UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A study of the life history and population dynamics of the sooty grouse, "dendragapus obscurus fuliginosus"… Bendell, James Francis S. 1954

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1954_A1 B4 S8.pdf [ 13.98MB ]
Metadata
JSON: 831-1.0106463.json
JSON-LD: 831-1.0106463-ld.json
RDF/XML (Pretty): 831-1.0106463-rdf.xml
RDF/JSON: 831-1.0106463-rdf.json
Turtle: 831-1.0106463-turtle.txt
N-Triples: 831-1.0106463-rdf-ntriples.txt
Original Record: 831-1.0106463-source.json
Full Text
831-1.0106463-fulltext.txt
Citation
831-1.0106463.ris

Full Text

A STUDY OF THE LIFE HISTORY AND POPULATION DYNAMICS OF THE SOOTY GROUSE, DENDRAGAPUS OBSCURUS FULIGIN0SU3 (RIDGWAY)  by James F. S. B e n d e l l  A T h e s i s Submitted i n P a r t i a l F u l f i l m e n t of the Requirements  f o r the Degree o f  DOCTOR OF PHILOSOPHY i n the Department of ZOOLOGY  We accept t h i s t h e s i s as conforming t o the standard r e q u i r e d from candidates f o r the degree o f DOCTOR OF PHILOSOPHY.  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1954  ABSTRACT A population of sooty grouse (Dendragapus obscurus f u l i g i n o s u s ) has been studied on i t s summer range over the years 1950 t o 1953.  Data on moult, aging c r i t e r i a , weight  and behaviour are presented as l i f e h i s t o r y . data are u t i l i z e d i n a consideration  Some of these  of the present popula-  t i o n status o f grouse on the study area. M o r t a l i t y , p r o d u c t i v i t y , emigration and immigration, have been studied as f a c t o r s i n f l u e n c i n g population s i z e and status.  The population i s apparently s t a b l e , a r e s u l t of an  e q u i l i b r i u m between death i n the o l d e r age classes and replacement by s u r v i v i n g young.  Disease i s an important m o r t a l i t y  f a c t o r i n the chicks and a major f a c t o r a f f e c t i n g population s i z e and s t a b i l i t y .  TABLE OF CONTENTS  Page  INTRODUCTION AND LITERATURE REVIEW  1  ACKNOWLEDGMENTS  8  BASIC MATERIALS AND METHODS Time and Place o f Study F i n a n c i a l Support F i e l d Equipment and Marking Techniques Recording Techniques Autopsy Procedure Weather Records and Week Numbers Vegetational Analyses  9 9 9 9 12 12 14 15  THE STUDY AREA  18  THE SPRING AND SUMMER CLIMATE  19  THE VEGETATION AS HABITAT  21  TOPIC I  *  TOPIC I I  NATURAL HISTORY . Moult Age C r i t e r i a Weight o f Y e a r l i n g s and Adults The Spring M i g r a t i o n T e r r i t o r i a l Behaviour o f the Adult Male Sexual A c t i v i t i e s o f the Adult Male General A c t i v i t i e s o f the Adult Male Seasonal Behaviour of the Adult Male The Behaviour o f the Y e a r l i n g Male Spring M i g r a t i o n i n the Y e a r l i n g Male Spring Behaviour o f the Female Nesting Behaviour of the Female The D i u r n a l A c t i v i t y Rhythm Time o f Incubation and Hatch Behaviour o f the Female and Brood Movements o f the Female and Brood Sex Ratio and Weight Development i n the Young The L i f e H i s t o r y Study as a Basis f o r the A n a l y s i s o f Population Dynamics  29 29 32 35 36 37 43 58 59 61 63 64 68 76 80 81 86 90 92  POPULATION DYNAMICS 96 Population S i z e and Status 96 M o r t a l i t y i n the Adults 101 M o r t a l i t y Factors i n the Adults , 103 M o r t a l i t y i n the Chicks 107 M o r t a l i t y Factors i n the Chicks 117 D i s t r i b u t i o n o f Dispharynx and Plagiorhyncfcs. 128  DISCUSSION  132  SUMMARY AND CONCLUSIONS  135  TABLE OF CONTENTS (Continued) Page LITERATURE CITED  142  APPENDIX  146  1 INTRODUCTION AND LITERATURE REVIEW The study has two purposes, the f i r s t the r e c o r d i n g and i n t e r p r e t a t i o n of data p e r t i n e n t to the l i f e h i s t o r y of the sooty grouse (Dendragapus obscurus f u l i g i n o s u s ) . the second t h e u t i l i z a t i o n o f some o f these data, i n a s s o c i a t i o n with environmental f a c t o r s , t o e x p l a i n the population s t a t u s o f the b i r d a t Quinsara Lake, Vancouver I s l a n d . Most o f the l i t e r a t u r e d e a l i n g w i t h t h i s genus r e f l e c t s the e a r l y phase o f o r n i t h o l o g y - c o l l e c t , c l a s s i f y and name. U n t i l 1939, references t o the blue grouse group (genus Dendragapus) are b r i e f o r d e a l w i t h the b i r d ? s occurrence i n a c e r t a i n area. The work o f Bent (1932) i s an exception, and i n c l u d e s most o f t h e n a t u r a l h i s t o r y data on the sooty grouse u n t i l t h a t time.  I n 1940  Beer, Wing and Tidyman began a study of the blue grouse i n the s t a t e o f Washington.  T h e i r work has given us f u r t h e r i n d i c a t i o n  of the l i f e h i s t o r y o f the b i r d and p a r t i c u l a r l y data on i t s food h a b i t s , brood behaviour and growth.  From t h i s research some o f  the p a r a s i t e s of the blue grouse have been described. Fowle, i n 1942, began a study of the sooty grouse on Vancouver I s l a n d .  This work i s valuable as a survey of the l i t e r -  ature and a c o n t r i b u t i o n to the knowledge o f t h e summer food h a b i t s o f the species.  The m a t e r i a l Fowle has gathered on the  l i f e h i s t o r y , and p a r a s i t e - d i s e a s e r e l a t i o n s h i p s o f t h e b i r d serves as a f i r m foundation f o r f u t u r e work. Up u n t i l the time of w r i t i n g , S c h o t t e l i u s i s the l a t e s t report on the genus Dendragapus.  1  study of 1951  2 As w i l l be appreciated from the l i t e r a t u r e review l i t t l e has been published on the sooty grouse.  There i s value then i n  the recording and i n t e r p r e t a t i o n o f new data p e r t i n e n t to the bird's biology.  Secondly, and perhaps more important, such a  l i f e h i s t o r y study i s fundamental to an understanding of the popuin l a t i o n ecology of t h i s or any other animal.  Thus/presenting t h i s  t h e s i s i n two p a r t s , part I i s intended to f u r n i s h these b a s i c b i o l o g i c a l data or the c h a r a c t e r i s t i c s of the organism.  Some o f  these data do not r e l a t e d i r e c t l y to the a n a l y s i s of population dynamics i n part I I . They are included because of t h e i r newness and c o n t i n u i t y w i t h d i r e c t l y r e l a t e d data. Once the b i o l o g y of the organism i s understood and proper study techniques are developed i t becomes the t a s k of a student of populations to examine the f a c t o r s of the environment and f i n d t h e i r e f f e c t on animal population.  The environmental f a c t o r s might be  broadly c l a s s i f i e d as those of weather or c l i m a t i c , the food supply, space r e l a t i o n s , predators, p a r a s i t e s and disease. Uvarov (1931) suggested a c l a s s i f i c a t i o n of the c l i m a t i c f a c t o r s a f f e c t i n g the abundance of a t e r r e s t r i a l species.  Gener-  a l l y , temperature and p r e c i p i t a t i o n , wind, pressure, storms, temperature and r a i n f a l l , temperature and humidity, temperature  and  l i g h t , and food q u a n t i t y and q u a l i t y as r e l a t e d to climate are categories of weather a f f e c t i n g an animal p o p u l a t i o n .  Kendeigh  (1942) studied l o s s e s i n the n e s t i n g of 51 species of b i r d s and showed that the number of i n f e r t i l e or addled eggs produced by hens was d i r e c t l y r e l a t e d to high and low temperatures.  The number of  addled eggs produced at medial temperatures was r e l a t i v e l y low as  compared t o the temperature extremes.  As another example,  Edminster (1947) r e p o r t s the d e l e t e r i o u s e f f e c t o f a severe rainstorm on broods o f r u f f e d grouse (Bonasa umbellus). The importance o f food as a f a c t o r i n f l u e n c i n g animal populations i s obvious.  A r e l a t i o n must e x i s t between t h e  growth and w e l l being o f an i n d i v i d u a l o r p o p u l a t i o n and food supply.  On the other hand food - animal r e l a t i o n s h i p s are  among the most d i f f i c u l t t o understand.  A complexity o f  p h y s i c a l and b i o t i c f a c t o r s d i r e c t l y and i n d i r e c t l y i n f l u e n c e food q u a l i t y and quantity.  Superimposed upon t h i s s i t u a t i o n  are the food requirements o f a p a r t i c u l a r animal o r animals a t any given time i n t h e i r l i f e h i s t o r y and the c o n d i t i o n s i n f l u e n c i n g t h e i r a b i l i t y t o forage.  As an example a range may  provide abundant forage f o r the a d u l t s o f a p o p u l a t i o n but be d e f i c i e n t i n foods f o r the young.  Studies on general m a l n u t r i t i o n  Schneider et a l (1949) have shown t h a t d i e t a r y d e f i c i e n c i e s g e n e r a l l y a f f e c t host p a r a s i t e r e l a t i o n s i n favour o f p a r a s i t e s which become more abundant and more pathogenic.  Thus t h e  q u a l i t y and quantity o f food and p a r a s i t i s m might operate t o e f f e c t a host p o p u l a t i o n . An a p p r e c i a t i o n o f the e f f e c t s o f p o p u l a t i o n d e n s i t y i s fundamental t o the understanding o f p o p u l a t i o n growth and s i z e . In the case o f the f r u i t f l y Drosophila grown i n c u l t u r e , Robertson and Sang (1944) concluded that f e c u n d i t y may be reduced by crowding.  This occurred, however, o n l y when the food supply  was inadequate.  MacLagen and Dunn (1936) showed t h a t the female  4 g r a i n w e e v i l S i t o p h i l u s would not o v i p o s i t at t h e i r maximum r a t e unless more grains were present i n the c u l t u r e containers than were a c t u a l l y u t i l i z e d .  This i n d i c a t e s more niches might  be required f o r a p a r t i c u l a r animal a c t i v i t y than are a c t u a l l y used and presents a new t w i s t to animal h a b i t a t r e l a t i o n s . Crombie (1944) has shown that i n c u l t u r e s of granary i n s e c t s Rizopertha and S i t o t r o z a , crowding among the l a r v a e r e s u l t s i n competition f o r space.  This i n t u r n r e s u l t s i n f i g h t i n g ,  m o r t a l i t y from f i g h t i n g or d i s p e r s i o n . With respect to mammals, E r r i n g t o n (1939) i n a study of the e f f e c t of drought i n muskrats (Ondatra), found as t h e i r water areas diminished i n s i z e an increase i n i n t r a s p e c i f i c s t r i f e occurred which r e s u l t e d i n an increased r a t e of m o r t a l i t y or emigration from the areas of intense competition.  In b i r d s ,  Nice (1937) argues t h a t t e r r i t o r i a l behaviour can act t o l i m i t the number of a given species l i v i n g i n a p a r t i c u l a r area and as she puts i t , "cause surplus b i r d s to go elsewhere".  Thus competition  f o r space might operate to limi^e( animal and p a r t i c u l a r l y b i r d populations i n a given area.  ^  On the other hand from the work of  Johnson (1941) on the a t l a n t i c murre (Uria aalge) crowding seems a n e c e s s i t y f o r reproduction.  Crowding r e s u l t e d i n f i g h t s which  seemed to i n t e n s i f y the d r i v e to incubate r a t h e r than vanquish a neighbour as a competitor f o r space. Predation, whether by animal or man i s g e n e r a l l y considered as a f a c t o r capable of a f f e c t i n g the p o p u l a t i o n status of a given prey species.  As an example, Foerster and R i c k e r (1941)  removed four important predators of the sockeye salmon (Oncorhynchus  5  nerka) i n Cultus Lake B r i t i s h Columbia.  With the r e d u c t i o n of  the predator populations there was a corresponding increase i n s u r v i v a l of immature sockeye salmon.  The increase of the prey  was a t t r i b u t e d d i r e c t l y to the planned r e d u c t i o n of the predators. L. Tinbergen (1946) i n an important study of predation by the European sparrow hawk ( A c c i p i t o r nisus) on the house sparrow (Passer domesticus), the c h a f f i n c h ( F r i n g i l l a c o e l e b s ) , the great t i t (Parus major), and the c o a l t i t (Parus a t e r ) concluded t h a t the sparrow hawks caused approximately 50% of the summer m o r t a l i t y f o r t h e house sparrow, 25% f o r the c h a f f i n c h and great t i t s and n e g l i g i b l e percentage f o r the c o a l t i t s . ton  On the other hand, E r r i n g -  (1937a) admits the removal of prey species by predators, but  suggests p r e d a t i o n i n general i s e s s e n t i a l l y a "by-product of population r a t h e r than a broadly dominant i n f l u e n c e on p o p u l a t i o n " . The a t t a c k s of p a r a s i t e s and disease i n an organism o f t e n r e s u l t i n i t s death.  A f a m i l i a r example i s the r e s u l t o f  besubonic plague i n Europe.  P a r a s i t e host r e l a t i o n s have been a  p r o f i t a b l e f i e l d f o r mathematical t h e o r i s t s , and s e v e r a l schemes of p a r a s i t e host i n t e r a c t i o n have been proposed as by Nicholson and B a i l e y (1935), Lotka (1934), V o l t e r r a (1926), and o t h e r s . Generally s e v e r a l t h i n g s might happen i n these i n t e r a c t i o n s , but of i n t e r e s t here i s the c o n c l u s i o n t h a t p a r a s i t e s can t h e o r e t i c a l l y c o n t r o l host numbers.  This has been the experience of workers  i n the f i e l d of pest i n s e c t c o n t r o l where introduced or indigenous p a r a s i t e s are capable of c o n t r o l l i n g host populations.  Parasites  are r e g u l a r l y found i n n a t u r a l v e r t e b r a t e populations yet t h e i r r o l e as a f a c t o r i n p o p u l a t i o n c o n t r o l has seldom been demonstrated.  6  Dymond (1947) considers disease as a n o n - s p e c i f i c f a c t o r capable of i n f l u e n c i n g population d e c l i n e .  In the B r i t i s h I s l e s ,  the Committee of Enquiry on Grouse Disease  (1900) has  a t t r i b u t e d " d i e o f f " i n the red grouse (Lagopus acoticus) to an i n t e s t i n a l protozoan o c c u r r i n g i n the chicks and on i n t e s t i n a l nematode o c c u r r i n g i n the a d u l t s .  Clarke (1937) considered  the  blood p a r a s i t e Leucocytozoon a l i k e l y f a c t o r causing c y c l i c d e c l i n e i n the r u f f e d grouse (Bonasa umbellus) i n Ontario.  Green,  Larson and B e l l (1939) stressed the importance o f shock disease as a f a c t o r capable o f decimating hare (Lepus americanus) populations.  With these examples then, there i s a b a s i s f o r  considering p a r a s i t i s m as a p o s s i b l e f a c t o r o f importance i n the c o n t r o l of vertebrate populations. The environmental  f a c t o r s i n v o l v i n g the e f f e c t of  climate on an organism are g e n e r a l l y considered as d e n s i t y independent.  That i s to say, they remove animals from the popula-  t i o n i r r e s p e c t i v e of t h e i r abundance.  The environmental f a c t o r s  i n v o l v i n g the e f f e c t s of space r e l a t i o n s h i p s , food, predators, p a r a s i t e s and disease are g e n e r a l l y considered as d e n s i t y dependent.  Such f a c t o r s a f f e c t animals i n the population i n proportion  to t h e i r abundance.  Changes i n population growth form or s i z e  are obviously caused by both p h y s i c a l and b i o t i c f a c t o r s , such as c l i m a t i c extremes i n one case, and food supply i n the other. However, Nicholson (1933) and Smith (1935) contend l a r g e l y on t h e o r e t i c a l grounds that d e n s i t y independent f a c t o r s operating alone cannot determine and maintain an average population density over a long period of time.  As an approach t o the study o f an animal p o p u l a t i o n the phenomena of m o r t a l i t y , n a t a l i t y and d i s p e r s a l can be considered as the response o f the organism t o a p a r t i c u l a r o r p a r t i c u l a r set o f environmental circumstances. The response can be measured i n terms of p o p u l a t i o n growth form.  The environmental  f a c t o r s climate, food, space, predators, p a r a s i t e s and disease can be considered as the causes a f f e c t i n g the response o f the organism i n terms o f t h i s population growth form.  Thus i t  becomes a problem to the student o f p o p u l a t i o n dynamics to f i n d the status o f a p a r t i c u l a r animal p o p u l a t i o n and t h e n to e x p l a i n how the environmental f a c t o r o r f a c t o r s are o p e r a t i n g on the m o r t a l i t y , n a t a l i t y and d i s p e r s a l of the animal to produce i t s observed p o p u l a t i o n s t a t u s .  This i s attempted i n a consider-  a t i o n o f the p o p u l a t i o n dynamics of the sooty grouse at Quinsam Lake.  8 ACKNOWLEDGMENTS Many persons have c o n t r i b u t e d time and e f f o r t t o t h i s study, and t o them the author i s deeply indebted.  Dr. I . McT.  Cowan and Dr. J.R. Adams have been c h i e f a d v i s e r s .  Dr. Adams  has i d e n t i f i e d most o f the p a r a s i t e s mentioned i n the t e x t and i s continuing with t h i s phase o f the work.  Mr. G.J. Spencer has  i d e n t i f i e d l i c e c o l l e c t e d as probably Lagopoceus obscurus and the louse f l y Ornithomyia f r i n g i l l i n a . while Mr. G.P. Holland o f Science S e r v i c e , Ottawa, i d e n t i f i e d the f l e a Ceratophyllus diffinis.  Dr. P.A. L a r k i n has s u f f e r e d interminable d i s c u s s i o n s  of the problem as have my colleagues o f hut M-30. The shortcomings of t h i s work i n no way r e f l e c t s upon them. In the f i e l d , the a s s i s t a n c e of,my a d v i s e r s , Mr. D.J. Robinson and Mr. R.S. Hayes o f the B.C. Game Department, Mr. P. Seaton, Mr. D a r r y l Rye and Mr. T. Hagemeier, i s g r a t e f u l l y acknowledged.  Weather recording equipment was k i n d l y loaned  through Dr. L. Robinson o f the Dept. o f Geography, U.B.C., while some camping gear was provided by the B.C. Game Dept. through Dr. J . Hatter.  Mr. H. Laing o f Comox granted permission t o use  h i s s u p e r l a t i v e telephoto p i c t u r e s o f male grouse i n F i g . 16 and 20.  Mr. E. H a r r i s a t Queen's U n i v e r s i t y , Kingston, copied and  photographed the drawings presented i n the t e x t .  F i n a l l y , I am  most pleased t o acknowledge the a s s i s t a n c e o f my w i f e who i n the f i e l d and l a b o r a t o r y phases o f the study assumed t h e s t a t u s o f a co-worker.  9  BASIC MATERIALS AND METHODS Time and Place of Study F i e l d work began i n June, 1950, at Quinsam Lake on Vancouver I s l a n d .  In the middle of August the w r i t e r l e f t  this  area and spent two weeks at Bald Mountain Game Reserve at Cowichan Lake.  A two day v i s i t was made to the Quinsam area i n  March of 1951 but i t was not u n t i l May t h a t the study was resumed at Quinsam Lake and continued throughout the summer u n t i l the f i r s t week i n August.  F i e l d work began again i n A p r i l 1952  as i n the previous year terminated e a r l y i n August.  and  I n 1953 the  study area was v i s i t e d i n June and J u l y to provide a d d i t i o n a l data on the r e t u r n of banded birds and o b t a i n an estimate of population s i z e f o r t h a t year.  During i n t e r v e n i n g p e r i o d s , data  were analyzed i n the Department of Zoology at the U n i v e r s i t y of B r i t i s h Columbia and i n 1952 at Queen's U n i v e r s i t y , Kingston, Ontario. F i n a n c i a l Support F i e l d work was supported i n the f i r s t year by an N.R.C. g r a n t - i n - a i d and the B.C.  Game Department.  Council financed the study t h e r e a f t e r .  The N a t i o n a l Research  During the u n i v e r s i t y a  sessions of 1950 and 1951 the w r i t e r held/Research C o u n c i l of Ontario s c h o l a r s h i p . T h i s , and f a c i l i t i e s provided by the Universi t y of B r i t i s h Columbia made the l a b o r a t o r y phase of the work possible. F i e l d Equipment and Marking  Techniques  Observations i n the f i e l d were made i n most part w i t h a 6 X 30 b i n o c u l a r . T h i s , along w i t h r e c o r d i n g m a t e r i a l s , compass,  10 noose and pole, puncture needles, microscope  slides,  banding  and marking k i t , c o l o u r bombs, S a h l i haemometer k i t , 2,000 gramme s c a l e , r u l e , a wool sock, shotgun, coloured s h i p p i n g tags and s e v e r a l l a r g e paper bags made up the f i e l d equipment. In work i n v o l v i n g the r e c o g n i t i o n of animals good capturi n g and marking techniques are o f inestimable value.  Grouse of  both sexes and a l l ages were captured by means of a simple noose and pole device which could be placed over t h e i r heads and then pulled taut.  The noose and pole consisted of a ten t o eleven  f o o t bamboo cane, w i t h a loop of black house f i x t u r e wire at the t h i n end.  The loop passed through two e y e l e t t e s and then as a  s i n g l e strand c a r r i e d to the base of the pole. I n c l e a r i n g s where males and females congregate, d r i v e nets were used w i t h some success.  These were simply o l d f i s h nets  strung across the c l e a r i n g on 6 foot stakes.  Behind the mouth  of the nets the mesh was staked to the ground p e r m i t t i n g a long sag between f r o n t and back.  Grouse were d r i v e n i n t o the n e t s , and  i n moving i n t o the mesh, became pinned by the long sag.  The netting  arrangement was too cumbersome to use beyond open c l e a r i n g s . Once captured, a grouse was held i n the wool sock, blood smeared, weighed, examined, marked and f i n a l l y before r e l e a s e the two outer t a i l r e t r i c e s were plucked f o r l a t e r use as age i n d i c a tors.  Each b i r d so handled was given a number corresponding to a  numbered aluminum B r i t i s h Columbia Game Department band placed on one l e g .  In a d d i t i o n , a coloured c e l l u l o i d band or bands were  placed on the other l e g so t h a t each b i r d could be i d e n t i f i e d i n  11 the f i e l d on subsequent contact.  To f u r t h e r f a c i l i t a t e t h i s  r e c o g n i t i o n , a b r i g h t l y coloured p l a s t i c square was a f f i x e d t o the t a i l o f each captured b i r d .  I n some cases a small b e l l was  a p p l i e d t o t h e l e g by threading the aluminum band through a c l a s p at  the back o f the b e l l . One marking method t h a t worked w e l l on b i r d s which con-  s t a n t l y evaded capture was a simple ink bomb technique. ink,  Printer's  a carbon substance o f b r i g h t colour and i n s o l u b l e i n water,  was d i s s o l v e d i n naphtha g a s o l i n e as 1 part i n k t o 2 p a r t s f l u i d . This s o l u t i o n was poured i n t o g l o b u l a r Christmas t r e e decorations approximately 3 inches i n diameter, and the decorations then sealed with a f i t t e d No. 5 cork.  This i s an improvement over Bendell and  Fowle's (1947) method i n which domestic hen's eggs were used as the container.  Best r e s u l t s were obtained when the bomb was  h u r l e d a t a b i r d crouched behind a t r e e o r shrub.  I n these  cases  the s h a t t e r i n g o f the bomb i n the v e g e t a t i o n created a spray o f ink which almost covered the b i r d .  Red, blue, orange, green and y e l l o w  i n k s were found best, and w i t h these c o l o u r s , and v a r i o u s regions o f the animal i n a d v e r t e n t l y inked, many d i s t i n c t i v e l y marked b i r d s were obtained.  The i n k remained f a s t throughout the summer and,  as i n the case o f the t a i l cards, was l o s t only i n the subsequent f a l l moult o f the f e a t h e r s . In 1952, tagging w i t h r a d i o a c t i v e wing c l i p s was t r i e d as a device t o l o c a t e n e s t i n g hens and cocks on t e r r i t o r i e s when not a c t i v e l y c a l l i n g o r hooting.  For t h i s experiment standard  p o u l t r y wing c l i p s were sent t o N.R.C. a t Chalk R i v e r where they  12 were hollowed and f i l l e d w i t h Rubidium 86 o f 0.5 mc. a c t i v i t y and a h a l f l i f e o f 19.5 days.  The procedure was t o capture, t a g , and  release n e s t i n g hens when they were feeding i n c l e a r i n g s and then to f o l l o w t h e i r l i n e o f f l i g h t with a Geiger counter u n t i l a nest was l o c a t e d by v i r t u e o f i t s r a d i o a c t i v i t y .  The technique  failed  to l o c a t e hens on nests, but succeeded w i t h respect t o l o c a t i n g a s i l e n t cock.  I n a b i l i t y t o detect r a d i a t i o n over 10 f e e t from the  source i s f e l t t o be a major cause o f f a i l u r e i n the case o f the hens. Recording Techniques A f t e r a b i r d had been marked i n the f i e l d by bands o r otherwise, the point o f i n i t i a l o r subsequent observation was surveyed.  This l o c a t i n g o f the point was done by t a k i n g compass  bearings on p r e v i o u s l y erected f l a g s o r markers placed about t h e study area.  L a t e r , i n the l a b o r a t o r y , simple t r i a n g u l a t i o n placed  the f i e l d p o s i t i o n a c c u r a t e l y on l a r g e s c a l e maps.  I n most cases  a b r i g h t l y coloured p a r a f f i n coated s h i p p i n g tag was t i e d t o the nearest t r e e o f height t o permit easy r e t u r n t o a p a r t i c u l a r p o i n t , which i n each case had i t s own time and date. A l l observations made i n t h e f i e l d were l a t e r coded i n t o a f i l i n g and punch card system.  This permitted r a p i d c l a s s i f i c a t i o n  and compilation o f data f o r a n a l y s i s and i n t e r p r e t a t i o n .  These  data and methods o f handling them w i l l be mentioned again i n l a t e r sections. Autopsy Procedure When a b i r d was c o l l e c t e d i n the f i e l d t h e p o i n t where taken was recorded as above.  The carcass was placed i n a paper  13 bag and brought to the laboratory f o r examination and autopsy. This included examination o f the bag and b i r d f o r e c t o p a r a s i t e s and moult, a weight r e c o r d , removal o f t a i l f e a t h e r s for age c r i t e r i a , a smear o f heart blood, examination o f the coelome and body organs f o r a b n o r m a l i t i e s , examination and volumetric measurement o f the l i v e r , spleen, t e s t e s o r o v a r i e s f o r disease and sexual c o n d i t i o n , and f i n a l l y the examination o f the crop, stomach and gut f o r food m a t e r i a l s and macroscopic p a r a s i t e s .  A l l chicks  c o l l e c t e d were skinned so that plumage development might be described i n d e t a i l a t a l a t e r date.  I n 1951 and 1952 the complete  d i g e s t i v e t r a c t s were bundled i n cheesecloth and immersed i n 10 per cent f o r m a l i n .  They were l a t e r examined i n the u n i v e r s i t y  laboratory. Other than three gut smears made i n 1950 and the examination o f 50 droppings c o l l e c t e d a t random over the study area, no search was made f o r i n t e s t i n a l m i c r o p a r a s i t e s . Data on grouse movements, weight, plumage, p a r a s i t e s and hunter success i n k i l l i n g grouse were supplemented by m a t e r i a l obtained a t the B r i t i s h Columbia Game Department annual road check of hunters a t Campbell R i v e r .  Hunters were stopped, questioned  as t o l o c a l i t y hunted, t h e i r bags examined, and i n some cases weights, blood smears and v i s c e r a were obtained.  This source o f  data was tapped by the author i n September o f 1950 and 1951. Blood smears were f i x e d i n absolute a l c o h o l , then stained i n stock Geimsa d i l u t e d 1 part dye t o 10 p a r t s d i s t i l l e d water. Each smear was examined under o i l immersion f o r Haemoproteus and then under low power f o r Leucocytozoon Trypanosoma and M i c r o f i l a r i a . A s l i d e was searched f o r one quarter hour before being designated  as negative.  14 Q u a n t i t a t i v e estimates o f i n f e c t i o n l e v e l s i n t h e  case o f Haemoproteus and Leucocvtozoon were made w i t h the a i d o f a Whipple counting d i s c on the b a s i s o f random counts o f 1,000 red blood c e l l s .  Estimates o f haemoglobin l e v e l s and number o f  r.b.c. per cu. mm. o f blood were made i n the f i e l d and l a b o r a t o r y . The S a h l i haemometer and the Spencer bright l i n e counting chamber and blood p i p e t t e s were used f o r these purposes. Ecto and endoparasites when discovered were placed i n p h i a l s o f 10$ f o r m a l i n and submitted t o the Department o f Zoology at U.B.C. f o r i d e n t i f i c a t i o n .  Some were sent t o Science Service  at Ottawa, others were i d e n t i f i e d by the author. Weather Records and Week Numbers A standard Stevenson screen equipped w i t h a r e c o r d i n g thermograph, hygrograph, Piche evaporimeter and maximum and minimum thermometer was used t o o b t a i n weather data.  Rainfall  was measured w i t h a standard U.S. Weather Bureau r a i n gauge. To estimate d u r a t i o n o f r a i n f a l l d a i l y records were kept i n which r a i n f a l l was expressed as a f r a c t i o n o f a 24 hour p e r i o d . r a i n from midnight t o noon would be one h a l f day's r a i n .  Thus Weather  data are t r e a t e d as weekly averages w i t h the exception o f d u r a t i o n of r a i n which i s a weekly sum. In the a n a l y s i s o f weather records and other data t o be met i n the t e x t i t was convenient t o d i v i d e the study p e r i o d i n t o weeks and a s s i g n each week a number.  A p r i l the 13th, the e a r l i e s t  date o f c o n s i s t e n t f i e l d work, i s the a r b i t r a r i l y chosen beginning of the s e r i e s .  I t and subsequent dates are included below.  15 Week o r Period  Date A p r i l 13 20 27  _  -  19 26 3 May  1 2 3  May  4 11 18 25  _  10 17 24 31  4 5 6 7  1 8 15 22 29  -  June  July  6 13 20 27  August  3 10 17  —  -  —  7 14 21 28 5 July  8 9 10 11 12  — -  12 19 26 2 August  13 14 15 16  —  9 16 23  17 18 19  —  _  -  V e g e t a t i o n a l Analyses A f t e r f a m i l i a r i t y w i t h the vegetation was "obtained i n 1950, i t was a r b i t r a r i l y c l a s s i f i e d i n t o 6 major types on the b a s i s of s h e l t e r value.  The l i m i t s o f each type were mapped on a s c a l e  of 1 i n c h t o 50 f e e t i n two 36 acre sample p l o t s .  This was done  by surveying the edges o f the various types w i t h compass and tape. Compass bearings were then taken from the map i n v a r i o u s vegetat i o n a l types and c a r r i e d to the f i e l d .  The v e g e t a t i o n was sampled  along these bearings by yard quadrats at t e n f o o t i n t e r v a l s and 100 foot l i n e i n t e r c e p t method.  Sampling was done a t the height  of v e g e t a t i o n a l growth. The i n t e r c e p t method was found s a t i s f a c t o r y f o r r a p i d measurement of s h e l t e r value i n the case of t r e e s , shrubs, l o g s ,  16 stumps and herbaceous v e g e t a t i o n such as bracken ( P t e r i s ) • In most cases t h i s s h e l t e r v e g e t a t i o n serves as food species, thus i t was i n c l u d e d i n the quadrat samples designed to i n c l u d e grouse food p l a n t s of l e s s e r s i z e and greater abundance such as h a r e s  1  ear (Hypochaeris) and s a l a l ( G a u l t h e r i a ) .  The value  of a plant as grouse food was taken from f i e l d observation and the s t u d i e s of Beer (1942, 1948) Fowle (1944) and o t h e r s .  In  t h i s treatment of the v e g e t a t i o n approximately h a l f the p l a n t species o c c u r r i n g i n the quadrat samples have been omitted. The s h e l t e r value of a p l a n t species was measured as the amount of l i n e i n t e r c e p t or quadrat i t covered at ground level.  The samples were averaged and expressed as a percentage  shelter value.  Food p l a n t s were sampled f o r amount o f ground  covered, frequency of occurrence and abundance.  For ease of  comparison these data were averaged, converted to a percentage and expressed i n rankings of cover and frequency a f t e r Oosting (1948) as: 1 - l e s s than 5$ o f the ground covered 2 - 5 to 25$ » n n n 3 - 25 to 50$ " " " " 4 - 50 to 75% n n n it 5 - 75 to 100$ « !« n n A - the species occurred i n 1 - 20$ of the quadrats B - " » " 21 - 40$ " " " C - " " " " 4 1 - 60$ " " " D-" " " 6 1 - 80$ " " " E - " " " " 8 1 - 100$ " " V n  n  Abundance o f a p l a n t species was measured as the average number of a given species o c c u r r i n g per quadrat. I d e n t i f i c a t i o n of p l a n t s has i n most cases been made by the author.  Representative c o l l e c t i o n s are at hand and w i l l  be preserved i n the herbarium of the Department of Botany,  17 U n i v e r s i t y o f B r i t i s h Columbia and t h e Department o f Botany, U n i v e r s i t y o f Toronto, One purpose o f the v e g e t a t i o n a l a n a l y s i s was t o enable a c o r r e l a t i o n between the p o s i t i o n s i n which grouse were observed and v e g e t a t i o n a l type.  To do t h i s t h e amounts o f each  cover type on the two study p l o t s were rated as a proportion o f unity.  The r e l a t i v e value o f each type was then d i v i d e d i n t o  the t o t a l number o f grouse observations made i n t h a t t y p e , t o produce a f i g u r e o f grouse u t i l i z a t i o n , expressed as a percentage of t o t a l s i m i l a r observations made i n a l l cover types.  This  c a l c u l a t i o n made comparable, values o f grouse u t i l i z a t i o n f o r each v e g e t a t i o n a l type o c c u r r i n g i n the study p l o t s .  18 THE STUDY AREA The study area i s s i t u a t e d near Quinsam Lake on an undulating coast p l a i n t h a t slopes east from a height of 600 f e e t t o sea l e v e l a t t h e s t r a i t s o f Georgia, F i g . 1.  To t h e  west and southwest the land continues t o r i s e i n t o the I s l a n d mountain ranges.  The c i r c l e i n F i g . 1 represents the approximate  range of the author, who observed, caught and c o l l e c t e d grouse over t h i s area.  I t i s c a l l e d the study area.  The squares I  and I I are two sample p l o t s o f 36 acres surveyed and blazed i n 1951.  On these, grouse and v e g e t a t i o n were s t u d i e d i n d e t a i l  and from here stems most o f the data on behaviour and population size.  They are c a l l e d p l o t I and I I . P l o t I I I was e s t a b l i s h e d  i n 1951 and i s an area where males were shot, t o experiment w i t h m i g r a t i o n and behaviour. The study area overlaps the r e g i o n studied by Fowle i n 1943.  This was close to the north and south banks of t h e  Quinsam R i v e r at Quinsam Lake.  The high incidence o f blood  p a r a s i t i s m he found here, coupled w i t h h i s b e l i e f t h a t the area was apparently optimum summer grouse range, i n f l u e n c e d the d e c i s i o n t o continue research i n t h i s l o c a l i t y .  19  THE SPRING AND SUMMER CLIMATE The elimate was recorded to study i t s e f f e c t upon grouse behaviour and the s u r v i v a l of young, e s p e c i a l l y i n the week o f , and a f t e r , hatch.  The data are expressed g r a p h i c a l l y  i n F i g . 2, from Table I appended. Generally, 1950, from the l i m i t e d amount of data a v a i l a b l e f o r t h a t year, was intermediate to 1951  and 1952 w i t h  respect to maximum weekly temperatures and days of r a i n .  1951  was a r e l a t i v e l y warm summer w i t h l i t t l e r a i n and associated high r a t e s of evaporation.  No r a i n f a l l was recorded a f t e r the  13th week or J u l y 6th and t h i s was general i n the Campbell R i v e r area f o r at t h a t time f o r e s t closure was enforced by the B r i t i s h Columbia Forest S e r v i c e .  1952 was recorded as r e l a t i v e l y c o o l  and wet through s p r i n g and i n t o e a r l y summer as compared to 1950 and 1951.  Minimum and maximum temperatures were at t h e i r  lowest u n t i l August of that year, w h i l e the greatest amount of r a i n , days of r a i n , and lowest r a t e s of weekly evaporation were recorded up u n t i l t h a t month.  I n August of 1952 l i t t l e  rain,  high temperatures, and high rates of evaporation r e s u l t e d i n another general f o r e s t c l o s u r e . Thus of the t h r e e , 1950 was the only year with a r e l a t i v e l y c o o l moist August without f o r e s t closure. w  i t h respect t o the e f f e c t of climate on the s u r v i v a l of  young (to be discussed below) the week of hatch June 15 to 21 (p.  BO) and two weeks t h e r e a f t e r are assumed c r i t i c a l .  Over t h i s  period the three years provide a valuable c o n t r a s t . This i s  1951  1950  u. 90  1952  o  280  n  Y]  3  |70  u  IT  E  <u " 60 50 o 2 40 >'  4  L  u i r  J  I I I L J I I I I 1I L  J I \L  J  II L  . 4 -  i  3  o -2 h a. _n  JI I I I I I I I I L  j IiI L  J l_  J I L  J I l_  J 1 L  4-  c 5  3-  a •a  1  2 -  •  o  ir J I L  J L  J II L  n  10 o  8 "  £ o >  6  11 10  Fig. 2  14  18  from Table I.  n  _l I I I I I I L 6  10  L r u Ln -I 1 1 I l_U I 1—1 L  14 18 2 6 10 14 18 Week of study Weolher data and week of study, 1950, 1951, 1952.  19 THE SPRING AND SUMMER CLIMATE The climate was recorded to study i t s e f f e c t upon grouse behaviour and the s u r v i v a l of young, e s p e c i a l l y i n the week o f , and a f t e r , hatch.  The data are expressed g r a p h i c a l l y  i n F i g . 2, from Table I appended. Generally, 1950, from the l i m i t e d amount of data a v a i l a b l e f o r t h a t year, was intermediate to 1951 and 1952 w i t h respect to maximum weekly temperatures and days of r a i n .  1951  was a r e l a t i v e l y warm summer w i t h l i t t l e r a i n and a s s o c i a t e d high r a t e s of evaporation.  No r a i n f a l l was recorded a f t e r the  13th week or J u l y 6th and t h i s was general i n the Campbell R i v e r area f o r at t h a t time f o r e s t closure was enforced by the B r i t i s h Columbia Forest S e r v i c e .  1952 was recorded as r e l a t i v e l y c o o l  and wet through s p r i n g and i n t o e a r l y summer as compared to 1950 and 1951.  Minimum and maximum temperatures were at t h e i r  lowest u n t i l August of that year, w h i l e the greatest amount of r a i n , days of r a i n , and lowest r a t e s of weekly evaporation were recorded up u n t i l t h a t month.  I n August of 1952 l i t t l e  rain,  high temperatures, and high r a t e s of evaporation r e s u l t e d i n another general f o r e s t c l o s u r e . Thus of the t h r e e , 1950 was the only year w i t h a r e l a t i v e l y c o o l moist August without f o r e s t closure. ^ith  respect t o the e f f e c t of climate on the s u r v i v a l of  young (to be discussed below) the week of hatch June 15 to 21 (p.  80) and two weeks t h e r e a f t e r are assumed c r i t i c a l .  Over t h i s  period the three years provide a v a l u a b l e c o n t r a s t . This i s  20  summarized i n the f o l l o w i n g t a b l e : Weather week 10 to week 12, 1950, 1951, 1952 • 1950  :  Av. Minimum temperatures, °F.:  1951  :  1952  52, 53,!• 43, 51, 49,  >  -  Av. R a i n f a l l , c.c.  :  T o t a l Day's r a i n  ::1, 2.5, 0  Av. Evaporation, c.e.  :  ! °' ! °'  .1, .1,  o,  .1/  0,  2,!:2.5, 2,  4,  7.:''4,  3.  ! l 2 , 11,  5,  Thus from the 3 year's records i n the c r i t i c a l c h i c k period, 1952 was cooler by 8 degrees, wetter by .2 c.c. o f r a i n that was prolonged over a period of 6 more days than 1951 and 5 more than 1950. F i n a l l y t h e evaporation r a t e over t h i s period i n 1952 was 18 c.c. l e s s than i n 1951.  21  THE VEGETATION AS HABITAT Mountain f o r e s t s of douglas f i r (Pseudotsuga f o l i a ) are the primaeval h a b i t a t of the sooty grouse.  taxiFrom  here they descend i n the s p r i n g to mountain meadows and more sparsiey wooded lowlands and breed, Bent (1932).  According to  B.C. Forest Service records, the Quinsam study area p r i o r to 1925 was mature f o r e s t of douglas f i r , western hemlock (Tsuga heterophylla) and western red cedar (Thuja p l i c a t a ) .  As such,  i t must have been u n s u i t a b l e breeding range f o r the sooty grouse. A f t e r 1925,  l i k e much of the east coast of Vancouver  I s l a n d , the Quinsam area was r a p i d l y logged, and i n the process burned.  There are records of l o g g i n g and burning i n the study  area i n 1927 and 1929.  F i n a l l y , i n 1933, a severe f o r e s t f i r e  swept 74,500 acres of logged and mature timber from Menzies Bay on the n o r t h , thence i n a swath two miles i n width to Courtenay on the south. edge of t h i s burn.  In F i g . 1 the l i n e represents the western  I n f o r e s t r y records; f i r e #230, B l o e d e l ,  Book 1936-41. Residents of t h i s area r e p o r t sooty grouse on the Quinsam range p r i o r t o 1938.  E v i d e n t l y w i t h the c l e a r c u t t i n g of timber  and subsequent burning, the r e g i o n had become s u i t a b l e summer range f o r grouse which over-wintered i n the higher timbered slopes.  What e f f e c t i f any the 1938 f i r e had on the Quinsam  breeding population i s unknown, but by 1943 the area was i n a c o n d i t i o n t h a t Fowle (1944) c a l l e d apparent optimum summer range f o r the species.  He a c c r e d i t e d t h i s t o the abundance of p l a n t and  22 i n s e c t food f o r the a d u l t s and c h i c k s . In an attempt t o f u r t h e r understand the summer h a b i t a t r e l a t i o n s of the sooty grouse i n the present stages of p l a n t succession at Quinsam Lake, the vegetation was  arbitrarily  c l a s s i f i e d i n t o 6 major s h e l t e r t y p e s , mapped on p l o t s I and I I , and described. The v e g e t a t i o n a l types once recognized were then c o r r e l a t e d w i t h grouse d i s t r i b u t i o n and a c t i v i t y to d i s c o v e r t h e i r utilization. Each s h e l t e r type was given a name a f t e r i t s dominant s h e l t e r species as f o l l o w s : F i r Dense  F.D.  Willow Dense  W.D.  F i r Open  F.O.  Willow Open  W.O.  Bracken Open  B.O.  Log Open  L.O.  The s h e l t e r types o c c u r r i n g on p l o t I are r e p r e s e n t a t i v e s of n a t u r a l burn succession, i . e . , Log Open, Bracken Open, Willow Open and Willow Dense.  These types occur on p l o t I I but here the  n a t u r a l p a t t e r n of succession has been a l t e r e d by l a r g e scale r e p l a n t i n g of the area and thousands of acres l i k e i t , by the B r i t i s h Columbia Forest S e r v i c e . While douglas f i r occurs r a r e l y i n unplanted areas, i n planted areas i t i s a major element of the vegetation and t h e r e f o r e i s i n c l u d e d i n the s h e l t e r type c l a s s i f i c a r t i o n as F i r Dense and F i r Open. A s t a t i s t i c a l d e s c r i p t i o n of the s h e l t e r types i n terms of ground covered and the amount of each type o c c u r r i n g on the two study p l o t s i s presented i n Table I I . The s h e l t e r value of each type i s expressed g r a p h i c a l l y i n Fig..3 from Table I I .  TABLE I I Ground covered by s h e l t e r p l a n t s i n percent. S h e l t e r type  F i r Dense  Number o f 100 f t . samples  F i r Open  Willow Dense  5  7  S h e l t e r component  Av. Range  Av. Range  Pseudostuga  S3  75-90  34  11-51  -  S a l i x spp.  3  1-6  2-8  82  Alnus oregona  -  -  4 3  0-21  -  Logs and stumps  6  5-9  12  6-21  11  2-28  Pteris aquilina  35  11-60  26  13-36  -  1-5  -  -  13  1  1-8  1  0-2  taxifolia  Lupinus spp. Vaccinium p a r v i f l o r u s Rubus p a r v i f l o r u s  -  -  Willow Open  5 Av. Ran^e  8  0-38  Log Open  10  8  4 Av. Range  56-100  Bracken Open  Av. Range  -  Av. . Range 2  0-7  50  33-66  5  2-13  2  1-7  1  0-5  4  0-30  1  0-1  8  4-13  10  4-40  15  2-41  42  31-56  42 21-63  13  3-28  1  0-2  -  -  19  0-68  -  -  -  5  0-23  5  0-28  Amount of each s h e l t e r type on p l o t I and I I i n percent Plot I  0  0  27  30  23  18  Plot I I  7  66  10  1  5  s  Fir  Dense  Fir Open  P. toxitolia Solix spp. A. oregona Logs and stumps1s> P. aguilina  ,  a)  Lupinus spp. V. parviflorus R parviflorus Willow Dense  P. tOlifoliO Solix spp. ^ ^ A. oregona Logs and stumpsfvX^  ^  Willow Open  ^  P. aguilina Lupinus spp. V. parviflorus R. parviflorus Bracken Open  Log  Open  P. taxi folia Salix spp. A. oregona Logs and stumps P. aguilina Lupinus spp. V. parviflorus R. parviflorus  0 Fig.  Average amount of ground covered in percent 3  from Table H Average amount of ground covered in percent by shelter plants in each of the six shelter types  24 Generally, although d i f f e r e n t i n plant component, F i r Dense, F i g . 4(a) and Willow Dense, F i g . 4(c and d) are s t r u c t u r a l l y a l i k e i n terms of average amount or percentage of ground covered by f o l i a g e and stems.  In the same way, F i r Open, F i g . 4(b) i s  s i m i l a r to Willow Open, F i g . 4(e and f ) , p a r t i c u l a r l y i n June and l a t e r summer when bracken reaches i t s maximum growth and c o n t r i butes to the shrub l a y e r . Bracken Open, F i g . 4(g and h) i s a s h e l t e r type i n which bracken, along w i t h l o g s and stumps i s the s o l e s h e l t e r species present.  On dry s i t e s bracken i s l o o s e l y a s s o c i a t e d as i n  F i g . 4 ( g ) i w h i l e on moist s i t e s i t forms a dense stand almost completely covering the ground, F i g . 4 ( i ) . In such cases l u p i n o c c a s i o n a l l y appears and may i n some cases dominate the bracken as i n F i g . 4 ( j ) .  This stand i s t r a n s i t o r y , however, and by e a r l y  August the bracken again becomes the major s h e l t e r p l a n t as the l u p i n s h r i v e l s and drys. Log Open i s the l a s t s h e l t e r type of the study p l o t s , and t h i s type, as the name suggests, has l o g s and stumps as the major s h e l t e r elements. Lake.  Logs and stumps are everywhere at Quinsam  They f i g u r e l a r g e l y i n the various cover types, e s p e c i a l l y  i n the spring before f o l i a g e has developed.  In Log Open type,  F i g . 4(k) they remain an important s h e l t e r element throughout the year, although here, huckleberry (Vaccinium p a r v i f l o r u s ) and thimbT,eberry (Rubus p a r v i f l o r u s ) make t h e i r g r e a t e s t c o n t r i b u t i o n as s h e l t e r v e g e t a t i o n . Of the s h e l t e r types discussed Log Open i s the most  F i g . 4(a) F i r dense t y p e  1  F i g . 4(b) F i r open type  F i g . 4(c) Willow dense type  F i g . 4(d) Willow dense, s p r i n g aspect •  I F i g . 4(e) Willow open type  hl?ir  Height.  d  f  F i g . 4 ( f ) Willow open, s p r i n g aspect  S ^ ! ^ , th S ° P °tographs i s 4 f e e t i n Each black o r white s e c t i o n i s 1 foot i n length. 0 0  1 1  l n  a n d  t h e r  h  F i g . 4(g) Bracken open type  F i g . 4(h) Bracken open, s p r i n g aspect  F i g . 4 ( i ) Bracken open type  F i g . 4 ( j ) Bracken open type  F i g . 4(k) Log open type  F i g . 4(1) Sedge open type  F i g . 4(m) Clover open type  F i g . 4 ( ) A t y p i c a l road  F i g . 4 ( 0 ) Quinsam area 1943 ( A f t e r Fowle 1944)  F i g . 4(p) Quinsam area 1953  n  25  s i m i l a r t o e a r l y stages of burn succession as described by Fowle (1944).  Since h i s study, the g r e a t e s t change i n the area  as a whole has been the advance of woody vegetation.  This i s  obvious from a comparison of F i g . 4 ( o ) , a 1943 p i c t u r e of the area by Fowle, with F i g . 4 ( p ) , a p i c t u r e taken i n the same area i n 1953. F i n a l l y mention may be made of two non-shelter types that complete the p a t t e r n of v e g e t a t i o n a l cover on the study plots.  Sedge Open, S.O.,  i s a cover type produced by  temporary  s p r i n g pools i n which the v e g e t a t i o n i s almost e x c l u s i v e l y sedge (Carex spp.) w i t h an underlying carpet of moss.  F i g . 4(1) i l l u s -  t r a t e s t h i s type with Willow Dense i n the background.  Clover Open,  F i g . 4(m), i s a cover type without s h e l t e r value but i n which, Clover (Trifolium spp. and Medicago l u p u l i n a ) makes up a major p o r t i o n of the food p l a n t s present.  Roads are included w i t h i n t h i s  type f o r although t h e i r edges are u s u a l l y Bracken Open the c e n t r a l swath commonly contains two of the three species of c l o v e r recorded on the study area.  Sedge Open covered l e s s than lfo of each p l o t  while Clover Open covered 2% of p l o t I and 3$ o f p l o t I I . Table I I I presents a d e s c r i p t i o n of food p l a n t s i n the s h e l t e r types and Clover Open and Sedge Open i n terms of percentage ground covered, frequency of occurrence and abundance. G e n e r a l l y , with respect to ground coverage by s h e l t e r species now considered as food p l a n t s the t a b l e presents s i m i l a r r e s u l t s as obtained by l i n e i n t e r c e p t method.  The abundance of 5 w i l l o w s per quadrat as  recorded i n Willow Dense i l l u s t r a t e s the " t h i c k e t " nature o f t h i s s h e l t e r type.  TABLE I I I D e s c r i p t i o n of food species; t r e e s , shrubs and herbs i n each cover type % ground covered"':FD FO WD WO BO LO CO SO Number of yard quadrats :30 40 30 30 60 45 35 5  Cover type  Food species Pseudostuga t a x i f o l i a S a l i x spp. Alnus oregona Pteris aquilina Lupinus spp. Ifabjyfell' ; p a r v i f l o r u s Vaccinium p a r v i f l o r u s Kubus v i t i i ' o l i u s Gaultheria s h a l l o n Mahonia nervosa Rosa gymnocarpa Mosses and Lichens Epilobeum sp. Hypochaeris r a d i c a t a Hieracium sp. V i o l a sp. Thu.ja p l i c a t a Cornus canadensis Campanula sp. Symphorycarpus a l b a V i c i a americana Linnaea b o r e a l i s Gramineae Sedge ,Fragaria b r a c h t i a t a T r i f o l i u m procumbens T r i f o l i u m repens Medicago l u p u l i n a M i t e l l a breweri Plantago l a n c e o l a t a ;  1  4 1 3 1 3 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1  2 1 1 3 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  5 1 2 2 1  3 3 1 2  3 3 1  2  2 1 1  2 1 1 1 2 1 1 1  1 1 1 1 1 1  1 1 1 1 1 1 1 1 1 1  1 1 2 1 1 1 1 1  1 1 1 1 1  1  1 1 1 1  1  1  1 1  1 1 1 2 1 2 i 2 2 1 1 3 1 1 1 1 1 1 1 1 1  1  1  Frequency $ FD FO WD WO BO LO CO SO 2  30  E A E  1  A 1  2  4  2 1 1 1 1 2 2 1 1 2 2 1 1  5  E C A A C A C A A A A A A A A A  35  5  A A C A B B E C B A E B C C A A A A  A  A  A  B  40 30 3 0 60 45  C A A E A A E B A A D B C B A A A A A A A A A  E A B C A E A D C D A A  E A D C A A A A B A  G E B D E A A D B D B A A A E C A  A A E C B A E A A A C B C B A A A A C  A  B A A A  A  A  E  A  E  D A A A  B A A C A A A  30 40 3 0 30 60  ^1 <1 <1 <l 5 <1 <1 7 s 1 6  C  D  Abundance3 FD FO WD WO BO LO CO SO  E  ^ 1 <i <1 <i 14 6 6 7 6 <1 <1 <1 <1 ^1 <1 <1 2 4 3 6 <1 <1 <1 <1 <1 2 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <: 1  <1 2  45  <1 2 <1 <i <i 5 9 3 2 15 <1 3 2 2 <1 <1 7 5 6 < 1 2 4 <1 <1 1 <1 <1 <1 14 <1 <1 <1 <1  35  1  2  <1 <1 2 4 38  <1  1 <1 <1 <1 <1 <1 <1 a a <i <i <i <1 <i <i l  < i 2 <i  <l l  2 <1 <i l <. 1 c i <i  5  TABLE I I I (continued)  $ ground c o v e r e d  3over type dumber of yard quadrats 3  :FD FO WD WO BO L0 CO SO :30 40 30 30 60 45 35 5  l a n t component Blechnum spicans P o l y s t i chum munitionDuff and mineral s o i l  1 4  T o t a l number o f food species  3  4  1 1 1 1 4  4  Frequency f<£  Abundance^  FD F0 WD WO BO LO CO SO 30 40 30 30 60 45 35 5  FD FO WD WO BO LO CO SO 30 40 30 30 60 45 35 5  1  1 3  A  3  4  22 24 23 21 24 22 19  4  E  E  A A E  E  A A E  A E  D  <1 C  <1 <1 <1  <1  •  1 - l e s s than 5 $ of the ground covered. 2 - 5 - 2 5 $ o f the ground covered 3 _ 25-50$ »  4 _ 50-75$ " 5 - 75-100$"  2 A  _ B -  t h e  s p e e i e s  "  "  occurred i n 1 - 2 0 $ o f the quadrats. " « 21-40$ " » •«  «  n  "  tt  D -  c _  n  "  "  tt  n  tt 4 i « 6 0 $  "  "  »  E -  "  »  "  « 81-100$ "  »  n  n  n 61-80$  «  »  «  "  »  »  "  »  Average number o c c u r r i n g per quadrat.  to  28 Rubus v i t i f o l i u s a major berry producing p l a n t shows a r e l a t i v e l y constant coverage, frequency of occurrence and abundance, throughout a l l types w i t h the exception of Clover Open and Sedge Open where i t i s not commonly found. abundant i n F i r Dense type.  I t i s most  Hypochaeris r a d i c a t a occurs i n a l l  types i n approximately the same per cent coverage, and high frequency of occurrence. type.  I t i s most, abundant i n Clover Open  The plant i s a major food item of the a d u l t s .  Mosses  and l i c h e n s occurred commonly i n each type sampled and thus have a r e l a t i v e l y high frequency of occurrence.  Duff and mineral  s o i l are common and covered a l a r g e p r o p o r t i o n of the ground i n a l l types sampled. In the remaining m a j o r i t y of food items recorded, there i s a general d i s t r i b u t i o n o f the p l a n t s i r r e s p e c t i v e of the s h e l t e r type l i m i t s , w i t h a r e l a t i v e l y s m a l l amount of ground covered, a low frequency of occurrence, and an abundance l e s s than 1 i n almost every case.  I t i s noteworthy t h a t each type,  excepting Sedge Open, has approximately the same numbers of food species o c c u r r i n g i n i t .  With respect t o food p l a n t s then, the  s i x s h e l t e r types are s i m i l a r , a f a c t which serves to place emphasis on d i f f e r e n c e s found i n the abundance and ground by species c o n s t i t u t i n g the s h e l t e r types.  covered  I f the d i s t r i b u t i o n  of grouse i s r e l a t e d to a p a r t i c u l a r s h e l t e r type t h i s then suggests the importance of s h e l t e r or s h e l t e r and food v e g e t a t i o n as a f a c t o r i n f l u e n c i n g t h i s d i s t r i b u t i o n .  29 TOPIC I  NATURAL HISTORY Moult  The observations on moult presented here are based on the  examination of 356 grouse on the breeding range from A p r i l  to September. the  At l e a s t 5 b i r d s were examined i n each week o f  three year study p e r i o d .  I n September o f 1950 and 1951,  several hundred grouse i n hunter's bags were examined f o r moult p a t t e r n and weight. According t o Bent (1932), the moult o f c h i c k plumage begins i n J u l y and August and continues i n t o October.  The post  j u v e n i l e moult i s complete except that t h e outer p a i r s of prima r i e s are retained f o r a f u l l year.  Van Rossem (1925) and Swarth  (1926) noted that the t a i l r e t r i c e s developed by the c h i c k s i n October were shorter and narrower than those possessed by adult b i r d s going i n t o t h e i r second o r l a t e r f a l l . the  Van Rossem was o f  o p i n i o n that most o f these r e t r i c e s o f y e a r l i n g b i r d s were  replaced during the f o l l o w i n g winter s p r i n g and summer.  Swarth  disagreed with t h i s and could f i n d no feather replacement i n the y e a r l i n g b i r d s u n t i l a f t e r what he c a l l e d t h e i r p o s t - n u p t i a l moult i n the middle o f J u l y and l a t e r o f t h e i r second year. From the present study the moult i n t h e young i s as described by Bent and Swarth with the exception that the chicks do not r e t a i n t h e i r c h i c k primary f e a t h e r s i n t o t h e i r second year. The n a t a l down of June i s replaced by chick body and f l i g h t feathers i n J u l y , which i n t u r n are added t o , o r shed and replaced completely so that by September the young o f the year  30  are i n adult plumage w i t h the exception o f the r e t r i c e s which are c h a r a c t e r i s t i c a l l y short and narrow.  With the  exception  of the development i n the r e t r i c e s , the moult i n sooty grouse chicks from egg t o adult plumage p a r a l l e l s the d e t a i l e d moult p a t t e r n described by Bump et a l (1947) f o r the r u f f e d grouse (Bonasa umbellus). There are minor d i f f e r e n c e s o f c o l o u r a t i o n between plumage o f young b i r d and adult and t h i s i s most noticeable i n males i n t h e i r second year.  At t h i s time the plumage o f the  y e a r l i n g male i s l i g h t e r and more speckled w i t h white than that found i n o l d e r b i r d s .  The most important f e a t u r e o f the y e a r l i n g  plumage i s , however, the s h o r t e r and narrower r e t r i c e s .  These  can be used as an age c r i t e r i o n on the breeding range t o separate y e a r l i n g males and females from the o l d e r a d u l t s .  The a d u l t birds'"  possess l a r g e r and wider t a i l r e t r i c e s , obtained i n the moult o f t h e i r second f a l l .  Thus on the breeding range b i r d s w i t h these  l a r g e r r e t r i c e s are two years o f age at l e a s t and i n t h e i r t h i r d or l a t e r summer. The two age c l a s s e s y e a r l i n g s and a d u l t s , of both sexes, begin i n e a r l y summer, what Swarth c a l l e d the p o s t - n u p t i a l moult. This moult according to Dwight (1900) i s a complete replacement of body and wing f e a t h e r s .  The a d u l t s o f two. years o r o l d e r are  replumaged with i d e n t i c a l f e a t h e r s , w h i l e the y e a r l i n g b i r d s i n the annual moult assume adult plumage. variance w i t h t h i s basic p a t t e r n .  There appears some  31 Adults and y e a r l i n g s of both sexes examined i n t h i s study begin moulting by the end of May.  At t h i s time the 10th  primary i s replaced and by the end of June primaries 9, 8 and 7 are e i t h e r f u l l y replaced or i n the process of a c t i v e growth. Body moult begins at t h i s time, u s u a l l y i n the head and neck and extending over the f l a n k s , back and s i d e s .  By the end of  J u l y the 6th and 5th primaries are shed and replaced, w h i l e the new primaries are f u l l grown and the o l d s t i l l t i g h t i n t h e i r sockets. ment.  Body moult continues w i t h f e a t h e r shedding and r e p l a c e -  I t i s most n o t i c e a b l e i n the cocks which show a white  black mottled appearance about the neck r e g i o n .  and  Concommitantly  the neck t i s s u e s of the male, swollen and deep yellow during A p r i l and May,  become t h i n and pale i n c o l o u r .  The same change  i s noted i n the caruncle. The August and September samples i n d i c a t e the 4th primary i s shed and replaced i n t h i s p e r i o d w i t h a c o n t i n u a t i o n of body moult.  The f i r s t t a i l r e t r i x i s shed by middle or l a t e  August, and these are replaced from the outside mediad.  In the  September shoot, most hens have a completely new t a i l or one nearly replaced.  The moult o f upper and lower t a i l coverts seems  to occur i n a s s o c i a t i o n w i t h the r e t r i c e s .  At no time i n the  body and wing moult are the b i r d s f l i g h t l e s s . An unusual f e a t u r e i n t h i s p a t t e r n i s the absence of wing covert and secondary f l i g h t f e a t h e r moult.  While the ten  primaries apparently f o l l o w a r e g u l a r l a t e r a d sequence of moult the wing coverts and secondaries do not conform.  Only two a d u l t s  32  examined showed secondary feather moult and t h i s was  erratic  with the 3 r d , 4 t h and 5 t h , of the 12 secondaries being replaced i n one, w h i l e the 2nd, 5th, 7 t h and 12th i n the other. these moults were observed i n e a r l y August.  Both of  There e x i s t s the  p o s s i b i l i t y then, i f a l l f e a t h e r s are to be a n n u a l l y replaced, that the secondary f e a t h e r s , wing c o v e r t s , and the remaining 3 to 1st primary are l o s t on the w i n t e r range. Some l i g h t has been shed on the problem by a June, 1953, examination of two adult males, marked or covered w i t h p r i n t e r s i n k i n May, 1952.  Since the f e a t h e r s were inked i n 1952  then replacement of f e a t h e r s from May, 1952, to June,  1953,  would be i n d i c a t e d by i n k f r e e p a r t s of the plumage.  In both b i r d s ,  head, neck, body, t a i l and l e g s , were uncoloured.  On the other  hand the f i r s t primary was coloured, as were a l l the secondaries except the 3 r d and 12th.  Most of the undercovert and overcovert  feathers of the wing were unmarked, although the f i r s t row of undercoverts to the secondaries were s o l i d l y dyed.  From t h i s  evidence i t appears that adult b i r d s do not r e p l a c e a l l t h e i r plumage i n the post n u p t i a l moult and r e t a i n most of the secondaries, some of the wing coverts and p o s s i b l y the f i r s t primary f o r more than a f u l l year. Age  Criteria  To check and r e f i n e the age c h a r a c t e r i s t i c s noted by Van Rossem (1925) the outer p a i r of t a i l f e a t h e r s of a l l b i r d s examined on the study area were c o l l e c t e d and measured f o r t o t a l  33  length.  These were compared w i t h the t a i l feathers of chicks  or b i r d s of the year sampled from hunter's bags at the Campbell River road check i n September of 1950 and 1951.  Although the  young at t h i s time resemble the a d u l t s s u p e r f i c i a l l y , several c h a r a c t e r i s t i c s can be used, other than the l e n g t h of t a i l , to a c c u r a t e l y i d e n t i f y them as b i r d s of the year.  The young u s u a l l y  r e t a i n i n t o September a few j u v e n i l e feathers as i n the a x i l l a e or upper t a i l coverts.  In the young males, the e x t e r n a l t i s s u e  of the neck i s not at a l l coloured, thickened or rugose i n nature as i n a d u l t males.  In the young of both sexes the  p o s t e r i o r edge of the sternum i s incompletely o s s i f i e d and be e a s i l y bent.  can  F i n a l l y and most c h a r a c t e r i s t i c a l l y , the bursa  of F a b r i c i u s i s a deep pouch of approximately  1 centimeter i n  the young, while i n the adults i t i s reduced to a s l i g h t pocket or scar i n the d o r s a l surface of the c l o a c a . The road check sample of y e a r l i n g t a i l feathers from 15 males and 21+ females and the sample of t a i l feathers taken from 84 male and 121 female grouse on the study area through A p r i l to August are compared g r a p h i c a l l y i n F i g . 5.  Here the average  length of the two outer t a i l feathers are placed i n 2 m.m. and p l o t t e d against t h e i r frequency of occurrence.  The  classes  solid  part of the histograms represents the t a i l f e a t h e r lengths of yearling birds.  The open part i s the c o n t r i b u t i o n of grouse on  the breeding range. In the case of males, there i s a c l e a r break between the f e a t h e r lengths of y e a r l i n g s and another c l a s s representing b i r d s i n adult plumage.  From the graph y e a r l i n g males have outer  26 -  Males  24 -  Birds of the year, rood check [  •° 20  | Study orea sample  'a  16  % 12 z 8 "  _ CI  ro 6 ro  1 7T /  ro ro ro OI OI cr> ro 6> i ro ro OI i OI ot ab — 6  ^ * oi  J L  ^ oi o< en u >i 6 " m ib u> cn u> o  en cn ro oi  i  oo —  a> cn -H  • ^ ^ J C D C D C O C D ( O < O < £  't ro ^|CBCOCO(O(0<fo  -J  ' oi (O ro ai cb — * - J O O J  Average outer tail feather length in cm.  S O U J I K J P J O I Q ) —  -  i  S  O  U  01 li> r b t i l  — — r o r o r o o i o i o i * ^ ^ ^ oi oi oi «  ai oi  CD —  « S Q U g i K l g ^ ( g  -H ~ j - g a > a > o o i o < o ( O Q  Average outer tail feather length in cm. Fig. 5.  Comparison of average outer tail feather length of adult and yearling grouse  34  t a i l feathers ranging i n length from 13.2 to 15.2 cm.  Adult  males have outer t a i l feathers ranging i n length from 16.1 to 19.4 cm.  With t h i s , 9 out o f the 84 cocks examined on the  study area can be classed as y e a r l i n g males. In the case of females, the break between age classes as found i n males i s not c l e a r cut, however, the two groups are s t i l l evident.  As a working f i g u r e hens were classed as y e a r l i n g s  i f t h e i r average outer t a i l feather l e n g t h f e l l between 11.7  cm.  and 13.4 cm. and as adult hens i f t h i s length f e l l between 13.5 and 16.1 cm. the  With t h i s , 78 out of the 121 females examined on  study area can be classed as y e a r l i n g hens. Since the adult t a i l f e a t h e r i s obtained i n both sexes  i n the f i r s t post n u p t i a l moult, then b i r d s w i t h adult t a i l f e a t h e r s are by hatching time i n June, two years of age or o l d e r , and i n t o t h e i r t h i r d or l a t e r year. r e f e r s to t h i s age group.  In t h i s study the term adult  The term y e a r l i n g , as the name  suggests, r e f e r s to b i r d s of the previous years hatch which are one year of age by the subsequent hatch and i n t h e i r second year. The term chick or young i s applied to b i r d s between hatching date and the end of September, when they acquire y e a r l i n g plumage. A f t e r a two year o l d b i r d has a t t a i n e d adult plumage there i s no i n d i c a t i o n that subsequent moults produce longer or shorter t a i l f e a t h e r s , which would confuse i t s age c l a s s i f i c a t i o n . Once a d u l t , as f a r as feather data goes, i t i s at l e a s t two, but may be an unknown number of years o l d e r .  35 Weight o f Y e a r l i n g s and Adults A sample of 14 adult males taken a t random from a l a r g e r f i e l d sample i n A p r i l and May was 1300 * 5 0 grammes 1  i n average weight.  A s i m i l a r sample taken i n June and J u l y  gave an average weight o f 1200 *. 25 grammes. The d i f f e r e n c e i s s t a t i s t i c a l l y s i g n i f i c a n t (by " t t e s t ) and i n d i c a t e s the males n  come from the winter range i n greater weight than they a t t a i n i n the summer months.  This i s not unusual, the l o s s i n weight  being a t t r i b u t a b l e to the strenuous a c t i v i t i e s of the breeding period. The hens i n A p r i l and May are heavy w i t h eggs, and thus make comparison w i t h t h e i r summer weight l e s s meaningful. In 24 recorded i n t h i s p e r i o d , the weights ranged between 850 and 1200 grammes. A sample of 20 adult hens weighed i n June and J u l y averaged 850 + 25 grammes. Eight y e a r l i n g males weighed i n June and J u l y averaged 1100 * 50 grammes. This i s s i g n i f i c a n t l y l i g h t e r than the 1200 * 25 grammes recorded f o r the adult cocks i n the same p e r i o d , and an i n d i c a t i o n t h a t the y e a r l i n g males do not a t t a i n adult weight u n t i l a f t e r J u l y i n t h e i r second year. Eleven y e a r l i n g females weighed i n June and J u l y averaged 780 • 25 grammes. This weight i s s i g n i f i c a n t l y l i g h t e r than the 850 2. 25 grammes average weight recorded i n the adult hens over the  same p e r i o d .  Thus, as i n the y e a r l i n g cocks, i t seems l i k e l y  that the y e a r l i n g hens do not a t t a i n adult weight u n t i l a f t e r J u l y of t h e i r second year. ^Standard e r r o r o f the mean.  36 The Spring M i g r a t i o n Observations on the a c t i v i t i e s of grouse were recorded i n the most part on study p l o t s I and I I , f o r i n these areas most b i r d s of both sexes were handed o r marked.  The p l o t s were  searched as s y s t e m a t i c a l l y as p o s s i b l e i n a l l hours of the day so that each r e g i o n was e q u a l l y i n v e s t i g a t e d .  Data on grouse  p o s i t i o n s w i t h i n the p l o t s were recorded and these p l o t t e d to construct maps of grouse d i s t r i b u t i o n throughout the f i e l d periods.  study  The maps and associated observations on a c t i v i t i e s  then serve as basic m a t e r i a l from which, a f t e r a n a l y s i s , some understanding of the mechanics of grouse behaviour can be obtained. Little study area.  i s known of the w i n t e r range of the birds on the  The distance they t r a v e l , or the d i r e c t i o n they  take i n going and coming from i t remain l a r g e l y a matter of speculation.  Anthony (1903) has recorded something of the down-  ward migration i n Oregon where on the f i r s t of March grouse appeared on the move down from high mountain slopes.  In crossing  r i d g e s they would g l i d e i n f l o c k s of 12 to 100 b i r d s from one crest to the next.  I f they f e l l short the b i r d s would climb on  foot t o the top of the attempted r i d g e and then g l i d e again towards the lowlands.  He also observed t h a t the l a r g e s t f l i g h t s seemed  to occur at sunrise and sunset, and t h a t the f i r s t sex to reach the lowlands was the male. Eight hours spent on the study area on the s i x t h of March, 1951, produced one observation on a s i l e n t male i n F i r Dense type, where i t may have spent the w i n t e r .  This and the  37 absence of droppings and t r a c k s i n the snow, s t i l l present on roads, i n d i c a t e d the b i r d s had not yet returned to t h i s p o r t i o n of the summer range. By A p r i l the 13th on the beginning of the t h i r d year of f i e l d work the study area was populated by grouse of both sexes, which gave good i n d i c a t i o n , p a r t i c u l a r l y i n the case of the males, t h a t they were r e s i d e n t b i r d s .  Thus i f the downward  migration occurs at the same time each year the b i r d s a r r i v e on the study area between March 6th and A p r i l the 13th. T e r r i t o r i a l Behaviour of the Adult Male Once on the summer range the behaviour of most a d u l t cocks i s c h a r a c t e r i s t i c and f a l l s i n t o the c l a s s i c p a t t e r n of t e r r i t o r i a l behaviour as described by Howard (1920), and modified through various studys by Nice (1937, 1941, 1943) on the song sparrow, Timbergen (1939) on the snow bunting, Kendeigh on the house wren, and others.  (1941)  The males take up and defend  area from other males of the species. From w i t h i n t h i s area or t e r r i t o r y they emit v o c a l c a l l s or hoots, a word d e s c r i p t i o n of the sound. When the p o s i t i o n s i n which males are observed hooting are mapped they present a p a t t e r n of p o i n t s representing the hooting s i t e s or s t a t i o n s of each male recorded i n the weeks of f i e l d study. Fig.  F i g . 6 i s a map of such hooting s i t e s i n p l o t I .  7 represents the observations of p l o t I I t r e a t e d i n a s i m i l a r  manner.  The data are from A p r i l to August, 1953.  By a r b i t r a r i l y  j o i n i n g up the outermost p o i n t s a perimeter i s created which  38 contains the maximum s i z e area o r t e r r i t o r y over which a given b i r d was observed hooting throughout the study p e r i o d . From these maps i t i s c l e a r , t h a t when hooting, each male c a r r i e s out t h i s a c t i v i t y i n a t e r r i t o r y p e c u l i a r to i t s e l f , i t i s i s o l a t e d from other males engaged i n s i m i l a r a c t i v i t y . Thus while the t e r r i t o r i e s observed on the study p l o t s vary i n s i z e i t i s noteworthy t h a t i n few cases do they o v e r l a p . I n some regions o f the p l o t s where hooting males are not adjacent such as F i g . 7 at (4,A) t h i s s i t u a t i o n i s impossible, simply by the l a c k of a nearby male.  I n the case o f males No. 162 a t  (14,D), No. 281 (17,J) male (11,1) and male (7,L) the s i t u a t i o n i s most apparent.  Despite the c l o s e p r o x i m i t y o f b i r d s , each  i s contained by a perimeter c l o s e t o , but l a r g e l y f r e e from another. The perimeters and contained hooting areas need f u r t h e r q u a l i f i c a t i o n t o gain t h e i r t r u e meaning.  I n some cases they  represent the extreme l i m i t s o f a given males t e r r i t o r y , i n others, they represent the greatest area over which a hooting male was observed. For a n a l y s i s of t h i s s i t u a t i o n , hooting observations of males No. 162 (7,L), (11,1), No. 281, and No. 147, F i g . 7, were c h r o n o l o g i c a l l y arranged and d i v i d e d i n t o a group of t e n , a group of t h a t t e n plus another t e n , and a group o f these 20 plus another t e n and so on u n t i l a l l p o i n t s were u t i l i z e d .  When  the outermost p o i n t s o f each group was joined on the map, and measured by planimetry the r e s u l t was an accumulative s e r i e s o f  39 areas over which the b i r d hooted throughout the summer.  If a  male was l i m i t e d i n i t s hooting p o s i t i o n s over the study period, then at some group of t e n p o i n t s the accumulative area should cease to grow i n s i z e .  The r e s u l t s of t h i s a n a l y s i s are  expressed g r a p h i c a l l y i n F i g . 8 from Table IV appended. Male (11,1) and (7,L) represent b i r d s whose perimeters as a r b i t r a r i l y mapped are the a c t u a l l i m i t s of t h e i r hooting areas.  This could have been predicted from the map.  The  inference here i s t h a t t h e i r observed areas correspond to the a c t u a l hooting areas u t i l i z e d throughout the summer.  On the  o t h e r hand, males No. 162, No. 281 and No. 147 are b i r d s which throughout the summer, e i t h e r extended the area over which they hooted, and thus t h e i r map boundaries represent the greatest area i n which they were observed, or f i e l d o b s e r v a t i o n f a i l e d to detect t h e i r true l i m i t s e a r l y i n the season.  However, whether  the areas are r e a l or apparent, there s t i l l remains the w e l l defined l i m i t s between adjacent b i r d s , and any expansion, once the boundary i s met i s away from i t . I t i s not d i f f i c u l t to appreciate how the boundary between two males i s e s t a b l i s h e d f o r i n A p r i l f i g h t i n g i s commonly observed. question.  When and where the l i n e i s to be i s another  In the case of Male (11,1) t h i s area was recorded at  near maximum s i z e i n A p r i l , and s i m i l a r l y f o r Male (7,L).  Thus  the l i m i t s of these b i r d s were determined e a r l y i n the s p r i n g . From a c o n s i d e r a t i o n of the p o i n t s of A p r i l observation i n F i g . 7, t h i s probably holds f o r a l l the b i r d s i n the p l o t p a r t i c u l a r l y with respect to the boundary between neighbouring males.  10  30 50 70 90 Number of points  90 "  Mole  (7,L)  50  70  Mole No. 281  70 -  30 -  10  30  -I L_  90  Number of points  10  Fig. 8  J  l  J — I — i — i i_ 50 70 90  Number of points  Mole (11,1)  10  30  Mole No. 147  I  I  L  30 50 70 90 Number of points  10  J—i—l  I  I  i_  30 50 70 90 Number of points  frbm Table E . Accumulative size of hooting areas and number of observations on five males of p l o t H .  40 As to where the boundary between hooting cocks might occur, some l i g h t i s shed on t h i s problem by comparing the d i s t r i b u t i o n of hooting males, as i n d i c a t e d by the perimeter of t e r r i t o r i e s , w i t h the d i s t r i b u t i o n of the cover types on each plot.  F i g . 9(a) superimposed  on F i g . 9(b) and F i g . 10(a) super-  imposed on F i g . 10(b) f a c i l i t a t e s t h i s comparison on p l o t s I and II.  Each t e r r i t o r y i n F i g . 9(a) i n c l u d e s some Willow Open or  Willow Dense type.  S i m i l a r l y , i n F i g . 10(a), a l l t e r r i t o r i e s  except (6,U) c o n t a i n e i t h e r F i r Dense, Willow Dense or both. There appears then, a r e l a t i o n s h i p between l o c a t i o n of t e r r i t o r i e s and the dense v e g e t a t i o n a l types which would provide concealment f o r a hooting b i r d . I t i s noteworthy that the t e r r i t o r i e s do not conform to the l i m i t s of the cover types, an i n d i c a t i o n t h a t hooting males, once l o c a l i z e d , are not r e s t r i c t e d i n t h e i r movements by the described v e g e t a t i o n .  This serves to emphasize the physiolog-  i c a l nature of the l i m i t s between adjacent hooting males. When t e r r i t o r i e s are close to a r e l a t i v e l y l a r g e area of dense vegetation as i n F i g . 9(a) at (13,D) (19,K) (15,U) and i n F i g . 10(a) at (7,H), they appear to border upon i t .  This edge  s i t u a t i o n p o s s i b l y r e f l e c t s a compromise between area i n p r o t e c t i v e s h e l t e r and open areas w i t h i n which hens feed and are e a s i l y seen. With the above considerations when males a r r i v e i n the s p r i n g and take up residence on the summer range, i t seems not u n l i k e l y that they s e l e c t an area or edge of Willow Dense or F i r  DENSE  E23  FIR  DENSE  ^  Dense and begin to hoot.  Thus the d i s t r i b u t i o n of the vege-  t a t i o n would be a primary f a c t o r i n c r e a t i n g a d i s t r i b u t i o n of hooting males.  Movements from the dense vegetation would  extend the l i m i t s o f t h i s hooting area and p o s s i b l y b r i n g the b i r d i n t o contact with another male.  At t h i s point a f i g h t  might ensue, the outcome which would supposedly f i x a p o r t i o n of the boundary of e i t h e r "males hooting area, or cause one to move to p o i n t s remote. I t f o l l o w s from the above, i f a male became l o c a l i z e d close to other males, i t s t e r r i t o r y would be s m a l l e r than a male located not so c l o s e l y to i t s f e l l o w s , assuming both b i r d s tended t o move out from the o r i g i n a l point of l o c a l i z a t i o n . This apparently i s what has happened on p l o t I I , F i g . 7 where the number of males about (7,L) and (11,1) has r e s u l t e d i n r e l a t i v e l y small t e r r i t o r i e s of .7 and 1 acres r e s p e c t i v e l y . The t e r r i t o r i e s of male No. 162 and No. 9, which are f r e e to expand, were both recorded at 2 acres i n s i z e .  Thus t e r r i t o r y  s i z e appears i n v e r s e l y p r o p o r t i o n a l to d e n s i t y of hooting males. A d d i t i o n a l evidence i n support of t h i s conclusion i s found i n comparing t e r r i t o r y s i z e and hooting male d e n s i t y or abundance over the years 1950 to 1953. Once a male has become l o c a l i z e d on a t e r r i t o r y i t returns o r "homes" to the same l o c a l i t y i n subsequent years. Thus male No. 9, F i g . 12 (4,D) was banded on t e r r i t o r y i n 1950 and was observed on the same t e r r i t o r y i n 1951, 1952 and 1953. This has been equally t r u e o f 46 hooting males, which marked i n one year, i f recorded i n subsequent years were i n t h e i r o r i g i n a l  42 areas, and i n most cases under the same t r e e , l o g o r stump where captured.  With t h i s behaviour, and a low y e a r l y turnover  i n adult males (see p.ioi) there has been l i t t l e recorded change i n t e r r i t o r i e s o r t h e i r occupancy as recorded over the years 1950 to 1952. This i s shown i n F i g . 11 and F i g . 12 which i l l u s t r a t e the p o s i t i o n s o f these t e r r i t o r i e s on p l o t s I and I I . Male No. 8 (10,Q) F i g . 12, banded i n 1950, d i d not r e t u r n to i t s t e r r i t o r y i n 1952 and was replaced by another male which was subsequently marked.  The t e r r i t o r y o f the new  male was recorded as l a r g e as that occupied by the o l d .  This  suggests the new and presumed two year o l d animal was e q u a l l y s u c c e s s f u l i n t e r r i t o r i a l establishment as No. 8 which was a t l e a s t two years o f age i n 1950 and at l e a s t three i n 1951. Again males No. 162 (13,D), No. 147 (15,R), No. 205 (24,V), No. 132 (21,E) and No. 9 (4,D) a l l at l e a s t three o r f o u r years of age i n 1951 have shown no s i g n i f i c a n t  change i n observed  t e r r i t o r y area over the two o r three years they have been banded. At the same time there has been l i t t l e change i n the d i s t r i b u t i o n of hooting males about them.  The t e r r i t o r y a t (16,S) was  vacated when male No. 33 banded i n 1950 d i d not r e t u r n i n 1951. In 1952 three new t e r r i t o r i e s were recorded a t (6,U), (10jW) and (22,V). In F i g . 11 Male No. 13 (11,S) banded i n 1950 returned i n 1951 but was not observed, nor was a new a r r i v a l , on t h i s t e r r i t o r y i n 1952.  Male No. 130 (13,0), adjacent i n 1951 expanded  i t s t e r r i t o r y i n 1952 and included area once occupied by male  .A  /  \  7  1  : ! 2  3  •  50'  ...-270" -'  -i ;  0  T  5  F i g . 11  /  s  ~I43 - _ \  1 1 1 I, I V I  DISTRIBUTION  OF TERRITORIES NESTS 1950 A 1951 A 1952 A  k .L ik  AND NESTS  r, 1  il> il Jo  1950 to 1952. PLOT  TERRITORIES 1950 1951 1952 •  I.  3  24  25  DISTRIBUTION  OF TERRITORIES NESTS 1950 A 1951 A 1952 A  AND NESTS  1950 to 1952. PLOT H .  TERRITORIES 1950 '951  1 9 5 2  43  No. 13; an i n d i c a t i o n that i n 1951 i t was l i m i t e d i n t h i s d i r e c t i o n of movement by the presence o f male No. 13. By June of 1953 a s t r i k i n g change had.occurred on Males p l o t I I , F i g . 12/(11,1), (7,L), (11,Q), No. 147 (17,R), No. 162 (13,C), No. 281 (17,J) and male No. 200 (20,U) were not observed on the study p l o t .  Of the seven marked males  three were replaced by new b i r d s which occupied the same general area as had males No. 200, No. 147 and (11,1).  The  t e r r i t o r i e s of (7,L), (11,Q) and No. 162 (13,C) were l e f t vacant or. overlapped by the hooting areas o f the new r e s i d e n t males. Male No. 132 (22,C), l i m i t e d i n expansion by Nos. 162 and 281 i n 1952, was recorded hooting i n i t s o r i g i n a l t e r r i t o r y and subsequently over a g r e a t e r part o f the t e r r i t o r i e s o f males No. 162 and No. 281 at (12,E), (10,B), (14,B), (21,C) and (17,J).  Here then the d e n s i t y of males was decreased, w h i l e  the observed t e r r i t o r y s i z e increased.  The r e c i p r o c a l s i t u a t i o n  to that of 1952, observed above, with a greater d e n s i t y o f hooti n g males.  Thus t e r r i t o r y s i z e appears t o be a d e n s i t y dependent  f a c t o r that i s i n v e r s e l y p r o p o r t i o n a l to abundance of hooting males. Sexual A c t i v i t i e s of the Adult Male The most apparent sexual a c t i v i t i e s o f the adult male are those of h o o t i n g , f i g h t i n g and c o u r t i n g .  Each a c t i v i t y i s  r e l a t e d to the observed p o s i t i o n s or movements o f the male and thus contribute to the changing o r d e l i m i t e d boundaries o f t h e i r territories.  44 Hooting i s the major a c t i v i t y o f the cock b i r d on i t s territory.  The c a l l o r hoot o f the sooty grouse i s a s e r i e s o f  deep sounds which might be i m i t a t e d with closed l i p s as, whrum whrm whrm whrm awhrm whrm. from 3 to 4 seconds.  Each complete song takes  The number o f songs per minute v a r i e s  between 2 and 4 i n steady daytime hooting to as many as 6 per minute i n periods o f peak sexual a c t i v i t y when i t appears t o gain i n volume. When hooting the male assumes a t y p i c a l stance, Fig.13 i n which the oesophagus i s s l i g h t l y i n f l a t e d and t h e head, w i t h mouth closed, i s held forward and down near or i n t o the swollen neck region.  Each phrase begins w i t h a c o n s t r i c t i o n o f t h e  b i r d s body which probably forces a i r through the s y r i n x c r e a t i n g the  sound.  There i s no d i s p l a y o f body p a r t s or plumage i n what  might be termed routine hooting a c t i v i t y . In beginning t o hoot, the male does not give the f u l l song.  Several o f the i n i t i a l phrases occur, then a pause, and  a r e p e t i t i o n o f the i n i t i a l phrases of t h e c a l l .  Usually a f t e r  4 o r 5 of these abortive attempts the f u l l song i s u t t e r e d and continued t h e r e a f t e r . I t i s d i f f i c u l t to appraise the d i s t a n c e over which hooting can be heard.  At times a hooting male can be a c c u r a t e l y  l o c a t e d from a d i s t a n c e o f 500 f e e t . ing  Others, apparently produc-  a muffled o r subdued song cannot be heard beyond 100 f e e t ,  at l e a s t t o obtain an idea o f t h e i r whereabouts. There i s no i n d i c a t i o n from t h i s study t h a t temperature, r a i n , pressure or wind d i r e c t l y influence t h e hooting o f the male.  F i g . 13  F i g . 16(a)  Hooting male ( A f t e r Laing)  F i g h t i n g posture  F i g . 16(b)  V i c t o r stance  45 The i n f l u e n c e of l i g h t , presence of females, hooting a c t i v i t i e s of other males, and the physiology of the b i r d i t s e l f make t h i s i s s u e complicated enough without r e s o r t i n g to the weather as an explanation of song a c t i v i t y or i n a c t i v i t y . In other s t u d i e s males have been recorded c a l l i n g from high f i r t r e e s i n dense f o l i a g e .  The a c t i v i t y i s by no  means so l i m i t e d f o r i n the study area cocks hoot from the ground or some prominence upon i t .  Throughout the hours of  d i r e c t s u n l i g h t males of p l o t I were recorded i n , or u t i l i z e d almost e q u a l l y , the cover types, Willow Dense, Willow Open and Bracken Open, w i t h a l e s s e r u t i l i z a t i o n of Log Open, F i g . 14 from Table V appended.  None was recorded i n Clover Open type.  On p l o t I I ( i n the same f i g u r e ) males showed a r e l a t i v e l y high u t i l i z a t i o n of F i r Dense type w i t h observations i n F i r Open, Willow Dense, Bracken Open and Log Open almost e q u a l l y numerous. Again none was recorded i n Clover Open type.  Although f r e q u e n t l y  recorded i n the open types, males are r a r e l y observed i n d i r e c t s u n l i g h t or open canopy i n the d a y l i g h t hours, and are i n the s h e l t e r of a l o g , shrub o r t r e e when hooting.  The s h e l t e r value  of the dense v e g e t a t i o n a l types would appear obvious, p a r t i c u l a r l y i n . e a r y s p r i n g aspect when herbaceous vegetation i s not present. Generally, males have regular hooting s t a t i o n s on t h e i r t e r r i t o r i e s and are most f r e q u e n t l y recorded at them.  As an  example male (20,N) F i g . 6 u t i l i z e d t h i s p o s i t i o n as a frequent hooting s i t e , w h i l e the clumping of observations i n t h i s f i g u r e  Plot I 100 c o o 50 N  i—i—I r rjd d d d o u. 5 5 CD -J o  Clockers  Nests  o  Males  Broods  Plot II  100  I  Females  50  TT~1 O Q d o  Q u:  u.'  o d Bd ?! cd J u  Clockers  O Q u: 3:  Nests  Fig. 14 from Table H.  p d o o 3f ai J d  Females  d d d d d d u; u: j j: cri J  Moles  Cover type utilization on plot I and H  d u  t fd bd .o  o d d  * $ * m' J u  Broods  i  46  as i n F i g . 7 i n d i c a t e s the same s i t u a t i o n i n other males. F i g , 15 i s a hooting s t a t i o n i n F i r Open o f male (22,M) F i g . 7 . The b i r d hooted from the dark recess i n the l o g at the f o u r foot rod. One f u n c t i o n o f male song from an e s t a b l i s h e d t e r r i t o r y i s as a mechanism whereby females are a t t r a c t e d t o t h e s i n g i n g male, Tinbergen (1939) Nice (1943).  Females have been  f r e q u e n t l y observed i n the t e r r i t o r i e s o f hooting males but there i s l i t t l e evidence from t h i s study t o i n d i c a t e they were a t t r a c t e d by the song.  With the l a c k o f other evidence, and i n  view o f the work o f o t h e r s , i t seems l o g i c a l t o b e l i e v e t h a t t h e loud hooting o f the male serves as an a t t r a c t o r mechanism and conditions the movements o f p h y s i o l o g i c a l l y r e c e p t i v e hens. When males are hooting i t i s unusual t o hear adjacent b i r d s c a l l i n g alone.  As an example, i n F i g . 7 males No. 162  (13,C), (11,H) and No. 28 (17,J) sang almost simultaneously throughout the breeding p e r i o d .  On the other hand, these males  might be s i l e n t while males No. 270 (24,B), No. 143 (16,B), No. 213 (15,E) and (13,G) on p l o t I F i g . 6 would be a c t i v e l y hooting.  When one o f an adjacent p a i r of males i s s i l e n c e d by  an i n t r u d e r , the other f r e q u e n t l y ceases to c a l l .  I t usually  resumes song when the d i s t u r b e d male again becomes v o c a l l y active.  These observations suggest the hooting o f one male  stimulates another o r others t o v o c a l a c t i v i t y . Over a period o f f i e l d study hooting males are recorded  F i g . 20(b)  Nest  F i g . 20(c)  Destroyed nest  47 away from t h e i r regular song s t a t i o n s so that a l a r g e r area i s u t i l i z e d and the d i s t a n c e between adjacent males i s reduced.  This dispersed nature o f hooting s i t e s , which i n  part creates the greatest extent o f t e r r i t o r y i s evident i n a l l males studied i n s u f f i c i e n t d e t a i l , F i g s . 6 and 7.  Twice e a r l y  i n A p r i l , the author was able t o e l i c i t a f i g h t r e a c t i o n i n a male and cause i t t o move towards him.  This was accomplished  by hiding and i m i t a t i n g the song close to a male.  In one  instance a b i r d came r a p i d l y towards t h e sound i n f i g h t i n g posture over a distance o f 30 f e e t .  I n the second case a male  was v i g o r o u s l y courting a female at a distance of 20 f e e t from the hide.  When the author i m i t a t e d the song, the cock immediately  ceased i t s courting d i s p l a y and ran towards the source of sound i n f i g h t i n g stance.  Movements of some males on t e r r i t o r y can  be simply explained on the basis o f an a t t r a c t i o n between c l o s e l y s i t u a t e d b i r d s as an example male No. 9 (4,C) F i g . 7 hooted i n A p r i l from (2,G) and when c a l l i n g here was heard w i t h another banded male hooting a t (E) and 100 f e e t o f f the p l o t . In June and J u l y when t h i s banded male was no longer heard and had apparently vacated i t s t e r r i t o r y , No. 9 moved to p o s i t i o n s (9,C), (7,G) and (7,0) which brought i t c l o s e r to males (11,1) and No. 2 6 l (13,0) which were s t i l l v o c a l l y a c t i v e . Thus the hooting of males i s not independent but appears to be stimulated by hooting a c t i v i t y of a nearby male or males.  I f a tendency f o r hooting males to move together i s  r e a l , then hooting between males can also be considered as a  48 f a c t o r i n f l u e n c i n g the extent of t e r r i t o r y or at l e a s t p a r t l y the cause of a male's movements upon i t .  Considering a new  a r r i v a l i n s p r i n g t h i s tendency f o r males to hoot together  may  i n part determine whether i t remains and becomes l o c a l i z e d or moves to places remote.  Thus presence of s u i t a b l e s h e l t e r vege-  t a t i o n and hooting male or males would be prime environmental factors i n i t i a t i n g t e r r i t o r i a l  behaviour.  I t may be, once hooting males have a t t a i n e d c e r t a i n proximity, v o c a l c a l l s alone are s u f f i c i e n t to prevent continued expansion and r e s u l t a n t overlapping of t e r r i t o r i e s .  The hooting  of one male would presumably warn the other of i t s presence, and the song could therefore be considered as a form of passive defence.  There i s l i t t l e evidence from the present study to  permit acceptance or r e j e c t i o n of t h i s conjecture. r  i g h t i n g i s an important a c t i v i t y of a t e r r i t o r y h o l d -  i n g male and i s associated w i t h a w e l l d e f i n e d p a t t e r n of behaviour.  I f a t r e s p a s s i n g male should appear w i t h i n the  l i m i t s of a male's t e r r i t o r y and show no apparent d i s p l a y , the resident male w i l l at f i r s t begin to adopt the c o u r t i n g d i s p l a y as e l i c i t e d by the presence of a female.  He then moves towards  the i n t r u d e r who may suddenly take f l i g h t , stand motionless or move towards the approaching male.  In the m a j o r i t y of f i g h t s  the outcome seems determined at t h i s p o i n t .  I f the i n t r u d e r  should stand motionless or perhaps mount a stump or l o g the resident male, a l l t r a c e s of c o u r t i n g d i s p l a y gone may run at the i n t r u d e r w i t h neck o u t - s t r e t c h e d and head down, i n t y p i c a l f i g h t i n g posture, F i g . 16(a).  Immediately the rush begins the  49 i n t r u d e r takes f l i g h t .  I f the r e s i d e n t male does not run  towards the i n t r u d e r by v i r t u e of i t s p o s i t i o n on a l o g o r stump (or f o r unknown reasons), i t then approaches s t e a d i l y i n f i g h t i n g posture and i n v a r i a b l y begins to emit a s t a c a t t o s e r i e s of sounds which might be w r i t t e n as, gug gug gug gug M  gug,"  as q u i c k l y emitted as the above symbols can be pronounced. While thus v o c a l i z i n g , the r e s i d e n t male begins t o pace i n a four or f i v e foot oval i n f r o n t of the s i l e n t and motionless i n t r u d i n g male or around and beside him on a stump or l o g . A f t e r a period of from 1 to 3 minutes of t h i s , a completed o v a l ends i n a quick rush at the i n t r u d e r who thereupon leaves. f i n a l l y , when two males meet, presumably on ground that each recognizes as i t s own hooting area, the outcome i s by no means sure.  In such encounters both males pace i n t i g h t  ovals with head down, neck out-stretched and emit sounds as described above.  P e r i o d i c a l l y they cease the pacing and  standing i n f r o n t of one another, s t r e t c h up t h e i r necks and bodies, then r e t u r n to the f i g h t i n g posture and pacing. Suddenly they engage, and there f o l l o w s a vigorous i f not p h y s i c a l l y harmful melee of pecking, b u f f e t i n g of wings and downward s l a s h i n g of f e e t . pacing and v o c a l i z a t i o n .  Upon breaking the b i r d s again resume At times i n pacing, the males peck at  d e b r i s on the ground although they do not a c t u a l l y feed. How long the pacing and c l o s i n g i n p h y s i c a l contact might continue i s a question. observed i n t h e i r e n t i r e t y .  Only two such fights.were In one l a s t i n g 5 minutes a b i r d  50 suddenly broke away from the point o f f i g h t i n g , was pursued by the other approximately 15 f e e t , and there the chase stopped. In t h i s case the pursued male moved away about 100 f e e t and began t o hoot, presumably from w i t h i n the r e g i o n i t s t i l l recognized as i t s own t e r r i t o r y .  I n the second case the  contact continued f o r 25 minutes with a c t u a l f i g h t i n g t a k i n g up about 1 minute o f t h a t time.  I n t h e i r pacing the two b i r d s  became separated by a mound o f earth and a small f i r t r e e . When t h i s occurred the o r i g i n a l i n t e n s i t y o f the contact seemed to d i m i n i s h , and one b i r d began t o feed, r u f f l e d i t s f e a t h e r s , began t o preen and then walked i n t o i t s t e r r i t o r y .  I t seems  l i k e l y t h a t such f i g h t s ( i n which both males play an aggressive r o l e ) r e s u l t i n the formation o f t e r r i t o r i a l boundaries. When the outcome o f a f i g h t has been decided and t h e i n t r u d e r o r contestant r e p e l l e d , t h e r e g e n e r a l l y f o l l o w s a r a p i d chase on foot o r i n the a i r .  The resident male, however,  pursues the i n t r u d e r only as f a r as what appears t o be the edge of i t s t e r r i t o r y .  Here i t stops o r s e t t l e s t o the ground.  U s u a l l y the s u c c e s s f u l male then adopts what might be termed a v i c t o r stance, F i g . 16(b) i n which i t stands at f u l l height w i t h neck upstretched, and head h e l d i n the d i r e c t i o n taken by i t s opponent.  This l a s t s a few seconds a f t e r which time the male  begins t o hoot.  I t i s noteworthy that t h e song i s only given  when the f i g h t i s over and the opponent out o f s i g h t .  Thus hoot-  ing at t h i s time may serve as a warning o r i n d i c a t e the proclama t i o n o f claimed area by the r e s i d e n t male.  51 F a i l u r e t o obtain observations i n l a t e March and e a r l y A p r i l leaves much t o be d e s i r e d f o r by t h i s time males appeared t o be e s t a b l i s h e d on t h e i r t e r r i t o r i e s and boundary disputes between adjacent males were not f r e q u e n t l y observed. An apparent boundary dispute was observed between male No. 162 and male No. 281 on A p r i l the 1 4 t h a t (15,G) i n F i g .  7-  It i s  noteworthy that (15,G) i s on the l i n e drawn f o r the t e r r i t o r y of No. 162 based on i t s recorded hooting p o s i t i o n s .  Similarly  i n eight other f i g h t s observed i n A p r i l between adjacent males the  disputes i n every case occurred on what was o r became the  boundary region between the two b i r d s as i n d i c a t e d by hooting stations. Instances o f t r e s p a s s i n g are more common and are observed throughout the time o f t e r r i t o r i a l a c t i v i t y .  As an  example male No. 132 (22,D) F i g . 7 was observed t o f l y from (22,D) to ( 1 2 , C ) .  S i m i l a r l y male No. 9 flew from (1,D) to .  (11,C) and male No. 126 o f p l o t I F i g . 6 f l e w from (20,Y) i n F i g . 6 to (12,B) i n F i g . 7 .  I n each case the males were i n  p u r s u i t o f females and landed i n the t e r r i t o r y o f male No. 1 6 2 . Immediate f i g h t posturing and rushes by male No. 162 repulsed the  trespassers almost as soon as they a l i g h t e d . There i s d i r e c t and i n d i r e c t evidence t o suggest f i g h t -  ing between males may r e s u l t i n the displacement o f one.  Male  No. 132 was f i r s t observed hooting a t (10,D) F i g . 7 on A p r i l 2 0 t h  of 1 9 5 2 . A l l other males were e s t a b l i s h e d about No. 1 3 2 , as i n the  f i g u r e , and a c t i v e l y hooting.  On A p r i l 22 a f i g h t was  52  observed at (9,G) between male No. 132 and the male of t e r r i t o r y (11,H), i n which No. 132 was defeated and chased to approximately (11,D).  Thereafter No. 132 was recorded hooting  on i t s t e r r i t o r y at (23,D) which i t had occupied i n 1 9 5 1 . On p l o t I , F i g . 6 a male was recorded hooting a t p o s i t i o n (5,N) i n A p r i l . (4,K). area.  At the same time a male was heard a t  Subsequently but one male was heard and i n the (4,K) This b i r d d i d not use the o r i g i n a l hooting s t a t i o n of  male (4,K).  I t seems l i k e l y that the male o f (5,N) had moved  i n t o the (4,K) t e r r i t o r y and forced the o r i g i n a l r e s i d e n t to places remote. Unfortunately at the time, n e i t h e r b i r d was marked, a c o n d i t i o n which leaves t h i s observation i n question. On p l o t I I F i g . 7 , a male was marked on A p r i l 1 4 t h , at p o s i t i o n (19,R).  L a t e r an unmarked male was captured which used t h i s  area throughout the summer as i t s t e r r i t o r y .  The marked male  of A p r i l 1 4 t h had moved to p o s i t i o n (22,J) and occupied t h i s area throughout the r e s t o f the summer.  I t would appear from  t h i s t h a t the captured male, p o s s i b l y a l a t e r a r r i v a l , had usurped the p o s i t i o n of the marked male which then s e t t l e d i n a new area.  Again t h i s observation i s open to question as the  marked male was never recorded hooting i n the (19,R) area and may have been a vagrant at the time. I f hooting behaviour i n part might b r i n g males i n t o contact, f i g h t i n g appears t o f u n c t i o n as a mechanism by which l i m i t s o r boundarys are e s t a b l i s h e d , between adjacent males once they have become l o c a l i z e d on an area and begin t o hoot.  53  I t i s also a mechanism by which t r e s p a s s i n g males are repulsed from an established male's t e r r i t o r y .  ^i^ny^  f i g h t i n g may  r e s u l t i n the displacement o f one male causing i t t o move t o areas remote. The courting a c t i v i t y of the adult male as a prelude to copulation can be considered  the prime feature of i t s t e r r i -  t o r i a l behaviour. Unlike v o c a l d i s p l a y , the c o u r t i n g d i s p l a y i s a combination of sound and body and plumage movement.  A  grouse landing with w h i r r i n g wings on or near a male's p o s i t i o n u s u a l l y i n i t i a t e s hooting, plumage and body d i s p l a y and causes the cock to move toward the sound.  Females i n movement, when  apparently seen by the cock are pursued to the l i m i t of the t e r r i t o r y and i f t h i s i s not an a c t u a l boundary, beyond. p u r s u i t s contribute then to the expanse o f t e r r i t o r y .  Such  Should  the female disappear i n the vegetation or beyond a c t u a l  terri-  t o r y l i m i t s , the cock ceases p u r s u i t and u s u a l l y begins or continues hooting presumably to a t t r a c t the female.  Should the  female remain s t a t i o n a r y w i t h i n a male's t e r r i t o r y ,  hooting  ceases and body and plumage d i s p l a y i s i n t e n s i f i e d as the cock moves towards i t . In f u l l courting d i s p l a y F i g . 17 the oesophagus i s i n f l a t e d which i n part a c t i v a t e s the e r e c t i l e feathers o f the neck.  These open and r e v e a l the thickened and rugose neck  t i s s u e which i n the spring and e a r l y summer i s an egg yolk yellow. The caruncle d o r s a l to the eye enlarges, r i s e s and becomes lemon yellow i n colour or sometimes a l i v i d red.  The t a i l i s held  F i g . 17  Courting d i s p l a y ( A f t e r Laing)  54 erect and spread w h i l e the wings are extended v e n t r a l l y .  The  male's cloaca puckers and d i l a t e s as i t approaches the female. When 2 to 20 f e e t from the hen the male drops i t s wings to the ground, and with s t i f f legs and r u s t l i n g p r i m a r i e s , swoops towards her.  This movement i s made i n a s l i g h t arc so that i t  approaches the hen from one side.  At the termination of the  rush and almost touching the female i t d i p s i t s head and emits a loud "whoot" sounding note, a c a l l shorter and higher pitched than the phrases o f the song.  At times the c a l l i s i n s t a n t l y  followed by a squeak or squeal which appears to be the i n s p i r a t i o n a f t e r the c o u r t i n g note e x p i r a t i o n .  I f the female should  jump, and move away the performance i s repeated.  I f she  remains, there begins an elaborate posturing with the cock standing motionless beside the female or t h r u s t i n g one side of i t s i n f l a t e d neck and then the other at her while the body i s jerked upwards and forwards. to 3 minutes.  This posturing may l a s t from 2  Gradually the male works behind and p l a c e s h i s  body and hanging wings over the crouching female u n t i l he touches her back.  At t h i s p o i n t , which i s the c l o s e s t to  c o p u l a t i o n that has been observed i n t h i s study, the female jumps forward and moves r a p i d l y away. her,  Again the cock pursues  o r may i f other females are present on the t e r r i t o r y , t u r n  to them.  A f t e r unsuccessful attempts at c o p u l a t i o n with one o r  s e v e r a l females, the male begins t o hoot, s t i l l i n the c o u r t i n g d i s p l a y although now the wings are held to the body.  He may  mount a l o g or stump and hoot from here while between c a l l s  55 t u r n i n g h i s head, apparently l o o k i n g i n a l l d i r e c t i o n s . F a i l u r e to observe a c t u a l c o p u l a t i o n obscures the meaning of the f u l l c o u r t i n g d i s p l a y .  L o g i c a l l y i t would  serve as mechanism i d e n t i f y i n g a r e c e p t i v e male to a receptive female, whereupon copulatory movements would ensue. Cowan (personal communication) has observed a c o p u l a t i o n i n which c o i t u s occurred immediately a f t e r the males rush "whoot" note.  and  I t seems l i k e l y then, the r e l a t i v e l y long time  observed i n d i s p l a y i n g and posturing by the male i s a r e s u l t of an unreceptive  c o n d i t i o n of the female.  On the other hand,  the time spent by the male i n posturing would suggest t h a t t h i s , as w e l l as the i n i t i a l phases of the d i s p l a y might f u n c t i o n as a mechanism r e l e a s i n g the copulatory response i n a not f u l l y receptive  hen.  Males, while s e x u a l l y a c t i v e , court a l l hens of the species without regard f o r t h e i r age or breeding c o n d i t i o n . Thus, whether non-laying, i n c u b a t i n g , or with young, hens e l i c i t the same response from the cock.  Trespassing  cocks whether  a d u l t or y e a r l i n g g e n e r a l l y e l i c i t the i n i t i a l phase of the c o u r t i n g d i s p l a y i n which the t a i l i s held erect and  spread,  the neck i n f l a t e d and the neck feathers d i l a t e d . Hooting cocks f r e q u e n t l y respond i n a s i m i l a r manner, when disturbed i n the f i e l d by an observer.  Thus i n i t i a l response to the hen or  t r e s p a s s i n g cock might be considered of a general nature.  The  completion of the c o u r t i n g d i s p l a y or the change to f i g h t i n g posture might be considered a more s p e c i f i c response to an i n t r u d i n g grouse once i t s sex i s recognized.  Since there i s no  56  apparent d i f f e r e n c e i n the posture o f t r e s p a s s i n g males as compared t o females, i t i s suggested that sex r e c o n g i t i o n by the male i s based on plumage or s i z e dimorphism o r both. The "whoof or c o u r t i n g note i s c h a r a c t e r i s t i c o f a male with female, and i s heard at no other time.  Although  the b i r d s may be out o f s i g h t , t h e sound serves to r e v e a l t h e i r p o s i t i o n as w e l l as i n d i c a t i n g when a cock and hen are together.  The courting c a l l of a male with a hen appears  to cause adjacent males to hoot more v i g o r o u s l y and draw as close t o the c o u r t i n g male and female as t h e i r t e r r i t o r y l i m i t s w i l l permit.  I t i s at t h i s time that the boundaries between  males are most apparent. As an example o f the c o u r t i n g c a l l ' s i n f l u e n c e on an adjacent male, male ( 1 2 , F ) was heard w i t h a female a t t h i s position i n Fig. 7.  From the f i g u r e , the point i s on o r near  the boundary between ( 1 2 , F ) and No. 1 6 2 .  The male (12,F) was  observed t o stand i n f u l l d i s p l a y then t u r n and run i n t o i t s t e r r i t o r y and begin to hoot.  At the same time No. 162 apparently  responding to the courting c a l l came running i n plumage and body d i s p l a y from deep i n i t s t e r r i t o r y and proceeded t o l o c a t e and court the banded female l e f t by male ( 1 2 , F ) .  She e v i d e n t l y  eluded him, o r he ceased t o f o l l o w , f o r he began t o hoot a t (13,G) the extreme upper edge o f h i s t e r r i t o r y . As an example o f the male's r e c o g n i t i o n o f i t s t e r r i t o r i a l boundary and that of another male, No. 162 was heard and seen w i t h a banded female at p o s i t i o n ( 1 4 , E ) i n F i g . 7 .  Males  57 No. 281 and No. 132 were hooting at the time.  Male No. 162  pursued the hen t o (16,G) and then at t h i s p o s i t i o n the boundary l i n e , turned back and began t o hoot. female continued i n the o r i g i n a l d i r e c t i o n .  The banded Near (16,G),  male No. 281, the resident o f t h i s t e r r i t o r y emerged from under a small f i r where i t had been v i g o r o u s l y hooting, began f u l l d i s p l a y and moved a f t e r the female.  Male No. 162 remained  hooting at the edge of i t s t e r r i t o r y , s i x t y f e e t from the banded female and male No. 281. In a s i m i l a r example, male (10,H) was v i g o r o u s l y c o u r t i n g a female on the road i n t h i s p o s i t i o n .  Sixty feet  up from i t male (8,J) was s i t t i n g on a stump at the edge o f the road i n plumage and body d i s p l a y .  Male (9,1) courted and  pursued the hen up the road t o (8,1) where he stopped and began to hoot.  At t h i s point (8,J) moved from the stump and began  to court the female which (10,H) had moved i n t o i t s t e r r i t o r y . C l e a r l y these males recognized how f a r they might go or at l e a s t i n what area they retained s u p e r i o r i t y over t h e i r neighbour with respect t o the use of area.  This appears t o  be the purpose of the t e r r i t o r i a l behaviour o f the male sooty grouse.  The undisputed possession of area, wherein hooting and  courting d i s p l a y can f u n c t i o n to f u l f i l l i t s reproductive requirements.  Thus the t e r r i t o r i e s can be considered mainly  as areas of d i s p l a y and c o u r t i n g a c t i v i t y .  58 General A c t i v i t i e s o f the Adult Male Most o f the d a y l i g h t hours o f A p r i l and May are spent i n hooting so that the male i s l o c a l i z e d and occupied with t h i s a c t i v i t y .  Observations on s i l e n t males i n and  a f t e r t h i s time i n d i c a t e they do not move f a r from t h e i r t e r r i t o r i e s while sexually active.  Thus most o r a l l the  a n c i l l a r y a c t i v i t i e s o f such males are c a r r i e d out w i t h i n the l i m i t s o f these hooting areas. In r e a c t i n g t o an observer cocks as w e l l as hens tend t o crouch and " f r e e z e " r a t h e r than take f l i g h t .  When  movement i s made i t i s u s u a l l y on f o o t as a slow g a i t or run. Generally a b i r d must be s t a r t l e d o r hard pressed before i t w i l l f l y ; a r a p i d beat o f the wings and a long f l a t g l i d e r a r e l y more than 20 f e e t above the ground. The males feed but l i t t l e throughout t h e day.  In  l a t e evening there i s a feeding p e r i o d , when they feed v i g o r ously and f i l l t h e i r crops.  Vegetable and a v a i l a b l e  seem the only p r e r e q u i s i t e s f o r a food species, although i f present c l o v e r s are taken before other v e g e t a t i o n .  From t h e  v e g e t a t i o n a l a n a l y s i s there appears t o be no shortage o f food on the t e r r i t o r i e s o f males. i n the f i e l d .  This i s obvious from observation  No male was observed t a k i n g water o r g r i t ,  although the l a t t e r was found i n the crop and g i z z a r d o f b i r d s . The frequent occurrence of dust baths i n f i n e sand or r o t t i n g d e b r i s , and t h i s m a t e r i a l i n f e a t h e r s would suggest dusting as an a c t i v i t y o f the male.  Preening and s c r a t c h i n g  59  the head r e g i o n have twice been observed.  Males have been  f r e q u e n t l y found s i t t i n g q u i e t l y under a shrub or l o g . This behaviour probably accounts f o r most of t h e i r time when not otherwise a c t i v e .  When r o o s t s have been found they were on  the ground and u s u a l l y at hooting s i t e s .  I t seems l i k e l y that  unless feeding i n an exposed s i t e , the males cease a c t i v i t y and begin again wherever n i g h t f a l l and daybreak f i n d s them. Seasonal Behaviour of the Adult Male The seasonal behaviour of the adult male can be i l l u s t r a t e d i n several ways.  In terms o f males recorded per  hour per week of the study period as i n F i g . 28(a) there i s a marked trend i n the number of males observed. i n almost every case were on hooting males.  The observations Thus from a peak  of observed hooting a c t i v i t y i n the f i r s t weeks o f the study the number observed per hour d e c l i n e s u n t i l by August they are r a r e l y observed on the study area. In terms of the i n d i v i d u a l males i n a study p l o t , t h e i r change i n behaviour i s r e l a t e d to the numbers observed holding t e r r i t o r y .  In A p r i l and May both p l o t I and I I  contained the greatest number of hooting males.  On p l o t I I i n  A p r i l , 18 hooting males were recorded, i n May, 16 i n June, 14 and i n J u l y , 6.  By the end o f J u l y but two males remained  a c t i v e l y hooting i n the p l o t . In terms of the d a i l y behaviour of males, the change over the summer i s most s t r i k i n g .  In A p r i l and May they are  hooting almost constantly from t h e i r t e r r i t o r i e s and do not  60 move f a r from them when s i l e n t .  By the end of June and i n  J u l y daytime hooting i s sporadic with general hooting heard only i n the morning and evening hours.  By the end o f J u l y no  hooting at a l l i s heard i n the d a y l i g h t hours, and r a r e l y i n the mornings and evenings. As the males cease to hoot, they no longer remain l o c a l i z e d on t h e i r t e r r i t o r i e s but apparently begin to wander. Thus male No. 132 F i g . 7, l a s t recorded hooting at (21,D) was subsequently observed at (19,1) then at [15,Q) F i g . 6.  One  apparently wandering a d u l t male was observed t o make contact w i t h a female and began to court and hoot.  I t was captured  but not seen again at t h i s s i t e although l a t e r observed  twice  at widely separated points on p l o t I I . Other males, and t h i s i s the usual case i n J u l y and l a t e r , show no r e a c t i o n t o females. As an example male No. 147, F i g . 7 was observed at (12,F) on August 6th.  Up u n t i l t h i s time i t had not been observed  the l i m i t s of i t s t e r r i t o r y at (18,Q).  outside  The male was beside a  f i r clump w i t h i n which two females were s i t t i n g i n f u l l view, yet i t d i d not react t o e i t h e r . The c e s s a t i o n o f hooting and abandonment o f t e r r i t o r i e s and sexual a c t i v i t y are l i k e l y preludes to the a l t i t u d i n a l migration o f the cocks.  From F i g . 28(a) and a c o n s i d e r a t i o n o f  the numbers of hooting males censused on p l o t I I from A p r i l to J u l y above, the movement i s not sudden or r a p i d but apparently begins i n June so that by August males are r a r e l y seen on t h e study area.  Cocks observed i n August have been alone and on  61 the ground.  T h e i r necks were t h i n , i n moult, and the caruncle  of the eye s c a r c e l y v i s i b l e .  F i v e males observed i n t h i s  month were o f f t h e i r t e r r i t o r i e s and three t h a t were banded had moved i n a d i r e c t i o n suggesting a r e t u r n t o the winter range. In searching an underlying mechanism f o r the seasonal behaviour of the a d u l t male i t i s noteworthy how the decreasing t e s t e s volumes of males measured i n each week of the study period, correspond to the events described.  F i g . 18 i s a p l o t  of t e s t i s volume of 51 a d u l t males and 5 y e a r l i n g males against weeks of the study p e r i o d . The average a d u l t t e s t i s volume of each weeks sample i s p l o t t e d f o r each week to produce the curve. The s i m i l a r i t y of the curve i n F i g . 18 to the curves of F i g . 28(a) i s s t r i k i n g .  Thus w h i l e the a c t i v i t i e s of the male are  determined i n part by e x t e r n a l f a c t o r s , i t i s l i k e l y the internal  sex physiology as measured here by t e s t i s volume, sets  the stage upon which e x t e r n a l f a c t o r s p l a y t h e i r  role.  The Behaviour of the Y e a r l i n g Male While over 300 adult males have been observed hooting on t h e i r t e r r i t o r i e s i n the study area but 1 y e a r l i n g male was so recorded i n the same time.  This b i r d and nine others make  up the t o t a l number of y e a r l i n g males observed over the years 1951 to 1953.  Of the t e n , two were captured on the study p l o t s  i n v a r i o u s p o s i t i o n s i n A p r i l and May.  One y e a r l i n g male was  observed with a female and both moved together. d i s p l a y was noted i n the male.  No sexual  Of the 2 banded y e a r l i n g s , one  • Volume of adult male testes o Volume of yearling male testes Average volume, yearlings excluded  o u S  3  </>  V  to tt) 0)  E 2 3 o  >  J  Fig. 18.  I  5  i  i  6 7 8 9 Week of summer  10  Testes volume in c.c. and week of summer  14  62 was seen twice again i n p o s i t i o n s on and o f f p l o t l l 1,000 f e e t apart.  Thus i t was not apparently l o c a l i z e d to a p a r t i -  cular region.  The second y e a r l i n g captured was banded i n t h e  t e r r i t o r y of a male a t (5,0) F i g . 6 i n 1951.  The b i r d was  not seen again u n t i l 1953 when i t was l o c a t e d as an a d u l t male hooting on a t e r r i t o r y 600 f e e t from the p o i n t o f capture. The observations obtained on y e a r l i n g males are s i m i l a r to those of a d u l t males a f t e r they have ceased t h e i r t e r r i t o r y holding a c t i v i t i e s ; v o c a l s i l e n c e , apparent wandering and no r e a c t i o n t o females.  The one y e a r l i n g male recorded hooting  was an exception to t h i s and had e v i d e n t l y a t t a i n e d a d u l t sexual development i n i t s f i r s t year.  Another y e a r l i n g was  observed t o court and hoot a female which landed and f e d on the t e r r i t o r y of male No. 9 F i g . 7.  When the hen l e f t the  area, the y e a r l i n g f o l l o w e d and both disappeared.  I t was not  observed again. Thus with t h e exception o f one hooting y e a r l i n g and another which was observed i n c o u r t i n g d i s p l a y , y e a r l i n g males observed on the study area do not manifest the sexual and t e r r i t o r i a l behaviour as found i n the a d u l t s .  C o r r e l a t e d , and  serving t o i l l u s t r a t e a r e l a t i o n s h i p between a d u l t male behaviour and sexual development, the t e s t e s volumes of 5 yearl i n g males have i n each case been l e s s than the t e s t e s volumes of adult males measured i n the same week, F i g . 18.  63  Spring M i g r a t i o n i n t h e Y e a r l i n g Male Generally, the y e a r l i n g males behave as females p r i o r to hatching time, and are found under t h e same c o n d i t i o n s .  In  the s p r i n g , however, when t h e i r behaviour i s comparable, y e a r l i n g hens are f r e q u e n t l y observed, while y e a r l i n g cocks but r a r e l y . Thus the small number o f y e a r l i n g s recorded on the summer range i s apparently r e a l , and not caused by t h e i r going unobserved. I t seems u n l i k e l y t h i s i s the true number o f y e a r l i n g cocks i n the population f o r there i s no apparent reason why the yearl i n g males should d i e o r move out o f the study area at a f a s t e r r a t e than the y e a r l i n g females t o produce the observed d i s p a r i t y i n spring sex r a t i o .  The simplest explanation i s t h a t they are  not w i t h the summer population o f females and adult males but i n places remote, l i k e l y the winter range on the mountain slopes. Wing  (1943)  has made reference t o the " b i g males" and  absence o f females observed on the winter range i n the summer. He suggests they a r e mature males but non-breeders.  Beer  (personal communication and f i e l d notes) states t h a t while c o l l e c t i n g i n Washington near Lone Frank Pass i n l a t e June a t 4,500  f e e t and above, he and h i s companions observed  grouse and a l l males.  50  blue  Ten b i r d s were c o l l e c t e d and each was  s e x u a l l y undeveloped w i t h respect t o t e s t e s s i z e and neck condition.  Beer recognized the p o s s i b i l i t y t h a t the b i r d s were  breeding males o f the spring which had returned i n June to t h e winter range, o r o l d males beyond reproductive age that had f a i l e d to make t h e s p r i n g descent.  From the l i g h t colour o f the  plumage and s o f t t e x t u r e of the neck t i s s u e s , however, Beer  64 concluded the t e n b i r d s sampled were a l l immature males hatched i n the preceding year.  I n t h i s study they are c a l l e d  y e a r l i n g males. These data from the w i n t e r range i n summer, coupled with the observations made i n the study area i n d i c a t e t h a t the observed absence o f y e a r l i n g males from the breeding range i s caused by t h e i r f a i l u r e to make a downward m i g r a t i o n i n the s p r i n g a f t e r hatch.  Thus most males l e a v i n g the summer range  as c h i c k s do not make the downward m i g r a t i o n u n t i l t h e i r second spring a f t e r hatch, and by t h i s time, i n a d u l t plumage.  From  t h i s , and the absence o f t e r r i t o r i a l and sexual behaviour the y e a r l i n g males observed on the study area, i t i s l i k e l y the s p r i n g m i g r a t i o n , as w e l l as sexual and t e r r i t o r i a l  behaviour  i n the male i s r e l a t e d t o sexual development. Spring Behaviour o f the Female Although Anthony (1903) suggests the females a r r i v e on the summer range l a t e r than the cocks, there i s no corrobora t i v e evidence from t h i s study.  As i n the case o f the males,  by the e a r l i e s t date o f f i e l d i n v e s t i g a t i o n , both sexes appeared to be e s t a b l i s h e d on the summer range. Although more y e a r l i n g hens make the descent than y e a r l i n g cocks, there e x i s t s the p o s s i b i l i t y t h a t they too remain i n numbers on the w i n t e r range over the f i r s t year.  The  reported absence o f females on t h e w i n t e r range i n summer, the breeding behaviour o f the y e a r l i n g hens which resembles t h a t o f  65 the a d u l t s , and the apparently f u l l numerical c o n t r i b u t i o n o f y e a r l i n g females t o the population on the study area suggests, however, the y e a r l i n g females descend to t h e lowlands i n t h e i r f i r s t s p r i n g a f t e r hatch. P r i o r t o hatching o f the young and between e a r l y morning and l a t e evening which are times of intense a c t i v i t y , the observation o f hens i n the f i e l d i s l a r g e l y a matter o f chance.  Unlike the hooting cocks, the hens make no sound o r  display to reveal their positions.  They are u s u a l l y observed  s i n g l y and s i t t i n g under a shrub o r l o g . At times two hens are seen together and t h i s most o f t e n i n the s p r i n g months.  On one  occasion as noted above, a y e a r l i n g male was observed with a hen. These observations might i n d i c a t e some tendency i n the hens t o make the downward descent together, or a more i n t e r e s t i n g s i t u a t i o n wherein y e a r l i n g males and females remain w i t h the mother female overwinter and descend with her i n the s p r i n g .  Such a  c o n d i t i o n might i n part e x p l a i n the m i g r a t i o n o f the few s e x u a l l y undeveloped y e a r l i n g males observed i n the study area.  Too few  data are a v a i l a b l e to make these suggestions anything but specula' tive.  I n the case o f hens together i t i s necessary t o c o l l e c t  both to make accurate age i d e n t i f i c a t i o n .  This has never been  done. Unlike the cocks the adult and y e a r l i n g hens do not occupy and defend t e r r i t o r y on the summer range.  From f i e l d  observations females move over r e l a t i v e l y l a r g e areas p r i o r t o i n c u b a t i o n and hatch.  F i g . 19 i s a map o f the observed p o s i t i o n s  0  1  2  3  ]_9 ! PREHATCH  4 5 6 7 10 II 8 9 DISTRIBUTION OF SEVEN FEMALES No 125 " 350  •  Q  17 18 19 20 21 22 23 12 13 14 15 16 AS RELATED TO NESTS AND MALE TERRITORIES PLOT n .No 15 ® No 285 • " 34 " 164 © a •• 292 O  66 of marked females without young on p l o t I I i n A p r i l and May of 1 9 5 2 .  l a r g e s t observed range was t h a t of female No. 125.  I t was noted over approximately 20 acres, i n c l u d i n g area o f f the plot.  From the distances between observations on other hens i n  the same f i g u r e , i t seems l i k e l y that movements of t h i s extent are not unusual. This r e l a t i v e l y l a r g e range of the female makes i n t e r pretation d i f f i c u l t .  Marked hens are observed f r e q u e n t l y enough  to suggest they are r e s i d e n t , or become l o c a l i z e d on an area p r i o r to l a y i n g and i n c u b a t i n g eggs.  Females No. 1 2 5 , No. 3 4  and No. 15 were not observed w i t h young at any time yet were observed on or near p l o t I I throughout the summer as apparent residents.  Again, any tendency f o r s u r v i v i n g females to r e t u r n  to the same area i n subsequent years i s obscured by t h e i r r e l a t i v e l y l a r g e movements.  Thus f a i l u r e to observe a hen  banded the preceding year does not n e c e s s a r i l y i n d i c a t e death or the abandonment of the area i n which i t was banded.  Five  hens marked p r i o r t o the hatch on p l o t I I i n 1950 were observed on the p l o t i n 1951.  Three of- these hens and 5 banded i n 1951  were observed on the p l o t i n 1952.  This suggests that as w i t h  cocks, the hens r e t u r n t o the same area i n subsequent years. Unlike the cocks, the hens then move independently over a r e l a t i v e l y large area which might be c a l l e d a home range. What f a c t o r s r e s u l t i n the movements of hens p r i o r to incubation i s l a r g e l y a matter of s p e c u l a t i o n .  As i n the males  the requirements f o r general a c t i v i t i e s such as f e e d i n g , d u s t i n g ,  67 preening and p o s i t i o n s i n which to s i t probably account f o r some of them.  On the study area, from F i g . 1 4 , hens i n p l o t I  show a tendency to u t i l i z e Willow Dense and Willow Open s h e l t e r types while the greatest u t i l i z a t i o n i s of Clover Open food type, that i s to say, the roads and small c l o v e r f i l l e d c l e a r ings.  On p l o t I I from the same f i g u r e , F i r Dense and Willow  Dense types are u t i l i z e d most, with Clover Open, as on p l o t I , f r e q u e n t l y used.  From t h i s i t would seem f a c t o r s i n f l u e n c i n g  the d i s t r i b u t i o n of females p r i o r to i n c u b a t i o n were i n part concealment found i n s h e l t e r vegetation, and p r e f e r r e d food found i n Clover Open type.  The u t i l i z a t i o n of the open types  i s most pronounced i n the e a r l y morning and l a t e evening, when the hens move a c t i v e l y to raads and other open areas and feed. Three observations have been made on hens i n or near standing water.  Once a d i v i n g b e e t l e ( d y t i s c i d a e ) was observed i n the crop  of a c o l l e c t e d hen.  Other than t h i s , there i s no evidence from  t h i s study t h a t f r e e water i s important i n the existence of the female. I t seems l o g i c a l to b e l i e v e t h a t the hen when g r a v i d w i t h eggs should under concommitant p h y s i o l o g i c a l stimulus respond to the hooting of a male or males and seek them out.  I t i s note-  worthy t h a t the home range p o s i t i o n s , as observed i n hens, p r i o r to being observed with young, are i n no way r e l a t e d to a p a r t i c u l a r male's t e r r i t o r y , F i g . 1 9 ,  S h females appear to move u c  f r e e l y about and i n so doing l i k e l y come i n t o contact with as  68 many males as t h e i r home range i n c l u d e s .  With the l a c k o f  other data on the mating behaviour of the female and from the c o u r t i n g r e a c t i o n of the cock while i n breeding c o n d i t i o n i t i s l i k e l y that sooty grouse of both sexes are promiscuous o f breeding h a b i t . Nesting Behaviour of the Female The d e s c r i p t i o n of n e s t i n g behaviour i s based l a r g e l y on the autopsy o f 22 hens.  At l e a s t f i v e were taken each week  of the period May 4th to June 1 s t .  These data are supported  by information from hens captured, examined and palpated i n the field. Two hens c o l l e c t e d i n l a t e A p r i l had undeveloped o v a r i e s w i t h no apparent ova, the o v i d u c t was s i m i l a r l y i n a c t i v e . By the f i r s t week i n May, ova were apparent i n numbers from 3 to 5 i n the hens sampled with the o v i d u c t thickened and enlarged.  By the second week i n May, t h e f i r s t shed o v a r i a n  f o l l i c l e s were observed i n d i c a t i n g the hens had begun t o deposit eggs.  Two hens captured i n the f i e l d  eggs i n t h e i r o v i d u c t s .  i n t h i s time had palpable  I n the t h i r d week of May maturing ova  were s t i l l v i s i b l e with the shed f o l l i c l e counts i n c r e a s i n g .  At  t h i s time hens were f i r s t observed w i t h a developing brood patch. By the end o f May a l l production of ova had ceased, and counts of shed f o l l i c l e s  had reached a maximum.  Birds taken a f t e r t h i s  time had complete brood patches. From t h i s i t appears" that the production of ova begins  69 i n l a t e A p r i l and e a r l y May and continues w h i l e the eggs are l a i d from the second to l a s t week of May.  The brood patch i s  i n c i p i e n t as the eggs are deposited and becomes f u l l y  developed  at the c e s s a t i o n of l a y i n g a c t i v i t y and the beginning o f incubation. The brood patch i s an area between the l e g s from the base of the f u r c u l a to a centimeter a n t e r i o r to the vent, devoid of contour feathers and w i t h the s k i n thickened and vascularized.  This i s e v i d e n t l y an adaptation p r o v i d i n g greater  warmth to the eggs from i n c u b a t i n g hens.  One hundred n e s t i n g  hens and hens with broods examined showed a w e l l formed brood patch, thus i t serves as an i n d i c a t o r of i n c u b a t i n g or breeding activity. The r a p i d i t y w i t h which the ovary s h r i n k s a f t e r the brood patch i s formed i s worthy of note.  I n a l l hens sampled,  once the brood patch was developed, o v a r i a n a c t i v i t y had and the ovary returned to non-breeding s i z e .  ceased  This would suggest  that once i n c u b a t i o n had begun a destroyed c l u t c h would not be replaced. The number of eggs l a i d i s an important s t a t i s t i c that i s d i f f i c u l t to o b t a i n because of the concealed nature of nests. As a best estimate of egg production the few data from nests are supported by counts of shed f o l l i c l e s and r i p e n i n g ova i n hens shot during the n e s t i n g season.  A shed f o l l i c l e or a r i p e ovum  does not n e c e s s a r i l y mean an egg has been or w i l l be deposited i n a nest.  T h i s , however, i s not considered an important source  70 of  error. °ix nests of a d u l t hens discovered i n the study area,  averaged 6 eggs per nest with a range of 5 to 7.  Nests of year-  l i n g hens have not been found, although hens of t h i s age c l a s s have been observed with brood patches and with young. 'On the b a s i s of r i p e ova and shed f o l l i c l e counts 9 y e a r l i n g hens c o l l e c t e d i n May produced an average c l u t c h of 4 eggs.  Thirteen  adult hens c o l l e c t e d i n the same period and examined i n a s i m i l a r manner produced an average c l u t c h of 5 eggs.  There i s  no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e (by " t " t e s t ) between these two averages which suggests on the b a s i s of r i p e ova and shed f o l l i c l e counts the p r o d u c t i v i t y of nesting adult and y e a r l i n g hens i s s i m i l a r .  With t h i s , and the data from s i x  nests, the average c l u t c h s i z e l a i d by n e s t i n g hens i n the study area appears to be 6 eggs or p o s s i b l y lower.  This f i g u r e agrees  with the l i t e r a t u r e , Fowle (1943), Bent (1932) and o t h e r s .  There are few data from t h i s study which might be c l a s s i f i e d as l a y i n g behaviour i n the female.  Most observations  on the hens i n d a y l i g h t hours f i n d them s i t t i n g under logs or t r e e s , not u n l i k e t h e i r behaviour at a nesting s i t e .  On May 20th  of 1952 a nest was located at the base of a f i r at (13,M) F i g . 19. I t held 5 eggs which were c o l d and r a i n wetted.  The eggs were  covered with debris and almost completely covered by lower branches of the f i r .  The nest was a shallow depression i n dead  P t e r i s stems and G a u l t h e r i a leaves which were not used i n a  71 c o n s t r u c t i v e manner.  No female was observed i n the v i c i n i t y -  then, nor on the second day when the nest was v i s i t e d .  On  May 22nd the female was on the nest, and again when v i s i t e d on the 2 3 r d .  On the 2 4 t h the hen was observed feeding at 0345  hours at (10,C) F i g . 1 9 . 6 warm eggs.  The nest was inspected and contained  Thus i n the i n t e r v a l  of four days she had l a i d  one egg, the s i x t h and l a s t , f o r from t h i s time on i n c u b a t i o n was i n progress. I t i s noteworthy t h a t the female was not observed  on  the nest u n t i l i n c u b a t i o n had begun and probably moved over i t s home range u n t i l l o c a l i z e d  by l a y i n g and i n c u b a t i n g a c t i v i t i e s .  The absence of the hen from the nest at 0345 hours i s a l s o worthy of note, f o r t h i s time i s w i t h i n the morning a c t i v i t y period and w i l l be mentioned again below. When i n c u b a t i o n i s i n progress, t h i s nest, as others observed, became more bowl shaped, approximately 6 inches i n diameter and 2 to 3 inches i n depth below the rim.  The arrange-  ment of d e b r i s as w e l l as the presence of f e a t h e r s i n the nest suggested some c o n s t r u c t i o n . The f e a t h e r s are probably those shed or plucked from the hen's v e n t r a l surface i n the formation of the brood patch. One of the s t r i k i n g features o f the nesting behaviour of the female sooty grouse i s the s e l e c t i o n of open v e g e t a t i o n f o r the nest s i t e , F i g . 1 4 .  Of the s h e l t e r types i n p l o t s I and  I I , Log Open and Bracken Open were the most f r e q u e n t l y u t i l i z e d .  72 Nests were not found i n the dense s h e l t e r types, although i n t e n s i v e search was made i n these areas t o d i s c o v e r them. I n the open types, the nests are u s u a l l y covered by l o g s , f i r branches o r shrubs, F i g . 20(a) and ( b ) . This cover i s completed by the body o f the incubating female. The nests found i n p l o t I and p l o t I I over the 3 year study p e r i o d were mapped t o determine t h e i r r e l a t i o n s h i p t o the t e r r i t o r i e s o f hooting males. and 12.  This i s i l l u s t r a t e d i n F i g s . 11  Some nests are w i t h i n the t e r r i t o r y of a hooting male  and some are without, there i s no apparent r e l a t i o n s h i p .  More-  over, the n e s t i n g behaviour of hens i s not apparently i n f l u e n c e d by the males except as she might make contact w i t h them i n her movements t o and from the nest.  Thus with the exception o f copul-  a t i o n and i t s p r e l i m i n a r i e s the two sexes are independent o f one another on the breeding range. The d e s c r i p t i o n o f i n c u b a t i o n behaviour i s based on v i s i t s t o , and $ hours o f observation on, 3 nests i n p l o t I I . Time spent at nests d i d not i n c l u d e a l l hours o f the day, t h e r e f o r e , the data are fragmentary.  Further, the almost complete  concealment o f hens on nests made observation d i f f i c u l t . The eggs- i n the three nests were marked w i t h p e n c i l and t h e i r p o s i t i o n s noted.  On subsequent v i s i t s they had been  rearranged and turned i n t h e nest, presumably by the hen.  Whether  t h i s i s by accident o r design i s a question. In 34 nest v i s i t s i n d a y l i g h t hours the females were observed o f f nest 6 times, thus most o f the d a y l i g h t hours are spent i n c u b a t i n g .  One nesting female observed from a hide i n  73 the day, was never recorded f a r o r long from her nest.  She  would c i r c l e the nest at approximately 30 f e e t , feed and dust. Three such s a l l i e s were recorded, each l a s t i n g ten minutes. was at 1100 hours, the other two at 1430 and 1500.  One  The absence  of droppings about nesting s i t e s suggests l i t t l e use o f the immediate area of the nest.  On the other hand, droppings may  not be voided i n the p r e c i n c t s . In 15 nest v i s i t s during e a r l y morning and l a t e evening periods o f a c t i v i t y , females were recorded o f f nest 9 times.  This r e s u l t i s supported by the number o f females w i t h  brood patches noted along t h e roads and i n the open types during these p e r i o d s .  When observing two hens a t the nest, both were  observed t o make evening f l i g h t s .  In. the case of one, she  emitted s o f t quavering notes, then suddenly moved and took f l i g h t from the nest at (11,0) F i g . 19. She returned i n 14 minutes from same d i r e c t i o n towards the nearest road i n which she had flown. On a r r i v i n g she landed w i t h s i l e n t wings w i t h i n a f o o t o f the . nest and immediately disappeared i n t o the surrounding v e g e t a t i o n . Another hen was observed t o land s i l e n t l y w i t h i n 20 f e e t o f her nest a t the completion o f a morning and an evening f l i g h t . The s i l e n c e o f f l i g h t i s noteworthy f o r i t has already been noted above that the w h i r r i n g o f wings i s s u f f i c i e n t to begin the c o u r t i n g d i s p l a y o f t h e male and cause i t t o move toward the sound.  Thus landing w i t h or without sound might  f u n c t i o n as a mechanism f o r the a t t r a c t i o n o f t h e cock o r the concealment from i t .  i  74 In the p o s i t i o n o f an observer on a road or i n a c l e a r i n g of the study area the commencement of the evening and morning a c t i v i t y i s marked by the sound of wings i n f l i g h t and the c a l l s o f the male and female.  While i n f l i g h t , o r t a k i n g  o f f during the a c t i v i t y p e r i o d s , hens have been heard to emit a qua qua quaaaa sounding c a l l .  From watching hens i n f l i g h t ,  movements of 5 0 0 f e e t are not uncommon.  Hen No. 125, F i g . 19  was recorded i n 1951 at distances o f 200 to 5Q0 f e e t from i t s nest l o c a t e d over the Quinsam River.  She was observed f e e d i n g  at (12,B), (13,M) and (10,B) on p l o t I I . Hen No. I 6 4 n e s t i n g at (11,0) was observed on the road a t ( 8 , J ) , while hen No. 285 with nest a t (14,M) was observed at (16,K) and (10,D) i n t h e same figure. As many as three banded hens have been observed i n one evening i n a p a r t i c u l a r area o f Clover Open o r Bracken Open w i t h one o r none observed the next.  Again as many as 9 hens have  been observed over a p a r t i c u l a r s e c t i o n of road i n t h e evening a c t i v i t y p e r i o d , w i t h but one observed i n the same area i n the morning p e r i o d . Thus i t does not seem l i k e l y t h a t t h e same distance or d i r e c t i o n i s taken by the hen each time a f l i g h t or ground movement from the nest i s made. A f t e r a r r i v i n g at t h e roads or open areas by f l i g h t o r walking, the hens begin t o feed and move about completely exposed. As i n the case o f the males almost everything vegetable i s consumed although Trifolium^Medicago and Hypochaeris are s e l e c t e d when present.  The f o r a g i n g o f hens i s o f t e n i n t e r r u p t e d by the  75  c o u r t i n g a c t i v i t y of the cocks p a r t i c u l a r l y i f the f e e d i n g area i s on t h e t e r r i t o r y o f a s e x u a l l y a c t i v e male.  Within a  h a l f hour a l l a c t i v i t y ceases as the hens move back to t h e i r nests or darkness f a l l s . While f e e d i n g or upon a r r i v i n g i n open areas hens have been observed to preen, dust, chase one another and defecate. In d u s t i n g the hen u s u a l l y pushes her bare v e n t r a l surface i n t o earth or g r a v e l i n one o r two quick motions and continues feeding.  On one occasion antagonism was noted between hens f e e d i n g  i n an open area.  One, a banded hen, p e r s i s t e n t l y chased a  second which appeared with her on two consecutive mornings. Perhaps t h i s i s a means by which a female separates i t s e l f from previous years young s t i l l i n consort. At a l l other times hens moved and f e d independently of t h e i r f e l l o w s . Grouse scats are f r e q u e n t l y found on the study area and can be recognized as s i n g l e , caecal and clocker droppings, F i g . 2 1 . The clocker dropping i s up t o t e n times the s i z e of a s i n g l e scat and wound as the c o i l s o f an elongated s p r i n g . Four incubating hens have been observed to deposit a c l o c k e r dropping upon a l i g h t i n g i n open areas d u r i n g morning or evening activity.  The Committee on the Enquiry into the Grouse Disease  (1911)  mentions the clocker as a dropping voided by incubating  hens.  With the above evidence and from common p o u l t r y  knowledge,  the dropping when found, can be used as an i n d i c a t i o n o f the presence of an i n c u b a t i n g hen. I n F i g . 1 4 , c l o c k e r droppings have been c l a s s i f i e d as  F i g . 24(b)  Defence d i s p l a y of female  F i g . 24(c)  Defence d i s p l a y of female  76 to v e g e t a t i o n a l type.  This i n t u r n r e f l e c t s the u t i l i z a t i o n  of these types by incubating hens.  The droppings are con-  centrated i n the open cover types w i t h the greatest number i n Clover Open.  This i l l u s t r a t e s the r e l a t i v e importance of these  areas as feeding grounds and suggests also that d e f e c a t i o n does not take place u n t i l the feeding ground i s reached.  In  nesting and feeding during incubation, the hens u t i l i z e the open types to the almost complete e x c l u s i o n of dense v e g e t a t i o n . Periods of intense morning and evening a c t i v i t y were observed from the e a r l i e s t date of f i e l d o b s e r v a t i o n , before and a f t e r the period of i n c u b a t i o n .  Non-breeding y e a r l i n g hens and  hens w i t h brood patches but never observed w i t h broods, p a r t i c i pated i n the a c t i v i t y .  Thus the morning and evening movements  or f l i g h t s are apparently made by incubating and non-incubating hens.  As hatching occurs, however, the number of females observed  along roads and i n open types diminishes u n t i l by the middle or end of June i t i s unusual to observe or hear a hen engaged i n morning and evening feeding a c t i v i t y . The D i u r n a l A c t i v i t y Rhythm To i l l u s t r a t e the d i u r n a l a c t i v i t y rhythm of male and female grouse two periods of f i e l d study were s e l e c t e d , A p r i l 13 to May 15th and May 16 to June 5th.  In these periods a l l s i g h t s  and sounds of grouse were recorded i n sample h a l f hours between 0300 to 2400 standard time, as the observer moved over the study plots.  The number of grouse observations were then expressed as  per h a l f hour of the 0300 to 2400 day i n the two p e r i o d s .  77 Sight, i s the observation of b i r d s i n f l i g h t or on the ground, w h i l e sound r e f e r s t o the number of males heard hooting, beat of wings, sound of f i g h t s , c a l l s of females, or the p e c u l i a r "whoot" note given when a male i s c o u r t i n g a female. The r e s u l t s of t h i s a c t i v i t y a n a l y s i s are presented g r a p h i c a l l y i n F i g . 2 2 from Table VI appended.  In both periods  the two a c t i v i t y peaks of each day, which correspond to the morning and evening hours of obvious.  0300  to  and  0500  1900  to  2200,  are  The g r e a t e s t part of t h i s a c t i v i t y i s as a  r e s u l t of the females appearing and f o r a g i n g on or near the t e r r i t o r i e s of males and subsequently being courted by them. Thus the large c o n t r i b u t i o n of males w i t h females to the a c t i v i t y columns.  However, hooting i s more general at t h i s time and i n  part e x p l a i n s the peaks.  From  0500  to  1900  or  2000  there i s a  l e s s e r but steady hooting a c t i v i t y over the study area w i t h the sound of males with females often heard, although l e s s f r e q u e n t l y than i n the morning or evening hours. . In comparing the two periods i t w i l l be observed t h a t a c t i v i t y begins l a t e r i n the morning and ends e a r l i e r i n the evening i n period A p r i l 1 3 to May 5 . peaks are s h i f t e d  accordingly.  The morning and evening  Some o f the p r e c i s i o n w i t h which  a c t i v i t y begins and r i s e s to a peak i s l o s t i n u s i n g the r e l a t i v e l y l a r g e number of days i n each p e r i o d .  While the peaks of  a c t i v i t y appear to occur over two hours of the morning or evening i n the f i g u r e i n any given day they l a s t but 1 0 to 3 0 minutes. Again, i n the middle of A p r i l , morning a c t i v i t y begins w i t h the  Fig. 22  10 12 14 16 18 20 22 24 Hours from Table 21. Grouse activity and time of day in the periods April 13 to May 15, May 16 to June 2 3 .  78 peak between 0430 and 0500 and the evening peak between 1900 and 1 9 3 0 .  In l a t e June a c t i v i t y begins w i t h the morning peak  between 0 3 0 0 and 0 3 3 0 and the evening peak between 2130  to 2 2 0 0 .  In the evenings a c t i v i t y q u i c k l y subsides a f t e r the short period of f l y i n g , f e e d i n g , c o u r t i n g and vigorous hooting so that the area i s s i l e n t u n t i l the morning hours. In each of the two periods the morning peak shows the l e a s t spread i n time, which would suggest i t was of s h o r t e r d u r a t i o n , or intense a c t i v i t y l a s t e d longer i n the evening. From f i e l d observation t h i s appears to be the case. In the f i e l d one can p r e d i c t the beginning of evening a c t i v i t y i n any given day from the measurement of l i g h t  intensity.  A General E l e c t r i c type DW-68 exposure meter was used to measure l i g h t i n foot candles, and i n so doing, held d i r e c t l y i n t o the open sky.  Light i n t e n s i t y , according t o time of day, f a l l s i n  a c h a r a c t e r i s t i c manner, w i t h a r a p i d and steep drop at sunset which g r a d u a l l y f l a t t e n s out to produce a negative exponential curve, w i t h a long t a i l .  The reverse i s t r u e at s u n r i s e .  The  curve i s nearly asymptotic at the i n t e n s i t y of 2 f o o t candles and t h i s s l o w l y drops to 1, the lowest l i g h t value measureable, over a period of 15 minutes to h a l f an hour depending on atmospheric conditions. Each day at 4 to 2 foot candles evening a c t i v i t y begins, and continues past 0 f o o t candles on the l i g h t meter.  The cessa-  t i o n of evening a c t i v i t y i s not as p r e c i s e and occurs as hens  79 move from on o r near the t e r r i t o r i e s o f males.  Hooting  continues, becomes sporadic and then ceases a t darkness w e l l beyond 0 l i g h t i n t e n s i t y as recorded on the exposure meter. In the morning hours a c t i v i t y begins before there i s a reading on t h e l i g h t meter and continues u n t i l 2 to 4 f o o t candles a f t e r which the s i g h t s and sounds o f morning a c t i v i t y r a p i d l y cease. Most o f peak a c t i v i t y i s a t t r i b u t a b l e to the females i n t h e i r morning and evening movements.  When t h i s behaviour  ceases i n l a t e June and J u l y , however, the cocks s t i l l conform to the d a i l y rhythm with peak hooting a c t i v i t y i n the morning and evening hours, although they may remain s i l e n t throughout the day.  This continues as long as they hold t e r r i t o r y . The p r e c i s i o n w i t h which the a c t i v i t y peaks occur,  t h e i r t i m i n g with respect to hour o f day, t h e i r tendency t o become e a r l i e r and l a t e r as the season progresses and the p r e d i c t a b l e nature of the evening a c t i v i t y at 2 t o 4 f o o t candles suggests that a changing l i g h t i n t e n s i t y o r low l i g h t intensity  are f a c t o r s i n f l u e n c i n g t h i s phenomenon.  Since morn-  ing a c t i v i t y ends and evening a c t i v i t y begins at 2 to 4 f o o t candles i t would appear that low l i g h t i n t e n s i t y was important. In the hens, low l i g h t l e v e l s would o f f e r a compromise between sufficient illumination  f o r e f f i c i e n t a c t i v i t y , yet not enough  to make t h e i r movements i n open v e g e t a t i o n dangerous. cocks are apparently i n f l u e n c e d by s i m i l a r l i g h t  The  levels,  independent o f the behaviour of hens, which i n s p r i n g serves to intensify their activity.  80  '  Time of Incubation and  Hatch  In the case of two recorded nests the hatching dates were June 7 t h and June 1 6 t h . recorded f o r but one nest.  The period of i n c u b a t i o n was For t h i s i t was 24 - 25 days.  According to Bent ( 1 9 3 2 ) 18 to 24 days have been recorded as the incubation p e r i o d . rp x  o f i n d the week of peak hatch, the number of week  o l d broods observed per.hour per week i n the f i e l d were p l o t t e d against weeks 6 to 16 i n 1 9 5 0 ,  1951 and 1 9 5 2 .  At one week o f  age the s i z e , plumage and behaviour of the c h i c k are characteri s t i c and can be used as aging c r i t e r i a .  A f t e r one week and  l a t e r , no absolute scale to a c c u r a t e l y age sooty grouse c h i c k s exists. 15  i n 1951  A t o t a l o f 40 week o l d broods were observed; 8 i n 1 9 5 0 , and 17  in  1952.  The r e s u l t s of t h i s a n a l y s i s are presented g r a p h i c a l l y i n F i g . 23 from Table V I I appended.  Time of hatch appears to  be spread over the same number of weeks i n each year's sample, with no apparent s h i f t i n time of peak hatch.  Thus the observed  d i f f e r e n c e s i n weather of the three years d i d not apparently a f f e c t time of peak hatch.  Each year, p a r t i c u l a r l y i n 1952,  r e l a t i v e l y l a t e hatches have been observed i n week 13 and i . e . the second and t h i r d week of J u l y .  14,  This may i n d i c a t e c l u t c h  d e s t r u c t i o n p r i o r to i n c u b a t i o n and subsequent r e l a y i n g . Over the three years, from F i g . 2 3 , 8 0 $ of the week o l d broods observed per hour have hatched i n the weeks 9 , 10 and 11,  or June 8 t h to June 2 8 t h .  Week 10 or June 15 to June 21 i s  taken as the week of peak hatch.  Then i n aging chicks on the  Fig. 23  Week of study  from Table 3ZLT. Number of week old birds observed per hour for week 6 to I6 , 1950, 1951,1952. th  ,h  81 basis o f weeks o f age from week 10, 80$ o f the time t h e i r a c t u a l age should be w i t h i n plus or minus 1 week o f t h a t p e r i o d . Behaviour o f the Female and Brood With the completion o f i n c u b a t i o n and hatch a s t r i k i n g change occurs i n the behaviour o f the female as she becomes the centre o f brood o r g a n i z a t i o n .  Generally a female w i t h young  i s observed i n the open, crouched on some prominence such as a l o g o r stump while the chicks move and feed about her.  Observa-  t i o n s on broods o f week o l d young suggest t h a t i n the e a r l y stages o f chick development the female remains on the ground, presumably i n a b e t t e r p o s i t i o n to brood.  The c h i c k s at t h i s  age are never found f a r from the female, distances of t e n f e e t are unusual.  They are unable to f l y and when disturbed s c a t t e r  i n d i f f e r e n t d i r e c t i o n s over the ground.  Some remain motionless  a f t e r a short movement, others t r a v e l as f a r as t h i r t y f e e t . I f a l o g o r other s h e l t e r i s near they w i l l u t i l i z e t h i s , p r e s s i n g themselves f l a t i n o r under the o b j e c t . I t i s i n the f i r s t week o f brood l i f e t h a t the defence d i s p l a y o f the female i s f i r s t observed. at t h i s time.  I t i s also most vigorous  Upon discovery o f a brood, and o f t e n before the  observer r e a l i z e s there i s a brood i n the v i c i n i t y the female rushes at the i n t r u d e r with erected neck f e a t h e r s , dragging wings and fanned t a i l , F i g . 2 4 ( a ) ( b ) ( c ) .  The rush i s i n v a r i a b l y  accompanied by a loud h i s s i n g sound and hard c l u c k i n g .  I f further  i n t r u s i v e movement i s not made, the attacks cease and the hen  82 r e t i r e s to a distance of t e n to f i f t y f e e t and s i t s a l e r t upon a prominence.  I n the i n t e r v a l the chicks have u s u a l l y vanished.  I f a chick i s captured or attempts are made at capture, the  attacks of the hen mount i n v i o l e n c e , and o f t e n she w i l l beat  her wings about the i n t r u d e r s head i n rushes from the ground or 1  nearby stump.  Twice hens have been caught by hand as they closed  w i t h the observer. The chicks when captured have a d i s t i n c t i v e " d i s t r e s s " c a l l o r s i g n a l which might be expressed as a s h r i l l peeeeeeer. r i s e s i n i n f l e c t i o n and i s repeated f r e q u e n t l y .  It  This again  e l i c i t s a v i o l e n t response from the female which rushes at the source of sound.  Often adjacent females w i t h broods w i l l respond  to t h i s c a l l and f l y two or three hundred f e e t to j o i n i n the general confusion. At two to three weeks of age the young have begun t o develop f l i g h t f e a t h e r s and can f l y twenty f e e t or more.  At t h i s  stage they are found f a r t h e r from the female which by now i s u s u a l l y observed crouched upon a stump or l o g . Upon disturbance the  hen clucks what i s apparently a "warning" note f o r a t i t s  sound the a c t i v e chicks cease movement and a l l appear a l e r t e d .  At  close contact with an observer the hen or a chick w i l l f l u s h , whereupon the m a j o r i t y of the brood takes wing.  In f l u s h i n g , the  hen i n v a r i a b l y clucks the "warning" s i g n a l and r e t i r e s f i f t y to s e v e r a l hundred f e e t .  The chicks f l y i n a l l d i r e c t i o n s , do not  h i d e , but land i n t r e e s and on stumps at varying d i s t a n c e s from the point of disturbance.  Upon capture o f a chick the " d i s t r e s s " c a l l  ensues with the r a p i d r e t u r n and defence r e a c t i o n of the female.  83 As i n younger b i r d s , there folloxvs a period o f s i l e n c e v a r y i n g from 5 t o 15 minutes. i s heard t o c a l l .  A f t e r t h i s time the f i r s t chick  The s i g n a l i s not u n l i k e t h e " d i s t r e s s " note  but w i t h a d i f f e r e n t i n f l e c t i o n .  I t might be expressed as  peeerwee, which i s repeated again and again. the  With t h i s s i g n a l ,  female e i t h e r u t t e r s t h e "warning" s i g n a l s or begins a  d i s t i n c t i v e c h a t t e r which might be termed the "come i n c a l l " . Generally, the presence of an observer i s r e l a t e d t o the "warning note", and with i t s sound the c a l l i n g o f chicks o r chick i s immediately s i l e n c e d .  I f the "warning note" i s not g i v e n the c a l  ing o f t h e chicks increases i n frequency and volume as s e v e r a l begin s i g n a l l i n g .  The note seems to regroup t h e young f o r they  begin to move together over the ground and through the a i r .  One  chick observed at 300 f e e t from the o r i g i n a l point o f f l u s h i n g was observed to drop from a t r e e i n which i t was perched and move toward a c a l l i n g chick as soon as i t began t o s i g n a l .  I f the  female takes no part i n the o r g a n i z a t i o n at t h i s time, the c h i c k s eventually regroup and c a l l together from a l o g o r prominence. U s u a l l y , at the f i r s t chick s i g n a l , i f the sharp "warning" cluck i s not given, the hen begins a "come i n c a l l " a s e r i e s o f c h a t t e r i n g , caterwauling phrases which sounds as 'queeeeer t a u tau t a u !  I t i s not u n l i k e the sound o f a wire  c l o t h e s l i n e being rotated around i t s spools.  With t h i s , the  chicks move towards the hen i n her new s i t e o r at the o l d , and as they approach her, and the brood reorganizes, t h e i r c a l l i n g s cease.  84 In observing undisturbed broods i n t h e f i e l d , other sounds from hen and chicks have been recorded t h a t remain l a r g e l y a mystery.  They probably c o n t r i b u t e t o the organiza-  t i o n of t h e brood and i t s movements. Observations i n the f i e l d i n d i c a t e that the hen feeds l i t t l e i n d a y l i g h t hours but takes some food i n the evening. Feeding i n a d d i t i o n t o s i t t i n g , dust bathing and preening appear to c o n s t i t u t e her d a i l y a c t i v i t i e s .  The c h i c k s on the other  hand are voracious feeders and are most f r e q u e n t l y observed t a k i n g food i n one end and passing t h e residue out the other. The young were observed to feed on p l a n t s and animals l i s t e d as food items by Fowle (1944), Beer (1947) and others. Invertebrates o f a l l kinds are consumed as w e l l as succulent f r u i t s and smaller v e g e t a t i o n , such as T r i f o l i u m flowers' and leaves and G a u l t h e r i a f l o w e r s . In f i v e observations on r o o s t i n g young, they were on the ground and under the hen.  This might have been expected i n  these cases f o r t h e broods were from 1 to 2 weeks o l d . I t seems l i k e l y that as the young are fledged brooding becomes unnecessary  and thus the r o o s t i n g h a b i t s might change.  Generally, the broods appear t o remain i n t a c t throughout the f i r s t f i v e weeks of chick l i f e , although observations on two o r three hens and t h e i r young i n c l o s e p r o x i m i t y are o f t e n made.  I n two cases s o l i t a r y hens have been observed w i t h chicks  of markedly d i f f e r e n t s i z e s i n t h e i r broods, an i n d i c a t i o n that s h u f f l i n g or at l e a s t chick adoption occurs during t h i s time.  85 By the end of J u l y o r at approximately eight weeks of  age the chicks have w e l l developed, i f not f u l l grown,  r e t r i c e s and wing feathers and are strong i n f l i g h t .  They  forage on a l l types of vegetation u t i l i z e d by the a d u l t s , although u n l i k e them, i n v e r t e b r a t e s are s t i l l taken.  The  c l e a r high pitched c a l l s of the young appear now t o be lowered i n tone and are o f t e n garbled i n t o a clucking sound.  The  female e x h i b i t s l i t t l e o f her former defence r e a c t i o n when disturbed and u s u a l l y flushes with the young.  She s t i l l remains  on stumps and l o g s throughout the day as apparent coordinator of  the brood. Wing (1944) reported t h a t the brood o r g a n i z a t i o n o f  blue grouse begins to break down i n l a t e J u l y and s h u f f l i n g of young from one brood to another takes place.  S i m i l a r observa-  t i o n s on the breakdown of brood o r g a n i z a t i o n were made i n the 1950 study period from the middle J u l y and l a t e r .  Within t h i s  time, i n 128 observations on broods, 37 were records i n which the  t y p i c a l brood o r g a n i z a t i o n had been changed.  In 27 of these  cases, two or t h r e e hens were associated w i t h from 10 to 20 young which were observed t o i n t e r m i n g l e .  I n 6 cases but a  s i n g l e female was observed w i t h from 7 to 15 chicks.  Finally  i n 4 instances from 1 to 4 chicks were observed alone. Contact between broods i s apparently brought about by t h e i r feeding a c t i v i t i e s , however, the r e a c t i o n of one hen and chicks to the c a l l s of another hen or chicks cannot be dismissed as a c o n t r i b u t i n g f a c t o r .  I t seems reasonable that as a brood  86 moves about feeding i t would become temporarily l o c a l i z e d i n an area of good food supply.  Other broods engaged i n the  same a c t i v i t y might become l o c a l i z e d i n the same area a brood communism.  producing  There i s no evidence to suggest the  hen  recognizes her own chicks or t h e i r number and thus i n the breaking up of the f e e d i n g group hens might be found with any number of the o r i g i n a l band.  This, i f t r u e , might e x p l a i n  the broods of 7 to 15 chicks observed with a s i n g l e female, or more than one female to a brood.  In 1 9 5 1 and 1952  observa-  t i o n s suggesting brood d i s o r g a n i z a t i o n were not made.  Both  J u l y and August of these years were d r i e r than the same months i n 1950,  and t h i s may have been a f a c t o r i n f l u e n c i n g brood  movements.  The moist summer of 1950 delayed d e s i c c a t i o n of  the vegetation.  This i n t u r n provided areas of good food  supply w i t h i n which the broods fed and intermingled. reverse was t r u e i n 1951 and 1952.  The  I f t h i s explanation i s  c o r r e c t i t suggests a summer's climate i n f l u e n c e s brood o r g a n i z a t i o n through i t s e f f e c t on food vegetation. Movements of the Female and Brood A n a l y s i s of movements of hens w i t h young i s based on the banding and subsequent observation of 2 5 hens with broods i n 1950.  The o b s e r v a t i o n a l period was a r b i t r a r i l y d i v i d e d i n t o  the three months, June, J u l y and August.  The observed p o s i t i o n s  of the hens i n these months were p l o t t e d on a map area, F i g . 2 5 .  of the study  In t h i s i l l u s t r a t i o n each hen with brood i s  represented by a symbol, while the number beside the symbol  87 represents the month i n which they were observed.  The  arrows i n d i c a t e the shortest l i n e and i t s d i r e c t i o n to o r from consecutive observations on a given hen. Generally, the observed range of the female and brood i s l a r g e r than the home range as observed i n hens p r i o r to incubation.  There i s , however, a great amount of v a r i a t i o n  i n the observed hen and brood ranges.  Hen (20,D) was not  observed o u t s i d e of p l o t I i n June and J u l y . had an observed range l e s s than 2 0 acres.  She and her young  I n the same months  hen and brood (19,K) moved to (3,J) a map distance o f approximately | m i l e .  Again, hen (19,K) was observed on o r  near p l o t I over the three months, and as contrast hen a.nd brood  (25,1)  observed i n June were recorded at  (5,1)  i n August,  another s t r a i g h t l i n e movement on the map of over a i m i l e . Thus the observed movements of females w i t h young vary considerably w i t h map distances up t o a g mile recorded between some observations. Factors that i n f l u e n c e the movements of the hen and brood on the summer range are mostly a matter of s p e c u l a t i o n . There i s no apparent r e l a t i o n s h i p between age of young and brood range.  Free water and adult males s i m i l a r l y bear no  apparent r e l a t i o n s h i p to the movements of the hen and brood, although s e x u a l l y a c t i v e males w i l l court a hen w i t h young o c c u r r i n g on i t s t e r r i t o r y . The open v e g e t a t i o n a l types are u t i l i z e d most frequentl y by the hen and brood, F i g . 14.  Thus Clover Open ranks f i r s t  ss i n u t i l i z a t i o n , with Log Open and Bracken Open next, but much l e s s i n value.  The s h e l t e r types Willow Dense and F i r Dense  are used but l i t t l e .  The u t i l i z a t i o n of open types would  appear r e l a t e d to the feeding a c t i v i t i e s of the c h i c k s , f o r i t i s along the edges of the roads and i n openings that invertebrates and succulent plant m a t e r i a l s occur i n q u a n t i t y . In these cover types the ground i s r e l a t i v e l y open, p e r m i t t i n g the chicks freedom of movement and an exposure to sunshine not found i n the dense s h e l t e r types of f i r and w i l l o w .  Since  the open types, Olover Open, Bracken Open and Log Open are important as h a b i t a t f o r the hen and brood the d i s t r i b u t i o n o f these types i s probably a major f a c t o r i n f l u e n c i n g t h e i r movements on the summer range. r  he d i r e c t i o n i n which the f a m i l y groups moved i n 1950  show no general tendency of movement towards the higher e l e v a t i o n s which are to the l e f t and bottom l e f t of the f i g u r e .  Thus  over the months studied what could be c a l l e d m i g r a t i o n a l movements were not observed.  I f t h i s i s t r u e , m i g r a t i o n occurred  a f t e r the month of August i n 1950.  I n support o f t h i s conclusion  the number of broods observed per hour per week i n J u l y and August of 1950 remained r e l a t i v e l y constant, F i g . 28(c).  On the  other hand, from the same f i g u r e , there has been an apparent drop i n the number observed per hour per week a f t e r week 14 (mid J u l y ) i n the years 1951 and 1952.  '^h±s  suggests that move-  ment from the lowlands had begun or a greater brood l o s s occurred i n J u l y and a f t e r of 1951 and 1952 as compared to 1950.  89 As mentioned above, 1951  and 1952 were r e l a t i v e l y -  dry summers which brought about r a p i d d e s i c c a t i o n of the food vegetation.  In t u r n , t h i s probably influenced the movements  of the broods and r e s u l t e d i n an e a r l y a l t i t u d i n a l migration. This seems the best explanation to the observed drop i n broods seen per hour and suggests that weather through i t s e f f e c t on food vegetation conditions the a l t i t u d i n a l migration o f hens with young. Some l i g h t i s shed on the problem of f a l l brood migration by the information obtained from hunters on banded b i r d s bagged.  The p o s i t i o n s i n which banded hens o r young were shot  are p l o t t e d on a map o f the Quinsam region i n F i g . 26.  A l l but  one o f the b i r d s were taken on the 6th of September i n 1950. The hen i n the upper r i g h t region of the point c l u s t e r i s the one exception to t h i s and was shot on September 16th i n 1952. In the case of two chicks and a hen which was with a brood when shot, there i s no apparent a l t i t u d i n a l m i g r a t i o n . During the time between banding and the hunt i n the second week of September, they apparently had moved distances comparable to the range of broods i n June to August.  This suggests that  complete m i g r a t i o n from the study area between August and September 16th does not occur. There i s a wide movement evident i n 3 of the banded b i r d s , two hens with broods, and a lone chick.  I n each case  movement has been towards higher land, although the d i r e c t i o n s taken have not been the same.  I f these l i n e s of t r a v e l are  90  projected t o the nearest highlands as an assumed winter range, grouse i n h a b i t i n g the study area as summer range would overwinter at d i s t a n c e s of nine m i l e s apart.  I n t h i s respect the  upward movement resembles a d i s p e r s a l r a t h e r than a m i g r a t i o n of uniform d i r e c t i o n .  Since hens once l o c a l i z e d on the  summer's range appear t o r e t u r n to the same r e g i o n of t h e lowlands i n subsequent years they would converge upon i t from the highland winter range.  I f t h i s be t r u e , i t suggests the  summer range i s a p a r t i c u l a r area, while t h e w i n t e r range occurs as a general area spread over the upland r e g i o n s . Sex Ratio and weight Development i n the Young In 138 chicks shot a t random over the period June 1 5 t h to August 1 5 t h i n 1951 and 1 9 5 2 , 70 were males, 68 were females. There i s no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e (by Chi-square t e s t ) between these two f i g u r e s which i n d i c a t e s the sex r a t i o i n chicks was apparently 5 0 : 5 0 over the period studied. The data on weight were obtained i n the study area, and at the road check s t a t i o n i n 1 9 5 0 , 1951 and 1 9 5 2 .  Chicks  c o l l e c t e d o r captured were weighed f o r t o t a l weight and these weights, c l a s s i f i e d as to sex, were averaged f o r each week from week of peak hatch (June 15 to June 2 1 s t ) .  The hunter sample  provided weights i n week 23 (Sept. 16) and i n week 21+ (Sept. 2 3 ) . The average weights and t h e i r confidence l i m i t s a t the 9 5 $ l e v e l  are p l o t t e d against week of age i n F i g . 27 from Table V I I I appended. A f t e r age 8 weeks or week 1 7 , few data were a v a i l a b l e  Fig. 27  from Table "VTTT  Weight development of chicks  91 from the study area u n t i l the hunter k i l l of age 14 and 15 weeks i n week 23 and 2 4 . l i k e l y i n error.  Thus between these times the averages are  The r e l a t i v e l y large road check sample, on the  other hand, provides a good estimate of weight i n week 23 and 2 4 . No s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e i s observed between the weight of male and female chicks to 9 weeks of age. At 14 weeks of age the males are s i g n i f i c a n t l y heavier than the females.  At 15 weeks of age the males have a t t a i n e d 884 ±.  grammes while the females are 724 I. 35 grammes.  Both weights are  lower than those recorded f o r y e a r l i n g males and females on the study area i n s p r i n g and summer. I f a best s t r a i g h t l i n e i s drawn through the p o i n t s i t s slope represents an average weekly growth r a t e .  In the males  t h i s i s approximately 60 grammes per week and i n the females approximately 50 grammes per week.  These values are comparable  to the growth r a t e s c a l c u l a t e d f o r blue grouse chicks i n Washington by Wing et a l (1944).  They found the growth r a t e s to be 66  grammes per week i n males and 59 grammes per week i n females. The greatest e r r o r i n the c a l c u l a t i o n of growth r a t e r e s u l t s from the i n a b i l i t y to a c c u r a t e l y age c h i c k s .  Thus i n  lumping the weights of chicks c o l l e c t e d i n any given week v a r i a t i o n i n hatching date i s ignored.  This e r r o r d o u b t l e s s l y c o n t r i b u t e s  to the l a r g e f i d u c i a l i n t e r v a l observed i n some samples.  The  use of chick weights obtained over the three years of study i s not considered a major source of e r r o r .  A sample of 18 weights  taken at the road check i n 1951 was tested against a s i m i l a r ^95% confidence l i m i t .  92 sample obtained i n 1952. averages (by t n  f l  The d i f f e r e n c e between the two  t e s t ) was not s t a t i s t i c a l l y s i g n i f i c a n t .  Assuming environmental e f f e c t s constant over the growth period of the two samples, t h i s r e s u l t would i n d i c a t e l i t t l e d i f f e r ence i n hatching date i n 1951 and 1952, and support the same conclusion drawn from a comparison of peak hatch i n the two years. The L i f e H i s t o r y Study as a Basis f o r the A n a l y s i s of Population Dynamics At t h i s point the i n f o r m a t i o n presented as l i f e h i s t o r y may be c u l l e d f o r data necessary f o r an understanding of population dynamics.  I t i s e n t i r e l y possible that social  behaviour plays a r o l e i n i n f l u e n c i n g p o p u l a t i o n . s i z e .  Thus  the t e r r i t o r i a l behaviour of the male sooty grouse should be considered i n t h i s respect.  Here i s a s o c i a l phenomenon which  obviously spaces s e x u a l l y a c t i v e males.  There i s evidence to  suggest t e r r i t o r i a l f i g h t i n g between males might r e s u l t i n the displacement of one.  Thus space f o r t e r r i t o r y might be a f a c t o r  l i m i t i n g the number of males r e s i d e n t i n the study p l o t s and i n t u r n s t a b i l i z e the population t h e r e i n .  Observational evidence  i n d i c a t e s t h i s i s not the case at Quinsam Lake.  This conclusion  i s supported by experimental evidence discussed below (p. 113 ). From o b s e r v a t i o n a l data, the m a j o r i t y of males were expanding t h e i r t e r r i t o r i e s throughout the summer.  There i s no  reason to b e l i e v e t h a t any t e r r i t o r y studied was at i t s minimal s i z e or a f u r t h e r c o n t r a c t i o n of perimeter would cause the  93 r e s i d e n t male to vacate.  Moreover, areas s u i t a b l e f o r  t e r r i t o r i e s were vacant and areas once occupied by s e x u a l l y a c t i v e males were vacated and not reoccupied. i n subsequent years.  A good example of the l a t t e r point occurred i n the  l o s s of 7 males and replacement of but 3 on p l o t I I i n 1953 (p. 43)*  Defence of t e r r i t o r y was not observed i n the females,  thus t h i s can be dismissed as a f a c t o r i n f l u e n c i n g hen populations.  There i s the p o s s i b i l i t y , however, t h a t mating  might l i m i t the number of s u c c e s s f u l matings..  behaviour  I f monogamy were  the r u l e the smallest number of the one sex would determine the number breeding. promiscuous.  The evidence suggests the sooty grouse are  Thus the s o c i a l behaviour of e i t h e r sex does not  have a d i r e c t bearing on p o p u l a t i o n c o n t r o l . The average c l u t c h s i z e of each age c l a s s i n the population i s an important s t a t i s t i c i n the c a l c u l a t i o n of productivity.  A knowledge o f the sex r a t i o i n the young permits  a c a l c u l a t i o n of the number of each sex produced from a given clutch.  This i s important i n t h i s p o p u l a t i o n study f o r y e a r l i n g  males are absent from the study area and t h e i r abundance must be i n f e r r e d from the number of y e a r l i n g females present.  I f the  chick sex r a t i o i s equal and each sex s u f f e r s equal m o r t a l i t y t h e i r c a l c u l a t i o n s based on one sex should hold f o r the other. Another category of l i f e h i s t o r y information permits the development of sound techniques of p o p u l a t i o n study r a t h e r than bearing d i r e c t l y on p o p u l a t i o n c o n t r o l .  P o s s i b l y the most  important are c h a r a c t e r i s t i c s of the b i r d which lend themselves  94 to accurate census techniques.  The t e r r i t o r i a l behaviour of  the male permits an accurate census by sample p l o t method. Males holding t e r r i t o r y on the p l o t s are counted as an of t h e i r abundance.  estimate  A knowledge of the r e l a t i v e l y wide and  random movement of the females before nesting permits the of the L i n c o l n index as a method of censusing t h i s sex.  use I f an  absolute or r e l a t i v e estimate of numbers i s to be made then an observer must understand the c o n d i t i o n s i n f l u e n c i n g h i s day to day or month to month counts.  Thus periods of incubation,  a c t i v i t y and migration must be appreciated and t h e i r e f f e c t upon counts taken i n t o c o n s i d e r a t i o n . In the c a l c u l a t i o n of age s t r u c t u r e i n the c r i t e r i a of age are of f i r s t importance.  population  The age c r i t e r i a  developed, can be used to i d e n t i f y y e a r l i n g s and a d u l t s .  as The  r e l a t i v e number of y e a r l i n g s to a d u l t s i n the population i s a crude s t a t i s t i c .  I t i s nevertheless i n v a l u a b l e as i t gives more  than anything e l s e an i n d i c a t i o n of the c o n t r i b u t i o n made by the chicks of a previous spring to the summer population.  The  ratio  of y e a r l i n g s t o adults can be used as one i n d i c a t i o n of populat i o n growth form. M o r t a l i t y rates are e s s e n t i a l f o r the understanding of population dynamics.  In t h i s study, m o r t a l i t y r a t e s are based  on the y e a r l y turnover i n adult banded males although banded males were never found dead.  The "homing phenomenon" i n adult  males occurs w i t h such r e g u l a r i t y that a f a i l u r e to r e t u r n to a  95  p a r t i c u l a r t e r r i t o r y i n a subsequent year can be taken as an i n d i c a t i o n of death.  I n the c a l c u l a t i o n o f c h i c k m o r t a l i t y  w i t h age, the average date o f hatch i s important as a s t a r t i n g point.  Then average brood s i z e s are p l o t t e d against time to  produce a death r a t e o r rate of decrease o f average brood s i z e . I f t h i s i s done, are repeated counts o f the same brood a l i k e l y source o f error?  I f brood counts are made i n June i s the same  population being counted i n August o r has t h e June group moved beyond the study area?  Questions of t h i s kind can be p a r t i a l l y  answered from a knowledge o f brood movements.  These appear to  be at random over the study area with movements up t o a h a l f mile recorded. l a t e i n August.  There i s no i n d i c a t i o n o f a m i g r a t i o n u n t i l Thus brood counts made over the study area and  i n t o August seem v a l i d samples o f the brood s i z e p o p u l a t i o n i n t h i s region.  As i n censusing the a d u l t s , the f a c t o r s i n f l u e n c -  ing brood counts should be appreciated and weighed.  Whether  the chicks hide o r f l u s h , group o r d i s p e r s e , remain i n t a c t i n f a m i l y groups o r s h u f f l e a l l profoundly a f f e c t count data. Ignorance o f these and other p e r t i n e n t l i f e h i s t o r y phenomena would r e s u l t i n a meaningless p o p u l a t i o n a n a l y s i s .  96 TOPIC I I . POPULATION DYNAMICS Population S i z e and Status Three methods were used to determine the s i z e of the adult and y e a r l i n g grouse p o p u l a t i o n i n the study area.  A first  method consisted of counting the number of t e r r i t o r i e s on p l o t s I and I I . This i n t u r n provided a count of s e x u a l l y a c t i v e a d u l t males (p. 37).  The p l o t data f o r 1950 are incomplete and not  considered here. 1951, 1952 and j  The f o l l o w i n g t a b l e summarizes the r e s u l t s f o r  1953: Number of s e x u a l l y a c t i v e males  1  Plot  .  :  I  :  :  II  :  !  Total  ]  :  ;  1952  1  1953  14  ;:  12  :  12  16  :  18  •  14  ::  30  :!  26  1951  30  1  :  :  There i s no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e (by chi-square) between the t o t a l numbers o f s e x u a l l y a c t i v e males on the two study p l o t s over the three years.  Averaging the t o t a l s and  d i v i d i n g by 72, the acreage of the two study p l o t s the f i g u r e of .40 males per acre i s obtained.  For a g a l l i n a c e o u s b i r d t h i s  d e n s i t y i s high i n the extreme. A count of the resident hens on the study p l o t s i s more d i f f i c u l t to o b t a i n by v i r t u e of t h e i r r e l a t i v e l y l a r g e home range (p. 6 5 ) .  Assuming presence on p l o t I I as an i n d i c a t i o n of  of residence there, a count of marked hens was made p r i o r to hatchi n g time.  This f i g u r e i s supported by an estimate of r e s i d e n t hen  97  numbers i n the same period by means of the L i n c o l n index, L i n c o l n (1930).  The technique seems a p p l i c a b l e i n the case o f  the hens as some are marked and other experimental c o n d i t i o n s are f u l f i l l e d , R i c k e r (1948).  Data f o r both census techniques were  obtained from observation o f hens w i t h i n t h e boundaries o f p l o t II.  The f o l l o w i n g t a b l e summarizes the r e s u l t s : !  Number of r e s i d e n t hens p r i o r t o hatch on p l o t I I  I A c t u a l count, marked hens | L i n c o l n index estimate and \ 95% confidence l i m i t s *  1  ;  1951  1  1  20  ;  22  .; 27,  20-40  ;; 28, 19-44  1952  C a l c u l a t i o n s made a f t e r Adams (1951). As w i t h t e r r i t o r i a l males there i s no d i f f e r e n c e between the numbers of r e s i d e n t females on p l o t I I i n the p e r i o d p r i o r t o hatch i n 1951 and 1952.  Since the author found i t impossible t o  mark a l l the females encountered on p l o t I I , the a c t u a l count f i g u r e s are low.  The L i n c o l n index values are taken as best  estimates, and provide an average hen d e n s i t y f o r l 9 5 1 and 1952 on p l o t I I of .78 hens to the acre.  Again, as i n the males, an  extremely high d e n s i t y . In comparing the average number o f 17 males on p l o t I I i n 1951 and 1952 w i t h the average number of 28 females r e s i d e n t p r i o r to hatch i n the same time and area, i t w i l l be observed the  98 sex r a t i o i s i n t h e f a v o u r o f females as 1.6  t o 1.  This  situa-  t i o n r e f l e c t s the absence o f y e a r l i n g males from t h e b r e e d i n g p o p u l a t i o n on the summer range and s u p p o r t s the c o n c l u s i o n reached above (p. 64) t h a t y e a r l i n g males do not descend from t h e w i n t e r range i n t h e i r f i r s t s p r i n g a f t e r h a t c h .  A second census method was  based upon t h e number o f  b i r d s observed per hour per week i n t h e f i e l d . d a y l i g h t p e r i o d s from 0800 t o 2000 hours. of  b i r d s was r e l a t i v e l y u n i f o r m (p. 77).  Census hours were  I n t h i s time the a c t i v i t y The o b s e r v e r t a l l i e d  s e p a r a t e l y , males, females and females w i t h broods, t h e n d i v i d e d the  t o t a l number observed per week by t h e number o f hours spent i n  the  f i e l d f o r t h a t week.  the  year 1950 t o 1953  The r e s u l t s a r e expressed g r a p h i c a l l y f o r  i n F i g . 28 ( a ) ( b ) and  (c) from Table IX  appended. Fig.  2#(a) p r e s e n t s the males observed per hour o f each  week spent i n the f i e l d .  I t i n d i c a t e s t h e r e l a t i v e abundance o f  t h i s sex over 4 y e a r s as w e l l as t h e s e a s o n a l t r e n d i n observed p o p u l a t i o n s i z e on t h e summer range  (p. 59).  G e n e r a l l y , the  curves show no d i f f e r e n c e i n r e l a t i v e abundance t h a t might  be  i n t e r p r e t e d as a change i n male numbers o v e r the f o u r y e a r s .  The  v a r i a t i o n i n the y e a r s , p a r t i c u l a r l y i n weeks 1 t o 5 can be a t t r i b u t e d t o v a r i a t i o n i n t h e a c t i v i t i e s o f males and the o b s e r v e r . Fig.  28(b) p r e s e n t s i n t h e same way  r e l a t i v e abundance o f females observed a l o n e .  as i n t h e males, t h e O b s e r v a t i o n s on such  hens are l a r g e l y a matter o f chance as any b i a s f a v o u r i n g d i s c o v e r y ,  3 0  2  £  4  6  8  10  12  14  16  18  20  Weeks observed per hour per week and weeks from April i3th.  Fig. 28(b).  Females  Fig. 28(c).  Females with broods observed per hour from April 13 th. Data from table I X  per week and weeks  99 such as the hooting a c t i v i t y of the male, does not occur.  In  t h i s respect the census technique i s b e t t e r s u i t e d as a r e l a t i v e estimate of hen abundance.  The r e s u l t s o f the hen per hour census  i n d i c a t e no r e a l change i n r e l a t i v e abundance over the years studied.  There i s a downward trend over each year which r e s u l t s  from the hatching of the young a f t e r week 10 (p. 80) and the departure of broodless females from the summer range. Fig.  28(c) i l l u s t r a t e s the r e l a t i v e abundance of hens  w i t h chicks over the f o u r years. the  Again the v a r i a t i o n observed i n  curves i s not considered i n d i c a t i v e o f a r e a l change i n  numbers, u n t i l week 15 i n 1950 as compared to 1951 and 1952. I t was suggested above (p. 89) that the observed drop i n these years r e f l e c t e d an e a r l i e r m i g r a t i o n i n 1951 and 1952 or a delayed migration i n 1950.  A t h i r d census technique was based on an estimate o f the  r e l a t i v e abundance o f c l o c k e r droppings found on the study  area i n the years 1951 and 1952.  This i n t u r n r e f l e c t s the  r e l a t i v e abundance of incubating hens (p. 75).  A l l c l o c k e r droppings  were t a l l i e d and the t o t a l f o r each year was d i v i d e d by the number of hours spent i n the f i e l d i n each year a f t e r the f i r s t dropping was found.  The r e s u l t s are presented i n the f o l l o w i n g t a b l e : ;Relative abundance of incubating hens as ;indicated by c l o c k e r droppings :  1951  1952  311  : • :  ' Hours i n f i e l d  ::  : Clockers found  ::  104  :  62  : Clockers per hour  :  .33  :  .28  222  100 The v a r i a t i o n observed i n the number of d o c k e r s found per hour i s not considered s i g n i f i c a n t .  The r e s u l t s o f t h i s  census suggest no change had occurred i n the r e l a t i v e abundance of incubating hens on the study area i n the years 1951 and  1952.  The r e s u l t s of a l l census methods used are i n accord and indicate the status of males, females and females with broods was unchanged over the years 1950 to 1953.  Thus i n the period  studied, these components of the sooty grouse population at Quinsam Lake have remained stable i n numbers or t h e i r increase or decrease has not been detected. Each census method has i t s l i m i t a t i o n s .  In counting  t e r r i t o r i a l males, b i r d s which abandon t e r r i t o r y early i n the year are  not recorded unless censused appropriately.  This s i t u a t i o n  i s l i k e l y the cause of the v a r i a t i o n i n numbers of males on plot I I i n 1953.  Males hooting at the plot edges create a  problem, f o r i n t h i s method, often one observation determines whether they are i n or out of the p l o t .  In t h i s study, a l l  t e r r i t o r i e s touching the plot boundaries were counted.  A count  of males based on t e r r i r o t i e s ignores the number of adult or yearling males not holding t e r r i t o r y .  This error i s corrected i n  part, by the i n c l u s i o n of a l l males observed per hour on the study area as i n the second census method.  This method, as the clocker  count, i s limited mostly by the i r r e g u l a r a c t i v i t i e s of the observer f o r any change i n study technique from day to day influences the number and kind of observations made.  The Lincoln  101 index method o f d e t e r m i n i n g hen d e n s i t y i s biased by t h e e  movements o f t h e females which l i k e l y extended byond the l i m i t s o f t h e p l o t i n which the technique was used. I f , however, movement o f banded and unhanded hens i n t o t h e census area e q u a l l e d movement out, a not u n l i k e l y c o n d i t i o n , then some o f t h i s e r r o r would  cancel.  I f t h e grouse p o p u l a t i o n ,  as censused, i s s t a b l e t h e n  one  o r a combination o f two c o n d i t i o n s would e x p l a i n i t s s t a t u s .  The  b i r t h r a t e equals the death r a t e and e m i g r a t i o n  immigration.  The b i r t h r a t e i s g r e a t e r o r l e s s than the death  r a t e and emigration  o r immigration r e s u l t i n p o p u l a t i o n  With t h i s , an e x p l a n a t i o n be obtained emigration  equals  o f t h e observed p o p u l a t i o n  stability.  s t a t u s can  from t h e c o n s i d e r a t i o n o f m o r t a l i t y , p r o d u c t i v i t y , and immigration i n t h e study  population.  M o r t a l i t y i n the Adults M o r t a l i t y i n a d u l t males was c a l c u l a t e d from time o f banding i n t h e s p r i n g and summer t o time o f o b s e r v a t i o n the following spring.  S i n c e a d u l t t e r r i t o r i a l males a r e r e a d i l y  observed and r e t u r n t o the summer range each year (p. 41) a percentage r e t u r n can be c a l c u l a t e d . assumed dead, the value  represents  I f non-returning  males a r e  a percentage s u r v i v a l .  The  number o f males banded each year i n the study area and t h e i r r e t u r n i n subsequent years i s summarized i n the f o l l o w i n g t a b l e :  102  : Return of adult males each year a f t e r banding : 1950 1952 : 1953 : 1951 !  : :  [No. Banded ;[ No. returned! ;No.returned '; No. returned : 6 : 19 ;: 9 :: !No. banded \'No. returned | No. returned : 15 :: : 7 [No. banded .,!No.returned : 8 : 5 1 2  1 4  As a best estimate of y e a r l y r e t u r n i n the a d u l t t e r r i t o r y h o l d i n g males, the r e t u r n f i g u r e s f o r each year are added, and expressed as a percentage of the numbers banded, i . e . 29 ^_i2 +- 9 H-15 -T14 X- \ ^  e  return.  Assuming non-  r e t u r n i n g males dead, the value represents a 69$ y e a r l y s u r v i v a l or a 31$ y e a r l y death or turnover r a t e i n the t e r r i t o r i a l adult male.  The i n d i v i d u a l v a r i a t e s suggest a r e l a t i v e l y uniform  m o r t a l i t y r a t e i n the adult males p a r t i c u l a r l y i n the case o f the 1950 sample f o l l o w e d through 3 years.  Since the samples  c o n t a i n s e v e r a l year c l a s s e s i t would appear death - occurred 5  independent of age.  Farner (1952) has shown a tendency i n b i r d s  towards uniform m o r t a l i t y r a t e s which do not vary e x t e n s i v e l y with age a f t e r a j u v e n i l e p e r i o d o f higher m o r t a l i t y .  This i s  t r u e of the sooty grouse. In the case o f the adult females, which are not l o c a l i z e d as the adult males on t e r r i t o r y , f a i l u r e to observe a hen cannot be taken as i n d i c a t i o n of i t s death.  F u r t h e r , most of the females  banded were captured when w i t h chicks and thus probably f a r from  103  t h e i r home range p r i o r to hatch (p. 87).  The chance of observ-  i n g such hens the f o l l o w i n g s p r i n g i s l e s s than t h a t o f observi n g the few hens banded on t h e i r prehatch range.  With the l a c k  of other data the y e a r l y turnover i n adult females i s assumed to be as found i n adult males -  31$.  M o r t a l i t y Factors i n the Adults What f a c t o r s operate to remove the a d u l t males and females from the population i s l a r g e l y unknown.  In the case o f  marked adult males, none was found dead on i t s t e r r i t o r y , r a t h e r the p l o t populations remained unchanged throughout the s p r i n g and summer except as a f f e c t e d by what i s taken as the abandonment of t e r r i t o r y at the c e s s a t i o n of sexual a c t i v i t y (p. 59). Some m o r t a l i t y occurs on the .summer range and i t i s worthy of mention here.  Over the years 1950  to 1952  the remains  of 7 a d u l t b i r d s and one y e a r l i n g have been found i n the area.  study  From animal s i g n at the remains, f o x (Vulpes f u l v a )  and an avian predator could be i n v o l v e d .  In the s p r i n g of  1952  a f o x and two pups were discovered by a den i n the edge of an o l d r a i l w a y embankment.  The ground i n and about the den  l i t t e r e d with grouse remains.  was  These were c l a s s i f i e d on the b a s i s  o f f e a t h e r colour and shape as the p a r t s of 12 a d u l t males and 3 adult females.  This would suggest t h a t f o x predation i s  heavier on the males than females, an observation i n accord w i t h the r e l a t i v e ease of l o c a t i n g and capturing hooting males. The Quinsam area i s hunted f o r grouse and b l a c k - t a i l e d  104  deer (Odocoileus columbianus).  A c c o r d i n g l y , human p r e d a t i o n  might be a f a c t o r c o n t r i b u t i n g t o a d u l t and c h i c k m o r t a l i t y . I n the case o f the a d u l t males, hunting has l i t t l e o r no e f f e c t on t h i s p o p u l a t i o n component by v i r t u e o f t h e i r upward m i g r a t i o n which occurs i n August and weeks before the opening of t h e grouse season i n September (p.60).  Thus i n 204 a d u l t b i r d s sampled a t  random a t the Campbell R i v e r road check i n 1950 but 4 were males. I n the case o f the a d u l t females and c h i c k s which bear the brunt o f the shoot, human predation i s more e f f e c t i v e .  There  i s no c l e a r i n d i c a t i o n , however, t h a t the e n t i r e female w i t h brood population bears a uniform k i l l .  There i s the p o s s i b i l i t y  t h a t as with t h e males, some hens and young escape hunter predat i o n by an upward m i g r a t i o n i n August.  For t h i s a n a l y s i s , however,  l e t us assume t h a t a l l banded females are subjected t o uniform hunting pressure, and a l l banded hens are r e p o r t e d . The second c o n d i t i o n i s a l i k e l y assumption supported by t h e checking o f most hunters o f the Quinsam area d u r i n g the periods o f g r e a t e s t harvest.  The f o l l o w i n g t a b l e summarizes the data on banded hens  shootable t o banded hens shot f o r t h e three year study p e r i o d :  : No. hens banded and shot i n each study year : Year  ;: No. banded :  : 1950  \  61  i  2  :  3  :  ::  27  :  0  ::  0  :  20  :  0  :  0  1 9 5 1  : 1952  No. shot ::  % shot  :  105 From t h i s , i t would appear the l o s s t o hunting was n e g l i g i b l e and a minor f a c t o r c o n t r i b u t i n g t o t h e assumed 31$ y e a r l y turnover o f the a d u l t hens. This c o n c l u s i o n i s supported by a c o n s i d e r a t i o n o f the sex r a t i o i n the summer range.  I f the shoot were having a  great e f f e c t on the a d u l t and y e a r l i n g male;, component o f t h e population, one would expect a d i s p r o p o r t i o n a t e sex r a t i o on the breeding range i n favour o f a d u l t males which escape t h e harvest and have a 69$ w i n t e r s u r v i v a l .  A  s  mentioned above,  the sex r a t i o i n the years 1951 and 1952 on p l o t I I was i n favour o f t h e females as 1.6 t o 1.  P a r a s i t i s m and disease does not appear a major m o r t a l i t y f a c t o r i n the a d u l t s and y e a r l i n g s , a t l e a s t on the summer range. This statement i s based upon the examination o f 174 blood smears taken from shot o r captured b i r d s and 103 autopsies. The sample, obtained over t h e years 1950 to 1952 i n the spring and summer months, f a i l e d t o r e v e a l any p a t h o g e n i c i t i e s o r effects attributable to parasite i n f e s t a t i o n .  The r e s u l t s o f  the p a r a s i t e survey i n a d u l t s and y e a r l i n g s are presented i n Table X. Dispharynx nasuta, Plagiorhyncus formosus ( o c c u r r i n g i n c h i c k s ) , Y s e r i a sp., Ceratophyllus d i f f i n i s and Lagopoceus obscurus are new host records f o r the genus Dendragapus. percentage and degree of i n f e c t i o n w i t h Dispharynx and  The  Table X P a r a s i t e s o f Adult and y e a r l i n g grouse examined at Quinsam Lake data o f 1950, 1951, 1952. • •  »  Parasite  :Degree of i n f e c t i o n : S i t e :Number :Number S % : found :examined : i n f e c t e d \ i n f e c t e d  Haemoproteus sp. Leucocytozoon sp. Trypanosoma sp.  blood blood blood  M i c r o f i l a r i a sp.  blood  174  Quadruple I n f e c t i o n s Dispharynx nasuta stomach 103 gizzard # ( C h e i l o s p i r u r a spinosa ( Y s e r i a sp. gizzard Rhabdometra n u l l i c o l l i s (?) i n t e s t i n e A s c a r i d i a bonasae intestine Plagiorhync^us formosus intestine Ceratophyllus d i f f i n i s Lagopoceus obscurus Ornithomyia f r i n g i l l i n a  external external external  169 148 134  97 85 77  1-500 per 1,000 r.b.c. 1-2 per 1,000 r.b.c. 1-20 per smear  139  80  1-25  99  57  4  23  4 22  1-5  40  39  1-20  14 0  14 0  1 0  11  11  1-4  39  38  1-300  2  2  per smear  1-6  1-2  These nematodes, maeroscopically a l i k e , were not d i f f e r e n t i a t e d i n autopsies. C. spinosa i s the more commonly o c c u r r i n g form. A new species of Y s e r i a i s yet to be described and named by Dr. J.R. Adams.  107  Plagiorhynqus i s i n extreme contrast w i t h i n f e s t a t i o n s o f these worms i n the chicks and w i l l be mentioned again.  The  4 cases o f Dispharynx i n f e c t i o n observed i n the t a b l e were from 3 y e a r l i n g s and 1 adult b i r d .  The degrees o f i n f e c t i o n  w i t h Haemoproteus. Leucocytozoon and Ornithomyia recorded i n the t a b l e must be regarded as best estimates obtained by counting techniques l i k e l y i n e r r o r . What e f f e c t p a r a s i t i s m might have on the a d u l t s once i n the  highlands and under g r e a t e r c l i m a t i c s t r e s s i s an i n t e r e s t -  ing question. With the l a c k of other evidence from the summer range, i t seems l i k e l y the g r e a t e r part of the 31$ y e a r l y m o r t a l i t y recorded i n the adult males, and assumed f o r adult females, occurs on the winter range.  Here, predation, or some  combination o f predation, weather, and d e b i l i t a t i o n through disease might act t o produce a major p o r t i o n o f the observed y e a r l y turnover. M o r t a l i t y i n the Chicks M o r t a l i t y i n the c h i c k s or young o f the year was  studied  i n terms o f decrease i n brood s i z e from the time of n e s t i n g , u n t i l the middle o f August i n each study year.  Time of hatch  was taken as June 15th t o June 21st o r i n the 10th week (p. 80). The number of c h i c k s observed i n each brood was t a l l i e d and an average brood s i z e c a l c u l a t e d f o r each week.  F i g . 29 from  Table XI appended i s a graphic p r e s e n t a t i o n of the r e s u l t s from the years 1950 to 1952.  • • 1950 -OO- 1951 • O — — O - 1952  10  12  14  16  Week 29  f r o m Table 2 1 . W e e k l y Data  of  average of  18  study brood size and  1950, 1951 and  1952  weeks.  108 S t a t i s t i c a l a n a l y s i s (simple a n a l y s i s o f v a r i a n c e ) i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e i n the weekly averages o f the  three years from week 10 to week 16. Byieek 17, however,  the  averages o f 1950 are a t variance w i t h the averages o f 1951 and  1952.  As noted above (p. 8 6 ) , i n August o f 1950, u n l i k e 1951  and 1952, a tendency towards brood d i s o r g a n i z a t i o n was observed i n t h e hens and young.  Under these conditions i t became  impossible t o a c c u r a t e l y count the progeny of any one female. Thus t h e data o f weeks 17 - 19 i n 1950 are not considered here. In each year the average brood s i z e increased from week 10 t o a high a t weeks 11 and 12.  I n the f i r s t week a f t e r hatch  some c h i c k s escape d e t e c t i o n , p a r t l y through the v i o l e n t d i v e r t ing a c t i o n o f the female, and p a r t l y by remaining motionless, or d a r t i n g under logs and d e b r i s . run  By week 12 the c h i c k s tend t o  and f l u s h r e a d i l y when t h e brood i s discovered (p. 8 2 ) , thus  accurate counts are p o s s i b l e .  With t h i s , and the above consider-  a t i o n o f 1950 data there i s a pronounced drop i n brood s i z e from the  c a l c u l a t e d average c l u t c h s i z e o f 6 eggs per hen (p. 70)  to approximately 2 chicks per hen a t t h e l a s t dates o f f i e l d observation.  A 67% decrease i n brood s i z e .  This m o r t a l i t y o r l o s s o f p r o d u c t i v i t y per hen i s a c t u a l l y greater than 67$, f o r i n counting the c h i c k s of hens w i t h broods, females that have l o s t a l l , o r never had young, go u n t a l l i e d . I t i s not p o s s i b l e t o consider the number o f lone hens seen as a brood s i z e o f 0, f o r females w i t h chicks are much more r e a d i l y observed by nature of t h e i r brood behaviour and r e a c t i o n to t h e chick d i s t r e s s c a l l .  I 109 As an estimate of the number of unproductive females and females which l o s e a l l young on the study area, the census date" o f F i g . 28(b) from Table IX appended, were used i n the f o l l o w i n g manner.  Assuming a l l lone females observed per hour i n  weeks 1 to 14 to be r e s i d e n t females and t h a t lone females are as r e a d i l y observed i n the s p r i n g weeks as i n the summer, then the average number of lone females observed per hour i n week 1 to 6, to the average number of lone females observed per hour i n week 10 to 14, i s a r a t i o o f females on the range i n s p r i n g to unproductive females and females which have l o s t a l l young, on the range i n summer. The periods 1 to 6, and 10 t o 14 were s e l e c t e d f o r s e v e r a l reasons.  One was t o remove any b i a s  created by n e s t i n g hens i n the approximately 3 weeks o f incubat i o n (p. 80).  This a c t i v i t y would remove them from the lone hen  population and b i a s the r a t i o i n favour of productive hens. This tendency would again occur a f t e r week 14 f o r there i s i n d i c a t i o n from the graph and the behaviour of the males, t h a t a f t e r t h i s time, unproductive hens and hens having l o s t a l l t h e i r chicks leave the summer range. From the data of 1950 to 1952, the average number of lone females observed per hour i n week 1 to 6 i s .55*  The average  number o f lone females observed per hour i n week 10 to 14 i s .22, a f i g u r e representing the number of unproductive hens and hens 22 of t o t a l brood l o s s on the study area a f t e r the hatch.  Thus -s-^j  or 40$ o f the females are without young and t h i s i n the weeks of the summer up to and i n c l u d i n g the 14th or to J u l y 19th.  110 I f females were l o s i n g a l l t h e i r c h i c k s as t h e summer progressed, one would expect an upward trend i n t h e number of females observed alone per hour.  Again r e f e r r i n g t o F i g . 28(b)  f o r the weeks 10 t o 14, t h i s does not occur.  I t would appear  then 1+0% o f the females l o s e t h e i r brood e a r l y i n the season, as by nest predation, o r a l t e r n a t i v e l y are unproductive. Another explanation i s that hens, once made broodless, the summer range.  leave  I f t h i s i s the case t h e t r u e r a t i o o f lone  hens i n s p r i n g to lone hens i n summer would be smaller w i t h a subsequent decrease i n p r o d u c t i v i t y .  With t h e above considerations, i t i s p o s s i b l e t o consider i n terms of c h i c k m o r t a l i t y and hen breeding success the p r o d u c t i v i t y o f the grouse population on the study area.  This  i n t u r n can be integrated w i t h data on a d u l t m o r t a l i t y , numerical s t a b i l i t y and chick s u r v i v a l , to e x p l a i n t h e population  status  of the grouse a t Quinsam Lake. In a t h e o r e t i c a l 100 hens on t h e study area i n s p r i n g , by week 14, 40$ are broodless.  By week 19, the remaining 60%  of the hens have broods o f 2 c h i c k s .  Thus 100 hens have  produced by week 19, o r the end o f August, 120 c h i c k s .  I f now,  31% i s taken as the winter turnover i n t h e 100 hens, by the f o l l o w i n g s p r i n g , assuming no f u r t h e r chick m o r t a l i t y and w i t h the 50:50 sex r a t i o observed i n the young (p. 9 0 ) , t h e hen population should c o n s i s t o f 129 b i r d s , 60 y e a r l i n g s and 69 adult hens.  A c o n d i t i o n i n whieh the y e a r l i n g s make up 1+7% o f an  Ill  i n c r e a s i n g hen population.  The s i t u a t i o n would be s i m i l a r i n  the males. Over t h e f o u r year study p e r i o d , as concluded above, the population o f females and a d u l t males i n the study area has remained s t a b l e , w i t h no increase o r decrease observed.  To  determine the p r o p o r t i o n of y e a r l i n g s i n the hen population 66 hens were shot at random, before i n c u b a t i o n had begun, i n the years 1951 and 1 9 5 2 .  The r e s u l t s o f the sampling are summarized  below: P r o p o r t i o n of y e a r l i n g hens to adult hens i n s p r i n g Year  : Sample s i z e :•No. y e a r l i n g s :% y e a r l i n g s  1951  ::  25  J  1952  :!  41  :  T o t a l :\  66  !  6  !!  24  11  i:  27  17  :  26  From t h i s , the number o f y e a r l i n g hens o c c u r r i n g on t h e summer range i s not t h e predicted 4 7 $ but c l o s e r to t h e 31% winter turnover assumed t o occur i n t h e hens of a year o r more o l d e r . Thus t o maintain the observed s t a b l e population and produce an expected 31% y e a r l i n g hen c l a s s i n t h i s population 1+7% o f t h e 120 chicks s u r v i v i n g t© week 19 must d i e between t h i s time and the f o l l o w i n g s p r i n g , migrate t o regions remote, o r do some combination o f both.  I n d i r e c t studies on migration suggest a  47% m o r t a l i t y occurs i n t h e chicks between week 19 and the f o l l o w ing spring.  This i s supported by a c o n s i d e r a t i o n o f chick  mortality factors.  112 From observations on the breeding a d u l t s i t was shown that t h i s p o r t i o n of the p o p u l a t i o n r e t u r n s each year t o the same l o c a l i t y of the summer range, u n t i l presumed dead (p. 41). No d i r e c t evidence e x i s t s to show t h a t the young of t h i s l o c a l i z e d breeding p o p u l a t i o n r e t u r n to the l o c a l i t y of b i r t h . t o t a l of 37 c h i c k s wass banded i n the study area i n 1950 1951.  A and  None was recorded on the summer range i n subsequent  years.  One explanation f o r t h i s , other than emigration, would  be the l a r g e m o r t a l i t y o c c u r r i n g i n c h i c k l i f e before and a f t e r hunter p r e d a t i o n .  As another explanation, i n banding c h i c k s ,  they could not be ringed u n t i l l a r g e enough to hold the bands. This was at 4 to 5 weeks of age.  From the movements of females  w i t h young (p. 86) such chicks caught and banded might be up to one h a l f mile from the nest, a c o n d i t i o n making t h e i r discovery near the hatching s i t e u n l i k e l y even i f , as a d u l t males, they became l o c a l i z e d and conspicuous on t e r r i t o r y . Nice (1937) has shown that y e a r l i n g song sparrows (Melospiza melodia) tend to r e t u r n to the l o c a l i t y of b i r t h . This has been demonstrated studies.  i n other, but not a l l , banded b i r d  Nice (op. c i t . ) a l s o suggests t h a t on the r e t u r n of  the young song sparrows i f some f a c t o r such as space be l i m i t i n g , they move on to new l o c a t i o n s .  Assuming t h a t sooty grouse young  r e t u r n to the r e g i o n o f t h e i r b i r t h there i s no apparent  reason  why they should leave i t , or a t l e a s t why immigration i n t o the study area from other places should not occur.  This seems most  obvious i n the case of breeding hens f o r which food, p r o t e c t i v e cover and nesting s i t e s are i n abundance at Quinsam Lake.  113 Moreover, no behaviour mechanism has been observed i n the hens which might l i m i t t h e i r d e n s i t y i n a given area, f o r u n l i k e the cocks they do not occupy and defend t e r r i t o r y . Moffat (1903) Nicholson (1933) Nice (1937) and others have s t r e s s e d the importance of t e r r i t o r i a l behaviour i n male b i r d s as a mechanism capable of l i m i t i n g population s i z e i n a given area.  Stuart and A l d r i c h (1951) attempted t o e l i m i n a t e  the breeding male population from s e v e r a l sample s t r i p s i n a spruce-fir forest.  As q u i c k l y as one male was shot, however,  another took i t s p l a c e .  They concluded from t h i s t h a t most o f  the t e r r i t o r y niches were occupied before shooting began and the r a p i d replacement of new males i n d i c a t e d a " f l o a t i n g " population of b i r d s which had l o s t i n the competition f o r space to other members o f t h e i r s p e c i e s .  They agree w i t h Nice (op. c i t . )  who s t a t e s , " I t ( t e r r i t o r y ) ensures that there w i l l be no crowding and no overpopulation s i n c e surplus b i r d s must go elsewhere". From the study o f marked males on p l o t I and I I , there i s no c l e a r i n d i c a t i o n t h a t t e r r i t o r i a l behaviour i s l i m i t i n g the present male population s i z e , producing a surplus male population o r c r e a t i n g an emigration pressure.  To f u r t h e r t e s t  t h i s c o n d i t i o n , i n May o f 1952, 16 hooting males were removed from a sample area, p l o t I I I , F i g . 1.  Two banded males were  l e f t i n the p l o t as "inducers", w i t h the b e l i e f t h a t t h e i r hooting would i n f l u e n c e members o f a " f l o a t i n g " population to s e t t l e . In no case was an emptied t e r r i t o r y reoccupied i n t h a t year. The two banded b i r d s remained throughout the summer as the only  114 r e s i d e n t males.  I n June o f 1953 p l o t I I I was recensused.  One banded male was replaced and 3 new a r r i v a l s occurred on the area i n regions where t e r r i t o r i e s had not been recorded i n the years 1950 to 1953.  On the b a s i s o f 18 males i n the  p l o t i n 1952, a 31% turnover and a s t a b l e population, the number o f new a r r i v a l s was p r e d i c t e d as 6. occurred.  As noted above, 4  This l e f t 13 s u i t a b l e t e r r i t o r y "niches" vacant.  I f then, sooty grouse young do home, there appears no b a r r i e r preventing t h e i r f u l l numerical c o n t r i b u t i o n t o the study area p o p u l a t i o n , o r as an a l t e r n a t i v e , immigration i s apparently unobstructed.  With the l a c k o f other evidence on  the movements o f young p r i o r t o t h e i r l o c a l i z a t i o n as breeding b i r d s on the summer range i t would appear a f u r t h e r 47% mortali t y occurs i n the c h i c k s that s u r v i v e t h e period from nest t o week 19, and t h i s before t h e f o l l o w i n g s p r i n g .  Thus t h e  population s t a t u s observed a t Quinsam Lake can be explained as a c o n d i t i o n wherein 40% o f t h e females are unproductive o r l o s e a l l young. 60% o f the females l o s e 4 out o f 6 o r 67% o f t h e i r young i n the summer months. The s u r v i v i n g young have a 47% f a l l and w i n t e r m o r t a l i t y which reduces t h e i r numbers t o a l e v e l t h a t equals t h e 3 1 % y e a r l y l o s s observed i n the o l d e r age c l a s s e s and r e s u l t s i n the observed s t a b l e population. With these data, the population dynamics of t h e sooty  115 grouse at Quinsam Lake can be summarized i n a l i f e t a b l e and s u r v i v o r s h i p curve drawn from i t , Table X I I , begins the l i f e t a b l e w i t h a t h e o r e t i c a l 1,000  eggs i n the nest.  The  first  l o s s i s from broodless females, which may have l o s t a l l t h e i r young or been unproductive.  S t r i c t l y speaking, the l o s s o f  eggs through unproductive hens occurs before or without nesting  and should not be considered here.  Since n o n - p r o d u c t i v i t y  i n the hens i s a minor l o s s of young (to be discussed below) and f o r the sake of s i m p l i c i t y , i t i s considered here.  Other  than t h i s the t a b l e i s orthodox i n s t r u c t u r e . Fig.  30 i s drawn from Table X I I and can be c a l l e d a  survivorship l i n e .  I t i s a n e g a t i v e l y skewed r e c t a n g u l a r curve  or a concave J i n shape.  This r e f l e c t s the production o f a  l a r g e number of eggs by a s i n g l e female w i t h extremely heavy m o r t a l i t y i n the e a r l y stages of l i f e .  According to Hickey  (1952) the o n l y approach to t h i s n e g a t i v e l y skewed curve thus far of  reported f o r b i r d s i s found i n Deevey s (1947) reanalyses f  Nice's (1937) work on the song sparrow. B u r k i t t (1926) gives a formula f o r c a l c u l a t i n g the  average length of l i f e of an animal given the c o n d i t i o n where the number of s u r v i v i n g young equals the number of a d u l t s that die  yearly.  I f a b i r d l i v e s n years then there d i e i b i r d s . n I f the y e a r l y turnover of a d u l t grouse i s 31$ w i t h the number dying each year e q u a l l i n g the number of s u r v i v i n g young then .31 = i or n * 3.2 years as the average l e n g t h of l i f e of a n grouse once i t has reached y e a r l i n g age.  116 Table X I I L i f e t a b l e f o r the sooty grouse at Quinsam Lake Primary data  '  : : x : I x Ti 2 l qx J :Survivors:(age i n years):(Cohort : dx : ( i n %) : : •:of 1.000 : :  Eggs o f 100 females  600  1,000  Complete brood l o s s  360  600  400  40  Summer chick l o s s  120  198  402  67  105  93  47 31  0  F a l l to spring loss  63  1  31% adult winter loss  43  1-2  72  33  2-3  50  22  3-4  34  16  4-5  23  11  5-6  16  7  6-7  11  5  7-8  8  3  8-9  6  2  9-10  4  2  10-11  3  1  11-12  2  1  12-13  1  1  13-14  0  0  1. l x , number l i v i n g a t beginning o f each age i n t e r v a l . 2. dx, number dying w i t h i n the age i n t e r v a l . 3. qx, the r a t e o f m o r t a l i t y i n per cent.  1000 b  K  800  c >  600  0)  .o E  3  400  200 h  6 Age Fig.  30  from Table  TK  8 in years  10  12  ( x)  A survivorship curve  for the sooty  grou  117 M o r t a l i t y Factors i n the Chicks The l i f e t a b l e c a l c u l a t i o n s begin w i t h the s u p p o s i t i o n t h a t each female on the summer range l a y s 6 v i a b l e eggs.  There  e x i s t s the p o s s i b i l i t y that some females do not l a y or i n so doing produce non-viable or addled eggs.  E i t h e r c o n d i t i o n might  e x p l a i n the 40$ broodless females observed i n the study area. an a n a l y s i s of t h i s s i t u a t i o n i n the spring of 1951 and 1952,  As 61  hens were shot or captured at random, aged and examined f o r breeding c o n d i t i o n .  The r e s u l t s are l i s t e d below i n t a b u l a r form:  Breeding hens i n each age c l a s s i n per cent :Number in:Breeding c r i t e r i o n :: No. :: $ : Age ::sample of:and number of hens::breed-:ibreedf:: i n g :: ing.: Class :: 61 hens :classed by i t Y e a r l i n g ;: Adult  :  •  13  48  :Brood patch :Ripe ova :Shed f o l l i c l e s  2 :: 2 : 5 :  9  •  :Brood patch 7 :\ :Ripe ova 5 :Shed f o l l i c l e s 34 :  4 6  1: i:  70  9  6  !  *  There i s a s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e (by c h i square t e s t ) between the number of y e a r l i n g and adult,hens engaged i n breeding a c t i v i t y .  On the b a s i s of t h i s sample,  70$ of the y e a r l i n g hens and 96$ of the a d u l t hens are p r o d u c t i v e . I f then, y e a r l i n g s make up approximately 26$ of the hen populat i o n then i n 100 hens on the s p r i n g range 18 are breeding y e a r l i n g s and 71 are breeding a d u l t s .  I n another way, 89$ of the females  i n the study area are breeding or productive b i r d s . This s i t u a t i o n r e f l e c t s i n the r e l a t i v e numbers of each age c l a s s found w i t h broods.  In sampling hens w i t h young  118  i t i s assumed t h a t each age c l a s s i s as l i k e l y t o l o s e nests and young and each i s sampled without b i a s .  From the above  c a l c u l a t i o n s , a f t e r the hatch the r a t i o o f y e a r l i n g s w i t h c h i c k s  to a d u l t s w i t h chicks should be 18 t o 71 o r . 2 5 . I n 1951 and 1952, 48 females were shot o r captured when w i t h broods.  Of these, 9  were y e a r l i n g s and 39 were a d u l t hens, a r a t i o o f 9 t o 39 o r .23, a d e v i a t i o n from the expected r a t i o which i s not s t a t i s t i c a l l y s i g n i f i c a n t (by chi-square t e s t ) .  I f 89% o f the hens on the summer range are p r o d u c t i v e , or 11% unproductive, then n o n - p r o d u c t i v i t y alone does not e x p l a i n the 40% hens observed without broods and i n d i c a t e s most loss., of young occurs a f t e r the eggs are l a i d . Data on the number o f addled or i n f e r t i l e eggs l a i d by nesting hens are meagre.  Of the nests found i n the study area  but 3 y i e l d e d data on addled eggs.  I n other cases, while addled  eggs may have been l e f t i n the nest a f t e r the remainder had hatched, they could have been destroyed o r c a r r i e d away by predators before discovery.  I n the 3 nests mentioned, 1 egg  i n a c l u t c h o f 6 , 2 i n a c l u t c h o f 7 and 2 i n a c l u t c h o f 4 were addled.  From s t u d i e s on g a l l i n a c e o u s b i r d s by Bump et a l  (1947) Patterson (1952) and o t h e r s , i n f e r t i l i t y has not been a  major f a c t o r i n c h i c k l o s s .  While t h i s unexplained phenomenon  may help decrease the brood s i z e by a c h i c k o r two, i t i s not considered a s o l e f a c t o r c r e a t i n g brood l o s s a t Quinsam Lake.  119 Nest d e s e r t i o n and/or p r e d a t i o n appears a r e l a t i v e l y l a r g e m o r t a l i t y f a c t o r i n young grouse p r i o r to hatch.  This  conclusion i s based upon the f a t e o f 36 nests discovered over the three year study p e r i o d .  Of the 36 nests only 6 were found  p r i o r to s u c c e s s f u l hatch o r d e s t r u c t i o n .  The remaining nests  were c l a s s i f i e d as to a s u c c e s s f u l or unsuccessful hatch on the basis of s h e l l fragments i n and around the nest.  Thus d e s e r t i o n  of the nest might have occurred before depradation.  I n the 6  nests mentioned above, 2 were l o s t through p r e d a t i o n , r a t h e r than nest d e s e r t i o n . S i m i l a r l y a l l unsuccessful nests have shown evidence of p r e d a t i o n .  With the l a c k of other d a t a , i t  seems l i k e l y t h a t most nest f a i l u r e i s as a d i r e c t r e s u l t of predation r a t h e r than d e s e r t i o n . I n the sample of 36 nests 9 or 25% were apparently l o s t through depredation.  This f i g u r e , w h i l e not high i n comparison  w i t h other s t u d i e s , i s probably greater than the a c t u a l nest destruction.  When a nest has been destroyed the eggs are broken  and s c a t t e r e d about i n a manner that a i d s i n the i d e n t i f i c a t i o n of the predator and the d i s c o v e r y of the nest, F i g . 20(c).  In  a s u c c e s s f u l hatch the s h e l l s are pipped c h a r a c t e r i s t i c a l l y and remain w i t h i n the nest s t r u c t u r e , s t i l l p a r t l y hidden by logs and v e g e t a t i o n .  There i s no doubt t h a t these s u c c e s s f u l nests  are l e s s o f t e n found than the u n s u c c e s s f u l , a c o n d i t i o n t h a t introduces i n t o the c a l c u l a t i o n an unknown b i a s i n favour o f nest destruction. I d e n t i f i c a t i o n of nest predators i n the study area i s  120 based on c i r c u m s t a n t i a l evidence.  Bump et a l (1947) describe  and i l l u s t r a t e nests of r u f f e d grouse destroyed by v a r i o u s animals.  On t h i s b a s i s , and from faeces, h a i r feathers and  odour at the destroyed nests an attempt was made to i d e n t i f y the predator. In the 9 observed cases o f nest depredation, 1 appeared t o be the r e s u l t o f f o x , 4 f o x or raccoon (Procyon l o t o r ) , 1 raven (Corvus corax) and 3 unknown.  From the above c o n s i d e r a t i o n s , non-productivity, nest d e s e r t i o n and depredation do not e x p l a i n the 40$ broodless females observed on the study area.  Nor do these m o r t a l i t y  f a c t o r s e x p l a i n the drop i n brood s i z e i n week 10 t o week 19 i n 1950, 1951 and 1952.  C l e a r l y , both c o n d i t i o n s are a r e s u l t  of m o r t a l i t y i n the young a f t e r hatch. The p a t t e r n o f chick death as i l l u s t r a t e d i n F i g . 29 has been s i m i l a r over the years 1951, 1952 and e a r l y 1950, w i t h a downward trend from week 11 and 12 to week 19, the end of f i e l d observation.  The gap i n r e l i a b l e data on brood s i z e between time  of hatch and the t h i r d week of age leaves much t o be d e s i r e d . I t might be assumed the trend begins a t 6 eggs i n the nest and f o l l o w s the same "slope" of m o r t a l i t y as i n the o l d e r age c l a s s e s . On the other hand, conditions p e c u l i a r t o s u r v i v a l i n e a r l y chick l i f e might be a c t i n g t o remove young b i r d s from the p o p u l a t i o n and cause a sudden drop t o what i s observed as maximum brood s i z e i n week 11 and 12.  Addled eggs o r a s i c k l y chick per brood which  perishes s h o r t l y a f t e r the hatch might be considered i n t h i s respect.  121 Beer (1943), Fowle (1944) and others r e p o r t blue grouse chicks t o be i n s e c t i v e r o u s i n d i e t u n t i l about t e n days of  age when they begin to take vegetable food.  While plant  m a t e r i a l i s obviously p l e n t i f u l a t Quinsam Lake, a shortage of acceptable i n v e r t e b r a t e s might e x i s t and t h i s , caused by o r associated w i t h inclement weather, might remove week o l d c h i c k s from the broods.  I t i s noteworthy, however, that the decrease  i n brood s i z e continues beyond t h e 12th week despite t h e f a c t that the chicks by t h i s time are on an adult d i e t . Inclement weather per se, o r i n a s s o c i a t i o n w i t h food shortage, might r e s u l t i n the death o f week o l d grouse, p a r t i c u l a r l y i f some chicks are separated from the hen and brood. Assuming other m o r t a l i t y f a c t o r s constant, however, the r e l a t i v e l y cool wet spring recorded i n 1952 (p. 20) appears t o have had no markedly d e l e t e r i o u s e f f e c t on brood s i z e as compared t o 1950 and 1951.  This seems so from a comparison of average brood s i z e s  over the three years, which f a i l to show a s t a t i s t i c a l l y s i g n i f i cant d i f f e r e n c e from week 11 to week 16. Predation d o u b t l e s s l y removes chicks from the broods i n the f i r s t week o f hatch and a f t e r .  I t i s d i f f i c u l t , however,  to r e c o n c i l e t h e l o s s of 2 o r even 1 chick per brood t o predation i n t h e e a r l y stages o f l i f e .  On t h e other hand, human predation  during t h e hunting season i s an apparent cause o f chick m o r t a l i t y . Road check data of 1950 (Taylor, unpublished B.C. Game Report, 1950) i n d i c a t e d chicks formed a minimum o f 80% o f the t o t a l bag checked i n 1950.  Thus f o r every 1 hen, approximately 4 chicks are  122 taken i n the f a l l harvest.  I f t h e hunter success i n t a k i n g  females i n 1950 to 1952 i s averaged as 1% then t h i s would suggest k% o f the c h i c k s are shot.  I n 1950 and 1951, 37 c h i c k s  were banded and r e l e a s e d . Assuming the i n t a c t sample present on the summer range p r i o r t o the harvest, an u n l i k e l y assumption, the number shot as t o number banded would give some i n d i c a t i o n of hunter success. hunters.  Of t h e 37, 3 o r 8$ were shot and reported by  From t h i s , and t h e above, there i s no i n d i c a t i o n t h a t  predation, human o r otherwise, i s a major m o r t a l i t y f a c t o r i n t h e chicks on the summer range.  W i t h i n t h i s patchwork of p o s s i b l e but u n c e r t a i n m o r t a l i t y f a c t o r s p a r a s i t i s m and disease begin t o appear as environmental f a c t o r s capable of c r i p p l i n g and k i l l i n g c h i c k s .  Table X I I I  summarizes the p a r a s i t e s found i n c h i c k s c o l l e c t e d from week 10 to week 19 i n the years 1950 t o 1952 a t Quinsam Lake.  The data  are from 89 chicks smeared f o r blood examination and 107 c h i c k s autopsied f o r v i s c e r a l p a r a s i t e s .  Not i n c l u d e d i n the t a b l e i s  the record o f one t i c k (Ixodes a u r i t u l u s ) removed from the head o f a chick examined at the 1950 road check i n Campbell R i v e r .  In  the 1950 study period b a c t e r i a l i n f e c t i o n s occurred i n 10 out o f a sample o f 60 chicks examined i n the f i e l d .  The i n f e c t i o n s were  apparently caused by mechanical i n j u r y t o the f e e t and other body parts w i t h subsequent b a c t e r i a l i n v a s i o n .  No cases were recorded  i n 1951 and 1952. Comparing Table X I I I t o p a r a s i t i s m recorded i n the a d u l t s  Table X I I I P a r a s i t e s found i n chicks from 1 to 9 weeks of age. 1950, 1951 and 1952. *>. •>  Quinsam Lake data o f  •  » »  : S i t e :Number : Number rDegree of i n f e c t i o n : found :examined:infected :infected  Parasite Haemoproteus sp.  89  59  66  34  38  1-50 per 1,000 r.b.c. .. -1 per 1,000 r.b.c. 1-10 per smear  Leucocytozoon sp.  blood blood  Trypanosoma sp.  blood  18  20  Microfilaria  blood  0  0  5  6  stomach 107 gizzard gizzard Rhabdometra n u l l i c o l l i s ( ? J i n t e s t i n e A s c a r i d i a bonasae 'intestine  68  64  11  10  Plagiorhynous formosus  intestine  Ceratophyllus d i f f i n i s  Triple  Infections  Dispharynx nasuta ^ ( C h e i l o s p i r u r a spinosa (Yseria  0  1-430  1-2 22  21  4  4  1  53  50  1-33  external  0  0  0  Lagopoceus obscurus  external  21  20  1-50  Ornithomvia  external  7  7  fringillina  1-20  1-2  #Th ese nematodes, macroscopically a l i k e , were not d i f f e r e n t i a t e d i n autopsies. _C. spinosa i s the more commonly o c c u r r i n g form.  123*  and y e a r l i n g s , Table X, s e v e r a l d i f f e r e n c e s w i l l be noted. Generally, w i t h the same sampling r e s e r v a t i o n s as noted i n the case o f the a d u l t s , the number and degree of i n f e c t i o n s are lower i n the c h i c k s .  This i s more apparent than r e a l since  the c h i c k sample includes week o l d young. although p o s s i b l y p a r a s i t i z e d may  These animals,  not show detectable stages  of p a r a s i t e s and thus introduce a bias not found i n the o l d e r age c l a s s e s i n favour o f n o n - p a r a s i t i z e d .  F i g . 31 from Table XIV  appended, i s a graphic presentation o f the p a r a s i t i c i n f e s t a t i o n s observed i n chicks w i t h age.  The data were obtained from  samples taken each week of the study i n 1950 to 1952 of peak hatch.  from week  Thus v a r i a t i o n i n the date of hatch i n any  one  sample i s an obvious source of e r r o r i n t h i s treatment as w e l l as the small sample s i z e s i n each week.  Lumping data i s not  considered a serious e r r o r as the samples of each year have been comparable, Bendell ( i n manuscript). As i t might be expected the number o f i n f e c t i o n s w i t h most p a r a s i t e s increases as the chicks age.  This i s evident  from a c o n s i d e r a t i o n of the i n f e c t i o n trends o f Haemoproteus. Leucocytozoon. Dispharynx. Plagiorhyncps Rhabdometra.  and perhaps of  I n these p a r a s i t e s number of hosts i n f e c t e d i n l a t e r  chick l i f e equals or exceeds the f i g u r e f o r the a d u l t s and lings.  year-  M i c r o f i l a r i a was apparently absent from the blood of  c h i c k s over the period studied. A most s t r i k i n g and noteworthy d i f f e r e n c e between chick and a d u l t parasitemia i s observed i n the occurrence of  Haemoproteus  Leucocytozoon  Trypanosoma  Dispharynx  Cheilospirura •and Yseria J  L  J  c  I  I  Rhabdometra  Ascaridia I  I  I  I  L  Plagiorhynqys  I  2  3  4  5  6  7  8  9  -I—lo  Age in weeks Fig.  31  from Table I E .  Age and infections in chicks  O  124 Dispharynx and Plagiorhyncus as common p a r a s i t e s of the young. The 4 Dispharynx i n f e c t i o n s recorded i n Table X occurred i n 3 y e a r l i n g s and 1 a d u l t b i r d w i t h the l e v e l of i n f e c t i o n from 1-6  worms.  grouse.  Plagiorhyncus was not found i n a d u l t or y e a r l i n g  I n the chicks at 4 to 5 weeks of age 87 - 94$ were  i n f e c t e d w i t h Dispharynx and 67 - 73$ were i n f e c t e d w i t h Plagiorhvncus.  In t h i s age group, 53 - 73$ of the chicks  examined c a r r i e d both worms, Table XlV appended. Dispharynx and P l a g i o r h y n y i s were the most damaging p a r a s i t e s encountered d u r i n g the study. both  According t o "  S i n i t s i n (1929), Cram (1931 bVworms are vectored by isopoda, a common item i n the d i e t of c h i c k s .  W i t h i n the c h i c k s  Dispharynx occurs i n the stomach or p r o v e n t r i c u i u s and here causes obvious l e s i o n s .  I n severe i n f e s t a t i o n s of 100 - 300  worms, the s o f t stomach i s diseased and p r o l i f e r a t e d i n t o long f i b r o u s shreds.  This and profuse q u a n t i t i e s of mucus occur  i n the stomach lumen c r e a t i n g a b a r r i e r to food passage.  The  worms themselves are found i n t h i s t i s s u e , o r embedded i n the glands of the stomach, which are i n most cases devoid of secretion.  The stomach o f t e n enlarges to f o u r times i t s  healthy s i z e and i s streaked and blotched w i t h red inflammat i o n as compared to i t s normal l i g h t grey or beige c o l o u r . The acanthocephalan Plagiorhyncfeis has i t s h a b i t a t i n the lower small i n t e s t i n e of chicks and w h i l e not a s s o c i a t e d with as great a host r e a c t i o n as recorded i n the ease o f Dispharynx s t i l l creates obvious t i s s u e damage.  The worm  125 g e n e r a l l y occurs w i t h i t s head o f spines embedded i n the intestinal wall.  Twelve cases have been observed where the  gut was perforated and the worms f r e e i n t h e coelome o r under the i n t e s t i n a l mesentery.  I n such cases b a c t e r i a l i n f e c t i o n  from gut t o coelome l i k e l y occurred.  Generally t h e gut tube  i s c o n s t r i c t e d and thrown i n t o a t i g h t c o i l about the s i t e o f acanthocephalan i n f e c t i o n w i t h apparent blockage o f t h e intestine. c  h i c k s w i t h severe i n f e c t i o n s of Dispharynx and  Plagiorhync us o r Dispharynx alone, are emaciated, weak and easily ;  caught i n the f i e l d .  Their body organs, e s p e c i a l l y the  kidneys appear blanched and p a l e , w h i l e the i n t e s t i n e i s f i l l e d w i t h a slimy l i q u i d and gas.  F i v e young grouse were  c o l l e c t e d i n the study area, apparently near death from the ravages o f these worms.  Observations on one are as f o l l o w s :  " J u l y 9, 2130, 350°S, 60OF, female and brood o f 3 observed i n Log Open two chicks f l u s h , 1 remains near female which clucks and moves s l o w l y away with s l i g h t neck d i s p l a y .  Attempt  capture o f remaining c h i c k w i t h noose, stroke head, back and t a i l w i t h noose, and then move i n and capture chick by hand.  Prepare t o band i t f o r release and note extremely  l e t h a r g i c responses, place i t i n bag, i t remains motionless on i t s s i d e " . I n every respect t h i s behaviour was a t y p i c a l from what i s u s u a l l y experienced i n capturing and banding apparently healthy chicks (p. 82). An estimate o f % haemoglobin i n t h e  126  blood by S a h l i technique and the number of r e d blood c e l l s per cu. mm.  of blood was 45% and 1,200,000 per cu.  respectively.  mm.  Both f i g u r e s are about h a l f t h a t recorded i n  apparently healthy young, Table XV appended.  The l u n g , l i v e r  and kidneys of the c h i c k were pale i n eolour, the stomach was inflammed and swollen, the i n t e s t i n e was f l u i d f i l l e d and acanthocephalans were v i s i b l e i n the gut lumen.  The diseased  stomach y i e l d e d 150 Dispharynx and the i n t e s t i n e 17 acanthocephalans one of which was i n the coelome of the b i r d . What converts an i n f e c t i o n with Dispharynx or Dispharynx and Plagiorhyncus i n t o a l e t h a l c o n d i t i o n i s unknown. Edminster (1947) considers 20 - 30 Dispharynx capable of a f f e c t i n g the h e a l t h of r u f f e d grouse while more may fatal. occurs.  prove  He designates t h i s p a r a s i t e a major pathogen when i t I n f e c t i o n s w i t h 50 and more Dispharynx and 1 to 5  acanthocephalans are commonly encountered i n chicks shot as apparently healthy.  F i g . 32 i l l u s t r a t e s the frequency of  occurrence of Dispharynx i n f e c t i o n s recorded i n 112 chicks c o l l e c t e d i n the study area.  Perhaps a 10 worm i n f e c t i o n  would be l e t h a l i n young chicks w h i l e 50 worms i n o l d e r b i r d s would have no e f f e c t .  The s i t u a t i o n i s made more complex by  i n t r o d u c i n g the e f f e c t s of host r e s i s t a n c e , other p a r a s i t e s , weather and food supply as a d d i t i o n a l v a r i a b l e s .  One or a  combination of these f a c t o r s might t i p the balance of a Dispharynx i n f e c t i o n from recovery to death.  60 -  0 - 20 Fig.  32.  40  60  80  100  120  140  160  180  Number of worms  200 220  240  260  280  300 +  Distribution of infections with Dispharynx in 106 chicks autopsied at Quinsam Lake. Data of  1950 to 1953  127  The pathogenicity of Dispharynx and P l a g i o rhyncus i n f e c t i o n s cannot be doubted.  There remains t o be shown a  c o r r e l a t i o n between chick m o r t a l i t y and p a r a s i t e a t t a c k . The downward trend i n average brood s i z e from week 12 has been noted above.  I t i s worthwhile t o consider the v a r i a t e s  i n each week's average brood s i z e as an explanation of the observed drop.  F i g . 33 i l l u s t r a t e s the frequency of brood  s i z e occurrence f o r weeks 10 to 19 i n 1950 to 1952.  It i s  noteworthy that beginning with week 12 the f i g u r e s change shape so that by week 14 a brood s i z e o f 1 i s the modal c l a s s and remains a r e l a t i v e l y common brood s i z e t h e r e a f t e r . The frequent occurrence of 1 chick per brood suggests t h a t t o t a l l o s s of chicks occurs and r e s u l t s i n broodless hens. This occurrence of low brood s i z e s i n the study area c o r r e l a t e s w i t h the b u i l d up o f Dispharynx and Plagiorhynqus i n f e c t i o n s i n terms o f per cent young i n f e c t e d and average number o f worms per i n f e c t i o n with each week o f age, F i g . 34 from Table XVI appended.  A f t e r the 14th week there  appears a downward trend i n the number of chicks i n f e c t e d which might r e f l e c t the removal of h e a v i l y i n f e c t e d b i r d s from the population, a developing age immunity i n the young, or both.  Nevertheless, i n a sample o f 16 chicks obtained at  Quinsam Lake i n September o f 1950 and 1951, 12 were i n f e c t e d w i t h 1 to 300 Dispharynx. w h i l e 6 were i n f e c t e d w i t h from 5 t o 9 acanthocephalans, an i n d i c a t i o n that these p a r a s i t e s are c a r r i e d onto the winter range.  Week 12  20 16 12 8 4 1 2  3  4  5  6  7  I  Week 13  20 16 12 -  Week 17  20 I6h 12 8 4 2  3  4  5  6  7  6  7  Week 18  2 or  16 12  « *-  •O 4 " o '— o  2  3  2824 20 o 16 12 8 ». 4 -  4  5  6  7  1 2  Week 14  0  I  -O  2  3  4  5  3  j  7  5  Week 19  20 •6 12 86  4  i  I  I  2  I  3  V/YZ2 4  5  6  i i  E  1950 data  Week 15  20 16 12  Histograms comparing brood sizes for weeks  8 4 1 2  3  5  6  i  j  7  Week i6  20 16 F 12 8 4 I  4  2  3  4  -l  5  Brood  L  6 7  size  12 - 19.  Data of 1950, to 1952.  7  Dispharynx  100  4  100  5 6 Age, weeks  7  Plagiorhyncus  100  100  80  80 %  T3  a> o 60 a>  infected 60 40  3« 4 0  i  o w  a> E  1  v o> o at  20  20 <  average no. of worms  4 5 6 Age, weeks 10 Fig.  | o  34  12  7  8  9  13 14 15 16 Week of study  17  18  10 19  from Table X E L . % infection, average number of worms per infection and age of chicks. Data of 1950 to 1952.  128 With t h i s , and i n view of the 8 9 $ p r o d u c t i v i t y o f the hens, the d o u b t l e s s l y high estimate of nest d e s t r u c t i o n and the apparently n e g l i g i b l e e f f e c t of predation i t seems l o g i c a l to conclude that the p a r a s i t e s Dispharynx  and  Plagiorhyncus are important as c h i c k m o r t a l i t y f a c t o r s . They would e x p l a i n i n most part the 4 0 $ broodless hens and the 6 7 $ chick l o s s recorded on the summer range.  Moreover,  i t seems l i k e l y under conditions of w i n t e r s t r e s s , c h i c k s c a r r y i n g these p a r a s i t e s would s u f f e r g r e a t e r m o r t a l i t y than the o l d e r age c l a s s e s . This was c a l c u l a t e d at 4 7 $ between f a l l and s p r i n g as compared to a 31$ y e a r l y turnover i n the older birds.  Thus, as causal agents of extreme chick m o r t a l -  i t y , Dispharynx and Plagiorhyncus can be considered as major f a c t o r s e f f e c t i n g population s i z e and s t a b i l i t y on the study area. kD i s t r i b u t i o n of Dispharynx and Plagiorhyncus I f disease plays a major r o l e i n p o p u l a t i o n c o n t r o l on the study area, it.seems worthwhile to speculate on i t s importance as a p o p u l a t i o n c o n t r o l i n other regions.  The  study area, as already mentioned, i s r e p r e s e n t a t i v e of 7 4 , 5 0 0 acres once under climax f o r e s t , now logged and burned.  Since  t h i s e n t i r e area i s i n the same stages of plant succession and w i t h i n the known range of sooty grouse i t i s l i k e l y t h a t conditions o p e r a t i n g over the l a r g e r area are s i m i l a r to those found a t Quinsam Lake.  C e r t a i n l y i f Dispharynx and Plagiorhyncus  129 are present i n numbers, the wide range of chicks before and i n m i g r a t i o n (p. 87, 89) would f a c i l i t a t e i n d i s p e r s a l o f the p a r a s i t e s , given the necessary intermediate hosts. Since sooty grouse are hunted over the Quinsam r e g i o n and beyond, i t was p o s s i b l e through the cooperation of hunters to o b t a i n v i s c e r a o f young grouse taken i n various l o c a l i t i e s .  The l o c a l i t i e s sampled and the  presence  or absence of Dispharynx and Plagiorhyndjus are l i s t e d i n Table XVII.  F i g . 35 i s a map o f the d i s t r i b u t i o n of these  two p a r a s i t e s over the sampled area.  From t h i s , i t appears  Dispharynx occurs over the e n t i r e 74,500 acre burn, and l i k e l y Plagiorhyncus i f enough samples had been taken.  This  d i s t r i b u t i o n of the two pathogens suggests they may be operating as population c o n t r o l s i n other regions than Quinsam Lake or at l e a s t over the 1938  burn.  On the other hand, a r e l a t i v e l y l a r g e sample of 31 young shot i n the Campbell Lake r e g i o n i n 1952 was f o r both Dispharynx and Plagiorhyncus. r e g i o n and i n 1951 was severely burned.  negative  This i s a logged Thus the absence of  the two p a r a s i t e s may mean t h a t the area never was  infested,  or the f i r e of 1951 destroyed the isopod intermediate hosts. C l e a r l y , however, the p a r a s i t e ecology o f t h i s r e g i o n i s quite d i f f e r e n t than t h a t at Quinsam Lake, and other populat i o n c o n t r o l s must be o p e r a t i n g , or w i l l operate, to remove grouse by death or emigration.  With t h i s d i f f e r e n c e i n  environmental f a c t o r s a f f e c t i n g a species over a r e l a t i v e l y  130  Table XVII D i s t r i b u t i o n of Dispharynx and Plagiorhyncus i n f e c t i o n s from hunter k i l l e d young. September 1951, 1952.  Locality  • •  • k:Map :Sample : Dispharynx : Plagiorhyncus :No. : S i z e :Infected: % : I n f e c t e d : Jo  Boot Lake  1  6  2  1  Upper Campbell Lake  2  6  0  0  Camp 5  3  7  1  0  Roberts Lake  4  3  3  0  Sayward  5  2  0  0  Middle Campbell L.  6  31  0  Ladore F a l l s Dam  7  4  1  0  Mohun Lake  8  7  2  1  Iron River Road  9  1  1  1  Quinsam Lake  10  16  12  Constitution H i l l  11  2  2  0  75  0  4 2  0  25  Fig. 35  r~| O Q #  approx. scale l" = 10 miles  from Table Z S H . Distribution of Dispharynx and Plagiorhyncus based on hunter killed young 1950,1951. Logged and burned in, and prior to, 1938 ( Bloedel fire no. 230,1938) Study area Hunter sample, negative Hunter sample, Dispharynx Hunter sample, Dispharynx and Plagiorhyncus Numbers refer to locality in table  131 small p o r t i o n o f i t s known range, i t i s d i f f i c u l t t o accept the suggestion o f Leopold (1933) Wing (1943) and Fowle (1944) that the sooty grouse are c y c l i c , a t l e a s t as i n v e s t i g a t e d i n t h i s study.  The evidence suggests one must l o o k f o r  populations, each responding t o the environmental c o n d i t i o n s of i t s p a r t i c u l a r l o c a l i t y .  132 DISCUSSION The abundance of sooty grouse i n the study area d o u b t l e s s l y r e f l e c t s the s u i t a b i l i t y of the v e g e t a t i o n on i t s summer and winter range.  From a c o n s i d e r a t i o n of the  h a b i t s of the males they apparently have a wide environmental tolerance.  Thus males are observed hooting o r / s e x u a l l y  a c t i v e i n dense stands of douglas f i r or beside a l o g i n near minimum of s h e l t e r v e g e t a t i o n . The hens on the other hand, show a marked s e l e c t i o n of open v e g e t a t i o n f o r f e e d i n g , nesting and when w i t h c h i c k s .  Fowle (1944) d i d not record  the intense f l i g h t s and feeding a c t i v i t y of the hens i n e a r l y morning and l a t e evening.  Since the Quinsam area at the time  of h i s s t u d y was i n an e a r l i e r stage of burn succession, there i s the suggestion then, t h a t the changing environment r e s u l t e d i n a change i n behaviour of the hens.  has  As p l a n t  succession advances i t seems l i k e l y t h a t the breeding hens w i t h a r e l a t i v e l y narrow environmental t o l e r a n c e w i l l be the population component f i r s t a f f e c t e d .  This may r e f l e c t i n a  f a i l u r e to breed, nest, o r s u c c e s s f u l l y r a i s e young.  Thus  the s t a b l e p o p u l a t i o n as observed now at Quinsam Lake seems destined to dwindle and disappear, p r i m a r i l y as a r e s u l t of the ecology of hens.  The occurrence of Plagiorhyncus and Dispharynx as host records coupled w i t h t h e i r abundance and p a t h o g e n i c i t y leads to f u r t h e r s p e c u l a t i o n .  Both p a r a s i t e s are common.  new  133  ^ispharynx has a cosmopolitan d i s t r i b u t i o n and occurs i n t h e r u f f e d grouse, crow (Corvus brachyrhyncos), r o b i n (Turdus migratorius) and other b i r d s , Coble (1945).  P l a g i o rhyncus  occurs i n o l d world avifauna, and P. formosus has been recorded from the r o b i n i n Alaska, Van Cleave and W i l l i a m s (1951). I f the f a i l u r e o f Beer (1944) and Fowle (1944) t o f i n d the two pathogens i s r e a l , then t h i s may i n d i c a t e the sooty grouse has acquired these p a r a s i t e s i n r e l a t i v e l y recent times.  The  extreme host r e a c t i o n would tend to support t h i s conclusion, f o r i n long host p a r a s i t e a s s o c i a t i o n s , each member becomes adapted t o the other and both l i v e together more o r l e s s harmoniously.  Assuming Dispharynx and Plagiorhyncus endemic  i n the r u f f e d grouse and r o b i n p r i o r t o man's l o g g i n g and burning, then the stage i s s e t f o r a new host p a r a s i t e r e l a t i o n ship i n v o l v i n g the sooty grouse.  With a tremendous increase  i n numbers by v i r t u e o f the new range made a v a i l a b l e , the chances o f host p a r a s i t e contact through t h e isopod v e c t o r are increased a c c o r d i n g l y , u n t i l i f necessary, a sooty grouse form of Dispharynx and Plagiorhyncus becomes e s t a b l i s h e d , ^hua a change i n population s i z e has r e s u l t e d i n the i n t r o d u c t i o n o f a new environmental f a c t o r a f f e c t i n g the s u r v i v a l o f the s p e c i e s . As plant succession i n e v i t a b l y reclaims the new summer range to climax f o r e s t , the sooty grouse must r e t r e a t t o a more primaeval h a b i t a t o f t h e higher timbered slopes and mountain meadows beyond the range o f the r u f f e d grouse and robin.  Dispharynx and Plagiorhyncus would now be i s o l a t e d i n  13k  the sooty grouse.  Granted the necessary intermediate hosts  and assuming genetic mutation, or n a t u r a l s e l e c t i o n or both would occur i n the newly e s t a b l i s h e d forms, t h i s e c o l o g i c a l i s o l a t i o n would f u l f i l l the f i r s t r e q u i s i t e of s p e c i a t i o n .  135 SUMMARY AND CONCLUSIONS 1. A population o f sooty grouse (Dendragapus obscurus f u l i g i n o s u s ) has been s t u d i e d on i t s summer range over the years 1950 t o 1953. 2. Sooty grouse chicks by September of t h e i r f i r s t year are i n plumage s i m i l a r t o the a d u l t s with the exception o f shorter and narrower t a i l r e t r i c e s .  The annual post n u p t i a l moult  f o l l o w s a recognizeable p a t t e r n w i t h the replacement o f wing t a i l and body f e a t h e r s .  There i s evidence that annual  wing f e a t h e r moult i s not complete i n a d u l t b i r d s . 3. As c r i t e r i a o f age, y e a r l i n g males have outer t a i l feathers ranging i n length between 13.2 and 15.2 cm.  The outer  r e t r i c e s o f adult male b i r d s o f 2 years and o l d e r , range between 16.1 and 19.4 cm.  Y e a r l i n g females have outer t a i l  feathers ranging i n l e n g t h between 11.7 and 13.4 cm.  The  outer r e t r i c e s o f a d u l t females range between 13.5 and 16.1 cm. 4. A sample o f 14 adult males i n s p r i n g averaged 1300 • 50 g. i n weight.  A s i m i l a r summer sample averaged 1200 * 25 g.  A sample o f 20 adult hens weighed i n the summer averaged 850 • 25 g. 5. Eight y e a r l i n g males and 11 y e a r l i n g females weighed i n June and J u l y averaged 1100 ± 50 g. and 780 • 25 g. r e s p e c t i v e l y , an i n d i c a t i o n that y e a r l i n g males and females do not a t t a i n adult weight u n t i l a f t e r J u l y of t h e i r second year.  136 6c L o c a l i z a t i o n , i s o l a t i o n and vocal d i s p l a y on an area w i t h w e l l defined boundaries between adjacent males a r e f e a t u r e s c h a r a c t e r i s t i c o f t e r r i t o r i a l behaviour i n the a d u l t male. 7. T e r r i t o r y s i z e as determined i n t h i s study might be r e a l and represent the maximum area over which a given b i r d hooted throughout a study p e r i o d , o r apparent and represent the maximum area over which a given b i r d was observed t o hoot. 8. There appears a r e l a t i o n s h i p between the l o c a t i o n o f t e r r i t o r i e s and the dense v e g e t a t i o n a l types which would provide concealment f o r a hooting b i r d .  No r e l a t i o n s h i p was found  between t e r r i t o r y l i m i t s and t h e l i m i t s o f t h e described v e g e t a t i o n a l types.  T e r r i t o r i e s c o n t a i n open areas i n which  hens feed and are e a s i l y seen as w e l l as dense s h e l t e r vegetation. 9. Adult males e x h i b i t a "homing" behaviour i n r e t u r n i n g t o t h e i r previous y e a r s t e r r i t o r i e s i n subsequent s p r i n g s . f  10. T e r r i t o r y s i z e appears t o be a density dependent f a c t o r which i s i n v e r s e l y p r o p o r t i o n a l to abundance o f hooting males. 11. The males i n d a y l i g h t hours show a r e l a t i v e l y high u t i l i z a t i o n o f F i r Dense type w i t h the remaining s h e l t e r types l e s s f r e q u e n t l y used. 12. The hooting a c t i v i t y o f a male appears t o be stimulated by that o f adjacent males and hooting p o s s i b l y i n f l u e n c e s i t s  137 movements c o n t r i b u t i n g to the extent of t e r r i t o r y .  The  presence of hooting males and s u i t a b l e s h e l t e r vegetation might be considered  as f a c t o r s i n i t i a t i n g t e r r i t o r i a l  behaviour. 13. F i g h t i n g appears to f u n c t i o n as a mechanism by which t e r r i t o r i a l boundaries between adjacent males are and trespassing males are repulsed.  I t may  established r e s u l t i n the  displacement of one male by another. 14. T h e o r e t i c a l l y the f u l l courting d i s p l a y would serve as a mechanism i d e n t i f y i n g a r e c e p t i v e male t o a r e c e p t i v e female. The i n i t i a l stage of the courting d i s p l a y i s a response of a general nature.  I t may  become the f u l l c o u r t i n g d i s p l a y  or the f i g h t i n g posture depending upon a more s p e c i f i c response at sex r e c o g n i t i o n .  Sex r e c o g n i t i o n i s apparently  made through plumage or s i z e dimorphism or both. 15. The purpose of t e r r i t o r y appears t o be i n the undisputed use of area wherein hooting and c o u r t i n g d i s p l a y can f u n c t i o n to f u l f i l l the reproductive  requirements of the male.  T e r r i t o r i e s can be considered  mainly as areas of d i s p l a y and  courting a c t i v i t y . 16. There i s a marked seasonal behaviour i n the a d u l t male i n terms of t e r r i t o r i a l behaviour, sexual a c t i v i t y , and from the summer range i n June to August.  migration  There appears a  r e l a t i o n between these phenomena and a decrease i n t e s t e s volume.  138  17. Y e a r l i n g males do not manifest the sexual and  territorial  behaviour as found i n the a d u l t male, and are apparently vagrants on the summer range.  The r e l a t i v e l y s m a l l t e s t e s  volume observed i n y e a r l i n g males appears c o r r e l a t e d w i t h these phenomena. 18. Most males l e a v i n g the summer range as chicks do not make the downward m i g r a t i o n u n t i l t h e i r second s p r i n g a f t e r hatch.  The migration i n the male appears r e l a t e d to sexual  development as measured by t e s t e s volume. 19. As the cocks, the hens appear t o r e t u r n t o the same area of the summer range i n subsequent years.  Unlike the cocks they  move independently over a r e l a t i v e l y l a r g e area which might be c a l l e d a home range. 20. Hens p r i o r t o i n c u b a t i o n showed tendency to u t i l i z e the dense v e g e t a t i o n a l types and Clover Open which would provide s h e l t e r and food r e s p e c t i v e l y . 21. It i s l i k e l y that sooty grouse of both sexes are promiscuous of breeding h a b i t . 22. The production of ova apparently begins i n l a t e A p r i l and e a r l y May,  and continues w h i l e the eggs are l a i d from the  second t o the l a s t week of May.  The brood patch i s apparent-  l y i n c i p i e n t as the eggs are deposited and becomes f u l l y developed at the c e s s a t i o n of l a y i n g a c t i v i t y and the beginning of i n c u b a t i o n .  23. The average c l u t c h s i z e l a i d by nesting hens appears t o be 6 eggs o r p o s s i b l y lower.  On the basis of r i p e ova and  shed f o l l i c l e counts the p r o d u c t i v i t y o f nesting adult and y e a r l i n g hens i s s i m i l a r . 24. The open v e g e t a t i o n a l types are u t i l i z e d f o r nest s i t e s , 25. Morning and evening movements of t h e hens are part o f a w e l l defined d i u r n a l a c t i v i t y rhythm of t h e grouse i n the study area.  L i g h t i n t e n s i t y up t o 4 foot candles appears  to be a f a c t o r i n f l u e n c i n g the r e l a t i v e l y intense a c t i v i t y of morning and evening as compared t o the remainder o f the day. 26. The v a r i a t i o n s i n climate as recorded i n 1950, 1951 and 1952 had no apparent e f f e c t on time of peak hatch.  Over  the three years 80$ o f the hatch occurred between June 8th and June 28th.  June 15th to June 21st i s taken as the week  of peak hatch. 27. There i s a marked change i n hen behaviour as she becomes the centre o f brood o r g a n i z a t i o n .  S i g n a l s from the hen and  chicks are f a c t o r s i n e a r l y brood o r g a n i z a t i o n and chick behaviour. 28. Brood o r g a n i z a t i o n and chick behaviour change w i t h age. I n J u l y and a f t e r o f 1950 brood d i s o r g a n i z a t i o n occurred.  It  i s suggested a summer's c l i m a t e , through i t s e f f e c t on food vegetation, i n f l u e n c e s brood o r g a n i z a t i o n .  140  2 9 . The observed movements of females w i t h young vary cons i d e r a b l y w i t h map distances up to £ mile recorded between observations. 3 0 . The open v e g e t a t i o n a l types are u t i l i z e d most f r e q u e n t l y by the hen and brood.  This h a b i t a t preference appears  r e l a t e d t o the a c t i v i t i e s o f the c h i c k s . 31.  The a l t i t u d i n a l migration o f the hens with young began a f t e r August i n 1950 and i n J u l y o f 1951 and 1 9 5 2 .  I t i s suggested  a summer's climate through i t s e f f e c t on food v e g e t a t i o n conditions the a l t i t u d i n a l migration o f hens w i t h young. 3 2 . A sample o f 13# chicks c o l l e c t e d over the period June 15 to August 15 i n 1951 and 1952 was equal i n sex r a t i o . 3 3 . Over the period June 15 t o September 23 the average growth r a t e o f young males was 60 grammes per week, and young females 50 grammes per week. 3 4 . Over the years 1950 to 1953 s e x u a l l y a c t i v e males, females and females w i t h broods have Remained s t a b l e i n numbers, o r t h e i r increase o r decrease has not been detected. 35.  The y e a r l y turnover i n a d u l t males i s 3 1 $ o r a y e a r l y s u r v i v a l of 6 9 $ . I t i s assumed the same i n a d u l t females. The average length o f l i f e of a sooty grouse once i t has reached y e a r l i n g age i s c a l c u l a t e d as 3 . 2 years.  36. The p o p u l a t i o n status observed at Quinsam Lake can be explained as a c o n d i t i o n wherein 40% of the females are unproductive o r l o s e a l l young, 60% o f the females l o s e 4 out of 6 or 67% of t h e i r young i n the summer months. The s u r v i v i n g young have a 47% f a l l and w i n t e r m o r t a l i t y which reduces t h e i r numbers t o a l e v e l that equals the 31% y e a r l y l o s s i n the o l d e r age c l a s s e s and r e s u l t s i n the observed s t a b l e population. 37. 70% of the y e a r l i n g hens and 96% o f the adult hens on the  study area are breeding h i r d s .  38. Dispharynx and Plagiorhync us are important c h i c k m o r t a l i t y A  f a c t o r s and e x p l a i n i n most part the 40% broodless females and 67% brood decrease observed i n the study area.  These  p a r a s i t e s l i k e l y produce a f u r t h e r m o r t a l i t y on the w i n t e r range and contribute t o the 47% f a l l to s p r i n g m o r t a l i t y c a l c u l a t e d f o r the c h i c k s .  Disease, caused by Dispharynx  and Plagiorhyncus can be considered a major f a c t o r e f f e c t i n g p o p u l a t i o n s i z e and s t a b i l i t y on the study area. 39. The d i s t r i b u t i o n of Dispharynx and Plagiorhyncus suggests they may be o p e r a t i n g as p o p u l a t i o n c o n t r o l s i n other regions than Quinsam Lake o r at l e a s t over the 1938 burn.  142  LITERATURE CITED Adams, L.  1951. Confidence l i m i t s f o r the Petersen or L i n c o l n index used i n animal p o p u l a t i o n s t u d i e s . J . Wild. Man. 15:13-19.  Anthony, A.W.  1903. 24-27.  M i g r a t i o n of Richardson's grouse.  Auk 20:  Beer, J . and Wayne Tidyman 1942. The s u b s t i t u t i o n of hard seeds f o r g r i t . J . Wild. Man. 6:70-82. 1943. Food h a b i t s of the blue grouse. 7:32-44. 1944. P a r a s i t e s of the blue grouse. 91-92.  J . W i l d . Man. J . Wild. Man.  8:  1948. Notes on the food habits of some western grouse. Murrelet 29:18-20. B e n d e l l , J.F. and CD. Fowle 1950. Some methods f o r t r a p p i n g and marking r u f f e d grouse. J . W i l d . Man. 14:480-482. Bent, A.C.  1932. L i f e h i s t o r i e s of North American b i r d s . I n s t . U.S. Nat. Mus. B u l l . 162:103-114.  Smith.  Bump, G. et a l . 1947. The r u f f e d grouse, l i f e h i s t o r y , propogat i o n and management. New York State Cons. Dept. B u r k i t t , J.P.  1926.  I b i d 20:91-101.  Clarke, C.H.D. 1936. F l u c t u a t i o n s i n numbers of r u f f e d grouse, Bonasa umbellus (Linne) w i t h s p e c i a l reference to Ontario Univ. Toronto s t u d i e s , B i o l . Ser. 41:1-118. Committee of Inquiry on Grouse Disease 1911. The grouse i n h e a l t h and disease. Smith, E l d e r and Co., London. Cram, E.B.  1931(b). Developmental stages of some nematodes of the Spiruroidea p a r a s i t i c i n p o u l t r y and game b i r d s . U.S. Dept. A g r i c . Tech. B u l l . 227. 2? pp.  Crombie, A.C. 1944. On i n t r a s p e c i f i c and i n t e r s p e c i f i c competitor i n l a r v a e of graminivorous i n s e c t s . J . Exper. B i o l . 20:135-151. Deevey, Edward S. J r . 1947. L i f e t a b l e s f o r n a t u r a l populat i o n s of animals. Quart. Rev. B i o l . 22:283-314.  143 Dwight, J . J r . 1900. The moult of the North American t e t r a onidae ( q u a i l s , p a r t r i d g e s and grouse) Auk 17: 143-166. Dymond, J.R.  1947. F l u c t u a t i o n s i n animal populations w i t h s p e c i a l reference t o those of Canada. Trans. Royal Soc. Canada, 4 1 i S e r . 3 , Sec. 5:1-34.  Edminster, Frank C. York. E r r i n g t o n , P.L.  1947.  1937(a).  The r u f f e d grouse.  MacMillan, New  What i s the meaning of predation?  Smith. I n s t . , Ann.  Rep.  1936:243-252.  1939. Reactions o f muskrat populations t o drought. Ecology> 20:168-186. Farner, D.S.  1952. The use of banding data i n the study of c e r t a i n aspects of the dynamics and s t r u c t u r e s o f avian populations. Northwest Science 26(2,3,4): 41-50, 79-94, 119-144.  F o e r s t e r , R.E. and W.E. R i c k e r 1941. The e f f e c t of r e d u c t i o n of predaceous f i s h on s u r v i v a l of young sockeye _ salmon at Cultus Lake. J . F i s h Res. Bd. Canada 5:315-336. Fowle, C. David 1944* The sooty grouse on i t s summer range. Unpublished Thesis i n the Department of Zoology, U n i v e r s i t y of B.C. Goble, Frans C. and H.L. Kutz 1945. The genus Dispharynx (Nematoda:acuariidae) i n g a l l i f o n n and passeriform b i r d s . J . P a r a s i t . 31:323-331. Green, R.G.,  C . L . Larson and J.F. B e l l 1939. Shock disease as the cause of the p e r i o d i c decimation of t h e snowshoe hare. Amer. Jour. Hygiene, 30:83-102.  Hickey, Joseph J . 1952. S u r v i v a l studies of banded b i r d s . S p e c i a l S c i e n t i f i c Report, W i l d l i f e No. 15. U.S. Dept. of I n t . F i s h and W i l d l i f e S e r v i c e , Washington. Howard, H.E.  1920. T e r r i t o r y i n b i r d l i f e . Go. New York.  E.P. Dutton and  Johnson, R.A. 1941. Nesting behaviour of the a t l a n t i c iriurre. Auk 58:153-163. Kendeigh, S.C. 1941. T e r r i t o r i a l and mating behaviour of the house wren. 111. B i o l . Monog. 18:1-120. 1942. A n a l y s i s of the l o s s e s i n the nesting of b i r d s . J . W i l d . Man. 6:19-26.  144 Lack, David  1946. The l i f e o f the r o b i n . Witherby Ltd., London.  Leopold, A. 1 9 3 3 . Game management. New York and London.  H.F. and G.  Chas. Scribner's Sons,  L i n c o l n , F.C. 1930. C a l c u l a t i n g waterfowl abundance on the b a s i s o f banding r e t u r n s . U.S. Dept. o f A g r i c . C i r c u l a r No. 118. Lotka, A.J.  1934. Theoric analytique des a s s o c i a t i o n s b i o l ogiques. A c t u a l i t e s s c i e n t i f i q u e s et i n d u s t r i e l l e s 187:1-45.  MacLagen, D.S. and E. Dunn. 1936. The experimental a n a l y s i s o f the growth o f an i n s e c t p o p u l a t i o n . Proc. Roy. S o c , Edinburgh, 55:126-139. Moffat, C.B. 1903. The s p r i n g r i v a l r y o f b i r d s . Some views on the l i m i t t o m u l t i p l i c a t i o n . I r i s h N a t u r a l i s t 12:152-166. Nice, M.M.  1937. Studies i n the l i f e h i s t o r y o f the song sparrow. I . Trans. L i n n . Soc. New York, 4:1-247. 1941. The r o l e o f t e r r i t o r y i n b i r d l i f e . Mid. Nat. 26:441-457.  Am.  1943. Studies i n the l i f e h i s t o r y o f the song sparrow. I I . The behaviour o f the song sparrow and other passerines. Trans. L i n n . Soc. New York, 6:1-328. Nicholson, A.J. 1933* h e balance of animal populations. J. Anim. E c o l . 2:132-178. T  and V.A. B a i l e y 1935. The balance o f animal populations. Part I . Proc. Zool. S o c , London, 1935:551-548.  Oosting, H.J. 1 9 4 8 . The study o f plant communities. Freeman and Co. San F r a n c i s c o .  W.H.  Patterson, R.L. 1 9 5 2 . The sage grouse i n Wyoming. Wyoming Game and F i s h Commission, Sage Books Inc. Denver. Robertson, F.W. and Sang, J.H. 1 9 4 4 . h e e c o l o g i c a l determinants o f population growth i n a Drosophila c u l t u r e . I. Fecundity o f adult f l i e s . Proc. Roy. S o c , T  London, s.B. 1 3 2 : 2 5 8 - 2 7 7 .  145  R i c k e r , W.**.  1948. Methods o f estimating v i t a l s t a t i s t i c s of f i s h populations. Indiana U n i v e r s i t y P u b l i c a t i o n , Science S e r i e s No. 15.  Schneider, H.A. 1949. infection.  Influence of n u t r i t i o n i n experimental Bact. Rev. 13:99-134.  S c h o t t e l i u s , B.A. 1951. Studies on blue grouse (D.O. p a l l i d u s swarth) i n the Methow V a l l e y of Washington. M.S. Thesis, State College of Washington, Pullman, Washington. Smith, H.S.  1935. The r o l e of b i o t i c f a c t o r s i n the determinat i o n of p o p u l a t i o n d e n s i t i e s . J . Econ. Entom. 28: 873-898.  Stewart, R.E. and John W. A l d r i c h 1951. Removal and repopulat i o n of breeding b i r d s i n a s p r u c e - f i r f o r e s t community. Auk 68:471-482. Swarth, H.S.  1926. Report on a c o l l e c t i o n of b i r d s and mammals from the A t l i n r e g i o n , northern B r i t i s h Columbia. Univ. C a l i f . Pub. i n Zoo. 30:51-162.  Taylor, E.W.  1950. Report on Vancouver I s l a n d blue grouse harvest, 1949-1950. Unpublished B.C. Game Report.  Tinbergen, L. 1946. De sperwer a l s r o o f v i j a n d van zangvogels. Ardea 34:1-213. Tinbergen, N. 1939. The behaviour of the snow bunting i n s p r i n g . Trans. L i n n . Soc. New York, 5:l»-94. Uvarov, B.D.  1931. Insects and climate. London, 79:1-247.  Trans. Entom. S o c ,  Van Cleave, H.J. and R.B. W i l l i a m s 1951. Acanthocephala from passerine b i r d s i n A l a s k a . J . P a r a s i t . 37:151-159. Van Rossem, A.J. 1925. F l i g h t f e a t h e r s as age i n d i c a t o r s i n Dendragapus. I b i s 1 2 : 4 1 7 - 4 2 2 . V o l t e r r a , V i t o 1926. V a r i a z i o n i e f l u t t u a z i o n i d e l numero d ' i n d i v i d u i i n specie a n i m a l i c o n v i v e n t i . Mem. Accad. L i n c e i , 2(6):31-113. Wing, L.  1943.  B  l u e grouse.  Am. For. 49:58-59, 96.  , J . Beer and Wayne Tidyman 1944. Brood h a b i t s and growth of blue grouse. Auk 61:426-440. 1947* Seasonal movements of the blue grouse. Wild. Conf. 12:504-511.  N.A.  Table I Weather data. Year 1 •  1950  1951  1952  1953  Week No.  :  i:  2!  3:  4!  5:  6:  7:  s: :  Av. Temp. °F. Av. Max. Av. Min. Av. Rain c.c. Day's Rain Av. Evap. c.c.  Av. Temp. °F. Av. Max. Av. Min. Av. Rain c.c. Day's Rain Av. Evap. c.c. Av. Temp. °F. Av. Max. Av. Min. Av. Rain c.c. Day's Rain A'v. Evap. c.c.  9 :; 1 0 : I I ! 1 2 : 1 3 ! 69 78  0  Av. Temp. °F. Av. Max. Av. Min. Av. Rain c.c. Day's Rain Av. Evap. c.c. 51  60  42 0 0 5  2  2  60 35 0 0 7  52 45 58 53 38 35 .1 .5 4 2.5 4 5  1950, 1951, 1952, 1953.  Weekly Records.  57 60 41 .2 3 4  56 64 47  64 44  2 4  1 7  61 69 47 0 0 5  59 65 46 .1 3 4  .1  .1  61 70 44 .1 1 7  68 79  HI 15:  59 68  72 85  64 77  69  80  76 86  65 78  1 2.5  0  2  .5  1  2  70 77 53  72 75 54 .2 1 6  64 73 54 0 0 4  77 51 0 0  73 76 53 0 0 8  69 75 53 0 0 7  61 71  0 0  53 0 0'  76  63 67 50 .1 2 4  73 84 51 0 0 9  71 84 53 0 0 8  67 82 52 0 0 4  58 71 44 0 0 4  66 74 46 0 0 12  72  61 55 58 66 62 65 41 44 43 .1 .1 .1 .5 3.5 2.5 6 11 4  62 69 51 .1 2 5  60 64 49 .1 4 3  87 51 0 0 11  69 77 51 0 0 10  61 73 49  56 67 45  70 51  60  62 74 49  66 77 56  70 50  3 1.5  1  1  65 73 47 0 0 9  67 51 0 0 4  1 6 ! 17*. 1 8 : 19  81  52 0 0 11  a  2 7  60  2 1.5  65 77  65 79  2 1.5  51  67  80  Table IV Number of observations and accumulative area u n i t s o f 5 males of p l o t I I Male No. 162  :  Male (7,L)  No. : Acc. :No. : Acc. P o i n t s : A r e a :Points : Area x  : Male (11,1)  :: Male No. 147  :•No. : Acc. :Points : Area  ::No. Points: Acc. :No. : Acc. : Area : Points : Area  : Male No. 781  10  :  13  :  10  ::  10  :  10  :  12  :  10  :: 11 :  10  !  12  20  :!  23  :  20  :  13  :  20  ::  18  ,:  20  !: 16 i:  20  :!  16  30  :  24  \ 30  i:  15  :  30  it  19  :  - 22 ::  30  !:  29  40  :  25  i  ;  40  ::  20  :  50  '.  31  :  i 70  i ! ' I  80  ;  60  x  43  i i  43  !  31  :  40  1 15  50  .\  16  To convert to acres m u l t i p l y by . 0 5 .  :  Table V Cover type and u t i l i z a t i o n on p l o t s I and I I  Type  \ Males \'Females w i t h broods Nests ! Females Clockers ! No. : U t i l - : % U t i l - : No. : U t i l - :% U t i l - ": No. : U t i l - : % U t i l - : No. : U t i l - :% U t i l - :: No. : U t i l - :% U t i l •noted : i z a - : i z a t i o n :noted : i z a - : i z a t i o n : noted: i z a - :i z a t i o n •noted : i z a - r i z a t i o n : noted: i z a - r i z a t i o r :tion : :tion • :tion : :tion Z ; :tion • x  Plot I : F.D. F.O. W.D. W.O. B.O. L.O. CO.  :  • : : :  6 6 47 13 31  22 20 204 72 1550  1 1 11 4 83  ": :  1 13 3 0 4  14 20 30 0  1 2 3 o 9 12 73  : :• : •: : :: :  :: ::  r  0 2 5 6 0  0 7 22 33 0  0 12 35 53 0  : : : « ::  20 19 8 6 5  74 63 35 33 250  16 14 8 7 55  !  62  : : :  50 19 0  0  0  0  :  32 40 25 0 1 2 9  460 61 250 0 20 25  42 5 22 0 2 2 27  : : :: :: :: :' ::  :  :  91  230 300 220 105 0  27 35 26 12 0  : .: :: :: •:  800  60 10  :: :  16 12 13  19 40 70 67 650  2 5 8 8 77  2 43 5 0 5  29 65 50 0 100  3 7 5 0 11 14  5 12  Plot II F.D. F.O. W.D. W.O. B.O. L.O. CO.  • •  : : x  8  19  80  100 633  11 0 0 4 5 0  17  0 0  80  62 0  11  0 0 50 39 0  :  :' : : •: :•  300  Number noted d i v i d e d by p r o p o r t i o n of v e g e t a t i o n a l type on each plot^Table I I ) .  56 90  21 0 5 8  0  135 210 0 100 100 0  16  0 7 7 0  : : : : :  11 17  137 566  60  _ £  P  ^  (iv) Table VI Grouse a c t i v i t y and time of day i n the periods A p r i l 13 to May 1 5 , May 16 to June 5 : A p r i l 13 - May 15 May 16 - June 5 i£ hrs:Males :Other:Males •.Other :£ hrs.rMales :Other:Males rOther : i n rwith : a c t i v -cwith r a c t i v - : i n rwith ractiv--rwith ractiv(standard) :-f i e l d : f e - •: i t y:females : i t y : f i e l d : f e - : i t y:females : i t y m ales • :per £ :per £ males :per £ :per £ • • • :hour rhour rhour rhour Time of day  •> *  *  0 2 3 0 0 3 0 0 :: 0300 0330 :: 0330 0400 .: 0 4 0 0 0 4 3 0 ': 0 4 3 0 0 5 0 0 :: 0500 0530 •: 0 5 3 0 0600 .: 0600 0630 •: 0630 0700 :: 0700 0730 :: 0730 0800 •:  0800 0830 .: 0830 0 9 0 0 :  2 2 2 5 4 3 2 2 1 2 2  8 14 0 9 0 0 0 9 3 0 : 21 0 9 3 0 1000 : 19 1000 1030 : 21 1 0 3 0 1100 .: 22 1 1 0 0 1130 •: 19 1130 1 2 0 0 : 16 1 2 0 0 1 2 3 0 . 18 1230 1 3 0 0 .: 18 1 3 0 0 1330 ,: 19 1330 1400 1430 1500 1530  1400 1430 1500 1530  : : :  14 13 11  • 13 1600 : 12  1600 1630 •  : : : : : :  13 14 10 6 4 2 5  2030 2100 :• 2100 2130 : 2130 2200 : 2200 2230 : 2230 2300 :  7 2 2 2 2  1630 1700 1700 1730 1730 1800 1300 1830 1330 1900 1900 1930  0 0 1  10 56 10 0 0 1 0  0 4 0 7  10 20 17  3 10 6 0 7 1 2 0 1 1 0  10 5 1 0 0  19 1930 2000 : 12 67 2000 2030 : 16 122 10 0 0 0 0  0 0 8 23  67 7 4  10  3 9 6 24  45 67 55  58 71 60 43 48 43  65 49 38 31 44  20 19 27  31  7  13 9 22  74  134  27 0 0 0 0  0 0 .5 2 14 3 0 0 1 0 0  .5  0 .3 .5 1 .8 .2 .6 .3 0 .3 .1 .2 0 .1 .1 .0  .7 .5 .1 0 0 4 6 8 1 0 0 0 0  0 0 4 5  17 2 2 5 3 5  3  3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 2 1 2 3 1 3 4 5 6 9 4 0 0 0 0  :: :: : :•  2 3 6 2 : 1 : 1 : 1 1 : 1 2 .: 2 : 6  : 10 :1 15 : 16 '• 15 :: 16 :' 15  :: 10 :• 8 4 :: :: 2 •: 4 :' 4  • 6  7 :. :: 9 :: 11 :: 10 : 8 :• 6 : 5 2 : 2 : 5 : : 6  : 16 16 :: 13  J  • :: .•  2 2 2  0 2 38 1 0 0 0 0 0 0 3 0  1 1  3 2 0  12 3 0 0 2 0 4 0 2 0 0 0 0 4 3 0 0  1  153 144 94 9 0 0  0 14 30 9 5 3  5  2 0  1 21 22 24 29  23 31 24 17 19 18 5 18 5 14 5  15 19 18 19 16 11 5 8  15 19 117 166 103 14 0 0  0 .7 6 .5 0 0 0 0 0 0 .5 0 .1  .1 .2 .1 0 1 .4 0 0 .5 0 .7 0 .2 0 0 0  0  1 1 0 0 .2 3 3  7 4 0 0  0 5 5 5 5 3  5  2 0  .5 3 2 2 2 2 2 2 2 2 5 3 5 1 2  .7 2 2 2 2 3 2 3 4 3 3 7  10 9  7  0 0  !  Table V I I Number o f week-old broods observed per hour i n weeks 6 t o 16, 1950, 1951, 1952. No. : : : No. : : : No. : :Hrs. in:week- : No. i 1951 :Hrs. i n : week-: No. :: 1952 ;Hrs. in:week- : No. : f i e l d : o l d : per ' . f i e l d : o l d : per ; f i e l d : o l d : per : :broods:hour :broods: hour : :broods: hour » »  1950 Week 6  -  -  -  •> •>  15  0  0  :  :  19  0  0  :  27  0  0  !  :  20  0  0  :  33  2  .06 :  :  6  0  0  i  32  5  .16 !  !  23  4  .17  :  22  5  .23 :  i  13  4  .30  .09 !  20  2  .10  7  j  8  ;  9  :  25  1  .04  10  :  32  2  .06  11  :  24  4  .17  !  22  2  12  j  26  0  0  :  24  0  13  i  28  1  27  1  37  0  0  -  -  -  7  0  o  :  .04 '  14  !•  29  0  0  15  :  24  0  0  16  I  33  0  0  I :  :  :  '.  :  16  0  0  .04 :  :  27  4  .11  20  3  .05  12  0  0  17  0  0  0  •  :  : :  (vi)  Table V I I I Weight development with age i n 224 c h i c k s , 1950, 1951, 1952. Week  Age :Sample: Males, average weight:Sample:Fjemales, average weeks: s i z e : and 95% c o n f i - : s i z e : weight and 95% . dence l i m i t : : confidence l i m i t  10  1  9  11  2  10  12  3  13  38 ± 16 gms.  3  34 113 gms.  9  n  12  11  104 i 15  n  10  4  10  189 t 55  «  14  5  7  260 i 106  15  6  13  250 t 50  n  15  230 i 29  ft  16  7  11  283 i 95  n  9  293 1 46  n  17  8  14  394 ±66  n  11  361 ± 80  n  18  9  2  515 + 221  n  3  460 *112  n  19  10  3  573 t387  n  20  11  21  12  22  13  -  23  14  14  825 i 88  24  15  20  884  42 i  -  £ 48  tt  • 22  n  t  37  tt  $  130 1 17  tt  9  207 - 44 n  -  66 105  -  -  14  632 •• 20  ft  20  724  35  n  t  Table IX Males, females, and females w i t h broods observed per hour per week i n study a r e a , to 1953.  1950  j  1952 : 1950 1953 ; 1951 :: Week : :Broods ,Gen- :Males : Fe- :Broods :Broods: Cen- :Males :Fe:Broods : Cen- :Males :Feof :;Cen- :Males :Fe: per m a l e s : per : per :males : per :sus : per :males : per ::sus : per :males : per :sus study :sus :hours:hour : per :hour : hours:hour : per :hour : hours :hour : per :hour : hours:hour : per :hour 4 in * i • : :hour •• thour •» i in :hour » i: i n • :hour •• in i • • * » • • field: • • : f i e l d• • field * • :field • *  t  •  i  •  18  1.03  .56  0  2  :  39  2.2  .55  3 4  : :  29 38  2.7 2.6  .41 .61  0 0 0  :.  28  2.5 2.2  .58  0  .70  0  1.5 1.3  .39 .66  0 0  1.4 1.8  .31 .08  1.5  .51 .32 .15 .26 0  .13 .08 .20  1  5 6 7 8 9 10 11 12 13  14 15 16  17 18 19  !  :  !  19  1.6  .37  0  :  32  1.5 2.1  .66  o o  1.3 1.4 1.2  .49  15 : : : ;  25 32 24  1.0 1.1 1.1  .68 .38 .26  .06 .25  : ; : : ; \  •> ' =. ';  26 28 29  1.0 .47  .' ; «:  24  .21  .23 .11 .21 .16  .19 .75 .79 .88  ;: : ,:  33 22  .30  31  0 0  :  :  0  3  .41 .14  0  .81 .27 .14 1 . 3 0 1.3 0 3.1  :  i! :  :  :  .  27 33 32 22 22 24 27 38  .48  .06  .28  .06 .45 .87  .15 .27  .23 .09 .21 .19 .08  0 0  0 0  .71  o 7 33 0  :  i  19 20 6  :  23  : ;  13 20  :  16 27 20  :  .31  .95 .79  ;  .25  :  :  :  .41 «  . 6 7 ;; : . 2 9 !: . 1 8 ;: >  1  2  17 10 0  1.4 .96 .67 .49 .12 .3  .06 .3  .38 .56 .92  : :  ,  ; 3 :: 18  1.5 1.7  : n  l.o  !  9 0 :: 20 '  .49 .53 .3  H*  '  1.3 .88  0 .11 0 0 .25  0 .06 .10 .59 1.1  (viii)  Table XI Average weekly brood s i z e s , f o r the three-year study p e r i o d . 1950 1952 ! 1951 :Aver: No. :Aver: No. : No. :Average :Week: :broods rage rbroods :age rbroods: s i z e • : :size >* : s i z e •• * »  Date  -  21  10  3  1.7  14  2.5  9  3.3  28  11  6  4.0  19  3.3  5  3.2  5  12  7  2.7  12  4.3  11  3.3  6  -  12  13  21  2.9  21  3.6  14  2.6  13  -  19  14  25  2.4  25  2.6  28  • 1.9  26  15  19  2.4  -  -  6  2.5  2  16  55  2.7  4  2.7  18  2.1  9  17  28  3.2  11  1.8  9  2.0  16  18  44  3.2  13  1.5  23  19  9  3.8  7  1.7  June 15 22 29  July  Aug.  20  -  27  -  3 10 17  -  -  -  Table XIV Lumped data 1950,  Age and i n f e c t i o n s i n c h i c k s . Age, weeks Sample s i z e Infected  !  Infected  :  2  :  3  11  :  io  :  io  • •  » •  :No, ;  2 0 1 0  Haemoproteus Leucocytozoon Trypanosoma Microfilaria Sample s i z e  1  %  18 0 9 0  :No.:  6 0 3 0  :  :  4  .  ii  •  %  :N0,  •  60 0 30 0  8 2 4 0  5  :  .  6  •  8  %  :  7 4 1 0  40  0  14  • :  No.  ;  13  \ %  •No!:  Dispharynx Cheilospirura) Yseria j Rhabdometra Ascaridia , Plagiorhyncus  2 0 0 0 2  14 0 0 0 14  4 0 0 0 3  Ceratophyllus Lagopoceus Ornithomyia  0 0 0  0 0 0  0 0 0  !  ;:  No. \ fo :No.  0 0 0 30  6 0 1 0 6  46 0 8 0 46  13 2  0 0 0  0 5 0  0 38 0  0 4 0  40  4 0 10  7  .  12  .  7  66  4 3 0 0  64 35 9 0 15  \  '.  % s:No, I 5  3 3 0  50  0 0  •  :  6  :  15  !  8  :  9  :  .  9  :  13  :  0  io  100  7 5 2 0  42 25 25  29 0  ::  21  »  »  1 2 1 11  7 0 1 1 6  70 0 10 10 60  17 6  0 0 3  0 0 20  0 5 0  0 50 0  0 6 2  14  0  9 1 11  *  1  ;  : fo :No.: 4, \  9  % 'tNo.  ages  A H  89  k*  100 78 22 0  • •  :  •  * m  • •  9 7 2 0  72  94 7 13 7 73  87 13 27 0 67 0  :No. : % ;:No.  :No.: % ::No.:  No.:  27  :  %  1952.  :  •  Not :* fo '  80 20  :  1  1951,  11 10 2 0 :  ;  85 77  :\\ :::  :  5 2  50  5 1 4  56 22 56 11 45  0 29 11  0 1 2  0 11 22  - -  :  #  66 38 20 0  34 18 0  0  fo : No.:  81 29 43 5  No. 59  15  o  m  109 No.  68 11  _  _  - -  22 4 53  —  _  21  —  —  0 7  • •  fo  64 10 21 4 50 0 20 7  (x) Table XV $ Haemoglobin l e v e l s of 2 5 a d u l t grouse by S a h l i haemoglobinometer. 100, 85, 91, 83, 73, 85, 73, 90, 75, 90, 93, 108, 95 85, 88, 100, 68, 90, 95, 80, 78, 70, 86,1 C8, 75. Arithmetic mean 87$ $ Haemoglobin l e v e l s of 25 grouse chicks by S a h l i haemoglobinometer. 70, 85, 7 2 , 95, 88, 83, 80, 88, 83, 80, 79, 90, 70 82, 8 4 , 80, 80, 93, 80, 62, 80, 82, 70, 75, 80. Arithmetic mean 80$ Number o f r.b.c. per cu. m.m.  o f blood i n 2 adult grouse  2,080,000 2,040,000 Number o f r.b.c. per cu. m.m.  of blood i n 5 grouse chicks  1 week o f age - 1,800,000 1,800,000  over 2 weeks of age - 3,360,000 2,680,000 2,560,000  Volume i n c.c. o f l i v e r s from 39 adult grouse 19, 27, 19, 29, 20, 20, 22, 25, 18, 18, 20, 18, 18. 18, 20, 19, 16, 30, 20, 20, 28, 28, 22, 26, 17, 22. 18, 24, 13, 20, 23, 20, 20, 13, 12, 20, 16, 18, 20. Volume i n c.c. o f spleens from 39 a d u l t grouse 1.3, 0.8, 1.5, 2.0, 1.0, 3.0, .5, 1.0, 4.0, 3.0, 0.8, 1.0, 1.0. 1.5, 1.5, 2.0, 2.5, 2.0, 0.5, .75, 1.0, 1.2, 1.0, 1.0, 1.0, 1.0. 0.5, 1.5, 2.5, 2.0, 2.0, 0.5, 2.0, 3.0, 1.0, 1.0, 0.5, 1.0, 1.5.  Table XVI Age ^ f c h i c k s , percent i n f e c t e d , and i n f e c t i o n l e v e l s w i t h Dispharynx and P l a g i o r hyncus. Lumpted data, 1 9 5 1 and 1 9 5 2 . Age, weeks  :  i  :  2  1  3  Sample s i z e  :  14  :  10  :  13  No. i n f e c t e d w i t h Dispharynx % infection  :  \  4  1  5  :  6  :  ;  15  :  15  :  10  :  :  7  :  8  21  :  9  2  4  6  13  14  7  17  5  14  40  46  87  94  70  81  56  6  42  60  44  27  86  Average No. worms per i n f e c t i o n Range  2 (1-2)  No. infecte^d w i t h Plagiorhyncus  2  3  6  10  11  6  11  4  14  30  46  67  73  60  50  45  Average No. worms per i n f e c t i o n Range  1 (1-2)  1 (1)  11 (3-33)  8 (3-20)  5 (1-13)  4 (1-9)  12 (1-47)  10 (7-15)  No. i n f e c t e d w i t h both parasites  1  1  6  8  11  4  10  4  % infection  1  1  46  53  73  40  48  44  % infection  (2-14) ( 1 2 - 1 0 0 ) ( 1 3 - 2 0 0 ) ( 2 - 1 3 6 ) (2-50) ( 1 - 4 3 0 )  69 (2-175)  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0106463/manifest

Comment

Related Items