a c t that deer are inherently capable of recovering any l o s t weight over a summer (Bandy, 1965 ). Nevertheless, there were indications that the 1955-56 winter adversely affected males at le a s t , and that the 1964-65 winter had no abnormal effects on condition. As may be seen from Table 23, the average weights of al 1 age-classes of males but 4 .5-year-olds declined s i g n i f i c a n t l y between the 1955 and 1956 hunting seasons, whereas no such decline was noted between 1964 and 1965. 68 Weights of female deer (Fig. 11) exhibited no clear pattern over either of these two winters that can be attributed to the e f f e c t s of weather. Table 23 : Changes i n weight of males between 1955 and 1956 hunting seasons at Northwest Bay Age-Class 1955 Weight 1956 Weight t d.f. Significance = Level .5 44.9 39.5 1.8858 25 .05 1.5 71.8 64.1 3.6119 73 .005 2. 5 98.8 89.6 2.3769 41 .025 3.5 119.0 101.0 2.7108 21 .01 4.5 112.4 99.2 .9769 9 N.S. VI Factors A f f e c t i n g the Sample The current study was both hanpered and enhanced by the use of hunters to c o l l e c t much of the sample material, but in general the advantages outweighed the disadvantages. Advantages lay i n the fact that by using hunt e r - k i l l e d deer, much larger samples were possible. Samples a l s o became available over an extended period of time. Without these two advantages, the study could not have been done. The disadvantages hinged around the v a l i d i t y of the sample coll e c t e d by hunters. One problem has already been discussed (page 40)--the fact that fawns were probably under-represented prior to I960. A second disadvantage lay i n the retention of 69 jaws of larger bucks by hunters. While i t was quite understand-able that hunters with such aiimals wished to have the head intact for trophy purposes, i t meant that the jaw was not a v a i l -able for aging, thus b i a s i n g the age-class d i s t r i b u t i o n of males. While a s i g n i f i c a n t number of ^ws were retained by hunters, i t did not a f f e c t between-years comparisons of male age-class structure since there was no reason to believe that a greater proportion of hunters retained jaws i n one year than in another. A t h i r d factor a f f e c t i n g the v a l i d i t y of the hunter sanple was deer wariness. As may be; seen from Appendix 1, there was a h i g h l y - s i g n i f i c a n t decline i n the numbers of deer sighted by hunters a f t e r the f i r s t two weekends of hunting in 1966. Tests showed that wariness continued to increase over the e n t i r e hunt-ing season. Even within the antlerless season there were s i g n i -ficant declines in success, but these declines did not seriously affect the v a l i d i t y of the sample. Since no buck-season data were u t i l i z e d in computing hunter success, wariness was Rot con-sidered to be a severe problem. A fourth f a c t o r possibly a f f e c t i n g the v a l i d i t y of the sample was daily weather. Data (summarized in Table 24 and Fig, 17) indicated that wet weather s i g n i f i c a n t l y increased hunter success i n September and October but did not a l t e r success i n November. Since a l l hunter success data were based on November figures, the weather problem was minimal. 70 Table 24: E f f e c t s of wet and d r y weather upon hunter s i g h t i n g s of a n t l e r l e s s a n i m a l s a t Northwest Bay i n 1966., PERCENT EXPECTED PERCENT OBSERVED R a i n Dry R a i n Dry 53.26 46 .74 6 7 . 3 32 .7 52 .55 4 7 . 4 5 63 .3 3 6 . 7 57 .91 42 .09 5 3 . 5 4 6 . 5 55.61 4 4 . 0 9 62 .9 3 7 . 1 c h i - s q u a r e f o r Sept. c h i - s q u a r e f o r O c t . c h i - s q u a r e f o r Nov. c h i - s q u a r e f o r a l l mon — 7 1 . 6 9 ( . 005 ) — 1 7 . 6 9 ( . 005 ) — 3 .43 (N.S.) s — 3 4 . 3 1 ( . 005 ) FIGURE 17: Changes i n success at sighting a n t l e r l e s s deer, by month, i n wet and dry conditions at North-west Bay i n 1966. SEPTEMBER OCTOBER NOVEMBER 72 PART FIVE: THE POPULATION MODEL I t was of i n t e r e s t t o compare r e s u l t s found i n a n a l y s i s o f t h e Northwest Bay deer p o p u l a t i o n w i t h a t h e o r e t i c a l model. T h e r e f o r e I c o n s t r u c t e d a model s u i t a b l e f o r s i m u l a t i o n on an IBM 7044 computer. In t h e c o n s t r u c t i o n of any model, a b a l a n c e must be s t r u c k between p r e c i s i o n and a b s t r a c t i o n . I d e c i d e d t o b u i l d the model on t h e most p r e c i s e i n f o r m a t i o n a v a i l a b l e , r e s o r t i n g t o a b s t r a c -t i o n o n l y where p r e c i s e i n f o r m a t i o n was not a v a i l a b l e . For ex-ample, r e p r o d u c t i v e r a t e s were a s s i g n e d i n the f o l l o w i n g manner. S i n c e r e p r o d u c t i o n i s a f f e c t e d by a number of v a r i a b l e s , t h e most d e s i r a b l e approach was t o c o n s t r u c t the model i n c o r p o r a t i n g e q u a t i o n s r e p r e s e n t i n g t h e e f f e c t s of each v a r i a b l e . But s i n c e t h e s e e q u a t i o n s are at b e s t p o o r l y u n d e r s t o o d I u t i l i z e d r e p r o -d u c t i v e f i g u r e s g a t h e r e d f o r t h e Northwest Bay p o p u l a t i o n by Thomas (Unpub. mat.) w i t h o u t c o n s i d e r i n g more than s u p e r f i c i a l l y the c i r c u m s t a n c e s which r e s u l t e d i n t h e s e f i g u r e s . T h i s n e c e s -s a r i l y r e n d e r e d t h e model l e s s v a l i d f o r o t h e r s e t s o f c o n d i t i o n s , but f o r t h e given t i m e and p l a c e such a model s h o u l d be t h e o -r e t i c a l l y s a t i s f a c t o r y . The approach r e p r e s e n t e d by th e above d i s c u s s i o n was gener-a l l y f o l l o w e d whenever p o s s i b l e . I f no Northwest Bay i n f o r m a t i o n was a v a i l a b l e o r i f i t was c o n s i d e r e d u n s u i t a b l e for any r e a s o n , s t a t i s t i c s based on s t u d i e s of o t h e r deer p o p u l a t i o n s were u t i -l i z e d . Important parameters f o r the p o p u l a t i o n model, and t h e i r s o u r c e s , a r e d e s c r i b e d below. 73 I " C a r r y i n g C a p a c i t y " of the Environment The t e r m " c a r r y i n g c a p a c i t y " has c a r r i e d a c e r t a i n stigma due t o the v a r i a t i o n i n d e f i n i t i o n a p p l i e d t o i t , but i t i s n e v e r t h e l e s s a concept t h a t i s n e c e s s a r y f o r t h e c o n s t r u c t i o n of a r e a l i s t i c p o p u l a t i o n model. I t i s a x i o m a t i c t h a t a g i v e n a r e a of land i s a b l e to s u pport a g i v e n number of deer p r o v i d i n g t h a t c o n d i t i o n s do not change, but i t i s a l s o a x i o m a t i c t h a t c o n d i -t i o n s do change. The d e f i n i t i o n o f " c a r r y i n g c a p a c i t y " employed i n the c u r r e n t model t h e r e f o r e makes use o f the i m p l i c a t i o n s of change. Because of l a c k of e vidence to t h e c o n t r a r y , and the f a c t t h a t s t a r v a t i o n i s a common o c c u r r e n c e i n most deer p o p u l a t i o n s t h a t have been s t u d i e d , I assumed t h a t a v a i l a b i l i t y of f o o d i s t h e most i m p o r t a n t l i m i t i n g f a c t o r f o r Vancouver I s l a n d d e e r p o p u l a t i o n s . S i n c e a v a i l a b i l i t y of f o o d i s dependent p r i m a r i l y upon the presence or absence of f a v o r a b l e s e r a i s t a g e s , c o n s i d e r -a b l e e f f o r t was made to d e t e r m i n e the numbers of deer t h a t c o u l d be s u p p o r t e d by each s t a g e . F i g . 3 and Table 25 r e p r e s e n t i n d e -pendent a t t e m p t s to a s s e s s deer usage of v a r i o u s s e r a i s t a g e s , and i t i s i n t e r e s t i n g t o n o t e the c o r r e l a t i o n s t h a t a r e apparent between them. Because o f such agreements, and because G a t e s ' d a t a were c o l l e c t e d a t Northwest Bay, I f e l t t h a t t h e y s h o u l d be u t i l i z e d f o r t h e model. However, c e r t a i n problems were i n h e r e n t i n t h e use o f t h i s m a t e r i a l . F i r s t , t h e r e was no way of d e t e r m i n i n g w i t h the p r e s e n t d a t a whether the d i f f e r e n c e s between summer and w i n t e r usage ( F i g . 3) were due to r e a l d i f f e r e n c e s i n numbers o f deer between summer 74 Table 25: Changes i n deer populations following logging as indicated by p e l l e t group counts (from Dasmann and Hines, 1959 ) Years Since No. of Total No. Mean Pellets Range Logged Plots of Pellets Per Plot Pellets/Plot .80 Prob. Virgin Forest 14 3 0.22 0.02-0.40 I- 5 Years 18 29 1.6.1 0.90-2.30 6-10 Years 46 239 5.20 3.90-6.50 I I - 20 Years 18 14 0.78 0.50-1.10 21-50 Years 17 5 0.29 0.10-0.50 and winter uoage—(Fig. 3)? woro duo to r o a l diffor-ono oo in numbore of door botwoon cummor and winter, or whether the differences were due to some type of migration or change in behavior. Data presented i n Table 1 suggested the p o s s i b i l i t y of migration away from area 4 towards area 1, and If such migrations occurred, i t seemed l i k e l y that area 2 (in which Gates did his work) would be s i m i l a r l y affected. Second, the pellet-group data were collected during a period (1959-1962 ) during which the population may have been r e l a t i v e l y dense, e s p e c i a l l y i n area 2. It is probable that deer usage of these s e r a i stages may normally be lower than indicated by Fig. 3. A t h i r d problem arose as a c o r o l l a r y to t h e second. Since the population was probably high i n the area from which the sam-ples were taken, i t is doubtful that Gates' estimate of approxi-mately 40 deer per square mile i n mature timber would be accurate f o r areas i n generally less-favorable se r a i stages. The timber probably supported 40 deer per square mile during 1959-1962 only 75 because there was ava i lable food outside the timber patches. Cowan (1945) estimated that large unlogged stands of west coast Vancouver Island timber may support only one deer per square mi l e , and th i s i s probably more r e a l i s t i c than the estimate derived from Gates' p e l l e t counts(which, i n t u r n , are more r e a l -i s t i c for areas i n favorable sera i s tages) . However, i t i s probable that Cowan's estimate was too low. Table 25 indicates that there i s approximately a 2300 per cent increase i i n deer usage between v i r g i n timber and the most favorable s e r a i stages in C a l i f o r n i a . I f a s i m i l a r increase is c h a r a c t e r i s t i c of Van-couver Is land, and Gates' estimate of appro xima t e l y 140 deer per square mile i s r e a l i s t i c for the most favorable sera i stage, th en an estimate of approximately f ive deer per square mile of timber seems reasonable. F i g . 13 shows the type bf di f ferences which r e s u l t from using d i f ferent deer dens i t i e s in timber i n sera i c a l c u l a t i o n s . "Carrying capacity" for computer programming purposes was therefore defined a r b i t r a r i l y as the number of deer derived by the fol lowing c a l c u l a t i o n : SS X D where SS equals the number of square miles per s e r a i stage ( i n -cluding timber) and D equals the number of deer tha t each s e r a i stage supports according to F i g . 13. Since Gates' summer f i g -ures agreed more c lo se ly with tagging estimates than did his winter f i g u r e s , summer density f igures were used f o r these c a l -culat i o n s . 76 However, i t i s o b v i o u s t h a t e f f e c t s due to s e r a i s u c c e s s i o n a r e m o d i f i e d each y e a r by weather f a c t o r s (such as the presence of snow) t h a t may dec r e a s e or i n c r e a s e the c a p a c i t y by r e s t r i c t -i n g or i n c r e a s i n g t h e amount o f f o o d a v a i l a b l e . The computer program was t h e r e f o r e c o n s t r u c t e d so t h a t t h e " c a r r y i n g c a p a c i t y " became o p e r a t i v e as a r e s t r i c t i v e f a c t o r o n l y i n y e a r s when w i n -t e r weather (as d e f i n e d by mean w i n t e r t e m p e r a t u r e ) was more se v e r e t h a n u s u a l 9 I f the number o f deer e n t e r i n g the w i n t e r ( f o l l o w i n g h u n t i n g ) was l e s s than ^ c a r r y i n g c a p a c i t y " , no weather e f f e c t was f e l t 9 l u t i f the p o p u l a t i o n exceeded ^ g a r r y -i n g c a p a c i t y " and t h e w i n t e r was more severe, t h a n n o r m a l , the program was d e s i g n e d t o s i m u l a t e m o r t a l i t y such t h a t the popu-l a t i o n would be brought t o lower l e v e l s , t o a l i m i t o f 60 per cent m o r t a l i t y 9 To account f o r the f a c t t h a t deer n o r m a l l y decimate t h e v e g e t a t i o n i n an a r e a p r i o r to a p o p u l a t i o n c r a s h , t h e s i m u l a t e d h erd's r e p r o d u c t i v e p o t e n t i a l was reduced and the e f f e c t o f w i n t e r weather harsh en ed p r o p o r t i o n a t e l y a f t e r such a d i e - o f f . E f f e c t s were de c r e a s e d y e a r l y , u n t i l a f t e r 15 y e a r s b o t h r e p r o -duce on and w i n t e r weather e f f e c t were b a c k to n o r m a l . I I W i n t e r Weather I t i s d i f f i c u l t to a s s i g n to a s p e c i f i c parameter the r o l e of t h e c r i t i c a l f a c t o r by which weather makes i t s e l f f e l t upon deer p o p u l a t i o n s . Mean w i n t e r temperature, amounts o f snow, weather d u r i n g t h e p r e c e d i n g summer and f a l l , and other p a r a -meters a l l p r o b a b l y bear some r e l a t i o n s h i p t o t he way i n which 77 deer herds s u r v i v e w i n t e r s , b u t s t u d i e s i n t o t h i s problem have not y e t produced d e f i n i t i v e r e s u l t s . However, p r o v i d i n g t h a t one a c c e p t s t h e p r i n c i p l e t h a t deer herds d u r i n g some w i n t e r s are a d v e r s e l y a f f e c t e d by f a c t o r s a s s o c i a t e d w i t h weather, t h e r e i s no t h e o r e t i c a l n e c e s s i t y f o r e s t a b l i s h i n g the ex a c t cause of each a d v e r s e e f f e c t . For programming purposes, w i n t e r weather was s i m u l a t e d b y use o f a random number s e r i e s t h a t g e n e r a t e d c r i t i c a l numbers i n a p p r o x i m a t e l y t h e same p r o p o r t i o n s t h a t s e v e r e w i n t e r s o c c u r r e d on Vancouver I s l a n d o v e r the p e r i o d o f t h e s t u d y . These numbers were used i n the manner d e s c r i b e d on page 7 6 . The manner i n which s e v e r e w i n t e r s a f f e c t e d t h e s i m u l a t e d herd was based on s t u d i e s of o t h e r deer p o p u l a t i o n s , w h i c h have i n d i c a t e d a few g e n e r a l g u i d i n g p r i n c i p l e s . The f i r s t p r i n c i p l e was t h a t s e v e r e w i n t e r s e x a c t t h e i r g r e a t e s t t o l l among young a n i m a l s . For i n s t a n c e , B a r t l e t t (1950) s t a t e d t h a t i n M i c h i g a n fawns comprise over 90 per cen t of d e e r t h a t s t a r v e o v e r w i n t e r . In C a l i f o r n i a Lassen et a l (1952) e s t i m a t e d t h a t 82 per cent of t h e fawns had succumbed d u r i n g t h e w i n t e r of 1949 - 5 0 , w h i l e i n 1951 -52 t h e y e s t i m a t e d t h a t 19 per c e n t of t h e a d u l t s and 63 per c e n t of t h e fawns had d i e d over t h e w i n t e r , w i t h t o t a l l o s s e s amounting to about 35 per c e n t o f the herd. E r i c k s o n e t a l (1961 ) e s t i m a t e d t h a t fawns made up a p p r o x i m a t e l y 75 per cent of deer t h a t d i e d over the w i n t e r o f 1955-56 i n M i n n e s o t a . B a r t l e t t (1955 ) e s t i m a t e d t h a t fawns made up 34° 6 per c e n t of deer t h a t d i e d of s t a r v a t i o n on Navy I s l a n d , O n t a r i o , between March and A p r i l o f 1954 , w h i l e R o b i n e t t e et a l (1957) e s t i m a t e d 78 t h a t fawns d i e a t a r a t e two t o t h r e e t i m e s t h a t of a d u l t s . There was a l s o e vidence t h a t y e a r l i n g s succumb more r e a d i l y than a d u l t s . B a r t l e t t (1955) found t h a t 29.4 per cent o f the dead deer he examined on Navy I s l a n d were y e a r l i n g s , w h i l e R o b i n e t t e et a l (1957) e s t i m a t e d the l o s s o f y e a r l i n g s t o be 1.6 t i m e s t h a t o f a d u l t s . A second p r i n c i p l e ( B a r t l e t t , 1955 ) was t h a t the per cent of young a n i m a l s among dead d e e r g r a d u a l l y d e c r e a s e d i n p r o p o r -t i o n w i t h the i n c r e a s i n g s e v e r i t y o f the w i n t e r . I n o t h e r words, a d u l t deer c a n stand some a d v e r s i t y b e t t e r t h a n fawns, but i f c o n d i t i o n s become t o o s e v e r e , a d u l t s t o o succumb i n i n c r e a s i n g l y ^ l a r g e numbers. Data were c o n t r a d i c t o r y on the t h i r d p r i n c i p l e — t h e compara-t i v e death r a t e s f o r males and f e m a l e s i n d i e - o f f s . There were a number of s t u d i e s l i s t i n g t h e per c e n t s o f v a r i o u s age and sex c l a s s e s of d e e r t h a t were found dead, but few t h a t r e l a t e t h i s i n f o r m a t i o n t o h e r d c o m p o s i t i o n p r i o r t o the d i e - o f f . B a r t l e t t (1955 ) found t h a t 52,9 per cent of t h e a d u l t s t h a t d i e d were b u c k s , w h i l e S e v e r i n g h a u s et a l _ (1963 ) found t h a t female a d u l t s outnumbered male a d u l t s among dead deer by t h e f o l l o w i n g p e r -c e n t a g e s i n two a r e a s of New Y o r k : 29,27:14.44 and 8.07 t l . 8 8 . B a r t l e t t , however, s t u d i e d an a r e a p r o t e c t e d from h u n t e r s , whereas i n New York t h e r e were b u c k s - o n l y h u n t i n g r e g u l a t i o n s . In the New York s t u d y , female fawns outnumbered male fawns i n t h e two a r e a s b y the f o l l o w i n g p e r c e n t a g e s : 31.28:25.01 and 47.85:42.20. R o b i n e t t e e t a l (1957) e s t i m a t e d t h a t female fawns d i e a t a r a t e a p p r o x i m a t e l y 1.2 t i m e s t h a t o f male fawns. 79 The f i n a l p r i n c i p l e concerns the numbers o f deer t h a t may-be e x p e c t e d t o d i e of e f f e c t s r e l a t e d t o w i n t e r w e a t her. The consensus among deer b i o l o g i s t s i s t h a t w i n t e r deaths d i r e c t l y -r e l a t e d t o m a l n u t r i t i o n form a n im p o r t a n t cause of m o r t a l i t y , a t l e a s t d u r i n g some y e a r s . The e s t i m a t e o f a 35 per cent l o s s a t t r i b u t e d t o w i n t e r s t a r v a t i o n by Lassen et_ a l (1952) has a l -ready been d i s c u s s e d , but the l i t e r a t u r e i s r e p l e t e w i t h o t h e r examples, E r i c k s o n e_t a l (1961) e s t i m a t e d t h a t between 10 and 25 per c e n t of Minnesota deer s t a r v e d to d e a t h over t h e w i n t e r o f 1949-50, w i t h a f u r t h e r l o s s of between e i g h t and 10 per cent i n 1955-56. Marburger and Thomas (1965) e s t i m a t e d a l o s s o f 44 per c e n t of a h e r d of Texas d e e r over January to August of 1962, w i t h m a l n u t r i t i o n enhanced by drought b e i n g t h e p r o b a b l e c a u s e . B a r t l e t t (1955) e s t i m a t e d t h a t the l o s s on Navy I s l a n d was app r o x -i m a t e l y 60 per cent. The above s t a t i s t i c s were d e r i v e d from v a r i o u s s p e c i e s o f deer i n v a r i o u s c l i m a t i c c o n d i t i o n s , but c e r t a i n s i m i l a r i t i e s i n p a t t e r n were a p p a r e n t , and I i n c o r p o r a t e d t h e s e i n t o the com-p u t e r program. In t h e b e l i e f t h a t fawns would be most su s c e p -t i b l e , the program was c o n s t r u c t e d so t h a t t h r e e fawns d i e d f o r ever y a d u l t , up t o a maximum of 60 per cent o f t h e fawn c r o p . Once t h i s f i g u r e was r e a c h e d , m o r t a l i t y p a t t e r n s were changed so t h a t a h i g h e r p r o p o r t i o n o f a d u l t s would d i e . At the upper l i m i t s o f m o r t a l i t y , 80 per cent of the fawn c r o p would be k i l l e d by a severe w i n t e r , and an a d d i t i o n a l 50 p e r cent of the a d u l t c r o p would d i e . The a d u l t l o s s was c o n s t r u c t e d so t h a t 1 . 5-year-o l d s and anim a l s i n the o v e r - 1 0 . 5 - y e a r - o l d group d i e d a t a r a t e 80 up t o 1.6 t i m e s as g r e a t as t h a t of a n i m a l s i n the o t h e r c a t e -g o r i e s . The program was c o n s t r u c t e d so t h a t female fawns d i e d a t a r a t e 1.2 t i m e s t h a t of m a l e s , but no p r o v i s i o n was made f o r d i f f e r e n t i a l m o r t a l i t y among a d u l t s due to c o n f l i c t i n g r e -p o r t s i n the l i t e r a t u r e . Deaths due t o t h i s cause were c l a s s i -f i e d as "abnormal w i n t e r d i e - o f f a s s o c i a t e d w i t h m a l n u t r i t i o n " , and such deaths were not c o n s i d e r e d t o occur i n a l l y e a r s . I l l Hunting The program was c o n s t r u c t e d i n such a manner t h a t e f f e c t s o f v a r i o u s l e v e l s o f h u n t i n g upon t h e p o p u l a t i o n c o u l d be d e t e r -mined. S i m u l a t i o n i n v o l v e d the s u b t r a c t i o n of a d e s i r e d p e r c e n t -age of t h e p o p u l a t i o n a t t h e end o f t he summer i n a c c o r d a n c e w i t h e s t i m a t e d age and sex s p e c i f i c r a t e s o f m o r t a l i t y due t o h u n t i n g . Due t o b e h a v i o r a l d i f f e r e n c e s d u r i n g the a n t l e r l e s s season and f u r t h e r v u l n e r a b i l i t y i n the b u c k s - o n l y s e a s o n , males 1.5 y e a r s of age and o l d e r were k i l l e d more f r e q u e n t l y t h a n o t h e r age and sex c l a s s e s of d e e r a t Northwest Bay. However, the i n c r e a s e i n v u l n e r a b i l i t y was d i f f i c u l t t o c a l c u l a t e s i n c e e s t i m a t e d p o p u l a -t i o n p a r a m e t e r s were based upon the h u n t e r k i l l . S i n c e h u n t e r s p r o b a b l y shot d e e r randomly i n the p e r i o d 1960-1966, a l l s t a t i s t i c s were c a l c u l a t e d on t h e b a s i s o f data from t h e s e y e a r s ( F i g . 9)» To c a l c u l a t e the k i l l i n c rement due t o buck season, the number of animals k i l l e d i n buck season, f o r a p a r t i c u l a r a g e - c l a s s was compared w i t h t h e number of a n i m a l s k i l l e d i n a n t l e r l e s s season f o r t h a t a g e - c l a s s . The i n c r e m e n t s f o r v a r i o u s a g e - c l a s s e s were 1 8 1 Age Increment 1 . 5 • o 8 6 4 5 2 . 5 . 8 0 6 2 3 . 5 . 5 4 4 0 4 . 5 . 4 4 3 0 over 4 . 5 . 4 3 0 5 Further male v u l n e r a b i l i t y i s caused by loss of wariness i n the rut, with the result that males are over-represented in £he hunter k i l l . This over-representation was estimated by calcu-l a t i o n of the extent to which male fawns outnumbered female fawns i n the k i l l . Since the sex r a t i o is nearest 5 0 : 5 0 i n t h i s group, the difference between the two sexes i n the k i l l provided a reasonable estimate of the ef f e c t of decreased wari-ness of males. In the 1 9 6 0 - 6 6 k i l l males outnumbered females 3 9 4 to 3 1 2 , indicating a 2 5 . 6 per cent increment. It may be argued that an increment calculated on the b a s i s of fawn data w i l l not be representative of the older age-classes, since i t is often held that older bucks are more greatly affected by the r u t . It was therefore interesting to compare the propor-t i o n of males i n the f a l l counts with the proportion i n the hun-te r k i l l (Fig. 8 ) . Over the same period of 1 9 6 0 - 1 9 6 6 there was an average of 4 2 . 6 per cent males in the f a l l counts, and 5 0 . 6 per cent males in the k i l l (excluding fawns). The difference of eight per cent represented an 1 8 . 6 per cent increment over the f a l l count. Considering the v a r i a b i l i t y of the counts, t h i s figure tended to support the 2 5 . 6 increment calculated through the fawn method. 82 The program was t h e r e f o r e c o n s t r u c t e d so t h a t h u n t i n g mor -t a l i t y i n t h e s i m u l a t i o n c l o s e l y a p p r o x i m a t e d a c t u a l c o n d i t i o n s o v e r the p e r i o d 1 9 6 0 - 1 9 6 6 . L o s s by h u n t i n g r e p l a c e d w i n t e r s t a r v a t i o n as a m o r t a l i t y c a u s e , but n o t o t h e r m o r t a l i t y c a u s e s . In o r d e r t o s i m u l a t e c o n d i t i o n s as c l o s e l y as p o s s i b l e , I f e l t t h a t some a l l o w a n c e s h o u l d be made f o r t h e e f f e c t s o f c r i p p l i n g l o s s and i l l e g a l k i l l . An a r b i t r a r y f i g u r e o f 25 per cen t of t h e e x p l o i t a t i o n r a t e was c h o s e n , and a r a t e o f l o s s age and s ex s p e c i f i c i n the same manner as h u n t i n g m o r t a l -i t y was a s s i g n e d to i t . T h i s was p r o b a b l y u n r e a l i s t i c , i n t h a t does p r o b a b l y s u f f e r a p r o p o r t i o n a t e l y h i g h e r i l l e g a l k i l l t han m a l e s , b u t s i n c e no f i g u r e s were a v a i l a b l e f o r N o r t h w e s t Bay or f o r o t h e r a r e a s w i t h s i m i l a r h u n t i n g r e g u l a t i o n s , no a t t e m p t was made t o f o r m u l a t e d i f f e r e n t r a t e s f o r l e g a l and i l l e g a l h u n t i n g . IV Normal M i s c e l l a n e o u s M o r t a l i t y Deer p o p u l a t i o n s u s u a l l y undergo two t y p e s o f m o r t a l i t y . The f i r s t , abnormal w i n t e r d i e - o f f , I have a s s o c i a t e d p r i m a r i l y w i t h w i n t e r m a l n u t r i t i o n , bu t the mechanism of c o n t r o l w i l l work e q u a l l y w e l l i f t h e d e e r d i e a t i r r e g u l a r i n t e r v a l s i n a b n o r m a l l y - l a r g e numbers f rom o t h e r c a u s e s . A\ second type o f m o r t a l i t y o c c u r s i n most y e a r s — t h e r e g u l a r a n n u a l sex and age -s p e c i f i c d e p l e t i o n of numbers w h i c h i s e x p e c t e d to o c c u r i n any p o p u l a t i o n . Such d e a t h s I have te rmed n o r m a l m i s c e l l a n e o u s m o r t a l i t y , c a u s e d b y f a c t o r s s u c h as d i s e a s e , a c c i d e n t , and p r e -d a t i o n . H u n t i n g , p r o v i d i n g i t i s m a i n t a i n e d a t a s t a b l e l e v e l , 83 c o u l d a l s o have been i n c l u d e d h e r e , b u t f o r programming purposes i t was more co n v e n i e n t (and p r o b a b l y more m e a n i n g f u l , i n t h a t death r a t e s were d i f f e r e n t ) t o s e p a r a t e i t from other m o r t a l i t y causes <> No s t u d i e s have been done a t Northwest Bay on the e f f e c t s o f t h i s t y p e o f m o r t a l i t y , so one of the purposes o f the popu-l a t i o n model was t o a s s e s s the r e l a t i v e i m p o r t a n c e of t h e s e f a c t o r s , A r n o l d and Verme ( I 9 6 3 ) e s t i m a t e d a l o s s of about 1 2 per cent o f the numbers of deer p r e s e n t i n an e n c l o s e d h e r d i n M i c h i g a n , but gave few d e t a i l s . E r i c k s o n et_ a l ( 1 9 5 1 ) a s s i g n e d a f i g u r e of 16 per c e n t t o the l o s s t h rough wolves i n M i n n e s o t a , w h i l e L e o p o l d e t a l ( 1 9 5 1 ) e s t i m a t e d a minimum f i v e per cent l o s s t o v a r i o u s m i s c e l l a n e o u s causes i n C a l i f o r n i a . Many o t h e r a u t h o r s conceded t h a t such l o s s e s must be o c c u r r i n g , but did not have th e n e c e s s a r y i n f o r m a t i o n to p l a c e a q u a n t i t a t i v e e s t i m a t e on the i m p o r t a n c e o f such m o r t a l i t y . Deer p r o b a b l y d i e i r r e g u l a r l y throughout the y e a r , w i t h more a n i m a l s succumbing i n t h e w i n t e r due t o n a t u r a l c a u s e s t h a n i n the summer, but i t would b e u n r e a l i s t i c t o program s t r i c t l y f o r w i n t e r l o s s . To compensate f o r t h i s , two t y p e s o f normal mor-t a l i t y were e s t a b l i s h e d . The f i r s t was a p p l i e d t w i c e a y e a r , and e q u a l l y i n summer i n w i n t e r , w h i l e the second was a p p l i e d o n l y i n w i n t e r . The f i r s t type of m o r t a l i t y was c o n s i d e r e d t o be e x t r a p e n s a t o r y i n n a t u r e , w h i l e t h e second t y p e was compensa-t o r y w i t h r e g a r d t o h u n t i n g . M o r t a l i t y was made age- and sex-s p e c i f i c , and was based on l i f e - t a b l e i n f o r m a t i o n from t h e Northwest Bay h e r d . Where Northwest Bay dat a were c o n s i d e r e d 84 i n s u f f i c i e n t ( a s , f o r example , i n t h e c a s e of t h e o l d e r a g e -c l a s s e s ) r e f e r e n c e was made t o l i f e - t a b l e s f o r o t h e r p o p u l a -t i o n s c o n s t r u c t e d by T a b e r and Dasmann (1958) and W h i t e ( 1 9 6 6 ) . V- Fawn M o r t a l i t y I n a d d i t i o n t o m o r t a l i t y c a u s e s d e s c r i b e d a b o v e , s p e c i a l p r o v i s i o n was made f o r summer fawn m o r t a l i t y , p a r t i c u l a r l y i n t h e few d a y s i m m e d i a t e l y f o l l o w i n g f a w n i n g „ V a r i o u s s t u d i e s ( L e o p o l d e t a l , 1 9 5 1 ; T a b e r , 1 9 5 3 ; B r i g h a m , 1 9 5 8 ; B r own, 1 9 6 1 ; and W h i t e , 1966 ) have i n d i c a t e d t h a t s u c h fawn l o s s e s may r e a c h h i g h p r o p o r t i o n s , , S p e c i f i c i n f o r m a t i o n on f a w n m o r t a l i t y a t N o r t h w e s t Bay was a v a i l a b l e as a r e s u l t o f t h e t a g g i n g program f r o m 1959 t o 1963 <> T a b l e 4 s u m m a r i z e s i n f o r m a t i o n f r o m which i t was p o s s i b l e t o c a l -c u l a t e a rough e s t i m a t e of s u c h m o r t a l i t y d u r i n g t h i s p e r i o d „ Column E l i s t s the t o t a l number o f t a g g e d a n i m a l s t h a t were e i t h e r p o s i t i v e l y o r p r o b a b l y i d e n t i f i e d t h r o u g h s i g h t i n g s , or were l a t e r r e c o v e r e d , whereas co lumn D l i s t s the t o t a l number o f t a g g e d a n i m a l s t h a t were e i t h e r p r o b a b l y or p o s i t i v e l y a l i v e by t h e August f o l l o w i n g t a g g i n g . " P r o b a b l e s " were a n i m a l s w h i c h were s i g h t e d and r e c o r d e d as t a g g e d , b u t f o r w h i c h no p o s i t i v e i d e n t i f i c a t i o n c o u l d b e made. I n s u c h c a s e s t h e o b s e r v e r n o r -m a l l y saw a f l a s h of one o r two c o l o r s , so t h a t i t was p o s s i b l e t o n a r r o w i d e n t i f i c a t i o n down t o a v e r y few a n i m a l s . I f one o f t h e s e a n i m a l s was l a t e r p o s i t i v e l y i d e n t i f i e d , t h e " p r o b a b l e " r e c o r d was n o t c o u n t e d , even t h o u g h i t may have been y e t a n o t h e r a n i m a l . F o r t h i s r e a s o n , co lumns D and E p r o b a b l y r e p r e s e n t e d m i n i m a l r a t h e r t h a n m a x i m a l q u a n t i t i e s . 85 The d i f f e r e n c e between columns D and E was only 10 animals, which i n d i c a t e d t h a t only 10 animals were s i g h t e d between the ta g g i n g date and August, but never again s i g h t e d or r e c o v e r e d . This was e i g h t per cent d i f f e r e n c e , and may represent summer m o r t a l i t y of fawns. An a l t e r n a t i v e method of c a l c u l a t i n g p o s s i b l e m o r t a l i t y was to assume that a l l tags which were not e v e n t u a l l y s i g h t e d or rec o v e r e d were l o s t to m o r t a l i t y i n the f i r s t summer. This a s -sumption was not warrented, but c a l c u l a t i o n s made i n t h i s manner provided an ab s o l u t e upper l i m i t t o p o s s i b l e summer m o r t a l i t y . As i n d i c a t e d by column D, 114 of the o r i g i n a l 229 tagged a n i -mals were probably a l i v e by August, l e a v i n g a remainder of 115 (or 50.2 per c e n t ) unaccounted f o r . Therefore summer m o r t a l i t y could not have been g r e a t e r than 50.2 per cent f o r t h i s group of animals. A t h i r d method of e s t i m a t i n g summer m o r t a l i t y of fawns suggested t h a t m o r t a l i t y was n i l between the date of tagg i n g and August. Of the animals from which tags were l a t e r recovered (column B ) , o n l y 39 «3 per c ent were e i t h e r probably or p o s i -t i v e l y s i g h t e d p r i o r t o re c o v e r y of the t a g (column A). Since even column C (which just i n c l u d e d p o s i t i v e i d e n t i f i c a t i o n ) i n d i c a t e d that approximately 43 per cent of tagged animals were s i g h t e d , t h i s method suggested that summer m o r t a l i t y was n i l . As i t was u n l i k e l y t h a t fawn m o r t a l i t y was n i l a t North-west Bay, I a s s i g n e d to fawns an a r b i t r a r y m o r t a l i t y r a t e of t h r e e times n a t u r a l summer m o r t a l i t y . This m o r t a l i t y was not 86 considered part of natural summer mortality so that i f , for ex-ample, a natural mortality rate of 10 per cent was established, i t meant that an additional 30 per cent of the fawns would die. Estimates made in this manner coincided closely with results of other fawn mortality studies. VI Immigration and Emigration Construction of a model which makes adequate provision for immigration and emigration is not d i f f i c u l t provided certain i n -formation is available, but these factors were not utili z e d in the current model due to lack of adequate data. Providing emi-gration and immigration are made instantaneous in response to pressures within the population, a given population may be kept at optimal levels for as long as desired, but such an ideal situation has not been recorded in the literature--perhaps be-cause conditions which affect the herd under study are likely to affect herds in neighboring areas as well. If deer have no place to emigrate to, or i f other animals are moving i n as soon as some move out, the fact that emigration and immigration occur becomes unimportant. It is known that deer tend to remain on relatively small home ranges once they are mature, and tagging studies at Northwest Bay indicated that while some dispersal takes place, perhaps a majority of deer establish home ranges close to the original tagging site. As no clear pattern was apparent, the introduction of emi-gration and immigration factors to the program was f e l t to be 67 d e l e t e r i o u s o S i n c e i t was n e c e s s a r y t h a t t h e program c o n t a i n one l a r g e v a r i a b l e ( m i s c e l l a n e o u s n a t u r a l m o r t a l i t y ) , I f e l t t h a t a second v a r i a b l e would add n o t h i n g . V I I Re pro due t i on S i n c e a r e p r o d u c t i o n s t u d y was b e i n g c a r r i e d on i n Northwest Bay c o n c u r r e n t l y w i t h t h e present i n v e s t i g a t i o n (Thomas, Unpub. m a t . ) , i t was p o s s i b l e t o o b t a i n e s t i m a t e s o f the r e p r o d u c t i v e r a t e of Northwest Bay does. However, t h e f i g u r e s a p p l i e d o n l y to the p e r i o d 1964 t o 1966, and much important i n f o r m a t i o n was not known. For i n s t a n c e , w h i l e t h e r e were i n d i c a t i o n s t h a t s e r a i s u c c e s s i o n a f f e c t e d r e p r o d u c t i o n , no q u a n t i t a t i v e measures of such e f f e c t s were a v a i l a b l e f o r Northwest Bay. I d e a l l y , t h e program would have been c o n s t r u c t e d so t h a t c h a n g i n g s e r a i p a t -t e r n s would be r e f l e c t e d i n c o r r e s p o n d i n g r e p r o d u c t i v e changes, but t h i s was not done due t o t h e d i f f i c u l t y o f p l a c i n g r e a l i s t i c v a l u e s upon such changes. W h i l e t h i s u n d o u b t e d l y l e s s e n e d t h e v a l u e o f the model i n extreme s u c c e s s i o n a l s t a g e s , i t n e v e r t h e -l e s s was a s a c c u r a t e as p o s s i b l e f o r c o n d i t i o n s which p r e v a i l e d a t Northwest Bay o v e r t h e p e r i o d of t h e c u r r e n t s t u d y . One a r b i t r a r y v a l u e was a s s i g n e d t o r e p r o d u c t i o n . I n y e a r s of h i g h d e e r d e n s i t y , deer may s e v e r e l y damage v e g e t a t i o n i n an a r e a . I t has been i n d i c a t e d (Teer ejt a l , 1965) t h a t such damage may i n h i b i t r e p r o d u c t i v e s u c c e s s f o r some t i m e . The model was t h e r e f o r e c o n s t r u c t e d so t h a t i n y e a r s f o l l o w i n g a d i e - o f f , r e p r o d u c t i o n was d e c r e a s e d i n p r o p o r t i o n t o t h e s i z e o f t h e d i e - o f f . 88 Rates of reproduction u t i l i z e d in the program are shown i n Table 2 6 . Table 26 i Reproduction parameters u t i l i z e d i n the computer simulation of the Northwest Bay black-.tailed deer population (Figures based on work of Thomas (Un-pub. mat. )) Age of doe 1 2 3 4 over 4 No, of fawns 0 . 0 0 1.00 1.57 1.84 1.84 VIII Structure of the Model While the l o g i s t i c approach to modelling has been applied to many species of animals, i t i s doubtful that the t y p i c a l "S-shaped" population growth curve may be applied to Vancouver Island b l a c k - t a i l e d deer. For that matter, i t i s doubtful i f such a curve may be applied t o most ungulate populations, at least in i n i t i a l colonization phases of population development. The reproductive potential of deer of a l l species i s large in i d e a l conditions, and a number of studies have indicated that i t is not unusual for deer to approach reproductive poten-t i a l when conditions allow i t . Representative of such studies i s the one by Hesselton et a l (1965 ) at the Seneca Army Depot i n New York. In such situations the growth of deer herds tends to be explosive, f a r outstripping the "carrying capacity" with-out any sign of s i g n i f i c a n t decrease i n recruitment. The re s u l t 89 of such an increase can only be des truct ion of the range, f o l -lowed by a d i e - o f f , unless hunting and/or other morta l i ty causes remove the surplus before the damage becomes too great . Follow-ing such a crash , i t may take years for the population to again reach explosive l e v e l s , but that i t can do so is recorded by Russo ( I 9 6 4 ) , who studied Arizona mule deer on the Kaibab P l a -teau. It i s possible that i n mature, unchanging stands of vegetat ion, such v i o l e n t f luc tuat ions may become damped and eventual ly disappear as reproduct ion and m o r t a l i t y gradual ly become more equal ly -ba lanced . However, b l a c k - t a i l e d deer have apparently evolved in such a way that populations can take ad-vantage of s h o r t - l i v e d s e r a i changes, and as long as man c o n t i n -ues to manipulate the environment by accident or design, such f luctuat ions may be expected. A model incorporat ing these features was presented by Adams ( I960) f o r Alabama whi t e - ta i l ed deer, and no object ion i s apparent to i t s a p p l i c a t i o n to b lack-t a i l s . A f low-chart representing the computer program for such a population model is presented i n F i g . 1 8 . I d e a l l y , th is model must contain the p o t e n t i a l f o r rapid increase and regulatory mechanisms s imulat ing those employed in actual populations. As described above, much more i s known about reproduction than about m o r t a l i t y . In add i t ion t o the fact that i t i s more d i f f i -cult to measure m o r t a l i t y than reproduct ion, i t i s probable that regulatory mechanisms may d i f f e r considerably depending upon the circumstances i n which the herd e x i s t s . FIGURE 18: F l o w c h a r t r e p r e s e n t i n g computer model f o r p o p u l a t i o n s i m u l a t i o n . ( 1 = n a t u r a l m i s c e l l a n e o u s m o r t a l i t y ; 2 = w i n t e r d e a t h a s s o c i a t e d w i t h m a l n u t r i t i o n ; 3 = h u n t i n g m o r t a l i t y . ) A d u l t P o p u l a t i o n j s ^ a t End o f S p r i n g : 24 Age and Sex C a t e g o r i e s ADULT SUMMER MORTALITY A d u l t P o p u l a t i o n a t End o f Summer ADULT HUNTING MORTALITY A d u l t P o p u l a t i o n a t End of H u n t i n g Season Fawn P o p u l a t i o n I m m e d i a t e l y a f t e r B i r t h : 2 Age and Sex C a t e g o r i e s FAWN SUMMER MORTALITY Fawn P o p u l a t i o n a t End o f Summer FAWN HUNTING MORTALITY Fawn P o p u l a t i o n a t End o f H u n t i n g Season ADULT WINTER MORTALITY I 2 1 2 FAWN WINTER MORTALITY A d u l t P o p u l a t i o n a t End o f W i n t e r : 26 Age and Sex C a t e g o r i e s 91 At l e a s t two d i f f e r e n t models seem pro b a b l e <> I n t h e f i r s t , n ormal m i s c e l l a n e o u s m o r t a l i t y from such causes as p r e d a t i o n , a c c i d e n t , and d i s e a s e i s low, so t h a t t h e major d i r e c t r e g u l a -t o r y mechanism i s r e p r e s e n t e d by l o s s t h r o u g h m a l n u t r i t i o n and r e l a t e d f a c t o r s a s s o c i a t e d w i t h severe weather c o n d i t i o n s . ( S i m i l a r r e g u l a t i o n can be p r o v i d e d by i r r e g u l a r o u t b r e a k s o f d i s e a s e or a sudden i n c r e a s e i n p r e d a t i o n or o t h e r m o r t a l i t y f a c t o r s . ) S i n c e t h e d e e r ' s r e p r o d u c t i v e p o t e n t i a l i s g r e a t , under s u c h a model f l u c t u a t i o n s w i l l t e n d t o be r e l a t i v e l y r a p i d and extreme. I f , on t h e o t h e r hand, n a t u r a l y e a r l y m o r t a l i t y i s h i g h , w i n t e r d i e - o f f s o f major p r o p o r t i o n s would o c c u r much l e s s f r e q u e n t l y , and i f n a t u r a l y e a r l y l o s s i s h i g h enough, s e v e r e w i n t e r l o s s e s s i m p l y would not o c c u r . S m a l l annual i n c r e a s e s would b u i l d t h e p o p u l a t i o n u n t i l a s e v e r e w i n t e r o c c u r r e d , d u r -i n g w h i c h a l l t h e accumulated g a i n i n numbers would be wiped o u t . I t i s probable t h a t t h e p r o c e s s of s t a b i l i z a t i o n of deer p o p u l a t i o n s i n v o l v e s a g r a d u a l s h i f t f r o m t h e f i r s t t o t h e s e c -ond t y p e of model, w i t h an accompanying change i n r e p r o d u c t i o n so that expansion p o t e n t i a l i s not as g r e a t . In each c a s e , t h e p o p u l a t i o n would f l u c t u a t e w i t h i n l i m i t s d e t e r m i n e d by the con-d i t i o n of the r a n g e . Both models were s i m u l a t e d i n t h e c u r r e n t s t u d y . IX R e s u l t s of Computer S i m u l a t i o n The s i m u l a t e d Northwest Bay p o p u l a t i o n had a r a t e of r e p r o -d u c t i o n which r e s u l t e d i n fawns f o r m i n g a p p r o x i m a t e l y 3 5 per c e n t of t h e h e r d i m m e d i a t e l y a f t e r f a w n i n g . T h e r e f o r e , t o t a l 92 mortality calculated from the time of fawning had to average approximately 35 per cent annually to maintain the herd at r e a l i s t i c levels . Typical patterns of population derived from simulation are presented i n F i g . 19 and 20. In a l l cases, populations were presumed to suff e r f i v e per cent (of the summer population) mor-t a l i t y from causes associated with malnutrition in normal wint-ers, above the normal miscellaneous mortality which occurs equally throughout the year. Fig. 19 demonstrates the effect of a change i n normal miscellaneous mortality (from such causes as predation, disease, and accident). At a 2.5 per cent l e v e l of miscellaneous mortality every six: months the population tended to fluctuate much more v i o l e n t l y than with a 7.5 per cent l e v e l of m o r t a l i t y . It i s probable, i n f a c t , that the f l u c t u a -tions at a 7.5 per cent mortality rate would be even less ex-treme than the model indicated. As fluctuations are s t r i c t l y the r e s u l t of the type of program constructed, i t would have been possible to erase such fluctuations e n t i r e l y through pro-gramming t o reduce the extent of severe winter population crashes. As may be seen from Fig. 19$ the population with a 7.5 per cent mortality rate tended to remain at lower numbers than the one with a 2.5 per cent annual natural mortality rate. This too was a function of the type of program constructed and probably was not r e a l i s t i c , but no attempt was made to correct i t since no s a t i s f a c t o r y parameters were ava i l a b l e . These re-su l t s were d i r e c t l y attributable to the f a c t that fixed repro-ductive and mortality rates were maintained over extended FIGURE 19s Types of population patterns produced by changing levels of natural miscellaneous mortality in a simulated deer population, (Exploitation mortality = .0.0, snti deaths associated with mal-nutrition do not exceeu , C5 of the surn&er population in a normal winter. See text for- explanation.) RATES OF MORTALITY 0.025 0 . 0 7 5 30 50 TIMS DI YEARS 80 FIGURE 20: Types of population patterns produced by changing levels of exploitation i n a simulated deer population, (Winter deaths associated with malnutrition = .05 of the summer population . i n a normal year, and n a t u r a l miscellaneous mortality = ,025 every s i x months, See t e x t for explanation,) 95 periods of time i n these models—an unnatural s i t u a t i o n . In r e a l l i f e , the population with a 7.5 per cent mortality rate could be expected to respond to lowered numbers by increased reproduction, with the result that "carrying capacity" would be reached much more quickly than was indicated by F i g . 19. Fi g . 20 demonstrates the t h e o r e t i c a l e f f e c t of increased exploitation upon a population over an extended period of time. Again, the population became more stable under increased mortal-i t y . As i n F i g . 19, the fluctuations bf the population with a greater normal annual mortality rate would be much less severe in a natural s i t u a t i o n since only a s l i g h t increase i n any type of mortality would be enough to i n i t i a t e a decline. Thus numbers would be unlikely to reach explosive levels . Patterns of mortality that are probable f o r b l a c k - t a i l e d deer are shown in Table 27. As indicated by t h i s table, i f two types of mortality (exploitation and natural miscellaneous mor-t a l i t y ) were fix e d at c e r t a i n l e v e l s , then simulated populations could be maintained over r e l a t i v e l y wide ranges for the t h i r d type of mortality. It i s obvious from th i s table that the simu-lated populations were extremely r e s i l i e n t , even when the proba-b i l i t y of increased recruitment i n the face of increased mortal-i t y was not considered. This r e s i l i e n c y doubtless explains the success of the b l a c k - t a i l and other species of deer as game animals. It would take severe levels of exploitation to s e r i -ously af f e c t the population even i n stable environment. In improving habitat, such as those created by logging and f i r e , 96 T a b l e 2 7 : M o r t a l i t y p a t t e r n s d e r i v e d from computer s i m u l a t i o n of a h y p o t h e t i c a l b l a c k - t a i l e d deer p o p u l a t i o n (See t e x t f o r e x p l a n a t i o n , , ) E x p l o i t a t i o n = 0 . 0 L e v e l of M i s c e l l a n e o u s Range of W i n t e r M o r t a l i t y N a t u r a l M o r t a l i t y * Due P r i m a r i l y t o M a l n u t r i t i o n . 0 2 5 0 . 0 - . 2 0 . 0 5 0 0 . 0 - . 1 5 . 0 7 5 0 . 0 - . 1 0 . 1 0 0 0 . 0 - . 0 5 . 1 2 5 0 . 0 - . 0 0 E x p l o i t a t i o n = . 1 0 . 0 2 5 0.0-.-15 . 0 5 0 0.0-.10. . 0 7 5 0.0-.10 . 1 0 0 0 . 0 - . 0 5 E x p l o i t a t i o n = . 2 0 . 0 2 5 Q . 0 - . 1 5 . 0 5 0 0 . 0 = . 1 0 . 0 7 5 0 . 0 = . 0 5 E x p l o i t a t i o n = . 3 0 . 0 2 5 0 . 0 = . 0 5 . 0 5 0 0 . 0 - . 0 5 *. M i s c e l l a n e o u s n a t u r a l m o r t a l i t y c a l c u l a t e d f o r six-month p e r i o d , so t h a t y e a r l y m i s c e l l a n e o u s m o r t a l i t y i s some-what under t w i c e t h e i n d i c a t e d f i g u r e . 97 i t i s d o u b t f u l i f h u n t i n g can e f f e c t i v e l y l i m i t a p o p u l a t i o n p r o v i d e d t h a t c o n d i t i o n s s i m i l a r t o t h o s e a t Northwest Bay pre = v a i l . One o f the most imp o r t a n t of t h e s e c o n d i t i o n s would be t h e p r e s e n c e of adequate escape t e r r a i n . ^ Attempts t o s i m u l a t e t h e r e s u l t s o u t l i n e d e l s e w h e r e i n t h i s t h e s i s f o r t h e a c t u a l Northwest Bay p o p u l a t i o n o ver t h e p e r i o d 1954 t o 1966 by i n c l u d i n g a c t u a l numbers of h u n t e r s and o t h e r s t a t i s t i c s were not s u c c e s s f u l due to the l a c k o f p r e c i s e i n f o r -m ation on t h e e f f e c t of w i n t e r weather. W h i l e i t was p o s s i b l e to s i m u l a t e Northwest Bay r e s u l t s c l o s e l y by a l t e r i n g v a r i o u s parameters i n the model, i t was p o i n t l e s s t o do s o , f o r t h i s would have been m e r e l y a m a t h e m a t i c a l e x e r c i s e . The s i m u l a t i o n s conformed w i t h Northwest Bay o b s e r v a t i o n s i n t h e f o l l o w i n g a r e a s , however. 1. Under i n c r e a s e d h u n t i n g , t h e p r o p o r t i o n o f a d u l t males i n t h e p o p u l a t i o n d e c r e a s e d . 2. Under i n c r e a s e d h u n t i n g , the numbers of a n i m a l s tended to become more s t a b l e , and when h u n t i n g k i l l was h e a v i e s t , s i g -n i f i c a n t r e d u c t i o n s i n numbers o c c u r r e d . The l a t t e r was o f course e x p e c t e d ; the p o i n t of i n t . e r e s t , however, was t h e l e v e l of k i l l a t w h i c h such r e d u c t i o n s began t o o c c u r . C o n s i d e r i n g t h a t h u n t i n g m o r t a l i t y may have approached 20 per cent i n the y e a r s i n w h i c h r e d u c t i o n s were n o t e d , and c o n s i d e r i n g t h a t i t i s d o u b t f u l t h a t m a l n u t r i t i o n was i m p o r t a n t i n t h e s e y e a r s , a l e v e l of m i s c e l l a n e o u s n a t u r a l m o r t a l i t y amounting to a p p r o x i -m a t e l y 10 per cent per six-month p e r i o d was i n d i c a t e d , as shown by Table 27. 93 The model did not r e f l e c t Northwest Bay conditions when age-class structure was considered, however.. Under the levels of hunting mortality believed to be present at Northwest Bay-over the period 1954 to 1 9 6 6 , a s i g n i f i c a n t change in male age-class structure would be expected 0 Since t h i s change was not observed, i t provides an indication that some factor at Northwest Bay tended to counteract such a trend, or that the trend r e a l l y occurred but was not revealed by s t a t i s t i c a l a n a l y s i s . •PART SIX: DISCUSSION Results indicated that the Northwest Bay b l a c k - t a i l e d deer herd underwent changes in a number of parameters over the period 1954 to 1 9 6 6 , and s e r a i succession and hunting probably played a major r o l e in these changes. I E f f e c t s of Serai Succession The population model discussed above was based upon the assumption that deer populations w i l l expand to the l i m i t s placed upon them by food, with dir e c t regulation being accom-plished by combinations of mortality factors such as hunting, predation, disease, accident , and mortality connected with winter malnutrition. In. such a model serai succession must be of paramount importance, since i t ultimately determines the amount of food that is available in an area. 99 E v i d e n c e g a t h e r e d a t Northwest Bay tended t o s u p p o r t t h i s model c The d i f f e r e n c e s i n deer usage o f v a r i o u s s e r a i s t a g e s found by Dasmann and Hines (1959 ) and Gates (Unpub. mat.) may be e x p l a i n e d on t h e b a s i s of a v a i l a b l e n u t r i e n t s i n each s t a g e . Through c a l c u l a t i o n s based on G a t e s ' i n d i c e s , i t was d e t e r m i n e d t h a t t h e Northwest Bay c l a i m as a whole d e c l i n e d as deer h a b i -t a t over t h e p e r i o d 1954 to 1 9 6 6 , and two independent methods bf a s s e s s i n g t r e n d s i n d e e r numbers ( s p r i n g c o u n t s and h u n t e r suc-cess ) s u p p o r t e d t h e c o n t e n t i o n t h a t s i g n i f i c a n t d e c l i n e s i n numbers o c c u r r e d over t h i s p e r i o d . S e r a i t r e n d s were not t h e same i n d i f f e r e n t p a r t s o f the s t u d y a r e a , however, and w h i l e a r e a 1 d e c l i n e d m a r k e d l y as deer h a b i t a t over the p e r i o d 1954 to 1 9 6 6 , a r e a 4 a c t u a l l y was i m p r o v i n g i n i t s a b i l i t y t o s u p p o r t d e e r . The two a r e a s t h u s p r o v i d e d an e x c e l l e n t c o n t r a s t i n 1966 and, w h i l e s a t i s f a c t o r y counts were n o t a v a i l a b l e , i t was p o s s i -b l e t o compare h u n t e r s u c c e s s between the two a r e a s . T e s t s on t h i s p o i n t were c o n t r a d i c t o r y . W h i l e s u c c e s s was s i g n i f i c a n t l y h i g h e r i n a r e a 4 i n September and O c t o b e r , a s exp e c t e d , i t was s i g n i f i c a n t l y l o w e r i n a r e a 4 i n November. There are two p r o b a -b l e e x p l a n a t i o n s f o r t h i s f a c t . The f i r s t e x p l a n a t i o n , which seems most l i k e l y , i s t h a t due to h i g h e r h u n t i n g p r e s s u r e i n a r e a 4 the deer became s i g n i f i c a n t l y more wary t h a n deer i n area 1 , t h u s i n v a l i d a t i n g h u n t e r s u c c e s s as a c r i t e r i o n of numbers of deer l a t e i n t h e s e a s o n . T e s t s i n d i c a t e d t h a t a r e a 4 r e c e i v e d a p p r o x i m a t e l y t h r e e t i m e s as much hunting p r e s s u r e as a r e a 1 , i n terms of numbers o f h u n t e r s p e r square m i l e . While t h i s e s t i m a t e may be somewhat high (due t o t h e f a c t t h a t a l l a r e a 4 h u n t e r s 100 had t o r e p o r t to the check s t a t i o n , whereas a l l a r e a 1 h u n t e r s d i d not ), I n e v e r t h e l e s s b e l i e v e t h a t a r e a 4 d i d have s i g n i f i -c a n t l y g r e a t e r numbers o f h u n t e r s per square m i l e throughout the season than d i d a r e a L A second probable e x p l a n a t i o n f o r t h e a l t e r a t i o n i n s u c c e s s p a t t e r n s i n t h e two a r e a s l i e s i n m i -g r a t i o n of d e e r away from a r e a 4 i n November. There i s no q u a n t i t a t i v e e v i d e n c e t o e i t h e r s u p p o r t o r r e f u t e t h i s p o s s i b i l -i t y , a l t h o u g h i t i s b e l i e v e d by many o b s e r v e r s t h a t some de e r do make s u c h m i g r a t i o n s . E v i d e n c e t h e r e f o r e g e n e r a l l y s u p p o r t e d the h y p o t h e s i s t h a t d eer numbers a r e d i r e c t l y r e l a t e d t o s e r a i s u c c e s s i o n . However, c h a n g i n g s e r e s may a l s o be e x p e c t e d t o a f f e c t the p o p u l a t i o n i n o t h e r ways. I f v e g e t a t i o n a l p a t t e r n s u l t i m a t e l y determine amount o f food a v a i l a b l e to d e e r , i t would be e x p e c t e d that deer c o n d i t i o n would be l i n k e d t o s e r a i s u c c e s s i o n . R e s u l t s o f t e s t s on t h i s p o i n t y i e l d e d a c l e a r but s u b t l e p a t t e r n , w h i c h was a p p a r e n t l y c l o s e l y l i n k e d w i t h deer b e h a v i o r or o t h e r f a c t o r s . As e x p e c t e d , the o n l y s i g n i f i c a n t t r e n d s i n w e i g h t over the p e r i o d 1954 t o 1966 were downward, but o n l y t h r e e a g e - c l a s s e s of a n i m a l s — m a l e s between the ages of 0.5 and 2.5 — e x h i b i t ed s i g -n i f i c a n t t r e n d s . The two youngest a g e - c l a s s e s of f e m a l e s and t h e 3 o5=year-old males may have a l s o d e c r e a s e d i n average weight over t h i s p e r i o d , but d e c l i n e s were not s i g n i f i c a n t . These r e -s u l t s s u p p o r t t h e c o n t e n t i o n t h a t s u c c e s s i o n a l p a t t e r n s i n f l u -ence c o n d i t i o n o f d e e r , but i t seems l i k e l y t h a t some age and 1 0 1 • sex c l a s s e s o f animals are not s i g n i f i c a n t l y a f f e c t e d . P o s s i -b l y , t h e r e f o r e , o n l y t h e younger animals are a f f e c t e d . B e h a v i o r or o t h e r f a c t o r s may tend t o o v e r - r i d e t h e importance of s e r a i s u c c e s s i o n i n d e t e r m i n i n g c o n d i t i o n o f o l d e r a n i m a l s . The r e a -s ons f o r the d i f f e r e n c e s between males and f e m a l e s were not c l e a r . I t may be t h a t w i t h l a r g e r sample s i z e s young females woaald a l s o have demonstrated s i g n i f i c a n t d e c l i n e s i n weight over the p e r i o d 1 9 5 4 t o 1 9 6 6 , or i t may be t h a t t h e r e are r e a l d i f -f e r e n c e s between young males and young f e m a l e s i n t h e i r r e a c t i o n t o c hanging s e r a i c o n d i t i o n s . S i n c e males must grow more than f e m a l e s , i t would not be s u r p r i s i n g i f t h i s were s o . F u r t h e r s u p p o r t f o r t h e h y p o t h e s i s t h a t s u c c e s s i o n a l p a t -t e r n s tend t o i n f l u e n c e c o n d i t i o n of young males was p r o v i d e d by t e s t s comparing w e i g h t o f 1 . 5 - y e a r - o l d males from a r e a s 1 and 4 over the c o u r s e of t h e s t u d y . As e x p e c t e d , a n i m a l s from ar e a 1 e x h i b i t e d a s i g n i f i c a n t d e c l i n e i n w e i g h t over t h e p e r i o d 1 9 5 4 t o 1 9 6 6 o Data were not a v a i l a b l e p r i o r t o 1 9 5 9 f o r a r e a 4 , but s i n c e then average w e i g h t s o f l o 5 - y e a r - o l d h u n t e r - k i l l e d a n i m a l s tended to i n c r e a s e , a l t h o u g h t h e s l o p e of the l i n e of b e s t f i t over t h i s p e r i o d was not s i g n i f i c a n t l y d i f f e r e n t from zero o As the s l o p e i n v o l v e d o n l y s i x p o i n t s , i t was not s u r -p r i s i n g t h a t no s i g n i f i c a n t i n c r e a s e c o u l d be d e t e c t e d o How-e v e r , a t - t e s t i n d i c a t e d s i g n i f i c a n t d i f f e r e n c e s between t h e s l o p e s from t h e two a r e a s . S i n c e a r e a s 1 and 4 were s i g n i f i -c a n t l y d i f f e r e n t i n s e r a i p a t t e r n over t h i s p e r i o d , t h e s e r e -s u l t s tended to s u p p o r t t h e v i e w t h a t s e r a i s u c c e s s i o n i s c l o s e l y l i n k e d w i t h c o n d i t i o n o f young males. 102 I t was a l s o h y p o t h e s i z e d t h a t d e t e r i o r a t i n g h a b i t a t would c o i n c i d e with an i n c r e a s e i n t h e average age of the p o p u l a t i o n , but r e s u l t s d i d not i n d i c a t e t h a t such a change o c c u r r e d . W h i l e s i g n i f i c a n t changes i n a g e - c l a s s s t r u c t u r e d i d o c c u r over t h e p e r i o d 1954 t o 1966 , t h e s e a p p a r e n t l y f o l l o w e d r e g u l a r p a t t e r n s not a s s o c i a t e d p a r t i c u l a r l y w i t h s e r a i succession„ In 1966 t h e average age o f deer k i l l e d i n a r e a 1 was h i g h e r t h a n t h e average age of d e e r k i l l e d i n a r e a 4 8 b u t d i f f e r e n c e s were not s i g n i f i -cant o I I E f f e c t s of H u n t i n g E f f e c t s of hunt i n g were e x p e c t e d t o show up i n t h e p o p u l a -t i o n much more d i r e c t l y t h a n the e f f e c t s of a d v a n c i n g s u c c e s s i o n . G e n e r a l e f f e c t s o f h u n t i n g u s u a l l y i n c l u d e s i g n i f i c a n t d e c r e a s e s i n numbers i n y e a r s f o l l o w i n g heavy e x p l o i t a t i o n , a l o w e r i n g of the average age of the p o p u l a t i o n i f r e c r u i t m e n t of young a n i -mals i s i n c r e a s e d to make up f o r d e f i c i e n c i e s i n numbers, and changes i n s e x r a t i o i f h u n t i n g f a v o r s one s e x . I f h u n t i n g r e -s u l t s i n r e m o v a l of extreme s u r p l u s e s o f a n i m a l s , such as appar-e n t l y o c c u r r e d a t the Seneca Army Depot ( H e s s e l t o n e t al„ 1965 ) . i t would be expected t o r e s u l t i n improved c o n d i t i o n of a n i m a l s . S i n c e the onset of h u n t i n g v i r t u a l l y c o i n c i d e d w i t h the s t a r t of the d e c l i n e i n t h e Northwest Bay range, t h e e f f e c t s o f h u n t i n g upon numbers of a n i m a l s tended t o be somewhat o b s c u r e d . W h i l e h u n t i n g may have been one of t h e causes of t h e d e c l i n e , t h e d e c l i n e c o u l d have o c c u r r e d w i t h o u t h u n t i n g t h r o u g h any com-b i n a t i o n of e m i g r a t i o n , lowered r e p r o d u c t i o n , or i n c r e a s e d 103 m o r t a l i t y from other c a u s e s . To determine t h e e f f e c t s of hunt-i n g upon numbers o f d e e r , i t was n e c e s s a r y to determine the s i z e o f t h e p o p u l a t i o n . Two t y p e s o f e s t i m a t e s were, a v a i l a b l e , but b o t h were a p p l i c a b l e o n l y w i t h i n wide l i m i t s . The f i r s t method was based upon the c a l c u l a t i o n of t h e o r -e t i c a l p o p u l a t i o n s i z e s i n t h e manner d e s c r i b e d on page 1 7 , based on deer usage o f v a r i o u s s e r a i s t a g e s . This method p r o -duced minimum p o p u l a t i o n e s t i m a t e s o f a p p r o x i m a t e l y 4500 deer i n 1956 , d e c l i n i n g t o a p p r o x i m a t e l y 3500 deer i n 1963 , and maximum e s t i m a t e s o f a p p r o x i m a t e l y 7800 a n i m a l s i n 1956 and 6800 a n i m a l s i n 1963 ( F i g . 13 ). In a l l c a s e s , fawns were not i n c l u d e d i n the t o t a l , and the p o p u l a t i o n was c a l c u l a t e d on a summer b a s i s . T h i s method t h e r e f o r e p r o v i d e s f o r v a r i a t i o n amounting t o a p p r o x i m a t e l y 3300 a d u l t a n i m a l s . As e x p l a i n e d on page 7 5 , however, i t i s p r o b a b l e t h a t the t r u e f i g u r e s a r e closer t o the l o w e r e s t i m a t e s . A l l e s t i m a t e s must be viewed s u b j e c t i v e l y , however, i n view of ex p e c t e d d i f f e r e n c e s between numbers of deer s u p p o r t e d by t i m b e r i n r e l a t i o n t o s u r r o u n d i n g h a b i t a t . This method o f e s t i m a t i n g deer numbers can o n l y be c o m p l e t e l y v a l i d i f e s t i m a t e s are made o n l y f o r t h e ti m e and p l a c e i n which p e l l e t s were a c t u a l l y counted. Thus, a t N o r t h -west Bay t h e p o p u l a t i o n e s t i m a t e s d e r i v e d from p e l l e t counts conducted by Gates (Unpub. mat , ) would o n l y be v a l i d f o r the p e r i o d I 9 6 0 t o 1962 , when Gates was a c t u a l l y doing, h'is work, and t h e e s t i m a t e s would i d e a l l y o n l y a p p l y t o a r e a 2 , By u s i n g an e s t i m a t e of a p p r o x i m a t e l y 40 deer per square m i l e of t i m b e r (as found by G a t e s ) , a p o p u l a t i o n o f a p p r o x i m a t e l y 2700 a d u l t deer 104 was e s t i m a t e d f o r a r e a 2 f o r any y e a r over t h e p e r i o d I960 to 1962. T h i s e s t i m a t e s h o u l d be compared w i t h t h e e s t i m a t e of a p p r o x i m a t e l y 1800 a n i m a l s i n d i c a t e d by F i g . 14, i n which a f i g u r e of f i v e d eer per square m i l e of t i m b e r was u t i l i z e d . The e s t i m a t e of 1800 was p r o b a b l y l e s s a c c u r a t e than the e s t i -mate of 2700, but f o r e a r l i e r or l a t e r y e a r s t h e a c t u a l number of animals i n a r e a 2 may have been c l o s e r to the e s t i m a t e s shown i n F i g . 14 than e s t i m a t e s c a l c u l a t e d on t h e b a s i s of 40 deer per square m i l e . S i m i l a r l y , f o r the Northwest Bay study a r e a as a whole, i t i s p r o b a b l y most r e a l i s t i c t o u t i l i z e t h e f i g u r e of f i v e d eer per square m i l e o f t i m b e r , but t h e r e can be no doubt t h a t t h i s t e n d s t o u n d e r - e s t i m a t e numbers i n some a r e a s a t some t i m e s . The second method of e s t i m a t i n g p o p u l a t i o n s i z e was through t a g g i n g r e t u r n s . E s t i m a t e s f o r a r e a 2 ranged from 2006 t o 4692 a d u l t s i n summer d u r i n g a s i m i l a r p e r i o d , and from 2716 t o 6383 a d u l t d e e r over the Northwest Bay s t u d y a r e a as a whole. These e s t i m a t e s compared q u i t e f a v o r a b l y w i t h t h e e s t i m a t e s o f 2700 a d u l t s f o r a r e a 2, and between 4000 and 69OO a d u l t s f o r t h e e n t i r e Northwest Bay study a r e a , d e r i v e d by th e s e r a i c a l c u l a t i o n over t h i s same p e r i o d . As t h e s e r a i and tagging e s t i m a t e s o f p o p u l a t i o n s i z e p r o -duced c l o s e agreement f o r a r e a 2, c o n s i d e r a b l e c o n f i d e n c e may be p l a c e d i n e s t i m a t e s d e r i v e d by such methods f o r the Northwest Bay s t u d y a r e a , p r o v i d i n g tthat the s h o r t c o m i n g s o f both methods are kept i n m i n d . I t must be remembered t h a t ranges of e s t i -mates d e r i v e d by both methods were q u i t e w i d e , but t h a t t h e s e 105 ranges r e p r e s e n t e d v i r t u a l upper and l o w e r l i m i t s . For i n s t a n c e , t a g g i n g e s t i m a t e s were d e r i v e d from c a l c u l a t i o n s based upon p r o b a b l e minimum and maximum fawn m o r t a l i t y of z e r o and 50 per c e n t r e s p e c t i v e l y over the summer, w h i l e t h e s e r a i e s t i m a t e s were based upon t h e p r o b a b l e minimum and maximum numbers of deer t h a t would i n h a b i t t i m b e r under d i f f e r i n g h a b i t a t c o n d i t i o n s . I t would b e p o s s i b l e t o produce upper and l o w e r p o p u l a t i o n e s -t i m a t e s much c l o s e r i n range through use of more p r e c i s e i n f o r m a -t i o n on fawn m o r t a l i t y and on d e e r usage of t i m b e r . Such e s t i -mates f o r t i m b e r would be e x t r e m e l y d i f f i c u l t t o produce, and no a t t e m p t s were made t o do s o . Three d i f f e r e n t approaches t o fawn m o r t a l i t y were made, however, and the most v a l i d method (as d i s c u s s e d on page #4) r e s u l t e d i n an e i g h t per c e n t e s t i m a t e . T h e r e f o r e t h e p o p u l a t i o n a t Northwest Bay o v e r t h e p e r i o d 1960= 1962 was p r o b a b l y i n t h e v i c i n i t y of 3000-4500 a d u l t s . These e s t i m a t e s i n d i c a t e d t h a t h u n t i n g c o u l d have removed a s i g n i f i c a n t p o r t i o n of t h e Northwest Bay d e e r p o p u l a t i o n , e s p e c i a l l y d u r i n g 1962 and 1963, t h e y e a r s o f h i g h e s t h a r v e s t . To c a l c u l a t e the e f f e c t s o f h u n t i n g , i t was n e c e s s a r y to i n c l u d e fawns i n t h e p o p u l a t i o n , s i n c e fawns were t a k e n by h u n t e r s . Presuming t h a t fawns made up about 25 per cent of t h e f a l l h e r d , a f a l l p o p u l a t i o n of 4000-6000 a n i m a l s was i n d i c a t e d . By c o mbining s e r a i and t a g g i n g e s t i m a t e s of a d u l t p o p u l a -t i o n s t o produce a g e n e r a l range of 2700-6400 a d u l t s f o r any y e a r i n t h e p e r i o d 1960-1962, t o t a l p o p u l a t i o n s i n c l u d i n g fawns were c a l c u l a t e d . These c a l c u l a t i o n s produced minimum and maxi-mum f i g u r e s , and s h o u l d be c o n s i d e r e d i n c o n j u n c t i o n w i t h t h e 106 estimate of 4000=6000 animals presented above. Per cent fawns in population Minimum Maximum 18 3333 7901 35 4153 9846 Hunters took a known average of approximately 470 deer per year over this period, including 635 animals in 1962, and the actual k i l l was higher than t h i s due to unknown numbers of c r i p -pled and i l l e g a l l y - k i l l e d animals. It was therefore l i k e l y that hunters took an average of more than 10 per cent of the Septem-ber population during these years, and that i n years of heaviest hunting the t o t a l was probably closer to 20 per cent. These estimates t a l l i e d c l o s e l y with the calculations based on t o t a l tag returns. Provided that normal miscellaneous., mortality from preda-t i o n , accident, disease, and other factors was high enough, these l e v e l s of exploitation could have produced the s i g n i f i c a n t declines in the population that were noted aft e r each of the years of heaviest hunting k i l l . Providing that hunting mortal-i t y i n these years amounted to about 20 per cent , the population simulations indicated that normal miscellaneous mortality must have amounted to about 10 per cent each six-month period, ex-cluding fawn mortality, Sex r a t i o evidence tended to support the contention that hunting pressure was s i g n i f i c a n t i n l a t t e r years of the study. Males were subjected to proportionately higher rates of e x p l o i t -ation than females over this period, and an apparent general decline in the proportion of males i n the population coincided 107 w i t h t h e p e r i o d s o f h e a v i e s t h u n t i n g k i l l . I t i s of i n t e r e s t t h a t t h e p r o p o r t i o n of males i n t h e k i l l d u r i n g a n t l e r l e s s season r o s e s l i g h t l y i n the y e a r s f o l l o w i n g 1 9 6 3 , when the k i l l t ended to be lowest. This r i s e may have been due t o s a m p l i n g e r r o r , an a c t u a l change i n t h e p o p u l a t i o n , added hun t e r p r e f e r -ence f o r bucks i n t h e s e y e a r s , or any c o m b i n a t i o n of t h e s e f a c t o r s . Thus t h e r e were c l e a r i n d i c a t i o n s t h a t numbers and sex r a t i o s responded t o h u n t i n g , but t h e evidence f o r a change i n a g e - c l a s s s t r u c t u r e was l e s s c l e a r . W h i l e a n a l y s i s i n d i c a t e d t h a t a g e - c l a s s s t r u c t u r e d i d change over t h e p e r i o d 1 9 5 4 - 1 9 6 6 , tifaere was no e v i d e n c e t h a t t h e s e changes were due s o l e l y to h u n t i n g . The p r o p o r t i o n o f 1 . 5 - y e a r - o l d s i n t h e p o p u l a t i o n i n -c r e a s e d s t e a d i l y f r o m 1961 t o 1966, but a s i m i l a r i n c r e a s e a l s o t o o k p l a c e between 1955 and 1 9 5 8 . Comparisons of a g e - c l a s s s t r u c t u r e between 1954-1959 and 1960=1966 i n d i c a t e d s t r o n g l y t h a t no change towards e i t h e r a younger or o l d e r a g e - c l a s s s t r u c -t u r e o c c u r r e d . The most s i g n i f i c a n t c o n c l u s i o n , when t h e e f f e c t s of hunt-i n g were c o n s i d e r e d , was t h a t t h e d i f f e r e n c e between male and female a g e - c l a s s s t r u c t u r e s d i d not a l t e r s i g n i f i c a n t l y o v er t h e p e r i o d 1 9 5 4 - 1 9 6 6 . S i n c e males were t a k e n d i s p r o p o r t i o n a t e l y , and supposedly i n s i g n i f i c a n t numbers, t h i s r e s u l t was a t v a r i -ance w i t h p r e d i c t i o n s based on computer s i m u l a t i o n . T h i s con-t r a d i c t i o n was not s u r p r i s i n g , however. Sample s i z e s i n t h e o l d e r age c a t e g o r i e s were n o r m a l l y s m a l l enough t h a t such d i f -f e r e n c e s might n ot become r e a d i l y apparent , being masked by 108 sampling error. I therefore believe that such small d i f f e r -ences in age-class pattern did develop i n the Northwest Bay black-tail population in later years of the study, but that they were not detected because of the impossibility of obtain-ing accurate-enough samples. Life table information gave some support to this view. Comparison of l i f e tables based on samples collected in the f i r s t and last two years of the study indicated that male l i f e expectancy may have decreased for older animals and increased for younger ones over the period 1954-1966. Since female pat-terns were opposite, these figures provided some justification far concluding that male-female differences in age-class pattern were slightly enhanced by the effects of hunting. It was possible that hunting mortality was actually too high over the l a t t e r period of the study (a view held by many hunters), but this was extremely doubtful for a number of reas-ons. Perhaps the strongest evidence against such a conclusion was the fact that a decline in numbers was s t r i c t l y predictable in advance on the basis of serai information. In addition, there was no good evidence that female age-class structure responded in any significant way to the effects of hunting. Third, recruitment was not enhanced, and may have been reduced, over this period. And, fourth, condition of animals also ap-parently continued to decline over the period of heaviest ex-ploitation. Both the latter observations would not be expected if numbers were below optimal levels. These facts supported a belief that observers of Vancouver Island deer have commonly 109 h e l d - - t h a t t h e r e c r u i t m e n t p o t e n t i a l of the h e r d f a r o u t s t r i p s the a b i l i t y of h u n t e r s t o decimate the a n i m a l s . I f the N o r t h -west Bay a r e a were i s o l a t e d , i t i s p o s s i b l e t h a t under l e v e l s o f h u n t i n g m o r t a l i t y p r e v a l e n t between 1962 and 1966 t h a t deer numbers c o u l d have been reduced below o p t i m a l l e v e l s , b u t th e r e were no b a r r i e r s to i m m i g r a t i o n and s u r r o u n d i n g a r e a s were not h e a v i l y hunted. T h e r e f o r e I b e l i e v e t h a t h u n t e r s d i d not reduce deer numbers s i g n i f i c a n t l y below t h e number t h a t t h e a r e a c o u l d e f f e c t i v e l y s u p p o r t . I l l E f f e c t s of W i n t e r Weather and Other F a c t o r s While h u n t i n g may have been the major r e g u l a t o r y f a c t o r i n l a t t e r y e a r s , i t i s d o u b t f u l t h a t h u n t i n g was a s e f f e c t i v e i n c o n t r o l l i n g the p o p u l a t i o n p r i o r t o I 9 6 0 , when numbers of hunt-e r s were s m a l l . T h e r e f o r e o t h e r p o s s i b l e t y p e s of r e g u l a t i o n were i n v e s t i g a t e d . The f a c t t h a t s p r i n g c o u n t s and h u n t e r success c o r r e l a t e d w e l l i n d i c a t e d t h a t t h e f l u c t u a t i o n s i n numbers between y e a r s suggested by both of t h e s e methods o v e r t h e p e r i o d 1954-1962 were r e a l r a t h e r than a r t i f a c t s of t h e two methods. P o s s i b l e r easons f o r ax c h f l u c t u a t i o n s were many, i n c l u d i n g e m i g r a t i o n , i m m i g r a t i o n , d i s e a s e , changes i n the r a t e of r e c r u i t m a i t , and p e r i o d i c d i e - o f f s due t o the e f f e c t s o f m a l n u t r i t i o n a s s o c i a t e d w i t h w i n t e r weather. T e s t s i n d i c a t e d t h a t t h e w i n t e r o f 1955-56 had a d v e r s e e f f e c t s upon the Northwest Bay deer herd ( l o w e r e d number of a n i m a l s , d e c r e a s e d w eight of m a l e s , and d i s p r o p o r -t i o n a t e m o r t a l i t y of young f e m a l e s ) , s u g g e s t i n g t h a t t h i s 110 w i n t e r (which was u n u s u a l l y s e v e r e i n terms o f t e m p e r a t u r e and s n o w f a l l ) p r o b a b l y had r e g u l a t o r y effects» However, i t was commonly b e l i e v e d t h a t the w i n t e r b f 1964-65 a l s o had advers e e f f e c t s upon Vancouver I s l a n d d e e r , but no such e f f e c t s were demonstrable a t Northwest Bay. T h i s was u n d e r s t a n d a b l e i f ex-p l o i t a t i o n t h r o u g h h u n t i n g had reached such p r o p o r t i o n s t h a t numbers of d e e r e n t e r i n g the w i n t e r were r e d u c e d to l e v e l s low enough t h a t l i t t l e m o r t a l i t y would be exp e c t e d even i n the most s e v e r e of w i n t e r s . IV P o p u l a t i o n R e g u l a t i o n a t Northwest Bay Many o f th e changes t h a t a p p a r e n t l y o c c u r r e d t o the N o r t h -west Bay b l a c k - t a i l e d deer p o p u l a t i o n o v e r t h e p e r i o d 1954-1966 were p r e d i c t a b l e on the b a s i s o f t h e computer s i m u l a t i o n o f the model d e s c r i b e d above. These r e s u l t s p r o v i d e d c o n s i d e r a b l e j u s -t i f i c a t i o n f o r a c c e p t a n c e of the proposed model, w h i c h s t r e s s e d the importance o f s e r a i s u c c e s s i o n i n f i x i n g g e n e r a l p o p u l a t i o n l e v e l s . The e f f e c t s o f h u n t i n g , w i n t e r weather, and other normal m i s c e l l a n e o u s m o r t a l i t y were b e l i e v e d t o a c t as d i r e c t r e g u l a -t o r y mechanisms. The s t r o n g e s t support f o r t h i s model came from the manner i n which numbers of a n i m a l s a p p a r e n t l y f l u c t u a t e d over t h e p e r i o d 1954-1966 a t Northwest Bay. In g e n e r a l the p o p u l a t i o n a p p a r e n t l y d e c l i n e d over t h i s p e r i o d , w h i c h was t o be ex p e c t e d s i n c e range c o n d i t i o n s d e t e r i o r a t e d . F l u c t u a t i o n s i n numbers were p r o b a b l y f r e q u e n t and s u b s t a n t i a l p r i o r to 1962, w i t h f a l l I l l p o p u l a t i o n s b e i n g dependent b a s i c a l l y upon the numbers of a n i -mals t h a t s u r v i v e d t h e p r e v i o u s w i n t e r . The p o p u l a t i o n was p r o b a b l y at i t s l o w e s t p o i n t d u r i n g t h i s i n i t i a l p e r i o d i n 1956, a f t e r a s e v e r e w i n t e r . Numbers appeared t o i n c r e a s e s t r o n g l y o v e r the n e x t two y e a r s , and t h e n t e n d e d t o f l u c t u a t e u n t i l 1962. While c o n s i d e r a b l e c o n f i d e n c e may be p l a c e d upon the con-c l u s i o n t h a t w i n t e r weather caused the d e c l i n e of 1956, t h e r e were no s a t i s f a c t o r y i n d i c a t i o n s of s p e c i f i c causes o f d e c l i n e s i n o t h e r y e a r s up t o 1962, b u t many causes may be p o s t u l a t e d , i n c l u d i n g e m i g r a t i o n , i m m i g r a t i o n , s m a l l d i e - o f f s , and change i n r a t e o f r e c r u i t m e n t . In 1962 and 1963 t h e r e were r e c o r d numbers o f an i m a l s t a k e n out of t h e a r e a b y h u n t e r s , and e s t i m a t e s o f h u n t i n g m o r t a l i t y d u r i n g t h e s e y e a r s approached 20 per c e n t - -more than enough t o r e s u l t i n observed d e c l i n e s i n numbers o f animals over t h e s e y e a r s . A f t e r t h a t time h u n t i n g p r e s s u r e remained h i g h , s u c c e s s f e l l o f f ( i n d i c a t i n g a low p o p u l a t i o n ) and f l u c t u a t i o n s i n numbers a p p a r e n t l y v i r t u a l l y d i s a p p e a r e d . These r e s u l t s s u p p o r t e d w e l l the t h e o r y t h a t e x p l o i t a t i o n by h u n t i n g , i f heavy enough, can dampen or c o m p l e t e l y e l i m i n a t e s e v e r e o s c i l l a t i o n s i n numbers. I t was p r o b a b l e t h a t h u n t i n g s e r v e d t o r e d u c e numbers c l o s e to o p t i m a l l e v e l s , i n terms of t h e a b i l i t y of the a r e a t o s u p p o r t d e e r , o b v i a t i n g the need f o r r e g u l a t i o n by other mechanisms . The f a c t t h a t t h e a d v e r s e e f f e c t s o f the 1964-65 w i n t e r were e x t r e m e l y m i n i m a l , d e s p i t e s e v e r e weather c o n d i t i o n s , p r o v i d e d s t r o n g s u p p o r t f o r t h i s con-t e n t i o n . 112 R e s u l t s of t e s t s on changes i n c o n d i t i o n o f animals o v e r t h e p e r i o d 1954-1966 a l s o s u p p o r t e d t h e model d e s c r i b e d above. C o n d i t i o n of a n i m a l s (as i n d i c a t e d by average weight i n the f a l l ) a p p a r e n t l y c l o s e l y f o l l o w e d s e r a i p a t t e r n s . The f a c t t h a t t h e wei g h t of males d e c l i n e d s h a r p l y a f t e r t h e 19 5 5 - 56 w i n t e r b u t not a f t e r the 1964=65 w i n t e r gave s u p p o r t to the c o n c l u s i o n s about t h e e f f e c t s of h u n t i n g suggested above. Changes i n a g e - c l a s s s t r u c t u r e and sex r a t i o s a l s o tended to s u p p o r t t h e h y p o t h e s i z e d model, but the r e s u l t s i n t h e s e a r e a s were b y no means c l e a r - c u t . Both i n d i c e s o f sex r a t i o ( h u n t e r k i l l d u r i n g a n t l e r l e s s season and f a l l c o u n t s ) s u g g e s t e d t h a t the p r o p o r t i o n o f males i n t h e p o p u l a t i o n was a t a low l e v e l i n 1954, g e n e r a l l y i n c r e a s e d up t o i960, and d e c l i n e d from 1961 to 1966, There was some i n d i c a t i o n i n the hunter k i l l (but not i n the f a l l c o u n t ) t h a t t h e p r o p o r t i o n o f males may have i n -c r e a s e d s l i g h t l y from I963 t o 1966, The o n l y major e x c e p t i o n t o t h i s p a t t e r n o c c u r r e d i n 1956, when h u n t e r k i l l i n d i c a t e d t h e h i g h e s t p r o p o r t i o n o f males r e c o r d e d over the 13-year p e r i o d o f the s t u d y . A g a i n , however, t h e f a l l c o u n t s d i d not support t h i s p a t t e r n , and s i n c e the h u n t e r k i l l i n 1956 was t h e l o w e s t r e c o r -ded o v e r the p e r i o d t h a t t h e study was c o n d u c t e d , i t i s p o s s i b l e t h a t t h e d i f f e r e n c e may be a t t r i b u t e d t o s a m p l i n g e r r o r . A l t e r -n a t e l y , i f the h u n t e r k i l l i s r e g a r d e d as a more r e l i a b l e i n d e x of c o n d i t i o n s i n the p o p u l a t i o n t h a n a r e the f a l l c o u n t s , t h e h i g h p r o p o r t i o n o f males i n 1956 was perhaps due t o d i f f e r e n t i a l m o r t a l i t y among males and females over t h e se v e r e 1955-56 wi nt er 8 113 In any c a s e , the d i s p a r i t y cf the 1956 o b s e r v a t i o n s d i d not m a t e r i a l l y c h a i g e t h e g e n e r a l p a t t e r n o f an i n c r e a s e i n t h e p r o -p o r t i o n of males up t o I960, f o l l o w e d by a d e c r e a s e . The d a t a p r o v i d e d no adequate e x p l a n a t i o n f o r some of t h e apparent f l u c -t u a t i o n s i n numbers i n e a r l y y e a r s o f t h e s t u d y . I t was p o s s i b l e t h a t the change i n p r o p o r t i o n o f males was i n some way a s s o c i a t e d w i t h the change i n s e r a i c o n d i t i o n s over t h e p e r i o d 1954 t o I960, but t h e r e was no way o f a d e q u a t e l y a s s e s s i n g t h i s p o i n t w i t h t h e d a t a a t hand. The downward t r e n d i n the p r o p o r t i o n o f males i n l a t t e r y e a r s was e x p l a i n a b l e , however, on t h e b a s i s o f the e f -f e c t s of h u n t i n g upon the p o p u l a t i o n . Males i n a l l y e a r s s u f -f e r e d p r o p o r t i o n a t e l y h i g h e r h u n t i n g m o r t a l i t y t h a n females due to the b u c k s - o n l y season and b e h a v i o r a l d i f f e r e n c e s between t h e s e x e s , and t h e d e c l i n e i n the sex r a t i o c o i n c i d e d w i t h t h e onset of heavy e x p l o i t a t i o n by h u n t e r s . In a d d i t i o n , t h e r e were i n d i -c a t i o n s that c o i n c i d e n t a l w i t h a d e c r e a s e i n the number o f a n i -mals k i l l e d per y e a r , the p r o p o r t i o n of males i n t h e k i l l tended to i n c r e a s e s l i g h t l y . T h is d e c l i n e was,-in c o n t r a d i c t i o n w i t h the f a c t t h a t t h e r e was no e v i d e n c e t h a t h u n t i n g caused a change i n t h e p a t t e r n of a g e - c l a s s d i f f e r e n c e s between t h e two s e x e s . However (as de-s c r i b e d above ), i t was p r obable t h a t such a change a c t u a l l y d i d o c c u r , a l t h o u g h i t was t o o s l i g h t t o d e t e c t . The computer s i m u l a t i o n a l s o p r e d i c t e d t h a t a change i n a g e - c l a s s s t r u c t u r e f o r both sexes would be apparent under l e v e l s of h u n t i n g mor-t a l i t y b e l i e v e d present a t Northwest Bay o v e r t h e p e r i o d 1962= 1966. I a t t r i b u t e d the l a c k o f s u c h a change t o the e f f e c t s o f 114 a d v a n c i n g s e r a i s u c c e s s i o n . S i n c e the range was a p p a r e n t l y d e t e r i o r a t i n g o v e r t h e p e r i o d of the s t u d y , I c o n c l u d e d t h a t h u n t i n g m o r t a l i t y and a d v a n c i n g s e r a i s u c c e s s i o n t e n d e d t o can-c e l each o t h e r i n t h e e f f e c t s upon a g e - c l a s s s t r u c t u r e . The one t e s t t h a t might have been c r i t i c a l , a comparison of a g e - c l a s s s t r u c t u r e o f deer k i l l e d i n f a v o r a b l e and u n f a v o r -a b l e h a b i t a t s , produced i n s i g n i f i c a n t r e s u l t s , b u t t h i s may have been due to t h e u n s a t i s f a c t o r i l y - s m a l l sample f r o m t h e u n f a v o r -a b l e a r e a . The t r e n d i n a g e - c l a s s s t r u c t u r e was i n t h e expected d i r e c t i o n — t o w a r d s an o l d e r average i n the u n f a v o r a b l e a r e a . A n a l y s e s of t h e e f f e c t s o f h u n t i n g and a d v a n c i n g s e r a i s u c c e s s i o n upon a g e - c l a s s s t r u c t u r e were c o m p l i c a t e d by the c y c l i c a l n a t u r e of the d a t a . As may be seen from F i g , 7, t h e r e was i n c r e a s e d r e c r u i t m e n t o f 1,5-year-old a n i m a l s over the 1960 ?s (when h u n t i n g m o r t a l i t y was h i g h ) , and t h i s s u p p o r t e d the v i e w t h a t i n c r e a s e d h u n t i n g k i l l l e d t o b e t t e r s u r v i v a l of young a n i m a l s . However, t h i s c o n c l u s i o n may not be w a r r a n t e d . The f a c t t h a t the p r o p o r t i o n o f 1,5-year-olds i n the p o p u l a t i o n tended t o v a r y r e g u l a r l y w i t h o u t r e g a r d t o h u n t i n g i n e a r l i e r y e a r s , and t h a t the i n c r e a s e i n l a t e r y e a r s tended t o f i t i n t o t h i s p a t t e r n , s u g g e s t e d t h a t t h e e x p l a n a t i o n f o r t h i s p a t t e r n did not l i e w h o l l y w i t h response to h u n t i n g m o r t a l i t y . I t i s probable t h a t t h i s p a t t e r n was t h e r e s u l t o f a c o m b i n a t i o n of o t h e r f a c t o r s , one of which was h u n t i n g i n l a t t e r y e a r s . But. o t h e r e x p l a n a t i o n s were p o s s i b l e . For i n s t a n c e , one p r o b a b l e h y p o t h e s i s c o u l d be f o r m u l a t e d on t h e r e l a t i o n s h i p between num-ber of o l d e r a n i m a l s and r e c r u i t m e n t o f 1,5-year-olds, I f 115 r e c r u i t m e n t depends s i m p l y on t h e d i f f e r e n c e between t h e number of o l d e r a n i m a l s i n the p o p u l a t i o n and t h e number of a n i m a l s t h a t t h e a r e a i s capable o f s u p p o r t i n g , such a c y c l i c t y p e o f r e c r u i t m e n t c o u l d o c c u r . In s u c h a s i t u a t i o n , a y e a r o f good r e c r u i t m e n t would n e c e s s a r i l y r e s u l t i n p r o p o r t i o n a t e l y p o o r e r r e c r u i t m e n t i n t h e n e x t few y e a r s , u n t i l t h a t p a r t i c u l a r c o h o r t became so d e p l e t e d t h a t i t s e f f e c t on the p o p u l a t i o n was no l o n g e r s i g n i f i c a n t . The r e s u l t o f such a mechanism would be a c y c l i c s i t u a t i o n such as t h a t o b s e r v e d , i f o t h e r f a c t o r s d i d not d i s t u r b t h e p a t t e r n . PART SEVEN : SUMMARY l . A s t u d y of t h e b l a c k - t a i l e d d e e r a t Northwest Bay, Vancou-v e r I s l a n d , was c o n d u c t e d t o d e t e r m i n e the e f f e c t s o f s e r a i s u c c e s s i o n and h u n t i n g upon the h e r d over the p e r i o d 1954 t o 1966. The p o s s i b l e r e g u l a t o r y e f f e c t s o f w i n t e r weather were a l s o c o n s i d e r e d . 2. To p r o v i d e a t h e o r e t i c a l b a s i s f o r a n a l y s i s of d a t a , a deer p o p u l a t i o n model s u i t a b l e f o r computer s i m u l a t i o n was con-s t r u c t e d , based on s t a t i s t i c s a v a i l a b l e from Northwest Bay and s t u d i e s of o t h e r deer p o p u l a t i o n s . 3. I n f o r m a t i o n on t h e deer was g a t h e r e d from s p r i n g and f a l l c o u n t s , a t a g g i n g s t u d y , and the h u n t e r c h e c k i n g s t a t i o n a t Northwest Bay, which a l s o p r o v i d e d h u n t i n g s t a t i s t i c s . Weather i n f o r m a t i o n was based upon Nanaimo m e t e o r o l o g i c a l r e -c o r d s , w h i l e l o g g i n g h i s t o r y was p r o v i d e d by a n a l y s i s o f 116 M a c M i l l a n B l o e d e l Company maps. 4 . Two i n d i c e s of deer numbers i n d i c a t e d t h a t they f l u c -t u a t e d m a r k e d l y u n t i l 1962 , at which time a more s t a b l e but d e c l i n i n g p a t t e r n was n o t e d . Both c r i t e r i a i n d i c a t e d t h a t the p o p u l a t i o n d e c l i n e d s i g n i f i c a n t l y o v e r the p e r i o d 1954 t o 1 9 6 6 . 5. P o p u l a t i o n e s t i m a t e s were based on two s t u d i e s c o n d u c t e d over the p e r i o d 1959 t o 1963 - - t h e t a g g i n g s t u d y , and a stu d y t o determine r e l a t i v e deer usage of d i f f e r e n t s e r a i s t a g e s . The a d u l t summer p o p u l a t i o n f o r an a r e a i n f a v o r a b l e s u c c e s s i o n a l s t a g e s was c a l c u l a t e d t o be a p p r o x i m a t e l y 79 deer per square m i l e by the s e r a i method, and c a l c u l a t i o n s based upon t a g g i n g s u b s t a n t i a t e d t h i s e s t i m a t e . T o t a l f a l l p o p u l a t i o n s , i n c l u d i n g fawns, were e s t i m a t e d to range between 3333 and 9846 a n i m a l s f o r the Northwest Bay s t u d y a r e a as a whole o v e r t h i s p e r i o d . 6 . A n a l y s i s o f a g e - c l a s s s t r u c t u r e over t h e p e r i o d 1954 to 1966 i n d i c a t e d t h a t : a) Males and fe m a l e s have s i g n i f i c a n t l y d i f f e r e n t age-c l a s s s t r u c t u r e s , w i t h males h a v i n g a l o w e r average age. b) The p r o p o r t i o n of 1 . 5 - y e a r - o l d a n i m a l s i n the p o p u l a t i o n tended t o r i s e and f a l l r e g u l a r l y over t h e p e r i o d of t h e s t u d y . c ) There was no c o n s i s t e n t t r e n d toward e i t h e r a younger or an o l d e r a g e - c l a s s s t r u c t u r e f o r e i t h e r sex when the p e r i o d s 1954-1959 and 1960 -1966 were compared. 7. A n a l y s i s of sex r a t i o i n d i c a t e d t h a t the p r o p o r t i o n o f males i n the a d u l t deer p o p u l a t i o n was a t i t s l o w e s t i n 19543 r o s e s t e a d i l y u n t i l I960, and then d e c l i n e d a g a i n . 117. 8. L i f e t a b l e s c o n s t r u c t e d f o r both sexes d i d not d i f f e r s i g n i f i c a n t l y from l i f e t a b l e s c o n s t r u c t e d f o r o t h e r deer h e r d s . 9. Weight o f t h e youngest t h r e e a g e - c l a s s e s o f males de-c l i n e d s i g n i f i c a n t l y o v e r t h e p e r i o d 1954 to 1 9 6 6 , b u t w h i l e t h e youngest a g e - c l a s s e s o f females tended to f o l l o w t h i s p a t t e r n , t h e d e c l i n e was n o t s i g n i f i c a n t . 1 0 . The p r o p o r t i o n o f males i n t h e a d u l t p o p u l a t i o n was a t a low l e v e l i n 1 9 5 4 , r o s e u n t i l I 9 6 0 , and d e c l i n e d f r o m 1961 t o 1 9 6 6 . 1 1 . The s e r a i c o m p o s i t i o n of the h a b i t a t i n a l l y e a r s was d e t e r m i n e d from l o g g i n g maps. M u l t i p l y i n g the amount of l a n d i n each s e r a i s tage by t h e e x p e c t e d number of deer p e r square m i l e f o r t h a t s e r a i stage p r o v i d e d e v i d e n c e t h a t t h e Northwest Bay study a r e a d e c l i n e d s i g n i f i c a n t l y as deer h a b i t a t over t h e p e r i o d 1954 to 1 9 6 6 . 1 2 . T h i s d e c l i n e i n h a b i t a t was r e f l e c t e d i n a g e n e r a l de-c l i n e i n numbers of a n i m a l s and a d e c l i n e i n t h e c o n d i t i o n o f younger males. These t r e n d s were not apparent i n a p o r t i o n o f t h e s t u d y a r e a which improved as deer range o v e r t h i s p e r i o d . There were i n d i c a t i o n s t h a t d e e r from an u n f a v o r a b l e a r e a tended t o have an o l d e r a g e - c l a s s s t r u c t u r e t h a n deer from a f a v o r a b l e a r e a i n 1 9 6 6 , but d i f f e r e n c e s were not s i g n i f i c a n t . 13o H u n t i n g p r e s s u r e on the h e r d tended t o i n c r e a s e , both i n terms of numbers o f h u n t e r s and numbers of a n i m a l s t a k e n , over t h e p e r i o d 1954 t o 1963, a f t e r which h u n t e r s u c c e s s de-c l i n e d s i g n i f i c a n t l y but number o f h u n t e r s remained h i g h . 118 14 o Tagging s t u d i e s showed t h a t h u n t e r s t o o k 29.7 per cent of the tagged a n i m a l s , w i t h a f u r t h e r 3«.5 per cent o f t h e tagged animals r e p r e s e n t i n g t h e minimum c r i p p l i n g l o s s . Hunters k i l l e d 28.8 per cent of t h e t a g g e d f e m a l e s , whereas t h e y t o o k 37.3 per cent o f t h e tagged m a l e s . 1 5 . Hunting m o r t a l i t y p r o b a b l y approached 15 t o 20 per cen t of the f a l l h e r d i n 1962, a l t h o u g h i n most y e a r s i t was l e s s t h a n t h i s . Heavy h u n t i n g i n 1962 and 1963 c o i n c i d e d w i t h a s i g -n i f i c a n t d e c l i n e i n de e r numbers. 1 6 . Hunters sampled i n a random manner over t h e p e r i o d 1960=1966, but not p r i o r t o t h i s t i m e . Due t o d i f f e r e n c e s i n male and female b e h a v i o r , however, males were u s u a l l y o v e r -r e p r e s e n t e d i n the k i l l d u r i n g a n t l e r l e s s s eason. 17. Hunter s u c c e s s i s a f f e c t e d by r a i n o n l y i n September and O c t o b e r , b u t deer w a r i n e s s i n c r e a s i n g l y a f f e c t s h u n t e r s u c -c e s s throughout t h e seas o n . 1 8 . W i n t e r weather i n 1955=56 and 1964-65 was found t o have been more s e v e r e than normal a c c o r d i n g t o t h r e e i n d i c e s , which c o i n c i d e d with t h e common b e l i e f t h a t t h e s e w i n t e r s a d v e r s e l y a f f e c t e d t h e deer herds o f Vancouver I s l a n d , 19. S i g n i f i c a n t d e c l i n e s i n d e e r numbers and c o n d i t i o n o f males o c c u r r e d f o l l o w i n g the 1955=56 wint e r , but not t h e 1964 = 65 w i n t e r . Sample s i z e s were too s m a l l t o p e r m i t e f f e c t i v e a n a l y s i s of the e f f e c t of the two w i n t e r s upon a g e - c l a s s s t r u c -t u r e and s e x r a t i o s . There were i n d i c a t i o n s , however, t h a t female fawns and 1 . 5=year-olds s u f f e r e d d i s p r o p o r t i o n a t e mor-t a l i t y o v e r 1955-56. C o n f l i c t i n g r e s u l t s p r e c l u d e d any 119 c o n c l u s i o n s r e g a r d i n g t h e e f f e c t o f the 1964=65 w i n t e r on s u r v i v a l of f e m a l e s . 20. Computer s i m u l a t i o n s u g g ested t h a t n a t u r a l m i s c e l l a = neous m o r t a l i t y from such causes as p r e d a t i o n , a c c i d e n t , and d i s e a s e p r o b a b l y approached 10 per cent o f t h e p o p u l a t i o n every s i x months at Northwest Bay o ver t h e p e r i o d of the s t u d y , e x c l u d i n g fawn m o r t a l i t y i n t h e f i r s t two months of l i f e . 21. S i m u l a t i o n of a p o p u l a t i o n under h i g h r a t e s of. h u n t i n g produced r e s u l t s s i m i l a r t o t h o s e found a t Northwest Bay i n two main a r e a s : a) Year=by=year o s c i l l a t i o n s i n numbers of d e e r were re™ due ed. b) The p r o p o r t i o n of males i n t h e a d u l t p o p u l a t i o n was re= due ed. 22. C o n t r a d i c t o r y r e s u l t s between computer s i m u l a t i o n and a c t u a l c o n d i t i o n s were n o t e d f o r a g e - c l a s s s t r u c t u r e o f males. S i m u l a t i o n s u g g e s t e d t h a t under l e v e l s o f h u n t i n g m o r t a l i t y b e l i e v e d t o be p r e s e n t a t Northwest Bay, a s i g n i f i c a n t l o w e r i n g o f the average age of males should have o c c u r r e d . The f a i l u r e of such a change t o be o b s e r v e d was a t t r i b u t e d t o t h e p o s s i b l e c o u n t e r a c t i o n of d e t e r i o r a t i n g range c o n d i t i o n s , which m i g h t cause t h e average age t o become o l d e r i f no o t h e r f a c t o r s were o p e r a t i n g . 23. The most i m p o r t a n t r e g u l a t o r y mechanism f o r Vancouver I s l a n d deer p o p u l a t i o n s was concluded t o be s e r a i s u c c e s s i o n , w i t h r e g u l a t i o n a c c o m p l i s h e d b y any c o m b i n a t i o n o f h u n t i n g , nor= mal m i s c e l l a n e o u s m o r t a l i t y , and w i n t e r m o r t a l i t y . 120 REFERENCES CITED Adams s, W, H. I960. Population ecology of white-tailed deer in Northeastern Alabama. Ecol. 41 "706-715° Arnold, D. A., and L. J. Verme . 1963. Ten years' observation of an enclosed deer herd i n northern Michigan. Trans. N. Am. W i l d l . Conf. 28:422-430. Bandy, P. J. 1965 . A study of comparative growth in four races of b l a c k - t a i l e d deer, Ph, D. the s i s , University of B r i t i s h Columbia :1=189° Baranov, T, I. 1918. On the question of the b i o l o g i c a l basis of f i s h e r i e s , Nauch, Issledov. I k t i o l . Inst. Izv, 1(1): 23-327. B a r t l e t t , C. 0. 1955° Starvation of deer on.Navy Island. Tech. B u l l , , W i l d l , Ser. No. 5, Ont, Dept. Lands and Forests:1-18° B a r t l e t t , I. H. 1950. Michigan deer. Mich. Dept. Conserv, : 1-50. Brigham, J. H, 1958. Early mortality i n bl a c k - t a i l e d deer i n western Washington. Unpublished Masters t h e s i s , Washington State University :l - 4 7 Brown, E. R, 1961. The b l a c k - t a i l e d deer of western Washington. Wash. State Game Dept. B i o l . B u l l . No, 13:1-124, Chapman , D. G. 1948, A mathematic al study of confidence l i m i t s of salmon populations calculated from sample tag r a t i o s . B u l l , Inter, P a c i f i c Salmon Fisheries Comm. 2:67-85° Cowan, I, McT, 1945° The ecological relationships of the food of the Columbian b l a c k - t a i l e d deer (Odocoileus hemionus columbianus (Richardson) i n the coast forest region of southern Vancouver Island, B r i t i s h Columbia. Ecol, Monog, 15 :109-139° Dasmann, R, F,, and W. W. Hines, 1959° Logging, plant succes-sion, and bl a c k - t a i l e d deer i n the redwood region, Div. Nat. Res,, Humboldt State College 21-13° Erickson, A, B,, V. E. Gunvalson, M, H, Stenlund, D, Wo Bur c alow 8and L. H. Blankenship. 19610 The white-tailed deer of Minnesota. Min. Dept. Conserv. Tech, B u l l , No, 5:1-64, 121 G u i l f o r d s J„ P. 1 9 5 6 . Fundamental s t a t i s t i c s i n p s y c h o l o g y and e d u c a t i o n . M c G r a w - H i l l , Toronto :l - 5 6 5 « H e s s e l t o n , W, T., C. W. S e v e r i n g h a u s , and J. E, Tanck. 1 9 6 5 . P o p u l a t i o n dynamics of deer a t the Seneca Army Depot. N. Y. F i s h and Game J . 1 2 ( l ) : 1 7 - 3 0 . H i n e s , W. W. 1 9 6 7 . E c o l o g i c a l study of b l a c k - t a i l e d d e e r . Job Com p l e t i o n R e p o r t , Fed. A i d P r o j . W-51-R--9, Ore. S t a t e Game Cpmm. : l - 7 » K e l k e r , G..H, 1 9 4 3 . Sex r a t i o e q u a t i o n s and f o r m u l a s f o r de-t e r m i n i n g w i l d l i f e p o p u l a t i o n s . P r o c . Utah Aced. S c i . , A r t s , and L e t t e r s 2 0 : 1 8 9 - 1 9 8 . L a s s e n , R.. W„, C. M. F e r r e l , . and H, R. Leach. 1 9 5 2 . Food h a b i t s , p r o d u c t i v i t y , and c o n d i t i o n of t h e Doyle mule deer h e r d . C a l i f . F i s h and Game 3 8 ( 2 ) : 2 1 1 - 2 2 4 . Laws, R. M, 1 9 6 2 . Some e f f e c t s of w h a l i n g i n t h e s o u t h e r n s t o c k s o f b a l e e n w h a l e s . I n The e x p l o i t a t i o n o f n a t u r a l -a n i m a l p o p u l a t i o n s , E. D. LeCren and M. W. H o l d g a t e , ed., W i l e y , N. Y. : 1 3 7 - 1 5 8 . L e o p o l d , A. A., T. R i n e y , R. McCain, and L. T e v i s , J r . 1 9 5 1 . The Jawbone deer h e r d . C a l i f . Dept. Nat. Res. Game B u l l . No. 4 : 1 - 1 3 9 . L i , J . C. R. I 9 6 4 . S t a t i s t i c a l i n f e r e n c e . Edwards B r o t h e r s , Ann A r b o r : 1 - 6 5 8 , L o n g h u r s t , W. M. 1 9 5 5 . The r o l e of p a r a s i t i s m i n the p o p u l a -t i o n dynamics o f a he r d of b l a c k - t a i l e d d e e r . Proc. An. Conf. W. Assoc , S t a t e Game and F i s h Comm. 3 5 ' 1 2 4 - 1 3 4 . M a g u i r e , H, F., and C. W, S e v e r i n g h a u s , 1 9 5 4 . Wariness as an i n f l u e n c e on age c o m p o s i t i o n of w h i t e - t a i l e d deer k i l l e d by h u n t e r s . N. Y. F i s h and Game J . 1 ( 1 ) : 9 8 - 1 0 9 . M a r b u r g e r , R. G., and J . W. Thomas. 1 9 6 5 . . A d i e - o f f i n w h i t e -t a i l e d d e e r o f the C e n t r a l M i n e r a l Region o f Texas. J . W i l d l , Mgmt. 2 9 ( 4 ) : 7 0 6 - 7 1 6 . R i c k e r , W. E, 1 9 5 8 , Handbook o f computations f o r b i o l o g i c a l s t a t i s t i c s of f i s h p o p u l a t i o n s . F i s h e r i e s Res. Bd, o f Canada B u l l , No, 1 1 9 : 1 - 3 0 0 , R o b i n e t t e , W. L. 1 9 6 6 . Mule deer home range and d i s p e r s a l i n Utah. J . W i l d l . Mgmt, 3 0 ( 2 ) : 3 3 5 - 3 4 9 . • , J . So G a s h w i l e r , D. A. Jones, and H . S, Crane, 1955. F e r t i l i t y of mule deer i n Utah. J . W i l d l . Mgmt. 1 9 : 1 1 5 - 1 3 6 . 122 „ J , So Gash wi I e r , J . B. Low, and D. A. Jones, 1957. ~ D i f f e r e n t i a l ' m o r t a l i t y by s e x and age among mule d e e r , J . W i l d l . Mgmt. 21(1) :1-16. R o b i n s o n , D. J . 1956. P r e l i m i n a r y s t u d i e s upon the e f f e c t of log g e d o v e r a r e a s oh q u a l i t y and s i z e of d e e r p o p u l a t i o n s on Vancouver I s l a n d . B. C. Game Comm„:1=8. Russo, J . P. 1964. The Kaibab N o r t h deer h e r d — i t s h i s t o r y , problems , and management. A r i z . Game and F i s h Dept. W i l d l . B u l l . No. 7 . 1 - 1 9 5 . S e v e r i n g h a u s , C. W., S. F r e e , and W. T. H e s s e l t o n . I963. The g a i n s and l o s s e s i n a deer p o p u l a t i o n f o r f i v e s e c t i o n s of New York S t a t e . Fed. Aid Proj.W - 8 9-R, N. Y. S t a t e Gonserv. Dept. :1=18. Taber, R. D. 1953 •- . S t u d i e s , of b l a c k - t a i l e d deer r e p r o d u c t i o n on t h r e e c h a p a r r a l c o v e r t y p e s . C a l i f . F i s h and Game 39: 177-186. 1961 o The b l a c k - t a i l e d d e e r : a r e v i e w of e c o l o g y and management. La T e r r e e t l a V i e 2:221=245. . and R. F. Dasmann. 1958. The b l a c k - t a i l e d deer bf t h e c h a p a r r a l . C a l i f . Dept. F i s h and Game B u l l . No. 8: 1-163. Teer, J . G„, J . W. Thomas, and E. A. Walker. 1965. E c o l o g y and management of t h e w h i t e = t a i l e d deer i n t h e L l a n o B a s i n o f Texas. W i l d l . Monog. 15:1-62. W h i t e , M. 1966. P o p u l a t i o n e c o l o g y o f some w h i t e t a i l deer i n s o u t h Texas. D o c t o r a l t h e s i s , Purdue U n i v e r s i t y : 1 - 2 1 5 . 123 APPENDIX I Use o f Hunter S i g h t i n g s o f Deer as a P o p u l a t i o n Index Deer are s i g h t e d by h u n t e r s much more f r e q u e n t l y than t h e y ar e s h o t , and t h e r e f o r e i f s m a l l sample s i z e i s l i k e l y t o r e s u l t i n a t y p e I I e r r o r ( G u i l f o r d , 1956), the a c c e p t a n c e o f a n u l l h y p o t h e s i s when i t i s a c t u a l l y f a l s e , i t i s d e s i r a b l e t o use h u n t e r s i g h t i n g s o f d e e r as a p o p u l a t i o n i n d e x i n p l a c e o f num-ber o f d e e r k i l l e d - T h i s i s v a l i d , however, o n l y i f the t o t a l number o f deer r e p o r t e d as s i g h t e d by h u n t e r s c o r r e l a t e s w e l l w i t h t h e t o t a l number of deer k i l l e d over the same time p e r i o d . There i s no r e a s o n why h u n t e r s i g h t i n g s o f deer s h o u l d n o t c o r r e l a t e w e l l w i t h h u n t e r k i l l except f o r the p o s s i b i l i t y of f a u l t y r e p o r t i n g . Because of t h i s p o s s i b i l i t y , t h e r e has been a tendency f o r l e s s credence t o be p l a c e d upon i n f o r m a t i o n g a t h -ered from h u n t e r s i g h t i n g s of d e e r t h a n from d e e r t h a t h u n t e r s have produced f o r v i e w a t a check s t a t i o n . The w o r t h o f h u n t e r s i g h t i n g r e p o r t s was t e s t e d i n t h e f o l l o w i n g manner. The e s s e n t i a l p o i n t i s t h a t no m a t t e r how many c a s e s o f f a u l t y r e p o r t i n g o c c u r , i f h u n t e r s i g h t i n g s o f deer as r e p o r t e d at t h e check s t a t i o n c o r r e l a t e c o n s i s t e n t l y w i t h number o f deer k i l l e d , each may be used as an i n d e x o f t h e o t h e r , and the pop-u l a t i o n i n g e n e r a l . In such a c a s e , use o f h u n t e r s i g h t i n g s would p r o v i d e much l e s s chance of a t y p e I I e r r o r o c c u r r i n g . The f o l l o w i n g c o r r e l a t i o n s were t e s t e d : 1. Number o f bucks s i g h t e d and number of bucks shot per day t h r o u g h o u t the 1966 season ( F i g . 21). 2. Number o f bucks s i g h t e d and number of a n t l e r l e s s a n i m a l s FIGURE 21: Number of bucks sighted and shot per day at Northwest Bay i n 1966. (r = .81, d. f. = 2 3 ) SIGHTED SHOT SEPTEMBER OCTOBER , NOVEMBER 125 sighted f o r each day i n September and October combined, and Nov-ember separately, for 1966 (Fig. 22). Separations were made in t h i s manner due to the expected influence of the rut upon male behavior. 3» Number of a n t l e r l e s s animals sighted and number of bucks shot, by day, in September and October of 1966. As indicated by F i g . 21, the number of bucks sighted cor-related well (.81) with the number of bucks shot throughout the 1966 season when s t a t i s t i c s were considered on a day-by-day ba-s i s . The f a c t that the c o r r e l a t i o n was not higher was probably due to two f a c t o r s : sampling error, and the fact that the act of k i l l i n g a buck usually precluded the sighting of other bucks. The hunter k i l l was so low during October (for no day was the k i l l more than four animals) that i t was not surprising that sightings and numbers of animals k i l l e d did not agree too c l o s e l y It was for t h i s very reason that the use of sightings was f i r s t eonsid ered. It may be concluded, therefore, that hunter sightings of bucks probably provides at least as good a population index as does the actual k i l l . However, the problem of sample size was not solved by the use of sightings of bucks, because the sample was s t i l l low (less than 10 bucks sighted per day) throughout October. It was imperative, therefore, that the use of sightings of antlerless animals be investigated as an alternate index. Sightings of bucks and antlerless animals (Fig. 22) correlated highly (r = . 9 5 ) f o r September and October, but during November t h i s c o rrelation a l l but disappeared, presumably because of the FIGURE 22: Number of bucks and antlerless animals sighted and shot per day at Northwest Bay i n 1966. (r = .95 for September-October, with d. f. = 14) SEPTEMBER OCTOBER NOVEMBER 127 i n f l u e n c e o f t h e r u t upon male b e h a v i o r . Hunter s i g h t i n g s o f a n t l e r l e s s a n i m a l s c o r r e l a t e d a t a .93 r a t e w i t h number o f bucks sho t each day d u r i n g September and Oc t o b e r . The c o r r e l a t i o n s d e s c r i b e d above p r o v i d e d good j u s t i f i c a t i o n f o r t h e use o f h u n t e r s i g h t i n g s o f deer i n p l a c e o f , o r i n ad-d i t i o n t o , number o f d e e r k i l l e d . There was a l s o a s t r o n g im-p l i c a t i o n t h a t f o r September and O c t o b e r , h u n t e r s i g h t i n g s o f a n t l e r l e s s a n i m a l s p r o v i d e d a b e t t e r e s t i m a t e o f t h e buck k i l l t h a n d i d h u n t e r s i g h t i n g s o f b u c k s . These d a t a a l s o i m p l i e d t h a t because o f t h e i n f l u e n c e o f t h e r u t upon b u c k s , s t a t i s t i c s d e r i v e d from a n t l e r l e s s a n i m a l s a r e more l i k e l y t o p r o v i d e a s t a b l e p o p u l a t i o n i n d e x t h a n a r e s t a t i s t i c s d e r i v e d from males. Where a p p l i c a b l e , t h e r e f o r e , t h r o u g h o u t t h i s s t u d y use was made o f h u n t e r s i g h t i n g s o f a n t l e r l e s s a n i m a l s . 128 APPENDIX II Population Simulation C THE FOLLOWING PARAMETERS ARE OPERATIONAL IN THIS PROGRAM C 1 . FAWN MORTALITY = THREE TIMES NORMOR,IN GENERAL C 2. ILLEGAL KILL = .25 TIMES LEGAL KILL C 3 . WINTER DEATH ASSOCIATED WITH MALNUTRITION = . 0 5 , IN C GENERAL C C VARIABLES: C 1 . EXPLOI = EXPLOITATION C 2. NORMOR = NORMAL MISCELLANEOUS MORTALITY C 3 . WINMOR - WINTER MORTALITY ASSOCIATED WITH MALNU-C TRITION C C THIS PROGRAM HAS NORMOR = .10' DIMENSION AAAA(26 ) ,FAWNS (13 ).AAAB(26) ,AABB(26) SAAXX(26 )•-• 1AADD(26),BA(26 ),BB(26),BC(26),CA(26).CB(26),CC(26),CC(26} • DIMENSION BUCKSE(26),DEAD(26).SUMMOR(26),WMOR(26),C.ONCE(13), 1 EMMOR (13 ) , WINKIL (26 ), STARVE (26 ),D.R (20 ), SUC (20), DEAR (20 ), 2AGE(26) C TIME - MARKER CONTROLLING EXPLOI LEVELS C WEATHR = MARKER CONTROLLING WINMOR LEVELS TIME - 0 WEATHR - 0 970 IF (WEATHR .EQ.lv)- GO TO 1999 IF(WEATHR.EQ.2.) GO TO 971 IF(WEATHR.EQ.3.) GO TO 972 IF(WEATHR.EQ.4. ) GO TO 973 IF(WEATHR.EQ.5.) GO TO 974 IF(WEATHR.EQ.6.) GO TO 154 WINMOR - 0.0 ZILCH -.WINMOR GO TO 870 1999 WINMOR = ,05 ZILCH » WINMOR GO TO 870 971 WINMOR - ,10 ZILCH - WINMOR GO TO 870 972 WINMOR = .15 ZILCH - WINMOR GO TO 870 973 WINMOR - .20 ZILCH = WINMOR GO TO 870 974 WINMOR - .25 129 ZILCH = WINMOR GO TO 870 • 873 FORMAT (///, 2X, 26HNATURAL WINTER MORTALITY = , 1F12.4,20X„14HEXPL0ITATI0N = ,F12 . 4 , / / / ) 870 CONTINUE EXPLOI = OoO WINMOR =-ZILCH WRITE (6 , 873 ) WINMOR,EXPLOI GO TO 665 666 EXPLOI =0 . 0 5 WINMOR =•ZILCH WRITE (6,873) WINMOR,EXPLOI GO TO 665 667 EXPLOI - 0.10 WINMOR «•ZILCH WRITE ( 6 , 8 7 3 ) WINMOR,EXPLOI GO TO 665 668 EXPLOI = 0.15 WINMOR =•Z ILCH WRITE (6,873) WINMOR,EXPLOI GO TO 665 669 EXPLOI =0.20 WINMOR = •ZILCH WRITE ( 6 , 8 7 3 ) WINMOR,EXPLOI GO TO 665 670 EXPLOI -• 0.30 WINMOR ZILCH WRITE ( 6 , 8 7 3 ) WINMOR,EXPLOI GO TO 665 671 EXPLOI - 0 .30 WINMOR = ZILCH WRITE (6 , 8 7 3) WINMOR,EXPLOI GO TO 665 672 EXPLOI = 0.35 WINMOR ---ZILCH WRITE (6,873) WINMOR,EXPLOI GO TO 665 673 EXPLOI =0.40 WINMOR >=• ZILCH WRITE ( 6 , 3 7 3 ) WINMOR,EXPLOI 665 CONTINUE S = 0. C XSERAL - NO. OF YEARS IT TAKES VEGETATION TO RECOVER FROM C OVERBROWSING DURING A CRASH XSERAL =15. C SER = CONTROL FOR XSERAL (SEE WINTER WEATHER SECTION) SER =15. SERAL = SER/XSERAL MARK = 0 SADRAT = 0. WINWTH = 1. WINLST = 1. 130 AABB(3)=0. Y » RANDN(1.) M - 0 N - 1 C XILKIL = ILLEGAL KILL, EXPRESSED AS PERCENT OF LEGAL KILL XILKIL = .25 C BUCKSE = THE INCREMENT FOR BUCK SEASON (SEE EXPLOITATION C AREA) DATA BUCKSE/O.,0.,0.,0.,0.,0.jO.,0.,0.,0.,0.jO.jO.,0.0, 1.8645 j - 8062 j.5440,.443 0,.43 05,.4400,.4400,.4400,.4400, 2 . 4 4 O O ,.4400,.4400/ C DIFF = THE PERCENT THAT MALE FAWNS ARE SHOT OVER FEMALE C FAWNS DIFF — 1162 C NORMOR = NATURAL MORTALITY, NOT COUNTING STARVATION C NORMOR IS SAME IN SUMMER AND WINTER, AND IS DEDUCTED IN C EACH SEASON REAL NORMOR NORMOR = .10 C DEAD - DEATH RATE COMPARED TO•4-YEAR-OLD DOES-DATA DEAD/1.2,1.1,1.1,1.ljl-.O,1;0, 1.0,1.0,1.1,1.1,1.1,1.2, , 12.0,1.2,1.574,1.259,1.259.1.259.1.259s1.259,1.259}1.259, 21.259,1.259,1.259,1.259/ DO 50 I = 1,26 50 SUMMOR(I) = DEAD(I)*NORMOR C BFMOR AND FFMOR=THE FAWN MORTALITY.... SO MANY TIMES NORMAL BFMOR = 3. FFMOR =3. DO 51 I = 1,26 51 WMOR(I); - DEAD (I )*NORMOR C THE NEXT SECTION PREVENTS AN OVERKILL OF FAWNS FILL - SUMMOR(l) FALL - WMOR(l) BILL = SUMM0R(14) BALL = WM0R(14) C CONCE = NO. OFEMBRYOES CONCEIVED PER DOE DATA CONCE/0.0,0.0,1,000,1.57,1.84,1.84,1.84,1.84,1.84, 1 1.84,1.84,1.84,1.84/ C EMMOR = PERCENT EMBRYONIC-MORTALITY PER AGE-CLASS DATA EMMOR/.0,.0,.0,.0,.0,.0,.0,.0• ,.Q,.0,.0,.0,.0/ C STARVE » THE PERCENTS THAT DIE IN A STARVATION DIE-OFF DATA STARVE/3.2,1.6.1.0,1.0,1,0,1.0,1.0,1.0,1.0.1.1,-1 1.2,1.3,1.4,2.8,1.6,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.1,1.2, 2 1.3,1.4/ 137 DO 52 I = 1,26 52 WINKIL (I) - STARVE (I)*WINMOR DIE - WINKIL (3)*AABB(3) CRASH = 2.0*AABB(3) IF(CRASH.LT .DIE)GO TO 222 IF(S.EQ.l.)G0 TO 83 GO TO 153 222 DINFO =.,50 *AABB(1) WINKIL(l) • DINFO + (WINM0R-,20)*DEAD(1) 131 DINBO = .50*AABB(3) WINKIL(14) = DINBO + (WINMOR-.20)*DEAD(14) GO TO 8 3 1 5 3 CONTINUE C SERAL EFFECTS C DR = NO. OF-DEER PER SQUARE MILE PER SUCCESSION STAGE -DATA DR/5.0j0.0,82.0,120.33,139.42,140.74,130.54,114.07, 1 9 5 o 6 4 , 7 8 . 5 2 , 6 5 o 0 5 , 5 6 . 5 6 , 5 3 o 3 7 , 5 4 . 8 7 , 5 9 . 4 2 , 6 4 . 4 1 , 6 6 . 2 6 , 260 . 3 9,41 . 2 4,5.0/ C SUC = NO. OF SQUARE MILES PER SUCCESSION STAGE • • DATA SUC/679.'OjO. ,0. ,0. ,0. ,0. ,0. ,0. ,0.,0. ,0. ,0. ,0. ,0. 10.,0.,0.,0.,0.,0./ C THE ABOVE DATA STATEMENT MAY BE REPLACED BY A WORKING C EQUATION IF THE USER WISHES TO UTILIZE A CHANGING RATHER C THAN A FIXED HABITAT Q * # # # * * if if # ifif j J i S J C S ^ ^ S ^ ^ S S ^ ?!«!S5{< if -fi -fi * # if * >f if if * if # * if * * # * if if * * * * * * Sjc * S j O * # # C INITIALIZATION OF POPULATION C DEER = TOTAL NO. JUST PRIOR TO FAWNING DO 53 I = 1,20 DEER =0.0 5 3 DEAR(I) = DR(I)*SUC(I) DO 5 4 I = 1,20 DEER = DEER + DEAR(I) C RATIOF = PERCENT FEMALES AT BIRTH OF FAWNS RATIOF = . 5 0 RATIOM = 1,-RATIOF C DOE = PERCENT DOES IN POPULATION DOE = .60 BUCKK = l.-DOE DOES = DEER*DOE BUCKS = DEER*BUCKK C THE FOLLOWING DATA STATEMENT COVERS THE PER CENT OF ANIM-C ALS IN EACH AGE CLASS. TOTAL PER CENT EQUALS 200, SINCE C DOES AND BUCKS POPULATIONS ARE CALCULATED SEPARATELY AT C THIS STAGE. -DATA AGE/0.,.311,.227,.168,.109,.087,0O63,.045,.033,• 1 . 0 2 4 , .017, . 0 1 2 5 , .008,oO, . 4 0 0 , .221, . 1 7 3 , .HO, .070, .04, 2 . 0 3 , . 0 2 , . 0 1 , . 0 0 8 , . 0 0 5 , . 0 0 3 / DO 5 5 I = 2,13 5 5 AAAA(I) = AGE(I)*DOES DO 5 6 I = 15,26 5 6 AAAA(I) = AGE(I)*BUCKS NYEAR = 0 SUMMER = Oo FALL = 0. C SUMMER AND FALL ARE POPULATION TOTALS AT END OF EACH OF C THESE SEASONS. C %if if ifififififif^if *if if if if if ifi^ C LOOPS BEGIN HERE 1 0 0 0 CONTINUE S = 1 . C CARRY = CARRYING CAPACITY BASED ON SUCCESSION CARRY = DEER IF(EMM0R(3).GT.OoO) GO TO 1 0 0 1 DO 5 7 I = 2,13 132 57 FAWNS (I) = CONCE (I)*AAAA(I)/SERAL FAWN =0. DO 58 I = 2,13 58 FAWN = FAWN + FAWNS (I) GO TO 1003 1001 DO 59 I = 2,13 59 FAWNS(I) = AAAA(I)*C0NCE(I)*(1.-EMM0R(I))/SERAL FAWN = Oo DO 60 I = 1,13 60 FAWN « FAWN + FAWNS(I) 1003 CONTINUE SPRANG =0. DO 61 I - 2,13 61 SPRANG » SPRANG + AAAA(I) v SPRUNG =0. • . DO 62 1-15,26 62 SPRUNG = SPRUNG .+ AAAA(I) SPRING = SPRANG + SPRUNG IF(SPRINGoLEoCARRY/10. ) N = 100' C XINCR - PERCENT INCREMENT OF FAWNS C SURPLS « THE PERCENT AFTER FAWNING THAT MUST DIE IF NO C INCREASE IS TO OCCUR AAAA(l) - FAWN*RATIOF ' AAA A (14) - FAWN*RATIOM-IF(WINLSToEQo0.50) SUMMOR (1) - 0.60 IF(WINLST.EQ.0.50) SUMMOR (14) = 0.60 IF(WINLST cNE.0.50) SUMMOR (1) - FILL IF (WINLST.NE.0.50) SUMMOR (14) - BILL DO 63 I = 1,26 63 AAAB(I) - AAAA(I)*SUMMOR(I) APRING = SPRING + FAWN ZUP - NORMOR WRING SFUDGE a (ZUP/(AAAB(1) -f AAAB(2 ) + AAAB(3 ) + AAAB(4) + 1 AAAB(5 ) + AAAB(6) + AAAB(7) + AAAB(8) + AAAB(9) + 2 AAAB (10 ) + AAAB (II) + AAAB (12 ) + AAAB (13 ) + AAAB (14 ) + 3 AAAB(15) + AAAB(16) + AAAB(17) + AAAB(18) + AAAB(19) + 4 AAAB(20 ) + AAAB(21) + AAAB(22) + AAAB(23) + AAAB(24) + 5 AAAB(25 ) + AAAB(26))) DO 40 I - 1,26 40 AAXX(I)=AAAB(I)*SFUDGE DO 64 I = 1' 26 64 AABB(I)=AAAA(I)-AAXX(I) AABB (14)3=AABB(14)-AAXX(14 )*BFMOR AABB(1)=AABB(1)-AA.XX(1)*FFMOR DO 65 I - 1,26 65 IF(AABB(I).LE.AAAA(I)*.20) AABB(I)=AAAA(I)*.20 C SUMMER - NO. OF DEER JUST PRIOR TO HUNTING SUMMER - 0. • DO 67 I - 1,26 67 SUMMER - SUMMER + AABB(I) C 133 c 68 69 7 0 71 7 2 1048 18 SADRAT - THE PERCENT ADULT BUCKS IN THE POPULATION 73 74 75 76 97 77 78 C 79 C AFSUM • DO 68 AFSUM ABSUM DO 69 ABSUM SADRAT DO 70 I AADD(I) TOT = DO 71 TOT TAT -DO 72 TAT = WRITE 0 . • = 2 13 < AFSUM + AABB(I) 0 , - 15,26 ' ABSUM +.AABB(1) = ABSUM/(ABSUM + AFSUM) 1,26 AABB(I)/SUMMER Oo I » TOT Oo I -TAT (6 5,13 + AADD(I) 18,26 + AADD(I) 1048) N,SUMMER,CARRY, , v , ^ H - « y «  - , AADD (1), AADD (2 ), AADD (3 ), 1 AADD(4)ST0T,AADD(14),AADD(15),AADD(16),AADD(17),TAT, 2 SADRAT„WINMOR 12F8.0,12F8.4) FORMAT(IX,15 CONTINUE IF(N„EQolOOoAND, IF(N IF(N IF(N. IF(No IF(No IF(N. IF(No IF(No DO 73 EQ EQ, EQ, EQ EQ, EQ EQ EQ, I ,100< 100« ,100, .100, ,100, AND: AND, AND AND, AND, TIME. TIME, TIME, TIME, TIME, TIME, TIME, TIME, TIME, EQ, EQ, EQ, EQ, EQ, EQ. EQ EQ, EQ, 0 . > IX o 3. 4 o 5. ,6 o 7. 8 o GO GO GO GO GO GO GO GO GO TO TO TO TO TO TO TO TO TO 755 756 757 758 759 754 753 762 155 , 1 0 0 o AND, ,100.-AND. , 1 0 0 „ A N D , - 1 , 1 3 BA(I) - AABB{I)*EXPLOI=AABB(I)*EXPLOI*DIFF DO 74 I » 14 a 26 BA(I)=AABB(I}*EXPLOI+AABB(I)*EXPLOI*DIFF+AABB(I)*EXPLOI 1 *BUCKSE(I) ZAM - EXPLOI*SUMMER SO - 0 , - 1,26 + BA(I) ZAM/SO - 1,26 BA(I)*FUDGE - 1,26 DO 75 I SO = SO FUDGE -DO 76 I BB(I) -DO 97 I IF(BB(I).GEIAABB(I)*EXPL0I*3 DO 77 I - 1 , 2 6 IF(BB(I).GE.AABB(I)*.80) BB(I)« DO 78 I - 1 ,26 BC(I) - AABB(I)-BB(I)-BB(I)*XILKIL FALL = NO. OF DEER FOLLOWING HUNTING FALL - 0 . DO 79 I " 1 ,26 FALL = FALL + BC(I) s^s if if if if if if if if if if if :£j{< j[e # if if j[t if if if if if if sjc sj; yf if ajc if if if if if >f if if # i(fiffyif%.if%:ififif$:%:3fi!f.ifififc 0) BB(I)=AABB(I)*EXPL0I*3.0 AABB(I)*.80 134 C WINTER WEATHER C WWMEAN = MEAN WINTER TEMPERATURE TIMES FIVE WWMEAN « 199.5 C WWSTDV = STANDARD DEVIATION FOR MEAN WWSTDV = 8.692 WINWTH = WWMEAN+WWSTDV*RANDN(0.0) WW- ((WWMEAN-WINWTH)/WWSTDV) +.1, IF(WW.LEcl. ) WWKU WC= WW*(FALL/CARRY) WC-1.+WC/10. IF(FALL.IE.CARRY.OR.WW.LE.1.0) WC-1.0 C XILCH-THE PERCENT DYING ABNORMALLY, USUALLY IN WINTER XILCH=WC-lo0 WINMOR=ZILCH+XILCH IF(WINMOR.GEcO.45)M=0 IF(WINMOR.GE.0.45) SER=XSERAL*2.0 IF (SER .NE.XSERAL) SER-SER-l. SERAL - SER/XSERAL . IF(SER„NE.XSERAL) WINMOR=£ILCH+XILCH)*SERAL IF(FALL cLE.CARRY.OR.SER.EQ.XSERAL) SER =15. IF(WINM0R.GEo0.50) WINMOR = 0 . 5 0 WINLST » WINMOR GO TO 137 83 CONTINUE DO 80 I - 1,26 80 CA(I) = AABB(I)*WINKIL(I) ZIP - WINMOR*SUMMER CUP = 0.• DO 81 I 1,26 81 CUP - CUP + CA(I) FLIP = SUMMER=FALL WLIP « ZIP-FLIP WFUDGE = WLIP/CUP DO 88 I - 1,26 88 IF(WLIP.LE.OY) CA(I)-0. C CB - WINMOR SERIES C CC - NORMOR-SERIES DO 82 I = 1,26 82 CB(I) = CA(I)*WFUDGE DO 84 I ^  1,26 84 IF(CB(I).GE.BC(I)*.80) CB(I)= BC(I)*.80 DO 85 I - 1,26 85 CC(I) - BC(I)*WMOR(I) ZEP = FALL*NORMOR CAP « 0. DO 86 I - 1,26 86 CAP « CAP+CC(I) ZFUDGE=ZEP/CAP DO 87 I « 1,26 87 CC(I) - CC(I)*ZFUDGE DO 8711 I = 1,26 8711 IF(CC(I).GE.BG(I)*.-80) CC(I) = BC(I)*.80 DO 8 9 I » 1,-26 8 9 CD(I)«BX(I)*CA(I)-CC(I) DO 9 6 I - 1,26 9 6 IF(CD(I).LE.BC(I)*.10) CD(I)-BC(I)*.10 WINTER = Oo • DO 91 I = 1,26 9 1 WINTER = WINTER + CD(I) DO 9 2 I = 1,12 9 2 AAAA(I + 1)=CD(I) CD(13)»0. DO 9 3 I - 1 4 , 2 5 9 3 A AAA {I + l)-CD(I) CD(26)=Oo SPRONG =Oo DO 9 4 I = 2,13 9 4 SPRONG = SPRONG+AAA(D SPRANG » Oo • DO 95 I ^  1 5,26 95 SPRANG - SPRANG + AAA(I) SPRING - SPRONG + SPRANG IF(SPRINGoGTo2o*CARRY) M=2 IF(SPRINGoGTo3oSCARRY) M=3 IF(MoEQ„2) SERAL =2. IF(MoEQo3) SERAL = 3 ° N - N + 1 IF(N.EQ.IOO) GO TO 18 I F ( N o L T „ 1 0 0 ) GO TO 1000 7 5 5 TIME - 1 0 GO TO 6 6 6 7 5 6 TIME - 2„ GO TO 667 757 TIME « 3 o GO TO 668 7 5 8 TIME - 4 o GO TO 6 6 9 759 TIME = 5 » GO TO 670 7 5 4 TIME = 6 o GO TO 671 753 TIME = 7. GO TO 6 7 2 762 TIME = 8 . GO TO 6 7 3 155 WEATHR = WEATHR+lo TIME - 0.0 GO TO 970 154 STOP END 136 APPENDIX I I I Table 2 8 : E s t i m a t e d numbers of bucks s h o t d u r i n g days i n which r e s u l t s were not r e p o r t e d a t Northwest Bay-Sept o Oct. Nov. T o t a l 1954 1955 20 62 82 1956 6 18 24 48 1957 23 3 4 30 1958 26 20 44 90 1959 30 21 51 I960 56 28 84 T a b l e 29: Per cent s u c c e s s d u r i n g buck s e a s o n s , by month, when known, a t Northwest Bay Opening Weekend Sept.. Oct, Nov. 1954 .133 . 041 .061 .114 1955 .053 . 071 .130 1956 .064 1957 1958 .071 1959 d 2 9 .068 .111 I960 .104 .075 1961 .063 . 078 .070 1962 .072 .091 .039 .044 1963 .114 .065 .059 . 090 1964 .112 .063 .040 .048 1965 . 068 .059 .031 1966 .098 .054 .025 .037 137 Table 30: Ages and numbers of deer recorded during buck season at Northwest Bay che ck station • -Age--Class . 1_1 _L_£ hi kzl over 4<>5 unknown Total 1954 30 16 5 5 9 26 91 1955 34 6 6 2 2 60 110 1956 9 7 3 0 2 7 28 1957 9 2 0 1 0 22 34 1958 21 7 4 4 13 53 1959 27 10 7 5 12 10 71 I960 11 7 5 2 2 13 40 1961 8 1 1 2 1 39 52 1962 43 15 14 6 1 12 91 1963 79 38 16 4 4 29 170 1964 52 33 15 8 9 12 129 1965 26 23 6 5 3 10 73 1966 30 12 11 8 11 28 100 Table 31: Ages and numbers of bucks recorded during a n t l e r l e s s season at the Northwest Bay check s t a t i o n Age- Class OoJ L 111 2, 5 3.. 5 4«5 over 4 „5 unknown Total 1954 2 20 7 8 1 2 0 40 1955 23 17 19 7 5 13 33 117 1956 9 15 11 7 4 4 2 52 1957 28 23 13 7 4 4 23 102 1958 41 47 13 15 7 6 21 150 1959 35 39 10 10 6 11 18 129 I960 58 41 26 19 10 14 13 181 1961 47 27 19 24 11 13 14 155 1962 105 64 28 21 19 7 25 269 1963 86 53 34 26 9 4 23 219 1964 33 36 19 12 10 16 14 140 1965 38 32 20 10 8 10 11 129 1966 27 35 14 13 12 8 11 120 138 Table 32: Ages and numbers of does recorded during a n t l e r l e s s season at Northwest Bay check station Age-C la ss 1.5 2o_5 4.5 over 4 . 5 unknown Tot; 1954 3 12 12 7 6 10 19 69 1955 20 24 21 11 8 17 44 145 1956 12 7 3 6 6 3 3 40 1957 14 14 8 8 5 7 26 82 1958 30 30 12 13 11 17 20 133 1959 19 18 12 8 3 13 31 104 I960 51 26 16 12 7 17 14 143 1961 33 24 12 7 11 29 13 129 1962 92 31 36 48 21 20 27 275 1963* 59 31 34 11 15 19 44 213 1964* 37 42 21 13 7 21 14 155 1965* 23 26 23 11 5 15 17 120 1966 17 24 7 9 6 16 26 105 * The following number of does were taken f o r experimental pur poses (not included in the above figures 1963=64 winter: 77 does 1964=65 winter: 2 does 1965-66 winter: 8 does 139 Table 33 : Results of August counts at Northwest Bay Does Bucks Fawns Unidentified No. of Counts 1954 139 42 68 23 7 1955 1956 90 55 42 19 5 1957 79 63 50 58 4 1958 1959 29 25 21 28 6 I960 158 158 21 89 9 1961 118 94 58 43 6 1962 564 371 253 105 18 1963 104 93 40 36 7 1964 55 44 19 30 7 1965 139 65 60 59 9 1966 100 70 46 37 12 Table 34 : Results of spring counts at Northwest Bay Adults Yearlings Unidentified [ No. of counts 1955 202 93 73 9 1956 66 35 11 3 1957 128 79 69 7 1958 309 167 129 9 1959 79 25 21 4 I960 119 95 33 5 1961 80 27 12 4 1962 150 73 50 7 1963 109 81 67 11 1964 227 83 147 24 1965 127 51 49 11 1966 111 42 54 11 1967 98 40 19 7 140 T a b l e 35' T o t a l numbers o f h u n t e r s r e c o r d e d d u r i n g a n t l e r l e s s seasons a t Northwest Bay, 1954-1966 No. o f Hunters No. of Days 1954 386 4 1955 550 4 1956 471 4 1957 731 6 1958 781 6 1959 925 6 I960 986 6 1961 1213 8 1962 1971 9 1963 2171 9 1964 2195 11 1965 1900 9 1966 1583 7 

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