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UBC Theses and Dissertations

The population dynamics of Newfoundland caribou Bergerud, Arthur Thompson 1969

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THE POPULATION DYNAMICS OF NEWFOUNDLAND CARIBOU  by . ARTHUR T. BERGERUD B.Sc. Oregon S t a t e U n i v e r s i t y , 1953 M.Sc.  U n i v e r s i t y o f W i s c o n s i n , 1961  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n t h e Department of Zoology  We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1969  In p r e s e n t i n g an  this  thesis  advanced degree at  the  Library  shall  scholarly  by  his  of  this  written  University  of  permission  p u r p o s e s may  representatives.  be  available  granted  gain  Zoology  September  23,  Columbia  1969  for  for extensive  permission.  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, Canada  British  by  the  It i s understood  thesis for financial  Department o f  Date  fulfilment of  make i t f r e e l y  I f u r t h e r agree tha for  the  in p a r t i a l  shall  requirements  Columbia,  Head o f my  be  I agree  r e f e r e n c e and copying of  that  not  the  that  study.  this  thesis  Department  copying or  for  or  publication  allowed without  my  i  ABSTRACT  The p o p u l a t i o n dynamics o f c a r i b o u ( R a n g i f e r t a r a n d u s ) on t h e I s l a n d o f Newfoundland were s t u d i e d 1957 t o 1967. censused:  the Northern  the Avalon P e n i n s u l a — 130  Peninsula —  Four herds were r e c o g n i z e d and  450 animals  i n 1958 and 400 i n 1966,  125 i n 1957 and 720 I n 1967., the'. Humber R i v e r  —  i n 1956 and 115 i n 1964, and t h e I n t e r i o r -- 4600 i n 1957 and 6200  animals  i n 1966.  animals.  The I s l a n d p o p u l a t i o n 1900-1910 was e s t i m a t e d a t 40,000  A f t e r 1915 these herds r a p i d l y d e c l i n e d and r e a c h e d a low o f  perhaps o n l y 2000 animals The  by 1930.  a n n u a l r a t e o f i n c r e a s e Cr) o f a l l t h e herds was low. The' Humber  and N o r t h e r n  P e n i n s u l a herds showed no i n c r e a s e w h i l e t h e I n t e r i o r Herd  grew a t o n l y 0.044.  The A v a l o n P e n i n s u l a Herd showed t h e g r e a t e s t r a t e -  o f - i n c r e a s e 1961 t o 1967, r= 0.120. caribou i s probably Brunette  The p o t e n t i a l r o f Newfoundland  g r e a t e r t h a n 0.30.  A herd o f c a r i b o u introduced t o  I s l a n d i n c r e a s e d a t r=0.352, from 17 t o 100 animals  i n 5 years.  In t h e I n t e r i o r H e r d , b i r t h r a t e s were h i g h and c o n s t a n t and averaged 0.85 c a l f p e r doe 2-years-of-age and o l d e r and 0.94 c a l f p e r doe 3 y e a r s and o l d e r .  N a t u r a l m o r t a l i t y r a t e s were low beyond 6-months-of-age.  They were 4 p e r cent f o r does, y e a r l i n g s , and c a l v e s and 9 p e r cent f o r s t a g s 2-years-of-age and o l d e r .  The k i l l o f s t a g s by h u n t e r s was 11 p e r  cent and r e d u c e d t h e p r o p o r t i o n o f s t a g s i n t h e p o p u l a t i o n . The  s u r v i v a l o f c a l v e s t o 6-months-of-age was s t r o n g l y c o r r e l a t e d  w i t h growth o f p o p u l a t i o n s and appeared t h e main i n f l u e n c e on numbers ( c o r r e l a t i o n c o e f f i c i e n t r=0.922, P<0.01).  The m o r t a l i t y o f c a l v e s i n  t h e f i r s t summer was h i g h ; an average o f 69 p e r cent d i e d i n t h e I n t e r i o r Herd and i n t h e A v a l o n P e n i n s u l a Herd 30 p e r cent o f t h e c a l v e s d i e d .  ii  The major cause o f m o r t a l i t y o f c a l v e s was a p p a r e n t l y p r e d a t i o n by l y n x (Lynx c a n a d e n s i s ) .  As e a r l y as 2 weeks a f t e r c a l v i n g , 27 p e r cent  o f t h e c a l v e s were m i s s i n g . cover by l y n x .  They were a p p a r e n t l y dragged i n t o f o r e s t  Of 114 dead o r morbid c a l v e s l o c a t e d 74 p e r cent were  b i t t e n by l y n x , escaped and had developed  c e r v i c a l abscesses"; from- i n -  fections o f P a s t e u r e l l a multocida. The two major f a c t o r s l i m i t i n g p o p u l a t i o n s o f c a r i b o u i n Newfoundland 1900  t o 1967 appeared t o be lyn« p r e d a t i o n o f c a l v e s and s h o o t i n g m o r t a l i t y  of adults.  Poor r e c r u i t m e n t and h i g h l o s s t o h u n t i n g p r o b a b l y caused t h e  d e c l i n e o f t h e herds 1915 t o 1930.  The p r i m a r y f a c t o r l i m i t i n g numbers  i n t h e I n t e r i o r and A v a l o n H e r d s , 1957 t o 1967 was l y n x p r e d a t i o n o f c a l v e s i n t h e i r f i r s t summer.  I l l e g a l h u n t i n g was p r o b a b l y i m p o r t a n t i n t h e  N o r t h e r n P e n i n s u l a and Humber R i v e r herds 1957 t o 1967.  iii  TABLE OF CONTENTS Page ABSTRACT  i  TABLE OF CONTENTS  .  i i i  ' ACKNOWLEDGEMENTS  '  vi  LIST OF FIGURES  ,  v i i  INTRODUCTION  1  METHODS  •4  The Exchange o f A n i m a l s Between Herds and P o p u l a t i o n s . . . . . . . . . .  4  H i s t o r i c a l Research  5  Census  6  Measurement o f B i r t h Rates  8  Measurement o f A d u l t M o r t a l i t y .  9  M o r t a l i t y o f Calves Overwinter.  9  Time and Amount o f E a r l y M o r t a l i t y o f C a l v e s .  10  D e t e r m i n a t i o n o f Cause o f M o r t a l i t y o f C a l v e s from C e r v i c a l Abscesses  13  DISTRIBUTION OF HERDS AND POPULATIONS.  14  SIZE OF CARIBOU HERDS  18  Numbers 1900-1910  .  18  Numbers and Trends 1900-1956.  21  Numbers and Trends 1957-1967  23  BIRTH RATES.  26  Age o f B r e e d i n g . .  26  Fecundity.  27  ADULT MORTALITY. M o r t a l i t y Rates  .  32 32  iv  N a t u r a l Cause o f Death...  34  D i f f e r e n c e s i n Death Rates o f Males and Females................  38  Hunting M o r t a l i t y o f A d u l t s . . . . . . . . . . . . .  39  R o l e o f A d u l t M o r t a l i t y i n P o p u l a t i o n Growth...................  40  DEATH OF CALVES IN WINTER.  43  EARLY MORTALITY OF CALVES.  48  Time and Amount  .....................................  48  Weather i n M o r t a l i t y o f C a l v e s . Disease  54  and P r e d a t i o n .  R e j e c t e d Hypotheses o f P a s t e u r e l l a  ..  . ..  Etiology.  55 55  E x p e r i m e n t s w i t h Lynx t o I s o l a t e P a s t e u r e l l a . . . . . . . . . . . . . .  58  P r e d a t i o n by Lynx on C a l v e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62  Experimental  64  Removal o f Lynx  Sex V u l n e r a b i l i t y o f Males C a l v e s t o Lynx P r e d a t i o n . . . . . . .  67  V a r i a t i o n i n Lynx P r e d a t i o n Between A r e a s . . . . . . . . . . . . . . . . .  67  V a r i a t i o n i n Lynx P r e d a t i o n Between Y e a r s . . . . . . . . . . . . . . . . .  71  FACTORS LIMITING POPULATION GROWTH 1900 t o 1967. ................  76  Rate o f P o p u l a t i o n Growth  76  Reproduction  78  i n P o p u l a t i o n Growth..............................  N a t u r a l M o r t a l i t y o f Calves  • 79  P r e d a t i o n by Lynx on Male C a l v e s  82  The D e c l i n e o f C a r i b o u 1915-1930.  83  Lynx P r e d a t i o n and t h e D e c l i n e . . . . . . . . . . . . . . . . . . . . . . . . . . . .  84  H u n t i n g and t h e D e c l i n e  86  EVOLUTIONARY IMPORTANCE OF PREDATION. P o p u l a t i o n L i m i t a t i o n by P r e d a t i o n by Wolf.....................  88 88  V  Lynx P r e d a t i o n i n N a t u r a l S e l e c t i o n . SUMMARY.  .. —  91 .  LITERATURE CITED.  ....  94  ,  96  APPENDIX I TABLES  105  APPENDIX I I ANALYSIS OF REPRODUCTIVE TRACTS.  133  BIOGRAPHICAL  INFORMATION  \  ACKNOWLEDGMENTS Through the y e a r s a group o f d e d i c a t e d w i l d l i f e management o f f i c e r s w a l k e d a t my s i d e as we f o l l o w e d t h e c a r i b o u ; I w i l l always s t a n d i n t h e debt o f Stephen T. H a l l , M i c h a e l J . N o l a n , Bruce R. P o r t e r , H. L l o y d R u s s e l l , Samuel K e l l y and Hainan . Whalen. I w i s h t o a l s o thank w i l d l i f e o f f i c e r s D a v i d Lomond, M i c h a e l C. N u r s e , Raymond McGrath, A r t h u r B u t t , Robert M c N e i l y , for  t h e i r assistance.  My e x p e r i e n c e s  and M i c h a e l Walsh  w i t h p i l o t s A u s t i n G a r r e t t and  Robert G. Winsor w i l l l o n g be remembered.  The Canadian W i l d l i f e  Service  p r o v i d e d funds i n t h r e e y e a r s and the s e r v i c e s o f f o u r a b l e summer a s s i s t a n t s , E r n e s t S t e n t o n , Donald W. S i m k i n , Donald A. B l o o d , and K e i t h Sandilands.  Dr. John M. K i n g j o u r n e y e d t o Newfoundland i n 1958  and 1964- t o conduct p a t h o l o g i c a l i n v e s t i g a t i o n s o f young c a l v e s . D r s . H.T. G i e r and G.B. M a r i o n examined the r e p r o d u c t i v e t r a c t s o f female caribou. who  A d m i n i s t r a t i v e ' a s s i s t a n c e was p r o v i d e d by Douglas H. P i m l o t t ,  o r i g i n a t e d the s t u d y , H a r r y H. W a l t e r s , and S t u a r t S. P e t e r s .  A s s i s t a n c e i n p r e p a r i n g t h e m a n u s c r i p t was p r o v i d e d by Dr. James F. B e n d e l l , Dr. P e t e r A. L a r k i n , and Dr. I . McT. Cowan. d r a f t e d the p l a t e s f o r t h i s r e p o r t . o f my w i f e , Wy.  I w i s h t o acknowledge t h e a s s i s t a n c e  She t r a v e l l e d w i t h me i n t o many o f t h e w i l d e r s e c t i o n s  o f t h e i s l a n d and was a c o n s t a n t years.  D a n i e l T. Bergerud  source o f i n s p i r a t i o n during the t e n  T h i s p a p e r i s d e d i c a t e d t o t h e memory o f Stephen T. H a l l .  Steve  i s gone b u t he w i l l always be remembered by t h o s e o f us t h a t had t h e p r i v i l e g e t o t r u d g e t h e b a r r e n s i n h i s f o o t s t e p s and s h a r e a pot o f c o f f e e i n h i s comradeship.  vii LIST OF FIGURES  Figure  Page  1.  The l o c a t i o n o f c a r i b o u 1957-1967.  2.  P e r c e n t a g e o f a d u l t females w i t h v i s i b l e a n t l e r s  3.  Observations  o f animals  . ..  3  T  15  subsequent t o two m i g r a t i o n s  a f t e r tagging.  16  4.  Number o f c a r i b o u about 1900..  19  5.  C a r i b o u numbers from a e r i a l census  24  6.  The snow p r o f i l e a t Gander 1957-58 and 1958-59.  28  7.  Regression  30  8.  S u r v i v a l curve o f male c a r i b o u i n t h e i n t e r i o r  9. 10.  .11. 12. 13.  14.  15.  16.  o f counts o f parous does on r e c r u i t m e n t . .  33  C a r i b o u o b s e r v a t i o n by h u n t e r s compared t o r e c r u i t m e n t The r e g r e s s i o n o f nose b o t s p e r doe i n June on age and t h e r e g r e s s i o n o f nose b o t s p e r doe on w a r b l e p a r a s i t e s p e r doe i n June  35  A weak c a l f o b s e r v e d i n March 1959  44  The r e g r e s s i o n o f r e c r u i t m e n t o f y e a r l i n g s on r e c r u i t m e n t of calves  46  C a l f s u r v i v a l t o 11-months-of-age i n t h e I n t e r i o r Herd i n 1957  49  The s u r v i v a l o f c a l v e s u n t i l October i n r e l a t i o n t o m o r t a l i t y I n June  51  C a l f s u r v i v a l i n t h e I n t e r i o r and A v a l o n P e n i n s u l a h e r d s u n t i l 6-months-of-age  52  The p e r c e n t a g e o f c a l v e s i n f a l l i n t h e I n t e r i o r , and Humber R i v e r h e r d s , 1956 t o 1967  17.  The mean w e i g h t o f c a l v e s a t b i r t h  18.  C a l v e s b i t t e n by l y n x t h a t d e v e l o p e d a b s c e s s e s  37  Avalon, 53 '56 57  viii Figure  Page  19.  The P o t H i l l c a l v i n g ground.....  20.  The c a n i n e t e e t h o f a l y n x s k u l l i n s e r t e d i n t o f o u r  59  lesions  60  21.  Location o f lynx trapped a t Middle Ridge..........  65  22.  Male c a l v e s s t r a y e d f a r t h e r t h a n female c a l v e s from t h e i r dams The r e g r e s s i o n o f t h e p e r c e n t a g e o f c a l v e s i n t h e I n t e r i o r Herd i n October on t h e s e x r a t i o o f c a l v e s 1-4 weeks o f age  69  The r e g r e s s i o n o f t h e p e r c e n t male y e a r l i n g s on t h e r e c r u i t m e n t i n June f o r t h e I n t e r i o r Herd..................  70  The s u r v i v a l o f c a l v e s i n e a s t e r n and c e n t r a l Newfoundland on t h e t o t a l l y n x h a r v e s t e d . .  73  S u r v i v a l o f c a l v e s i n t h e Humber R i v e r Herd and p r o d u c t i o n o f snowshoe h a r e s  74  23.  24. 25.  26.  27.  The r e g r e s s i o n o f t h e r a t e - o f - i n c r e a s e on s u r v i v a l o f c a l v e s u n t i l 6-months-of-age  68  .80  INTRODUCTION  A major e c o l o g i c a l problem i s what d e t e r m i n e s the growth r a t e o f numbers.  One  animal  e x p l a n a t i o n i s t h a t p o p u l a t i o n s a r e r e g u l a t e d ; as numbers i n -  crease density-dependent c o n t i n u e d growth.  c o m p e t i t i o n i n t e n s i f i e s , reduces and f i n a l l y h a l t s  A second s c h o o l h o l d s , t h a t a l t h o u g h some p o p u l a t i o n s  be i n f l u e n c e d by density-dependent  may  c o m p e t i t i o n , most are l i m i t e d by a s h o r t -  age o f time when the environment p e r m i t s a p o s i t i v e r a t e - o f - i n c r e a s e ( r ) . T h i s v i e w emphasizes t h e r o l e o f a randomly f l u c t u a t i n g e x t e r n a l environment on p o p u l a t i o n g r o w t h , r a t h e r t h a n a d j u s t m e n t s a c t i n g w i t h i n p o p u l a t i o n s t o l i m i t numbers.  The  second t h e o r y argues a l s o t h a t t h e b a l a n c e o f n a t u r e  con-  c e p t i s f a l s e ; t h a t l o c a l p o p u l a t i o n s f r e q u e n t l y become e x t i n c t and d i s p e r s a l from b e t t e r h a b i t a t s i s important  i n r e e s t a b l i s h i n g populations ( f o r recent  arguments i n t h i s c o n t r o v e r s y see Lack 1966, E h r l i c h and B i r c h 1967,  and  S l o b o d k i n e t a l . 1967). In t h i s t h e s i s I r e p o r t on a study o f t h e f a c t o r s t h a t l i m i t e d t h e r a t e o f - i n c r e a s e of caribou (Rangifer tarandus terraenovae) 1900  t o 1967,  i n Newfoundland from  and d i s c u s s t h e r e l e v a n c e o f t h e r e s u l t s t o g e n e r a l t h e o r i e s  o f t h e growth o f a n i m a l numbers. the e a r l y 1900's ( M i l l a i s 1907  C a r i b o u were abundant i n Newfoundland i n  and Dugmore 1913).  Then from 1915  to  t h e h e r d s r a p i d l y d e c l i n e d and n e a r l y became e x t i n c t (Dugmore 1930). 1930  1930 Since  t h e r e has been a s m a l l i n c r e a s e i n numbers; however, t h e p o p u l a t i o n  n e v e r approached i t s former abundance even though t h e n a t u r a l p r e d a t o r  of  c a r i b o u , t h e Newfoundland w o l f ( C a n i s l u p u s b e o t h u c u s ) , went e x t i n c t i n (L. Tuck p e r s . comm.).  F u r t h e r l e g a l h u n t i n g was  o n l y a s m a l l k i l l p e r m i t t e d 1935  t o 1965.  has  p r o h i b i t e d 1924- t o 1934  A l s o t h e r e has been a g e n e r a l  c l i n e i n t h e i l l e g a l h a r v e s t o f c a r i b o u s i n c e moose ( A l c e s a l c e s ) became  1911 and decom-  2 mon about 1945. The  S t i l l t h e numbers o f c a r i b o u , i n e x p l i c a b l y , remained low.  c a r i b o u i n Newfoundland appears a s u i t a b l e a n i m a l upon which t o  i n v e s t i g a t e the important The  q u e s t i o n o f what l i m i t s p o p u l a t i o n growth i n n a t u r e .  a n i m a l s can be censused a c c u r a t e l y (Bergerud 1963 and S i n i f f and Skoog  1965)  and s e x , age, and b e h a v i o u r can be e a s i l y s t u d i e d i n t h e f i e l d .  The  c a r i b o u o f Newfoundland i s p a r t i c u l a r l y s u i t a b l e because i t s i s l a n d h a b i t a t m i n i m i z e s problems o f movement and y e t t h e s t u d y a r e a was s u f f i c i e n t l y l a r g e a t 42,000 square m i l e s t h a t d i s p e r s a l s h o u l d be t y p i c a l . the p r e s e n t l y o c c u p i e d  F i n a l l y , much o f  range o f t h e s p e c i e s i n Newfoundland p e r m i t t e d a s t u d y  in a natural setting. The work spanned t h e p e r i o d 1957 t o 1967.  I n t h e e a r l y y e a r s I compared  b i r t h r a t e s and death r a t e s o f c a l v e s and a d u l t s t o determine what changes were r e s p o n s i b l e f o r r a t e s o f growth o f p o p u l a t i o n . s i s was on t h e cause o f a h i g h e a r l y m o r t a l i t y o f c a l v e s .  numerical  L a t e r , t h e emphaI a l s o gathered  h i s t o r i c a l i n f o r m a t i o n on t h e s i z e o f t h e herds from 1900 t o 1956. The o b j e c t i v e was t o c l a r i f y e a r l i e r e v e n t s and e v a l u a t e t h e s e r e l a t i v e t o t h e r e c e n t study. Four c a r i b o u herds were s t u d i e d ;  t h e A v a l o n P e n i n s u l a , t h e Humber R i v e r ,  the I n t e r i o r , and t h e N o r t h e r n P e n i n s u l a  ( F i g . 1). A d d i t i o n a l l y , populations  o f t h e I n t e r i o r Herd c a l v i n g a t d i f f e r e n t c a l v i n g grounds were examined separately (Fig. 1). In order t o f a c i l i t a t e the o r d e r l y p r e s e n t a t i o n o f ideas i n the t e x t t a b u l o r m a t e r i a l has been assembled i n an a p p e n d i x (APPENDIX I , p. 1 0 5 ) .  3  PEN.  F i g . 1.  The l o c a t i o n o f c a r i b o u 1957-1967.  4 METHODS The p r i m a r y method was  t o o b s e r v e , c o u n t , and c l a s s i f y c a r i b o u as t o  sex and age from the a i r and ground (Appendix I , T a b l e 1 ) .  Emphasis  was  p l a c e d on c l a s s i f y i n g the a n i m a l s d u r i n g and a f t e r c a l v i n g and d u r i n g r u t t i n g season.  C a r i b o u were observed from t h e ground i n March 1959  M a r c h - A p r i l 1961.  the and  Snow c o n d i t i o n s i n t h e s e t h r e e months were maximum which  p r o v i d e d an o p p o r t u n i t y t o observe t h e a n i m a l s under extreme s t r e s s .  Caribou  were seen i n f r e q u e n t l y i n summer s i n c e most were under t r e e s by day t o escape harassment by  flies.  The Exchange o f A n i m a l s Between Herds and  Populations  Movement o f a n i m a l s between herds c o u l d confound measurements o f r a t e s o f b i r t h and d e a t h . by a e r i a l s u r v e y s  The degree o f s e p a r a t i o n o f c a r i b o u herds was  i n which i n d i v i d u a l a n i m a l s were p l o t t e d on maps.  assessed Normally,  the e n t i r e i n t e r i o r r e g i o n , from t h e r a i l r o a d on t h e e a s t c o a s t t o t h e T r a n s Canada highway on t h e west s i d e o f t h e i s l a n d was t o 10 m i l e s a p a r t .  searched  A d d i t i o n a l l y , t h e I n t e r i o r Herd was  d u r i n g i t s m i g r a t i o n i n f a l l and  spring.  The N o r t h e r n  i n two w i n t e r s w i t h f l i g h t l i n e s spaced a t 5 m i l e s .  on f l i g h t l i n e s 5  t r a c k e d from t h e a i r P e n i n s u l a was  S e v e r a l a t t e m p t s were  made t o t r a c k t h e Humber R i v e r Herd from t h e a i r t o d e t e r m i n e i f . i t the N o r t h e r n  P e n i n s u l a Herd ( F i g . 1 ) .  The A v a l o n P e n i n s u l a was  c a r i b o u i n 11 y e a r s w i t h f l i g h t l i n e s u s u a l l y spaced a t 2 m i l e A second method used t o study movement was streamers.  checked  joined  searched  for  intervals.  to tag caribou with p l a s t i c  N i n e t y - t w o a n i m a l s were c a p t u r e d and tagged w h i l e swimming Lake  V i c t o r i a i n November 1962.  An a d d i t i o n a l 84 a n i m a l s were i m m o b i l i z e d f o r t a g -  g i n g w i t h s u c c i n y c h o l i n e c h l o r i d e f i r e d i n d a r t s from Cap-Chur equipment  . 5' (Bergerud e t a l . 1964).  The  b r i g h t l y c o l o r e d s t r e a m e r s c o u l d be d i s t i n g u i s h e d  from the a i r . A t h i r d method used t o e v a l u a t e the m i x i n g o f p o p u l a t i o n s was mine the p e r c e n t a g e o f a d u l t does p o s s e s s i n g ber.  T h i s was  to deter-  hard a n t l e r s i n . O c t o b e r  and Novem-  d e t e r m i n e d f o r the f o u r main c a r i b o u herds and f o r f i v e r e g i o n a l  p o p u l a t i o n s o f the I n t e r i o r Herd so t h a t d i f f e r e n t c a l v i n g groups c o u l d be tinguished.  The  c a r i b o u i n t h e i n t e r i o r c a l v i n g a t Pot H i l l , Mt. P e y t o n , and  M i d d l e Ridge were combined ( F i g . 1 ) .  An assumption o f t h i s method was  s i g n i f i c a n t d i f f e r e n c e s between herds and p o p u l a t i o n s l e r e d provided  dis-  that  i n p e r c e n t a g e does a n t -  e v i d e n c e o f r e d u c e d gene f l o w .  To e v a l u a t e the method t h a t the p e r c e n t a g e o f a n t l e r e d does c o u l d be used t o d i s t i n g u i s h herds and p o p u l a t i o n s , I compared t h e v a r i a t i o n i n t h e  percent-  age o f a n t l e r e d does between y e a r s i n which f e e d i n g c o n d i t i o n s i n t h e  winter  had v a r i e d . (±95 44±6.  For example does w i t h hard a n t l e r s a t Sandy Lake i n 7 Octobers  per c e n t c o n f i d e n c e  was  l i m i t s ) : • 47±7, 47+7, 40±6, 46±9, 49±12, -44±7, and  A g a i n , two p o p u l a t i o n s t h a t had  separate  c a l v i n g grounds but t h e same  w i n t e r range were d i f f e r e n t i n t h e p e r c e n t a g e o f f e m a l e s w i t h a n t l e r s . The  g e n e t i c b a s i s o f a n t l e r c h a r a c t e r i s t i c s was  a l s o s t u d i e d by k e e p i n g  two a n t l e r e d does i n c a p t i v i t y f o r 5 y e a r s .  The a n t l e r s o f each female were  d i s t i n c t i v e ( c f . L i n s d a l e and Tomich 1953).  Another c a p t i v e female was  a n t l e r l e s s and w i t h o u t  antler pedicels.  always  Most o f t h e s k u l l s o f a n t l e r l e s s a n i -  mals c o l l e c t e d i n t h e autumn were a l s o w i t h o u t  protuberances.  H i s t o r i c a l Research  The  y e a r 1-900  was  t i o n c o u l d be f o u n d . p r o v i d e d by J.G.  chosen as t h e b e g i n n i n g I n t h e p e r i o d 1902  because l i t t l e e a r l i e r  t o 1911  informa-  a wealth of information  M i l l a i s (1907) and.A.A.R. Dugmore (1913).  Millais  was  travelled  6' e x t e n s i v e l y i n f o u r autumns i n e a s t e r n Newfoundland, and Dugmore spent s e v e r a l autumns p h o t o g r a p h i n g c a r i b o u d u r i n g t h e f a l l m i g r a t i o n near Grand Lake. Wildlife  officers  spent e i g h t weeks q u e s t i o n i n g o l d e r r e s i d e n t s about  p a s t c a r i b o u abundance and a n n u a l movements i n l o c a l a r e a s .  Diaries of  w i l d l i f e wardens and a n n u a l game r e p o r t s were a v a i l a b l e f o r some y e a r s between 1930 and 1950. K i l l s t a t i s t i c s were a v a i l a b l e f o r some y e a r s and were used t o e s t i m a t e population trends.  F u r t h e r , t h e number o f c a r i b o u observed p e r h u n t i n g day  was determined from h u n t e r l i c e n s e r e t u r n s f o r 1951 t o 1961.  Census  :  The g e n e r a l p r o c e d u r e was t o s y s t e m a t i c a l l y s e a r c h t h e i s l a n d and l o c a t e herds o f c a r i b o u . across i t .  by a i r  Then each herd was counted by f l y i n g t r a n s e c t s  The p r e l i m i n a r y f l i g h t l i n e s t o l o c a t e herds were u s u a l l y  at 5 m i l e i n t e r v a l s .  spaced  Dense c o n c e n t r a t i o n s were s u b s e q u e n t l y counted w i t h  a e r i a l t r a n s e c t s u s u a l l y 0.5 t o 1.0 m i l e a p a r t (Bergerud  1963a).  To i n v e s t i g a t e s a m p l i n g e r r o r , an e f f o r t was made t o secure maximum c o v e r age o f a p p r o x i m a t e l y 2000 a n i m a l s o c c u p y i n g 24-5 square m i l e s .  Forty transects  a v e r a g i n g 10 m i l e s i n l e n g t h were f l o w n which p r o v i d e d an a e r i a l scan o f 88 p e r cent o f t h e o c c u p i e d a r e a .  T h i s . s t u d y suggests t h a t 30.per c e n t o f an  a r e a s h o u l d be searched f o r an a c c u r a c y w i t h i n 10 p e r cent (Bergerud  1963a).  T r a n s e c t s were u s u a l l y f l o w n i n De H a v i l l a n d Beaver a i r c r a f t a t -80-100 mph. a t a c o n s t a n t h e i g h t o f 500 f e e t a c r o s s t h e i n h a b i t e d range.  U s u a l l y two  r e a r - s e a t o b s e r v e r s scanned a \ m i l e s t r i p on each s i d e o f t h e a i r c r a f t . The o u t e r b o u n d a r i e s o f a t r a n s e c t were determined by marks on t h e wing struts  t h r o u g h which t h e o b s e r v e r c o u l d p r o j e c t an i m a g i n a r y l i n e f o r w a r d .  7", The p l a c i n g o f t h e s e marks was determined b y , f l y i n g over markers s e t . a t known d i s t a n c e s on t h e ground.  A s k i o f t h e a i r c r a f t p r o v i d e d t h e i n s i d e boundary  of a . s t r i p . Without g l a n c i n g away from t h e window, b o t h r e a r - s e a t o b s e r v e r s r e p o r t e d t h e i r sightings to the  co-pilot.  He p l o t t e d a l l c a r i b o u on t o p o g r a p h i c maps.  A p a r t i a l c o r r e c t i o n f o r c a r i b o u m i s s e d by t h e r e a r - s e a t o b s e r v e r s was made by h a v i n g t h r e e men s i m u l t a n e o u s l y t a l l y t h e c a r i b o u on t h e r i g h t o f t h e p l a n e on r e v i s i t f l i g h t s t o f o u r h e r d s .  side  The f o r w a r d o b s e r v e r d e l a y e d  r e p o r t i n g h i s s i g h t i n g s u n t i l t h e c a r i b o u had been p a s s e d , so as n o t t o a l e r t the other observers.  The minimum number o f c a r i b o u . o v e r l o o k e d by t h e r e a r -  s e a t o b s e r v e r was determined by comparing o t h e r two o b s e r v e r s .  h i s t a l l i e s w i t h the counts o f the  The h i g h e s t t a l l y o f a n i m a l s i n an a g g r e g a t i o n was con-  s i d e r e d t h e most a c c u r a t e .  On t h e b a s i s o f t h i s t r i a l t o t a l s were n o r m a l l y  i n c r e a s e d -20 p e r cent t o compensate f o r a n i m a l s o v e r l o o k e d by t h e r e a r - s e a t observers. Herds were s t r a t i f i e d f o r census i n t o a r e a s o f l e s s t h a n 0.5 c a r i b o u p e r square m i l e o r g r e a t e r t h a n 0.5 a n i m a l s p e r square m i l e .  T h i s was n e c e s s a r y  because t h e l o w and h i g h d e n s i t i e s f r e q u e n t l y d i d not r e c e i v e e q u a l o b s e r v a tion.  The l o w d e n s i t y s t r a t u m was u s u a l l y counted d u r i n g t h e herd l o c a t i o n  t r a n s e c t s , w h i l e dense c o n c e n t r a t i o n s were surveyed w i t h r e p e a t e d census  strips.  The c a r i b o u i n t h e I n t e r i o r Herd t h a t summered on t h e Buchans P l a t e a u were counted from t h e i r t r a c k s i n t h e snow where t h e y c r o s s e d two l o g g i n g r o a d s i n f a l l migration. after tabulation.  T r a c k s were counted s e v e r a l t i m e s each day and o b l i t e r a t e d The a c c u r a c y o f t h e count was checked by c e n s u s i n g t h e a n i -  mals by p l a n e and comparing  t h i s t o t a l with the track  tally.  A t h i r d method o f census o f t h e I n t e r i o r Herd i n v o l v e d a complete count o f p o s t p a r t u r i e n t does on t h e c a l v i n g grounds.  aerial  These f i g u r e s were v a l i d  •8v o n l y as t r e n d s s i n c e o t h e r c a r i b o u were not p r e s e n t on many c a l v i n g grounds. The A v a l o n P e n i n s u l a Herd was counted each O c t o b e r , except 1963, by f l i g h t l i n e s spaced a t 1 o r 2 m i l e i n t e r v a l s . count.  The census was an attempt a t a complete  The Humber R i v e r Herd was censused i n most y e a r s by a November t r a c k  count and complete a e r i a l census on t h e w i n t e r range.  The N o r t h e r n P e n i n s u l a  Herd was censused i n 1958 and 1966 by t h e t r a n s e c t method d e s c r i b e d f o r t h e I n t e r i o r Herd.  Measurement o f B i r t h R a t e s ; The b i r t h r a t e was c a l c u l a t e d from t a l l i e s o f does w i t h e n l a r g e d udders i n p o s t c a l v i n g herds.  Does.were c l a s s i f i e d t h r o u g h a 20X s p o t t i n g . s c o p e as p a r o u s ,  i f w i t h a l a r g e u d d e r o r nonparous i f w i t h no v i s i b l e udder ( B e r g e r u d 1964a). f  S h o r t l y b e f o r e c a l v i n g a pregnant doe d e v e l o p s a l a r g e d i s t e n d e d udder which s h r i n k s a t d i f f e r e n t r a t e s depending upon i t s use (Bergerud 1964a). U n f o r t u n a t e l y , s t a t i s t i c a l e v a l u a t i o n o f t h e p e r c e n t a g e o f parous does c o u l d not be made s i n c e t h e number o f d i f f e r e n t a n i m a l s observed was unknown. D u p l i c a t i o n u n d o u b t e d l y o c c u r r e d when s e v e r a l men p e r i o d o f s e v e r a l days. random samples.  c l a s s i f i e d animals over a  However, I b e l i e v e t h e c l a s s i f i c a t i o n s were p r o b a b l y  The a r e a s used by t h e c a l v i n g herds were r e l a t i v e l y s m a l l and  t h e f i e l d m e n were a b l e t o v i s i t t h e p e r i p h e r i e s o f t h e c a l v i n g herds i n t h e i r d a i l y walks.  The p o p u l a t i o n s were not moving d u r i n g t h e c o u n t s .  Observations  o f tagged a n i m a l s - showed t h a t t h e r e was a c o n t i n u a l m i x i n g o f a n i m a l s between groups. I n a d d i t i o n t o udder c o u n t s , t h e b i r t h r a t e was measured from a count o f f e t u s e s i n t h e u t e r i o f 21 does k i l l e d by h u n t e r s i n November and December. An a d d i t i o n a l 58 does were c o l l e c t e d i n June t o d e t e r m i n e t h e number o f e s t r u s c y c l e s each doe e x p e r i e n c e d t h e p r i o r autumn.  O v a r i e s from t h e l a t t e r  sample  9 were examined by P r o f . H.T.  G i e r , Kansas S t a t e U n i v e r s i t y (Appendix I T ) .  Measurement o f A d u l t M o r t a l i t y A s p e c i a l s e a r c h was The  made t o l o c a t e a d u l t s d y i n g from n a t u r a l causes.  approximate age.at death o f 46 a d u l t s was  key d e v e l o p e d f o r A l a s k a n  d e t e r m i n e d from a tooth-wear  c a r i b o u by Skoog (1956).  C a r i b o u remains were sexed  on the b a s i s o f a n t l e r c h a r a c t e r i s t i c s , p e l v i c bones, o r l e n g t h o f t h e  dentary  bones ( B e r g e r u d 1964b). F o u r t e e n a d u l t s were a u t o p s i e d f o r p a r a s i t e s and d i s e a s e by Dr. John King, a pathologist.  W.  W i l d l i f e o f f i c e r s examined an a d d i t i o n a l 46 a n i m a l s ,  the f i e l d f o r macroparasites.  The  i n the l a b o r a t o r y f o r p a r a s i t e s .  in  i n t e s t i n a l t r a c t s o f 36 a d u l t s were examined P a r a s i t e s were i d e n t i f i e d by P r o f .  J.W.  E m s l i e , U n i v e r s i t y o f Glasgow, S c o t l a n d . The  age  s t r u c t u r e o f the l i v i n g s t a g p o p u l a t i o n was  mandibles ( T a b l e 2) p r o v i d e d by h u n t e r s from 1951 from t o o t h wear (Skoog 1956) 1963).  A d d i t i o n a l l y 126  estimated  t o 1965.  Age  was  from  693  estimated  and a n n u l i ( T a b l e 3) i n the cementum (McEwan  captured  does and.stags were aged by c o u n t i n g  the  a n n u l i i n an e x t r a c t e d i n c i s o r ( B e r g e r u d and R u s s e l l 1966). L e g a l h u n t i n g s t a t i s t i c s were s e c u r e d  from r e t u r n s o f h u n t e r l i c e n s e s .  Over 90 per c e n t o f the l i c e n s e h o l d e r s p r o v i d e d r e t u r n s each y e a r .  Data on  the i l l e g a l k i l l were based on i n t e r v i e w s w i t h c o n s c i e n t i o u s l o c a l r e s i d e n t s and t h e r e p o r t s o f w i l d l i f e wardens.  A l s o the remains o f i l l e g a l l y  killed  c a r i b o u and t r a c k s o f poachers were f r e q u e n t l y o b s e r v e d from t h e a i r .  M o r t a l i t y of Calves  The  Overwinter  p e r c e n t a g e o f 6-month-old c a l v e s i n t h e I n t e r i o r Herd was  compared t o  the p e r c e n t a g e o f the same c o h o r t i n t h e p o p u l a t i o n . a t 24-months-of-age t o  d e t e r m i n e i f young a n i m a l s d i e d a t g r e a t e r r a t e s t h a n a d u l t s . was  The  comparison  based on t h e number o f 2 - y e a r - o l d does c l a s s i f i e d on t h e c a l v i n g grounds  i n June. herd.  C o r r e c t i o n s had t o be added f o r t h e m i s s i n g s t a g component o f the  A l s o not a l l 2 - y e a r - o l d does' were p r o p e r l y d i s t i n g u i s h e d from a d u l t does.  The p e r c e n t a g e o f 2 - y e a r - o l d does m i s t a k e n l y c l a s s i f i e d a s . a d u l t s was  estimated  by comparing t h e p e r c e n t a g e o f male : female 6- t o 12-month-old a n i m a l s 17:59.83 n=1282), w i t h the sex r a t i o o f 17- t o 22-month-old a n i m a l s and '77 f e m a l e s ) .  The  (40.  (84 males  sex r a t i o determined f o r 6- t o 12-month-old a n i m a l s  is  l i k e l y r e p r e s e n t a t i v e o f t h e p o p u l a t i o n ; whereas a t 17- t o 22-months-of-age, a l l males a r e p r o b a b l y a c c u r a t e l y d i s t i n g u i s h e d by t h e i r s m a l l a n t l e r s but many o f t h e l a r g e y e a r l i n g f e m a l e s a r e c l a s s i f i e d as a d u l t does.  Since  do not grow from f a l l u n t i l s p r i n g , t h e p e r c e n t a g e o f f e m a l e s o v e r l o o k e d  caribou at  17-  t o 22-months-of-age s h o u l d be s i m i l a r t o t h e p e r c e n t a g e m i s s e d a t 24-monthso f - a g e , assuming no d i f f e r e n t i a l w i n t e r m o r t a l i t y . b e t w e e n The  males and.females.  c a l c u l a t i o n s t o determine the percentage of unrecognized  2-year-old  does  were:  059.83)(84)/(4O.17X) - 77 : (•59.83)(84) / (40.17X)  =  38.45 per  cent  Time and Amount o f E a r l y M o r t a l i t y o f C a l v e s :  E a r l y c a l f m o r t a l i t y was  assessed  by c o u n t i n g does w i t h c a l v e s and does  w i t h d i s t e n d e d udders but w i t h o u t c a l v e s . (Bergerud t h e c a l v i n g grounds o v e r a p e r i o d o f y e a r s :  1964b).  T h i s was done on  Buchans P l a t e a u (6 y e a r s ) ,  Grey  R i v e r (5 y e a r s ) , M i d d l e Ridge (3 y e a r s ) , and Pot H i l l (10 y e a r s ) . T h i s t e c h n i q u e was  f e a s i b l e because c a r i b o u g i v e b i r t h t o o n l y one  and c a l v e s always accompany t h e i r mothers i n f l i g h t .  calf  A doe t h a t i s s e p a r a t e d  from h e r c a l f w i l l c i r c l e - b a c k t o l o c a t e h e r c a l f .  These a n i m a l s are r e a d i l y -  recognized. F i d u c i a l l i m i t s c o u l d n o t be c a l c u l a t e d f o r t h e m o r t a l i t y r a t e s o f c a l v e s s i n c e some females were l i k e l y  c l a s s i f i e d more t h a n once.  F u r t h e r , such s t a -  t i s t i c s would have l i t t l e v a l u e i n d i s t i n g u i s h i n g d i f f e r e n c e s between areas because t h e d a t a were g a t h e r e d a t d i f f e r e n t t i m e s f o r each c a l v i n g a r e a . S i n c e some c a l v e s were-dying d u r i n g t h e s e c o u n t s , t h e m o r t a l i t y from t h e f i r s t c a l v i n g ground v i s i t e d c o u l d be l e s s t h a n t h a t - o f a second a r e a v i s i t e d  partial-  l y because o f t h i s t i m e - l a g . A second assessment^) o f c a l f m o r t a l i t y was made by l o c a t i n g and a g i n g t h e remains o f c a r i b o u t h a t d i e d from n a t u r a l causes.  The age ^of 'calyes ;at^de;ath  -was') based on a comparison o f t h e i r t o o t h i r r u p t i o n w i t h known age jawbones. Obvious b i a s e s i n t h e s e a r c h f o r remains were:  (1) more t i m e was  spent on  c a l v i n g grounds t h a n e l s e w h e r e , (2) no t i m e was  spent s e a r c h i n g f o r e s t cover  where many c a l v e s probably" d i e d , (3) c a l f remains were more d i f f i c u l t  to find  t h a n t h o s e o f a d u l t s , and (4) c a l f remains were more f r a g i l e , l i a b l e t o s c a t t e r i n g and d i s a p p e a r a n c e t h a n a d u l t c a r c a s s e s .  The n e t r e s u l t o f t h e s e b i a s e s  i s not known. Another method o f d e t e c t i n g t h e c h r o n o l o g y and s i z e o f c a l f m o r t a l i t y t o a s c e r t a i n t h e p e r c e n t a g e o f c a l v e s i n t h e h e r d by c l a s s i f i c a t i o n counts t h e young were 12-months-old.  was till  A s p e c i a l e f f o r t was d i r e c t e d a t d e t e r m i n i n g  when m o r t a l i t y o c c u r r e d i n t h e 1957, 1958, and 1959 c o h o r t s .  Herd c o m p o s i t i o n  counts o f t h e s e c o h o r t s were s e c u r e d a t 1-2 month i n t e r v a l s .  C a l v e s were r e -  corded e i t h e r as a p e r c e n t a g e o f t h e t o t a l a n i m a l s o r as c a l v e s seen p e r does seen.  100  I n t h i s paper t h e c a l v e s as a p e r c e n t a g e o f t h e h e r d (C/C+Y+A) w i l l  be used i n most d i s c u s s i o n s .  C a l f p e r c e n t a g e s a r e used r a t h e r t h a n c a l v e s per  100 does i n most c a l c u l a t i o n s because l a r g e r samples were a v a i l a b l e on a c a l f  12 percentage b a s i s .  A g a i n c a l f t o herd p e r c e n t a g e s have c u s t o m a r i l y been used  by o t h e r c a r i b o u workers'and a change i n t h e t r a d i t i o n would complex c o m p a r i sons between i n v e s t i g a t i o n s . The' p e r c e n t a g e o f c a l v e s i n autumn was a l s o e s t i m a t e d from a n i m a l s on r e t u r n s o f b i g game l i c e n s e s .  listed  Space was p r o v i d e d on t h e l i c e n s e f o r t h e  h u n t e r t o l i s t t h e number o f does, s t a g s , c a l v e s , and a n i m a l s o f unknown sex and age observed w h i l e h u n t i n g . c o u l d n o t be used.  Some r e t u r n s were o b v i o u s l y i n e r r o r and  These o b s e r v a t i o n s were v a l u a b l e because t h e y spanned 16  y e a r s and were from a l l s e c t i o n s o f t h e i n t e r i o r . A few d e t e r m i n a t i o n s  o f p e r c e n t a g e o f c a l v e s i n t h e I n t e r i o r Herd were  made by b i o l o g i s t s p r i o r t o my s t u d i e s . a v a i l a b l e f o r 1950,  1951,  1952, 1953,  P e r c e n t a g e o f c a l v e s i n f a l l were  and 1956.  A comparison o f m o r t a l i t y between male and female c a l v e s 'was' made by s e x ing  them by t h e i r e x t e r n a l g e n i t a l i a (Bergerud  were:  1961b).  Age c l a s s e s r e c o g n i z e d  b i r t h ( a c t u a l l y 0- t o 1-day-old a s judged on t h e b a s i s t h a t a man c o u l d  rundown t h e c a l f ) , 1-4- weeks, 5-6 months, 10 months, 12 months, and a s a d u l t s . C o r r e l a t i o n c o e f f i c i e n t s were c a l c u l a t e d t o e v a l u a t e t h e r e l a t i o n s h i p between t h e sex r a t i o o f c a l v e s and r e c r u i t m e n t .  The r e g r e s s i o n used was t h e  sex r a t i o o f c a l v e s a t 1-4 weeks-of-age on y e a r l i n g s p e r 100 does i n June. Sex r a t i o s a t 12-months-of-age were used i n l i e u o f f i g u r e s a t 6-months-of-age s i n c e t h e former were a v a i l a b l e f o r 9 y e a r s .  Again t h e percentage o f y e a r l i n g s  p e r m i t t e d a comparison o f t h e sex r a t i o on r e c r u i t m e n t by c a l v i n g grounds, a s w e l l a s between y e a r s . comparisons' i f :  The c a l c u l a t i o n s based on y e a r l i n g s a r e v a l i d f o r t h e s e  ( 1 ) t h e r e i s no d i f f e r e n t i a l sex m o r t a l i t y o v e r w i n t e r , ( 2 )  b o t h male•and female y e a r l i n g s r e t u r n t o t h e c a l v i n g grounds i n p r o p o r t i o n t o t h e i r abundance, and ( 3 ) o v e r w i n t e r c a l f l o s s e s a r e m i n i m a l o r p o s i t i v e l y c o r r e l a t e d w i t h m o r t a l i t y 0-6 months-of-age.  I b e l i e v e t h a t t h e s e assumptions  13 are  valid.  Determination  I n 1957  o f Cause o f C a l f M o r t a l i t y from C e r v i c a l Abscesses  I l o c a t e d s e v e r a l morbid o r dead c a l v e s a l l i n f e c t e d w i t h l a r g e  c e r v i c a l abscesses.  Others were found i n every subsequent s p r i n g .  e f f o r t i n the r e s e a r c h was  A major  t o determine the cause o f t h i s m o r t a l i t y .  Ab-  s c e s s e d c a l v e s were sent t o v a r i o u s Canadian l a b o r a t o r i e s f o r a u t o p s i e s . Newfoundland Department o f H e a l t h , The eases Research I n s t i t u t e , and Drs. H.C.  Department o f A g r i c u l t u r e A n i m a l D i s Gibbs and J.G.  W i l d l i f e S e r v i c e ) c u l t u r e d pus from a b s c e s s e s . were a u t o p s i e d by p a t h o l o g i s t Dr. J.M.  Cousineau (Canadian  Thirty-two i n f e c t e d calves  K i n g and a s s i s t e d . a t times by  m i o l o g i s t Dr. L a r s K a r s t a d and b a c t e r i o l o g i s t Dr. J.G. To t e s t whether the i n f e c t i o n was  The  epide-  Cousineau.  c o n g e n i t a l o r n o t , 117 newborn c a l v e s  were h e l d i n c a p t i v i t y f o r a minimum o f 3 weeks w h i l e f r e e - r a n g i n g c a l v e s were d e v e l o p i n g a b s c e s s e s .  Seven pregnant does were h e l d u n t i l p a r t u r i t i o n .  C a r i b o u were i n t r o d u c e d t o B r u n e t t e  I s l a n d ( F i g . 1) u s i n g s t o c k from the  M i d d l e Ridge p o p u l a t i o n where many a b s c e s s e d c a l v e s One  e x p l a n a t i o n o f the c o n d i t i o n was  from t h e dam 1959).  t h a t nose b o t s  (Cephenomyia trompe)  burrowed t h r o u g h the neck s k i n o f the c a l f ( P e t e r s and  T h i s was  neck o f c a l v e s .  King  t e s t e d by c o l l e c t i n g b o t s from does and p l a c i n g them on  the  A l l s i z e s o f b o t s were t e s t e d .  A n o t h e r t h e o r y was infection.  occurred.  t h a t the b i t e o f some o t h e r a r t h r o p o d  A r a i s e d p l a t f o r m was  A r t h r o p o d s were p r e v e n t e d  initiated  the  c o n s t r u c t e d i n the Pot H i l l c a l v i n g ground.  from c r a w l i n g up the s u p p o r t s o f t h e p l a t f o r m .  c a l v e s were h e l d on the stage i n June f o r two weeks.  An a d j a c e n t  on t h e ground h e l d seven c a l v e s exposed t o t e r r e s t r i a l and a e r i a l  Six  exclosure arthropods.  14 DISTRIBUTION OF HERDS AND POPULATIONS The^ c a r i b o u herds t h a t I r e c o g n i z e d  i n Newfoundland:  the Northern  P e n i n s u l a Herd, t h e Humber R i v e r H e r d , t h e I n t e r i o r Herd, and t h e A v a l o n P e n i n s u l a H e r d , appeared t o be d i s c r e t e u n i t s ( F i g . 1 ) .  I was u n a b l e t o  s e c u r e any o b s e r v a t i o n s • i n 11 y e a r s o r i n f o r m a t i o n from l o c a l r e s i d e n t s l i v i n g o r t r a v e l l i n g i n t h e a r e a between t h e herds t h a t i n d i c a t e d t h a t any a n i m a l s moved between t h e A v a l o n , Humber, and t h e I n t e r i o r Herds. Humber R i v e r Herd was f o l l o w e d from t h e a i r f o r -40 m i l e s . t o be moving i n t o t h e range o f t h e N o r t h e r n P e n i n s u l a Herd. p e r c e n t a g e o f does p o s s e s s i n g (Fig.  The  I t d i d n o t appear F i n a l l y the  v i s i b l e a n t l e r s v a r i e d between a l l f o u r herds  2 ) . I c o n c l u d e t h a t a l l f o u r herds were d i s c r e t e . The  I n t e r i o r Herd was d i v i d e d i n t o f i v e l o c a l p o p u l a t i o n s on t h e b a s i s  o f t h e i r c a l v i n g grounds:  La P o i l e R i v e r , Buchans P l a t e a u , Grey R i v e r , Sandy  L a k e , and t h e a n i m a l s u t i l i z i n g t h e P o t H i l l , M i d d l e R i d g e , and Mt- P e y t o n c a l v i n g grounds ( F i g . 1 ) . The l o c a t i o n o f t h e c a l v i n g grounds appeared t o be the most r e g u l a r l y v i s i t e d a r e a i n t h e i r movements. d i s t i n g u i s h local, populations  There was a need t o  s i n c e more c a l v e s d i e d a t some c a l v i n g grounds  than others. L i m i t e d e v i d e n c e suggested t h a t t h e c a r i b o u i n t h e f i v e p o p u l a t i o n s o f t h e I n t e r i o r Herd were n o t p a n m i c t i c .  The p e r c e n t a g e o f does w i t h a n t l e r s was  g r e a t e r i n t h e La P o i l e P o p u l a t i o n and l o w e r i n t h e Grey R i v e r P o p u l a t i o n t h a n elsewhere ( F i g . 2 ) . Observations 76 a n i m a l s may have s w i t c h e d 1961,  o f tagged a n i m a l s i n d i c a t e d t h a t o n l y 3 o f  c a l v i n g grounds ( F i g . 3 ) . A e r i a l censuses i n  1964, and 1966 showed t h r e e d i s t i n c t w i n t e r ranges o c c u p i e d  by: ( 1 )  t h e La P o i l e R i v e r P o p u l a t i o n , ( 2 ) c a r i b o u m i g r a t i n g from t h e Buchans P l a t e a u , Grey R i v e r , and Sandy Lake c a l v i n g g r o u n d s , and ('3) c a r i b o u from t h e P o t H i l l ,  15  •»**»• RAILROAD  TRACK  46±5 46 PER CENT DOES HAVE ANTLERS ± 95°/o C,L, (3) . NORTHERf PEN. HERD  CLASSIFIED IN THREE YEARS  88 + 9(1)  HUMBER' RIVER HERD 71 + 8 (3)< NO MOVEMENT ACROSS TRACK / BUCHANS PLATEAU 46±5(4) POPULATIONS LA POILE 59±6(2)  ALL  25  F i g . 2.  0 zdz  25  75  IN INTERIOR  MIDDLE R. 4POT HILL: 47+3(5)  GREY R. 36+4(5)  INTERIOR HERD 45+2 (9) 50  SANDY LAKE 45+3(8)  100  NO MOVEMENT ACROSS  P e r c e n t a g e o f a d u l t females w i t h v i s i b l e a n t l e r s i n t h e autumn.  16  F i g . 3.  O b s e r v a t i o n s o f a n i m a l s subsequent  t o two m i g r a t i o n s a f t e r t a g g i n g .  17 Mount P e y t o n , and M i d d l e Ridge c a l v i n g p o p u l a t i o n s . o f y e a r l i n g s and 2 - y e a r - o l d was  F i n a l l y , the percentage  c a r i b o u on v a r i o u s c a l v i n g grounds i n the s p r i n g  c o r r e l a t e d w i t h c a l f s u r v i v a l t o 6-months-of-age from t h e same a r e a s , as  noted l a t e r .  S i n c e t h e s u r v i v a l o f c a l v e s f r e q u e n t l y v a r i e d g r e a t l y between  c a l v i n g grounds t h i s c o r r e l a t i o n would not be expected i f s i g n i f i c a n t exchange had o c c u r r e d between p o p u l a t i o n s .  18 SIZE OF CARIBOU HERDS Numbers 1900-1910  The a n n u a l r e p o r t o f t h e Game and I s l a n d F i s h e r i e s D i v i s i o n 1950-51 stated:  "...by a l l accounts  e a r l y 1900's".  t h e c a r i b o u p o p u l a t i o n reached  a peak i n t h e  The i s l a n d p o p u l a t i o n i n t h a t p e r i o d was e s t i m a t e d by Dugmore  (1913)' t o c o n t a i n 150,000 animals and by M i l l a i s (1907) t o number 200,000. In c o n t r a s t t o t h e s e l a r g e e s t i m a t e s o f M i l l a i s and Dugmore, I b e l i e v e t h a t t h e r e was p r o b a b l y no more t h a n 40,000 c a r i b o u on t h e i s l a n d i n t h e i n t e r v a l 1900-1910.  T h i s f i g u r e was d e r i v e d from e s t i m a t e s p r o v i d e d by r e s i d e n t s i n  i n t e r v i e w s ( F i g . -4).  T h i s number seems more r e a s o n a b l e t h a n 150,000-200,000  when we c o n s i d e r t h e e x t e n t o f w i n t e r range about 1900 and even t h e n t h e r e were l a r g e a r e a s o f few a n i m a l s  (Fig. 4).  Dugmore's o b s e r v a t i o n s o f c a r i b o u were l i m i t e d t o s i g h t i n g s o f animals m i g r a t i n g a c r o s s t h e r a i l r o a d between Sandy Lake and M i l l e r t o w n J u n c t i o n . T h i s m i g r a t i o n was t h e most renowned and p r o b a b l y c o n t a i n e d t h e l a r g e s t conc e n t r a t i o n o f animals  i n a l l Newfoundland.  e s t i m a t e f o r t h e i s l a n d from t h e s e l i m i t e d The  Dugmore may have e x t r a p o l a t e d h i s observations.  1900 h e r d i n t e r c e p t e d t h e r a i l r o a d t r a c k s as t h r e e groups.  The f i r s t  group moved by B i g F a l l s on t h e Humber R i v e r and c r o s s e d t h e r a i l w a y t r a c k s a t Sandy Lake.  A second group from t h e N o r t h e r n P e n i n s u l a c r o s s e d B i r c h y Lake a t  S l a u g h t e r P o i n t and went a c r o s s t h e r a i l r o a d n e a r t h e h i l l named t h e G a f f Topsail.  A n o t h e r component o f t h e h e r d moved s o u t h from t h e B u r l i n g t o n P e n i n s u l a  and a l s o swam B i r c h y Lake and t h e n i n t e r c e p t e d t h e r a i l r o a d n e a r t h e G a f f Topsail.  A f o u r t h body o f animals  c r o s s e d t h e r a i l r o a d a t P a t r i c k s Marsh, M i l l e r -  town J u n c t i o n . The most complete h i s t o r i c a l i n f o r m a t i o n f o r t h e s e herds was s e c u r e d f o r  F i g . 4.  Number o f c a r i b o u about 1900 based on i n t e r v i e w s and t h e e x t e n t of winter range.  20 t h e a n i m a l s . c r o s s i n g a t Sandy Lake; p r o b a b l y more a n i m a l s moved s o u t h a t Sandy t h a n a t t h e o t h e r two c r o s s i n g s s i n c e more a n i m a l s were k i l l e d t h e r e (unpublished f i l e s ) . Sandy i n 9 days.  In one autumn Dugmore (1908) counted 1200 a n i m a l s a t  I n 1911 Dugmore (1912) s t a t e d t h a t 2000 a n i m a l s passed w i t h -  i n s i g h t i n a 2-week p e r i o d .  The l a r g e s t c r o s s i n g i n t h a t y e a r was  24 when 8 companies t o t a l l i n g 500 a n i m a l s passed s o u t h .  on  October  Three o l d e r r e s i d e n t s  i n t e r v i e w e d i n t h i s s t u d y each s e p a r a t e l y e s t i m a t e d t h e B i g F a l l s - S a n d y Lake p o p u l a t i o n a t 2000 a n i m a l s about 1915.  Two newspaper a c c o u n t s o f c a r i b o u ob-  s e r v e d d u r i n g h u n t i n g t r i p s l i s t e d t o t a l s o f 1800 a n i m a l s seen i n 1907 1000  i n 1908.  and  I t i s u n l i k e l y t h a t more t h a n 3000-4000 a n i m a l s c o u l d have  been i n v o l v e d i n t h i s m i g r a t i o n . A t t h e G a f f T o p s a i l and P a t r i c k s Marsh c r o s s i n g s t h e maximum d a i l y  counts  o f m i g r a t i n g a n i m a l s were s i m i l a r t o t h o s e a t Sandy and v a r i e d from 250 t o animals.  Most o f t h e h e r d c r o s s e d t h e t r a c k s i n a 2- t o 3-week p e r i o d .  t o t a l s f o r t h e s e two c r o s s i n g s would n o t have exceeded perhaps a n i m a l s i f two assumptions  are v a l i d :  500  The  3000 t o 4000  (1) t h a t t h e d a i l y f r e q u e n c y o f c a r i b o u  moving s o u t h f o l l o w e d a normal d i s t r i b u t i o n curve and (2) t h a t t h e maximum d a i l y counts ( t h e c e n t e r o f t h e normal c u r v e ) r e p r e s e n t e d 20 t o 30 p e r cent o f t h e t o t a l a n i m a l s i n each o f the t h r e e c o n c e n t r a t i o n s . These assumptions  are  v a l i d f o r t h e c a r i b o u t h a t p r e s e n t l y s t i l l m i g r a t e s o u t h from t h e Buchans P l a t e a u and pass by Lake V i c t o r i a ( p e r s o n a l f i l e s ) . The t o t a l p o p u l a t i o n t h a t m i g r a t e d between Sandy and M i l l e r t o w n J u n c t i o n can a l s o be judged from m o r t a l i t y and r e c r u i t m e n t s t a t i s t i c s and p o p u l a t i o n trends.  The a n n u a l h a r v e s t from t h e h e r d 1900 t o 1915 was between 2000 and  3000 a n i m a l s .  A p p r o x i m a t e l y h a l f t h e a n i m a l s were h a r v e s t e d a l o n g t h e r a i l r o a d  and such k i l l f i g u r e s c o m p i l e d by wardens (1911, ,1912, 1914, and 1915) from 1000 t o 1500.  ranged  In a d d i t i o n , a p p r o x i m a t e l y 100 h u n t e r s a n n u a l l y k i l l e d  21 a n i m a l s a t S l a u g h t e r P o i n t , B i r c h y Lake.  A l s o , n o n m i g r a t o r y a n i m a l s were shot  by l o c a l r e s i d e n t s t r a v e l l i n g by dog team t o t h e White and South H i l l i n March. I e s t i m a t e d t h e c a l f increment t o t h e h e r d d u r i n g t h e y e a r s o f heavy h a r v e s t at  20 p e r c e n t based on a count o f c a l v e s c l a s s i f i e d from t h e e x c e l l e n t  graphs i n Dugmore's book (1913).  photo-  The above k i l l and r e c r u i t m e n t f i g u r e s were  a p p a r e n t l y f a i r l y b a l a n c e d s i n c e t h e p o p u l a t i o n m a i n t a i n e d i t s numbers o r o n l y g r a d u a l l y d e c l i n e d i n t h e i n t e r v a l 1900 t o 1915. These comparisons t h o s e o f t h e t o t a l a n i m a l s e s t i m a t e d a t each o f t h e t h r e e r a i l r o a d  as w e l l as intercepts  suggest t h a t t h e l a r g e s t h e r d i n Newfoundland i n t h e e a r l y 1900's p r o b a b l y numbered l e s s t h a n 15,000 a n i m a l s . Millais'  (1907) d e t a i l e d o b s e r v a t i o n s o f c a r i b o u do n o t s u p p o r t h i s e s t i -  mate o f 200,000 c a r i b o u f o r t h e I s l a n d 1900-1910.  I n 1902 M i l l a i s  up t h e T e r r a Nova R i v e r ; he observed 306 does i n 36 days.  travelled  The n e x t y e a r he  canoed up t h e Gander R i v e r ; t h e f i r s t c a r i b o u were n o t seen u n t i l t h e p a r t y was w e l l i n l a n d and t h e n o n l y a few a n i m a l s were observed each day. I n 1905 he c r o s s e d t h e i s l a n d from Bay D ' E s p o i r t o Glenwood and saw many " l i t t l e ies"  o f a n i m a l s i n t h e v i c i n i t y o f P i p e s t o n e Lake.  part-  F i n a l l y , i n October 1906,  he j o u r n e y e d up Long Harbour R i v e r and r e a c h e d Mt. S y l v e s t e r .  On t h i s t r i p he  observed more c a r i b o u t h a n p r e v i o u s l y and remarked t h a t 4 o r 5 companies were seen each day a f t e r he had t r a v e l l e d i n l a n d 5 days.  The g r e a t e s t number o f  c a r i b o u were seen October 30— 124 a n i m a l s and October 3 1 — 1 5 9 c a r i b o u . :  o b s e r v a t i o n s do n o t g i v e t h e i m p r e s s i o n o f thousands  of caribou.  These  In fact i t  was p o s s i b l e d u r i n g t h i s s u r v e y f o r me t o observe as many c a r i b o u p e r day near P i p e s t o n e Lake as M i l l a i s d i d even though an a e r i a l census showed t h a t t h e r e were o n l y a p p r o x i m a t e l y 300 a n i m a l s i n t h e r e g i o n .  Numbers and Trends 1900-1956  22 The number o f c a r i b o u on t h e i s l a n d r a p i d l y d e c l i n e d from 1915 t o The decrease was  f i r s t n o t e d a t t h e r a i l r o a d c r o s s i n g s but soon s p r e a d t o a l l  segments o f t h e p o p u l a t i o n . p o r t e d as 1200  1930.  The l a s t l a r g e m i g r a t i o n . a t Sandy Lake was r e -  a n i m a l s i n 1925.  B i r c h y Lake was  1925.  The l a s t i m p o r t a n t c r o s s i n g a t S l a u g h t e r P o i n t ,  i n 1925 o r 1926.  Less t h a n 100 a n i m a l s swam B i r c h y Lake i n  The d e c l i n e was apparent i n t h e Southern Long Range Mountains  C a r i b o u d i s a p p e a r e d from t h e " A n g u i l l e Mountains from t h e Hodges H i l l s by 1920.  i n 1920.  about 1923 and were almost gone  C a r i b o u became s c a r c e i n a l l t h e s o u t h e a s t e r n  i n t e r i o r i n t h e i n t e r v a l 1920-25; h u n t e r s had t o t r a v e l as f a r as M i d d l e Ridge to f i n d animals. season was  By 1925 a l l t h e l a r g e herds had d i s a p p e a r e d and t h e h u n t i n g  c l o s e d f o r the  island.  The c a r i b o u r e a c h e d t h e i r n a d i r o f numbers between 1925 and 1930. (1930:127) s t a t e d :  "How  l i t t l e did I realize..that  the vast herds, seemingly  u n l i m i t e d and e n d u r i n g would p r a c t i c a l l y v a n i s h d u r i n g my own ten  Dugmore  l i f e time; that  s h o r t y e a r s from t h e day when I enjoyed w a t c h i n g t h e l o n g l i n e s o f  ...ani-  mals.. I s h o u l d be t o l d t o a l l i n t e n t s and purposes t h e y had v a n i s h e d ; v a n i s h e d w i t h an a s t o n i s h i n g a b r u p t n e s s , u n b e l i e v a b l e and i n c o m p r e h e n s i b l e .  I am  told  t h a t t h e r e are n o t two hundred c a r i b o u i n t h e whole i s l a n d t o d a y , and t h o s e a r e s c a t t e r e d i n ones and twos i n t h e w i l d u n i n h a b i t e d r e g i o n s " . I t seems l i k e l y t h a t c o n s i d e r a b l y more t h a n 200 a n i m a l s remained However, a l l t h e r e s i d e n t s i n t e r v i e w e d i n t h i s i n v e s t i g a t i o n  i n 1930.  agreed t h a t c a r i -  bou were much s c a r c e r i n 1930 t h a n i n 1957-58 when t h e f i r s t censuses r e v e a l e d l e s s t h a n 6500 a n i m a l s f o r t h e i s l a n d . numbers f o r t h e A v a l o n Herd was  Two r e s i d e n t s s t a t e d t h a t - t h e low i n  80 a n i m a l s .  There were p r o b a b l y l e s s t h a n  100  a n i m a l s r e m a i n i n g i n each o f t h e N o r t h e r n P e n i n s u l a and Humber R i v e r herds i n 1930. of  P o s s i b l y 1000  scarcity.  o r 2000 a n i m a l s p e r s i s t e d on the i s l a n d d u r i n g t h e y e a r s  23 The herds began t o i n c r e a s e by 1932-35.  A l e t t e r from t h e c l e r k o f t h e  Game and F i s h e r i e s Commission (November 10, 1936) r e p o r t e d :  " . . . c a r i b o u have  been r e p o r t e d as i n c r e a s i n g s l o w l y b u t s u r e l y , and d u r i n g t h e l a s t 4 o r 5 y e a r s s m a l l southward and n o r t h w a r d m i g r a t i o n s a l o n g t h e o l d r o u t e s have been r e p o r t ed".  A warden r e p o r t s t a t e d t h a t 60 t o 70 animals  in 1933—this animals  c r o s s e d by t h e G a f f T o p s a i l  was t h e l a r g e s t h e r d r e p o r t e d i n many y e a r s .  a t M i d d l e Ridge i n 1933.  Hunters n o t e d 200  By 1940 herds were a g a i n c r o s s i n g Sandy and  B i r c h y Lakes and c a r i b o u had r e t u r n e d t o t h e Hodges H i l l s and A n g u i l l e Mountains.  A peak p o p u l a t i o n may have been r e a c h e d about 1941 s i n c e h u n t i n g  suc-  cess d e c l i n e d i n 1942, 1943, and 1944 (Table '4). Commencing about 1946-47 t h e p o p u l a t i o n a g a i n expanded and o l d ranges were reoccupied  (personal f i l e s ) - ;  i n c r e a s e d (Table 4 ) .  l i c e n s e quotas were r e l a x e d and  kill.statistics  A n o t h e r peak o f abundance may have been r e a c h e d about  1951 ( T a b l e 4 ) ; t h e p o p u l a t i o n t h e n d e c l i n e d and was s t i l l d e c r e a s i n g when t h e c u r r e n t s t u d y began.  Numbers and Trends 1957-1967 The w i n t e r censuses o f t h e I n t e r i o r Herd i n d i c a t e d t h a t t h e p o p u l a t i o n i n c r e a s e d from 1957 t o 1961, p o s s i b l y d e c l i n e d 1962 t o 1964, and a g a i n i n creased  1965 and 1966 ( F i g . 5 and T a b l e 5 ) .  U n f o r t u n a t e l y , t h e La P o i l e popu-  l a t i o n was n o t a c c u r a t e l y counted i n t h e f i r s t t h r e e c e n s u s e s , t h u s t h e f i g u r e s f o r i t were e x c l u d e d f r o m T a b l e 5 t o p e r m i t a more v a l i d comparison o f the f i v e  counts.  The counts o f t h e p o s t p a r t u r i e n t doe c o n c e n t r a t i o n s showed a g r a d u a l l y i n c r e a s i n g p o p u l a t i o n (Table '6). v a r i e d w i d e l y between y e a r s  The t o t a l s o f does on some c a l v i n g grounds  (Table 6 ) .  These d i s c r e p a n c i e s l i k e l y r e s u l t e d  from changes i n t h e l o c a l d i s t r i b u t i o n o f animals  and sampling  errors rather  24  1  —i 57  1  1  1  1  1  1  1  1  1  58  59  60  61  62  63  64  65  66  YEARS F i g . 5.  r 67  COUNTED  C a r i b o u numbers from a e r i a l census o r t r a c k c o u n t s . Figures f o r the I n t e r i o r Herd do n o t i n c l u d e t h e La P o i l e p o p u l a t i o n .  . 25 t h a n movement between p o p u l a t i o n s .  I n some June counts t h e a n i m a l s were much  more c o n c e n t r a t e d and e a s i e r t o l o c a t e t h a n i n o t h e r y e a r s . F o r example, t h e counts o f t h e Buchans P l a t e a u p o p u l a t i o n i n 1963, 1964-, and 1965 y i e l d e d 643, 1341, and 892 a n i m a l s ( T a b l e 6 ) .  The tagged a n i m a l s  counted i n each y e a r were 9, 32, and 1 4 — y e t t h e s e a n i m a l s were tagged i n November 1962 and n o t l i k e l y dead. c a l v i n g grounds.  Moreover, t h e y were n o t observed on o t h e r  The i n f e r e n c e i s t h a t a group o f t h e Buchans P l a t e a u p o p u l a -  t i o n was o v e r l o o k e d i n 1963 ,' and 1965 and p o s s i b l y 1964. The autumn t r a c k count o f t h e Buchans p o p u l a t i o n , s i m i l a r t o t h e w i n t e r and June t a l l i e s , suggested t h a t i t had g r a d u a l l y i n c r e a s e d .  Track t o t a l s were:  1 9 5 7 — 5 9 2 , 1 9 5 8 — 5 8 5 , 1959--730, 1 9 6 1 — 1 0 4 2 , and 1 9 6 3 — 1 0 2 8 .  Aerial  gave a p o p u l a t i o n e s t i m a t e o f 1200 i n 1963 (Manuel  census  1964).  The October a e r i a l census o f t h e A v a l o n Herd showed a p o p u l a t i o n i n c r e a s e from 71 a n i m a l s i n 1956 t o 720 a n i m a l s i n 1966 ( F i g . 5 and T a b l e 5 ) .  The  t o t a l s f o r t h e y e a r s 1956 t o 1960 p r o b a b l y u n d e r e s t i m a t e d t h e p o p u l a t i o n . I t was n o t u n t i l October 1960 t h a t I d i s c o v e r e d a s m a l l group o f a n i m a l s (41 t h a t y e a r ) i n a r e g i o n not surveyed i n e a r l i e r y e a r s .  F u r t h e r , i n 1961, t h e New-  f o u n d l a n d government s e c u r e d i t s own a i r c r a f t ; t h i s p e r m i t t e d more i n t e n s i v e searches than p o s s i b l e w i t h c h a r t e r e d f l i g h t s .  The A v a l o n Herd i n 1956 l i k e l y  c o n t a i n e d about 125 a n i m a l s . The Humber R i v e r Herd showed no change between 1956 and 1964 and averaged 111 a n i m a l s ( F i g . 5 and T a b l e 5 ) . L i k e w i s e no t r e n d i n numbers was e v i d e n t f o r t h e N o r t h e r n P e n i n s u l a h e r d i n t h e o n l y two a e r i a l censuses made, 1 9 5 8 — 450 a n i m a l s and 1 9 6 6 — 4 0 0 c a r i b o u .  26  BIRTH RATES  "An a n i m a l ' s i n n a t e c a p a c i t y f o r i n c r e a s e depends upon i t s f e c u n d i t y , l o n g e v i t y , and speed o f development" (Andrewartha and B i r c h 1954:33).  I t was  e s s e n t i a l t o determine i f t h e slow r a t e - o f - i n c r e a s e o f t h e Newfoundland herds was a r e s u l t o f low b i r t h r a t e s .  I n t h i s s e c t i o n I w i l l d i s c u s s speed o f  development (age o f s e x u a l m a t u r i t y ) and f e c u n d i t y .  The n e x t s e c t i o n s on  a d u l t and c a l f m o r t a l i t y r e l a t e j t o s u r v i v a l and hence l o n g e v i t y .  Age o f B r e e d i n g  In  a n i m a l s t h a t have one young p e r y e a r t h e age o f s e x u a l m a t u r i t y has a  marked i n f l u e n c e on t h e i r p o t e n t i a l r a t e o f i n c r e a s e .  S t a r t i n g w i t h one male  and one f e m a l e , a s p e c i e s h a v i n g one young and b r e e d i n g a t 1 y e a r o f age c o u l d i n c r e a s e t o 63 a n i m a l s i n 10 y e a r s ( r = 0.361), assuming no m o r t a l i t y and a b a l a n c e d s e x r a t i o ; a s p e c i e s b r e e d i n g f i r s t a t 2 y e a r s would i n c r e a s e to  30 a n i m a l s ( r = 0.301) and one a t t a i n i n g p u b e r t y a t 3 y e a r s c o u l d r e a c h 22  a n i m a l s i n 10 y e a r s , r = 0.266 (numbers a t 10 y e a r s based on b r e e d i n g p o t e n t i a l t a b l e s of Leopold  1933).  The age o f p u b e r t y i n c a r i b o u i s u s u a l l y c o n s i d e r e d t o be 29 t o 30 months, Skoog (1968) r e p o r t e d 4 o f 31 (13 p e r c e n t ) does \\ y e a r s o f age pregnant and 28 o f 46 (61 p e r c e n t ) 2\ y e a r s o f age c a r r y i n g young.  K e l s a l l (1968) l i s t e d  1 o f 3 does l^g y e a r s o l d pregnant and 6 o f 1 5 (40 p e r c e n t ) 2\ y e a r s o l d . I n t h i s s t u d y o n l y 1 o f 9 2 - y e a r - o l d does c o l l e c t e d was parous c l a s s i f i e d o n l y 4 o f 327 2 - y e a r - o l d does parous i n 10 y e a r s . s h o u l d u n d e r e s t i m a t e parous  We  This figure  2 - y e a r - o l d s s i n c e o n l y an e s t i m a t e d 62 p e r c e n t o f  t h e young does were s e p a r a t e from a d u l t s . ed p u b e r t y as y e a r l i n g s .  (Table 7 ) .  I n c a p t i v i t y , 2 o f 3 females r e a c h -  Thus t h e s p e c i e s has t h e g e n e t i c p o t e n t i a l t o produce  . -27 young a t 24—months-of-age. The w i n t e r o f 1957-58 p r o v i d e d an o p p o r t u n i t y t o a s s e s s the r o l e o f t r e m e l y f a v o r a b l e weather and f o r a g e c o n d i t i o n s on t h e age snow f e l l unfrozen  of p u b e r t y .  exLittle  ( F i g . 6) and t e m p e r a t u r e s were above normal so t h a t l a k e s remained f o r much o f t h e w i n t e r .  C a l v e s weighed more a t b i r t h f o l l o w i n g the  m i l d w i n t e r t h a n i n any o t h e r y e a r (see page 56). t h e i d e a t h a t females had A s p e c i a l e f f o r t was i f many had 2-year-old  conceived  T h i s was  consistent with  f a r e d e x c e p t i o n a l l y w e l l during the made i n 1959  t o observe 2 - y e a r - o l d  winter. does t o determine  as y e a r l i n g s f o l l o w i n g t h e f a v o r a b l e w i n t e r .  does were r e c o r d e d .  Apparently,  No  parous  favorable winter forage i s i n s u f -  f i c i e n t a l o n e t o advance s e x u a l m a t u r i t y . Twenty-two c a l v e s were counted on B r u n e t t e  I s l a n d i n October 1966.  maximum number o f females on t h e i s l a n d 3-years and o l d e r was l e a s t 3 c a l v e s must have been b o r n t o t h e 5 o r 6 2 - y e a r - o l d herd.  19.  Thus a t  f e m a l e s i n the  Moreover, a number o f male c a l v e s had f o r k e d a n t l e r s ; t h i s  a n t l e r development was  The  never observed elsewhere' i n Newfoundland.  communities on t h e i s l a n d were s i m i l a r t o t h o s e on t h e m a i n l a n d .  superior The  plant  A superior  n u t r i t i o n a l s t a t e o f t h e a n i m a l s c o u l d have r e s u l t e d from t h e m a r i t i m e c l i m a t e o f the i s l a n d t h a t reduces i n s e c t abundance and p e r m i t s f o r a g i n g t h r o u g h o u t the  day.  Fecundity The  reproductive rate of a species breeding  once each y e a r i s a p r o d u c t o f  t h e p e r c e n t a g e o f females t h a t c a r r y . y o u n g t o p a r t u r i t i o n and t h e mean number o f young b o r n p e r parous f e m a l e .  I n Newfoundland c a r i b o u t h e r e p r o d u c t i v e  rate  depended o n l y on t h e a n n u a l p e r c e n t a g e o f pregnant ( p a r o u s ) does s i n c e t h e r e was  no e v i d e n c e o f m u l t i p l e b i r t h s .  Only 6 does were seen i n 11 y e a r s t h a t  28  DECEMBER  F i g . 6.  JANUARY  FEBRUARY  MARCH  APRIL  The snow p r o f i l e (depth o f snow on ground) a t Gander, Newfoundland, f o r t h e e x c e p t i o n a l l y m i l d w i n t e r o f 1957-58 and t h e v e r y s e v e r e w i n t e r 1958-59 .  a l l o w e d two  c a l v e s t o n u r s e simultaneously. On f o u r o c c a s s i o n s a second  appeared t o c l a i m the second c a l f .  Two  c a l v e s f r e q u e n t l y f o l l o w e d one  when a l a r m e d , but most o b s e r v a t i o n s showed t h a t the dam was  nearby.  The  doe doe  o f t h e second c a l f  o v a r i e s or u t e r i o f 73 parous females showed no s i g n s o f  multiple births. The  11-year frequency  c l a s s i f i c a t i o n was  84.5  o f parous does f o r the I n t e r i o r Herd based on udder  p e r cent ( T a b l e 8 ) .  T h i s f i g u r e agreed c l o s e l y w i t h  a pregnancy p e r c e n t a g e o f 86 p e r cent from the e x a m i n a t i o n t r a c t s p r o v i d e d by  o f 21  reproductive  hunters.  I attempted t o r e l a t e the parous d o e . s t a t i s t i c s s e c u r e d each y e a r i n T a b l e 8 t o v a r i o u s f a c t o r s o f t h e environment.. The  a n n u a l pregnancy r a t e s  showed no t r e n d s when p l o t t e d a g a i n s t s n o w f a l l i n t h e p r e v i o u s 1 and 2 y e a r s . The pregnancy f i g u r e s were n o t r e l a t e d t o a d e c l i n e o f s t a g s ( T a b l e 9 ) . Hunter d i s t u r b a n c e d u r i n g t h e r u t t i n g season d i d not appear t o be a f a c t o r . H u n t i n g p r e s s u r e was  h e a v i e s t on the Buchans P l a t e a u and l e a s t a t Grey R i v e r ;  y e t t h e p e r c e n t a g e s o f parous does were s i m i l a r i n t h e two areas ( T a b l e 8 ) . The numbers o f parous does however were s i g n i f i c a n t l y and n e g a t i v e l y c o r r e l a t e d w i t h t h e number o f c a l v e s b o r n 2 y e a r s b e f o r e  ( F i g . -7).  Changes i n r e -  2 c r u i t m e n t o f c a l v e s p r o v i d e d 72 p e r c e n t ( r ) o f t h e v a r i a t i o n i n p e r parous doe s t a t i s t i c s . frequency  I c o n c l u d e t h a t most o f t h e a n n u a l v a r i a t i o n i n  r a t e between y e a r s and a r e a s r e f l e c t e d changes i n the number o f n u l l i -  parous 2 - y e a r - o l d udder  cent  does e n t e r i n g t h e a d u l t p o p u l a t i o n and i n c l u d e d i n the June  counts. When few 2 - y e a r - o l d does were p r e s e n t on some c a l v i n g grounds, 94- t o 96  p e r c e n t o f the females 3-years and o l d e r ( a d u l t ) were p r e g n a n t .  F u r t h e r , the  June c l a s s i f i c a t i o n s from a l l y e a r s when a d j u s t e d f o r 2 - y e a r - o l d does c l a s s i f i e d as nonparous a d u l t s (see METHODS), i n d i c a t e d t h a t 94 per cent o f t h e  30  100  -I  BY  CALVING  POPULATIONS r = - 0.685 P<0.001 90  -  n = 23 -Y = 9 4 . 6 7 - 0 . 9 8 6 x  A UJ  z  80 A POT  UJ  O Q  70  HILL  •  BUCHANS  •  GREY  RIVER  OMIDDLE  -  •  SANDY  A LA  PLATEAU  RIDGE LAKE  POILE  RIVER  *100 a.  BY Y E A R S r=-0.850  z UJ  o a: UJ CL  P<0-02 n =9 90 • Y= 100.12 - 1 . 4 0 x  80  -  70  1  1  5 PER-CENT 20  F i g . 7.  1  10 CALVES  MONTHS  PRIOR  1  15 IN TO  20  POPULATION PAROUS  OR  DOE  HERD COUNTS  R e g r e s s i o n o f counts o f parous does on r e c r u i t m e n t 20 months p r e v i o u s . P r e f e r s t o t h e p r o b a b i l i t y o f t h e n u l l h y p o t h e s i s o f no d i f f e r e n c e .  25  31 • a d u l t does were p r e g n a n t . The causes o f b a r r e n n e s s i n 6 p e r c e n t o f t h e does a r e p r o b a b l y v a r i e d . A few females may have been s e n i l e .  I n a sample o f 19 nonparous does, f o u r  were a t l e a s t 10 y e a r s o l d ; whereas, o n l y one 10 y e a r o r o l d e r doe would have been e x p e c t e d i n t h i s sample on t h e b a s i s o f t h e female age d i s t r i b u t i o n i n t h e p o p u l a t i o n 1963-64, ( T a b l e 1 0 ) .  Some females p r o b a b l y d i d n o t r e a c h  p u b e r t y u n t i l 40-months-of-age ( T a b l e 7 ) .  One b a r r e n doe was c o l l e c t e d t h a t  had a u t e r u s a b n o r m a l i t y — w h i t e h e i f e r d i s e a s e ( K i n g p e r s . comm.).  Seven  b a r r e n females were c r i p p l e d ; l i k e l y t h e y c o u l d n o t s u p p o r t a s t a g ' s weight during coitus.  The h i s t o l o g i c a l e x a m i n a t i o n o f t h e o v a r i e s o f 9 mature non-  parous does (4 y e a r s o r o l d e r ) showed o n l y one female whose o v a r i e s had never been a c t i v e ( T a b l e 7 ) .  32 ADULT MORTALITY  E x c e s s i v e m o r t a l i t y o f a d u l t s c o u l d l i m i t p o p u l a t i o n growth. n a t u r a l and h u n t i n g m o r t a l i t y must be  Both  considered.  M o r t a l i t y Rates'  The n a t u r a l a n n u a l m o r t a l i t y was and averaged 6 p e r c e n t ( T a b l e 1 1 ) . ing  low on t h e A v a l o n P e n i n s u l a , 1961-66, There was  no known i l l e g a l h u n t i n g  t h i s i n t e r v a l and t h e f i r s t l e g a l h a r v e s t was  i n 1966.  l i k e l y had a s i m i l a r low n a t u r a l assumed m o r t a l i t y r a t e . 3-4 p e r c e n t p e r annum 1957 t o 1966  (later  eraged 14 p e r cent ( T a b l e 12, 1958-66). e s t i m a t e d t o t a l o f 6 p e r cent ( l a t e r  dur-  The I n t e r i o r Herd The h e r d i n c r e a s e d  s e c t i o n ) when f a l l increments  L e g a l h u n t i n g and p o a c h i n g took  section).  The n a t u r a l m o r t a l i t y  avan  left  amounted t o perhaps 5 p e r c e n t . The  I n t e r i o r Herd showed l i t t l e p o p u l a t i o n change 1961 t o 1966  ( F i g . 5).  The age a r r a y o f s t a g s k i l l e d i n t h i s p e r i o d showed a 22 p e r c e n t t o t a l mortality  ( F i g . 8).  i n t e r v a l was  The a n n u a l l e g a l and i l l e g a l h u n t i n g m o r t a l i t y i n t h e same  p r o b a b l y 14 p e r c e n t .  s t a t i s t i c s i n the formula:  q n  S u b s t i t u t i n g a n n u a l and h u n t i n g s u r v i v a l  = 100 - ( s / s , ) (see Bergerud h •  a n a t u r a l m o r t a l i t y of stags of 9 per cent.  1967a), i n d i c a t e d  I f n a t u r a l m o r t a l i t y o f both  stags  and does combined i s c l o s e t o 5 p e r cent and s t a g s c o n s t i t u t e 21 p e r c e n t o f t h e p o p u l a t i o n ( T a b l e 1 3 ) , t h e n t h e n a t u r a l m o r t a l i t y o f does and y e a r l i n g s s h o u l d be n e a r 4 p e r c e n t . per cent.  P o a c h i n g o f does was  e s t i m a t e d a t an a d d i t i o n a l 3  A n n u a l m o r t a l i t y o f 22 p e r c e n t f o r s t a g s and 7 p e r cent f o r does  i s s u f f i c i e n t t o a l t e r t h e male : female r a t i o o f a d u l t s i n 1957 a r a t i o o f 23:77 i n 1966  (Table 9 ) .  The  o f 32:68 t o  combined m o r t a l i t y s t a t i s t i c s f o r  b o t h sexes g i v e a t o t a l a n n u a l m o r t a l i t y 11 p e r cent f o r 1961-1966,:  33  0  Fig.  8.  1  2  3  4  5  6  AGE  7  IN  8  9  10  11  12  13  14  15  16  YEARS  S u r v i v a l o f male c a r i b o u i n t h e i n t e r i o r . The c a l f s u r v i v o r s h i p c u r v e i s based on t h e d a t a i n T a b l e s 16 and 19. The 1 c u r v e s f o r t h e a d u l t s a r e based on t h e ages o f c a r i b o u shot by h u n t e r s ( T a b l e s 2 and 3 ) .  34 Age  and  Annual M o r t a l i t y i n Percent  Sex  L e g a l Hunting  Poaching  Natural  Total  Does, y e a r l i n g s and 6-month c a l v e s A d u l t Stags  (2 yr.+)  0  3  4  7  11  3  9  22  3  3  5  11  Total Population  A t o t a l m o r t a l i t y of.11 p e r c e n t may be v a l i d a l s o f o r t h e y e a r s 1951 t o 1961.  I n t h a t i n t e r v a l h u n t e r o b s e r v a t i o n s o f c a r i b o u showed a d e c r e a s i n g  t r e n d when c a l f r e c r u i t m e n t f i g u r e s f e l l below 11 p e r c e n t f o r s e v e r a l cons e c u t i v e y e a r s ( F i g . 9 ) . There was an i n c r e a s i n g t r e n d i n t h e number o f c a r i b o u o b s e r v e d p e r h u n t e r when c a l f r e c r u i t m e n t exceeded 11 p e r cent as from 1959 t o 1961 ( F i g . 9 ) . The p o p u l a t i o n d i d i n c r e a s e i n t h e s e  years  (Table 5 ) .  N a t u r a l Cause o f DeathDeath from f i g h t i n g d u r i n g t h e r u t was t h e s i n g l e g r e a t e s t cause o f morta l i t y i n a d u l t s t a g s ( T a b l e 14).  Most o f t h e s e s t a g s were 4 t o 6 y e a r s o l d .  Stags were seen covered w i t h mud, b l e e d i n g , w i t h broken a n t l e r s , and c r i p p l e d legs.  S e v e r a l were found w i t h broken necks.  f i g h t had t o f r e e h i s a n t l e r s and jump c l e a r . backwards and sideways s n a p p i n g h i s neck.  A stag wishing t o quit a serious I f he f a i l e d he c o u l d be pushed  On t h e b a s i s o f t o t a l a n i m a l s  cen-  sused and t h e dead l o c a t e d , I e s t i m a t e a n n u a l r u t t i n g m o r t a l i t y a t 2 p e r cent i n 1957 and 1958. More females d i e d f r o m a b e r r a n t b i r t h s t h a n from any o t h e r cause ( T a b l e 14), One doe w i t h a b r e a c h e d b i r t h was s t i l l a b l e t o walk when I l e f t h e r i n t h e e v e n i n g , b u t was dead when l o c a t e d t h e next morning.  35  20  <  - i  1  U  o  hz  <  •  u ^ 10 H  ^-11 '/o  CE  <  VSS  '• — A  7  —m\"  4 -  I/>  cc UI  cc  3d Z UJ UI  l/>  0  r-  Z I  > CO  > < Q  CO  ct  z z i  n 51  i  1  1  1  1  52  53  54  55  56  r—i 57  58  i  r  59  60  r 61  YEARS F i g . 9.  C a r i b o u o b s e r v a t i o n s by h u n t e r s d e c l i n e d d u r i n g s u c c e s s i v e y e a r s when c a l f increment was l e s s than 11 p e r c e n t .  36 Heavy p a r a s i t e l o a d s c o u l d be f a t a l a l o n g w i t h s t a r v a t i o n .  Newfound-  l a n d c a r i b o u were h o s t t o r e l a t i v e l y few k i n d s o f p a r a s i t e s ( T a b l e 1 5 ) . There was no c o r r e l a t i o n between numbers o f w a r b l e s (Oedamagena t a r a n d i ) and age i n 38 does c o l l e c t e d i n J u n e ; however t h e number o f nose b o t s (Cepheriomyia  trompe) i n c r e a s e d w i t h age ( F i g . 1 0 ) . There was a weak c o r r e -  l a t i o n between t o t a l b o t s and w a r b l e s p e r i n d i v i d u a l doe, s u g g e s t i v e o f s l i g h t i n d i v i d u a l s u s c e p t i b i l i t y t o f l y a t t a c k ( F i g . 1 0 ) . The o n l y c a r i b o u death a t t r i b u t e d t o p a r a s i t e s i n 11 y e a r s was a s t a g t h a t was observed walki n g i n c i r c l e s ; autopsy showed t h a t nose b o t s had i n v a d e d t h e c r a n i a l c a v i t y . A d u l t c a r i b o u o b v i o u s l y i n c a p a c i t a t e d by d i s e a s e were n o t n o t e d i n t h e investigation.  A minimum o f 60,000 a d u l t animals were seen i n 11 y e a r s .  S i n c e t h e r e was n e v e r more t h a n 8000 a d u l t s on t h e i s l a n d a t one t i m e and t h e t o t a l 11-year r e c r u i t m e n t was about 14,000, many animals were seen several times.  A w i d e s p r e a d d i s e a s e c o u l d n o t have p a s s e d  Approximately  unnoticed.  3 i n 1000 c a r i b o u were o b v i o u s l y c r i p p l e d i n 11,239; maxi-  mum f i g u r e was 8 o f 884 lame i n May and June.  A close inspection of stragg-  l e r s i n a m i g r a t i n g A l a s k a n h e r d , s u b j e c t t o w o l f p r e d a t i o n , showed 1.8 p e r cent s i c k o r c r i p p l e d ( C r i s l e r 1956).  Skoog (1968) l i s t e d 22 o f 31,479  c r i p p l e d i n t h e N e l c h i n a Herd i n A l a s k a . t h i s herd was low i n most y e a r s  The w o l f d e n s i t y i n t h e range o f  (Rausch 1967).  l a t i o n between w o l f p r e d a t i o n and t h e f r e q u e n c y  There i s no o b v i o u s c o r r e o f c r i p p l e d animals.  I n many w i l d s p e c i e s , e s p e c i a l l y t h o s e s u b j e c t t o p r e d a t i o n as a d u l t s , few l i v e l o n g enough t o show s i g n s o f age.  But i n c a r i b o u ( a l s o many o t h e r  u n g u l a t e s ) t h e r e i s i n c r e a s e d m o r t a l i t y i n t h e o l d e r age c l a s s e s ( B a n f i e l d 1955)  i n d i c a t i n g a r e l a t i o n s h i p between s e n i l i t y and death.  i n t h i s study were l i s t e d as d y i n g from o l d age ( T a b l e 14). on June 23 c o u l d n o t s t a n d .  Three  animals  One.stag found  H i s t e e t h were worn t o t h e gums and he weighed  37r = 0.497 P<0O1  150-  n = 30 H  o  co  UJ O100z  u. O  DC  UJ CD  2  Y=. 2 5 . 6 3 + 6.44X  50 '  ZD  < i-  O  —T"  -r2  I  I  5  6  AGE 150  I 7  IN  —T  I  1  8  10  9  12  11  YEARS  -i  < z < Y= 3 9 . 6 0 + 0 . 3 3 x  oc  UJ Q-100'  1/5 h-  o  CO  u.  O  ce  50  -  UJ  CD 1 Z  V • ••  •  I  JUL  I  50 NUMBER  I  1  1  1  1  1  100 OF  WARBLES  1  r  1  1  150 PER  1  1  1  200  ANIMAL  F i g . 10. (above) The r e g r e s s i o n o f nose b'dts p e r doe i n June on age. (below) The r e g r e s s i o n o f nose b o t s p e r does on w a r b l e p a r a s i t e s p e r doe i n June.  38 o n l y 208 pounds a g a i n s t normal w e i g h t s o f over 300 pounds.  Many o l d e r animals  w i t h r e g r e s s e d a n t l e r s were n o t e d .  D i f f e r e n c e s i n Death Rates o f Males and Females  A d u l t males d i e d a t g r e a t e r r a t e s t h a n f e m a l e s .  The mean age o f s t a g s  c a p t u r e d d u r i n g t h e f a l l m i g r a t i o n was 3.0 y e a r s and does 4.7 y e a r s 10).  (Table  L e g a l h u n t i n g o f s t a g s o n l y s h o u l d n o t reduce t h e mean age o f males un-  l e s s h e a v i l y b i a s e d t o c e r t a i n age groups.  Even when t h e age c l a s s e s under-  r e p r e s e n t e d i n t h e k i l l were e x c l u d e d ( c a l v e s , y e a r l i n g s , and 2 - y e a r - o l d s t a g s , T a b l e 2)  t h e age o f females was g r e a t e r t h a n t h a t o f males ( T a b l e 1 0 ) .  B e t t e r e v i d e n c e o f a d i f f e r e n t i a l m o r t a l i t y by s e x was t h a t 21 dead s t a g s and o n l y 12 dead does were found d u r i n g t h e i n v e s t i g a t i o n .  The s e x r a t i o o f  l i v i n g a d u l t s v a r i e d from 32 t o 23 p e r c e n t s t a g s ( T a b l e 9 ) .  With e q u a l s u s -  c e p t i b i l i t y t o d e a t h , a minimum o f 40+ dead females might have been  expected.  A d d i t i o n a l e v i d e n c e o f g r e a t e r m o r t a l i t y o f males t h a n females was t h e d e c l i n e i n t h e p r o p o r t i o n o f males between r e c r u i t s a t 6-months-of-age and a d u l t s ( T a b l e s 16 and-9).  The s e x r a t i o o f c a l v e s 6- t o 12-months-of-age was  40±3 (95 p e r c e n t C L . ) p e r c e n t males.  The p e r c e n t a g e  o f a d u l t males i n 1957  and 1958 ( p r i o r t o r e s t r i c t i o n s l i m i t i n g h u n t i n g t o o n l y s t a g s ) was 32±2 ( T a b l e 9 ) . On t h e A v a l o n , where t h e r e was no l e g a l h u n t i n g p r i o r t o 1966, t h e p r o p o r t i o n o f males i n t h e c a l f increment was 47±10 p e r cent and i n t h e a d u l t s 40±4.  The s e x r a t i o o f c a l v e s a t 6-months-of-age i n t h e Humber R i v e r Herd was  53±15 p e r c e n t males and f o r a d u l t s 26±6 p e r c e n t .  Figures f o r  barren-ground  c a r i b o u i n t h e Northwest T e r r i t o r i e s , where b o t h sexes a r e h a r v e s t e d , showed t h a t males comprised  34 p e r c e n t o f t h e a d u l t s ( K e l s a l l 1968).  P r e d a t i o n by l y n x (Lynx c a n a d e n s i s ) might t a k e a h i g h e r p r o p o r t i o n o f s t a g s t h a n does.  Stags i n g e n e r a l a r e l e s s wary t h a n f e m a l e s .  Furthermore  39 more s t a g s than does f r e q u e n t t i m b e r e d r i v e r v a l l e y s i n the w i n t e r where l y n x p r o b a b l y t a k e a few a n i m a l s .  Four o f 23 l y n x s c a t s c o l l e c t e d i n such  c o n t a i n e d c a r i b o u h a i r and -3 o f 16 l y n x c o l l e c t e d i n l a t e w i n t e r had caribou.  eaten  An unknown p a r t o f t h i s consumption c o u l d be from c a r r i o n .  wounded s t a g i n a r i v e r v a l l e y i n March 1959. jumped on t h e c a r i b o u ' s back.  areas  I saw  a  I t appeared t h a t a l y n x had  A g a i n w i n t e r t r a c k s showed where two l y n x had  s t a l k e d a c a r i b o u l y i n g on t h e i c e a d j a c e n t t o a p o i n t o f t i m b e r . t r a c k s were f o l l o w e d t i l l a b a d l y wounded doe was  located.  (Lynx l y n x ) k i l l many r e i n d e e r i n the w i n t e r p r e d o m i n a t e l y s e l e c t i v e i n r e g a r d t o sex (Haglund 1966).  Caribou  Swedish l y n x young but a r e  not  Losses o f a d u l t s t o p r e d a t i o n even  i f b i a s e d towards m a l e s , were so minor ( T a b l e 1 4 ) , t h a t t h e y c o u l d not account for  t h e d i s p a r i t y i n numbers between s e x e s . In  summary, many f a c t o r s p r o b a b l y c o n t r i b u t e t o the g r e a t e r m o r t a l i t y o f  male than female.  However, the most i m p o r t a n t f a c t o r appears t o be a h i g h  m o r t a l i t y o f males d u r i n g the r u t .  Hunting M o r t a l i t y of A d u l t s The  l e g a l h a r v e s t from t h e I n t e r i o r Herd.averaged 184 a n i m a l s  56 t o 366) The  i n the p e r i o d 1956  season was  t o 1966  (Table 4 ) .  T h i s k i l l was  opened on the A v a l o n P e n i n s u l a i n 1966  42 y e a r s ; 27 a n i m a l s were s e c u r e d i n 1966  (extremes  l a r g e l y stags.  a f t e r being closed f o r  and 26 i n 1967.  There were open  seasons f o r t h e Humber and N o r t h e r n P e n i n s u l a herds d u r i n g t h i s  survey.  I l l e g a l h u n t i n g showed a g r a d u a l d e c l i n e d u r i n g t h e study as enforcement p r o c e d u r e s improved and the o l d e r g e n e r a t i o n gave up t r a d i t i o n a l h u n t s . became abundant about 1945  Moose  and s i g n i f i c a n t p o a c h i n g p r e s s u r e s w i t c h e d t o t h a t  species t h e r e a f t e r . The  i l l e g a l k i l l was  not c o n s t a n t between y e a r s and depended upon c a r i b o u  4-0 a c c e s s i b i l i t y ( d i s t a n c e from s a l t water and r o a d s ) , and w i n t e r t r a v e l l i n g cond i t i o n s f o r dog teams. annually.  I e s t i m a t e d t h a t between 150 t o 300 a n i m a l s were t a k e n  The La P o i l e p o p u l a t i o n s u s t a i n e d h e a v i e r l o s s e s t h a n t h e o t h e r s .  The maximum k i l l was a l l o c a t e d as f o l l o w s :  La P o i l e R i v e r  Buchans P l a t e a u p l u s Grey R i v e r P o p u l a t i o n s - - 5 0  Population—-150,  ( i n c l u d e s Sandy Lake  Popula-  t i o n ) , and t h e M i d d l e Ridge-Pot H i l l - - 1 0 0 . Q u i t e d e t a i l e d i n f o r m a t i o n was secured on p o a c h i n g l o s s e s f o r t h e A v a l o n P e n i n s u l a herd f o r t h e y e a r s 1955, 1956, and 1957. 25 a n i m a l s were t a k e n from t h e herd. 1959  I l l e g a l h u n t i n g had n e a r l y ceased by  because o f improved l a w enforcement. The N o r t h e r n  P e n i n s u l a Herd was p r i m a r i l y hunted by r e s i d e n t s l i v i n g  t h e west c o a s t o f t h e P e n i n s u l a . 1959  I n each year about 15 t o  when an e x t r e m e l y  along  The o n l y r e l i a b l e f i g u r e s were secured i n  l a r g e k i l l was made o f about 150 a n i m a l s .  A r o a d was  extended up t h e P e n i n s u l a a f t e r 1959 r e s u l t i n g i n more e f f e c t i v e l a w e n f o r c e ment and a r e d u c e d t a k e .  No k i l l comparable t o t h e i l l e g a l h a r v e s t i n 1959  o c c u r r e d 1960 t o 1966. The  Humber R i v e r Herd was poached by r e s i d e n t s o f Howley when t h e a n i m a l s  w i n t e r e d 4 m i l e s n o r t h o f t h e town ( F i g . 5 ) . Others were t a k e n a t B i g F a l l s during migration.  C a r i b o u were a l s o t a k e n i n t h e v i c i n i t y o f A d i e s Lake and  T a y l o r s Brook when t h e y were a c c e s s i b l e t o l o g g i n g  roads.  R o l e o f A d u l t M o r t a l i t y i n P o p u l a t i o n Growth The n a t u r a l m o r t a l i t y o f a d u l t s was a minor f a c t o r i n r e d u c i n g t h e growth o f t h e herds. 1957  The n a t u r a l m o r t a l i t y r a t e o f t h e A v a l o n Herd was 6 p e r c e n t ,  t o 1966, when t h e herd i n c r e a s e d by about 476 p e r c e n t .  Adults i n the  I n t e r i o r Herd had a s i m i l a r l o s s , 5 p e r c e n t , y e t t h i s herd i n c r e a s e d , 1957 t o 1967,  by o n l y 35 p e r c e n t .  Skoog (1968) r e p o r t e d t h a t a c a r i b o u herd i n A l a s k a  41 i n c r e a s e d a n n u a l l y a t 9 p e r cent w i t h a n a t u r a l m o r t a l i t y r a t e o f perhaps per c e n t and a h u n t i n g m o r t a l i t y o f 8 per c e n t .  6  A c a r i b o u herd i n Southern  Labrador had a c a l c u l a t e d n a t u r a l m o r t a l i t y r a t e o f o n l y 6 per c e n t (Bergerud 1967a).  The above m o r t a l i t y r a t e s a r e s i m i l a r and a r e i n l i n e w i t h what might  be expected f o r a s p e c i e s w i t h a convex s u r v i v o r s h i p c u r v e and a maximum e c o l o g i c a l l o n g e v i t y o f about 17 y e a r s . I l l e g a l h u n t i n g c o u l d not account f o r t h e slow growth o f t h e I n t e r i o r Herd s i n c e o n l y an e s t i m a t e d 3 p e r cent o f t h e herd was annually.  i l l e g a l l y harvested  A g a i n i l l e g a l h u n t i n g o f t h e A v a l o n Herd was m i n i m a l a f t e r  1958.  However, p o a c h i n g was heavy on t h e A v a l o n Herd 1956 t o 1958 and p r o b a b l y a c counted f o r t h e r e l a t i v e s t a b i l i t y i n numbers i n t h e herd d u r i n g t h i s p e r i o d . The p o p u l a t i o n i n 1956 was perhaps 125 a n i m a l s .  The approximate r e c r u i t m e n t  and known minimum p o a c h i n g l o s s was f a i r l y w e l l b a l a n c e d :  i n 1956 and  1957:  1 9 5 6 — 1 8 r e c r u i t s v s . a p o a c h i n g l o s s o f 15 and 1957, 22 v s . 17.  Poaching  ceased i n 1959 and t h e herd i m m e d i a t e l y began t o i n c r e a s e ( T a b l e -  5.)  The poaching o f a d u l t s i n t h e Humber and N o r t h e r n P e n i n s u l a herds d u r i n g t h i s s t u d y p r o b a b l y p r e v e n t e d t h e s e herds from i n c r e a s i n g ( F i g . 5 ) .  The mean  p e r c e n t a g e o f c a l v e s i n t h e Humber Herd i n 7 w i n t e r s was 15 per cent ( T a b l e 1 8 ) , c o n s i d e r a b l y above t h e 5-6 p e r cent a d u l t n a t u r a l m o r t a l i t y r a t e s determined f o r t h e I n t e r i o r and A v a l o n h e r d s .  The percentage o f c a l v e s on t h e N o r t h e r n  P e n i n s u l a i n October 1961, t h e o n l y y e a r c l a s s i f i e d , was 19 p e r c e n t . i l l e g a l h a r v e s t o f about 150 a n i m a l s from t h e P e n i n s u l a i n 1959 was  The  probably  s u f f i c i e n t a l o n e t o account f o r t h e l a c k o f p o p u l a t i o n change between t h e censuses i n 1958 and  1966.  The a n n u a l l e g a l h a r v e s t o f 11 p e r c e n t o f t h e s t a g s i n t h e i n t e r i o r act u a l l y improved t h e r a t e o f i n c r e a s e o f t h e h e r d .  The c a l c u l a t i o n s a r e as  f o l l o w s ( K e l k e r 1947  r = 1 + (does / a d u l t s ) y,  and Buechner 1960):  antilogy  42 where y = number o f young p e r female ( i n c l u d i n g y e a r l i n g s and 2 - y e a r - o l d does).  I f we assume t h a t a l l c a l v e s l i v e and c o n t r i b u t e t o t h e nonbreeding  y e a r l i n g s and 2 - y e a r - o l d female c o h o r t s , t h e n y would p r o b a b l y . b e near 0.50. The a d u l t sex r a t i o  i n 1957 was p r o b a b l y . 4 7 males p e r 1 0 0 does (based on t h e  r e g r e s s i o n Y = 83.90 - 0.910X, T a b l e 9) and was a l t e r e d by t h e h a r v e s t o f s t a g s 1958 t o 1966 t o 31:1-00.  These s t a t i s t i c s p r o v i d e r =0.292 i n 1957 and r =  0.322 i n 1966, o r an i n c r e a s e i n t h e r a t e o f i n c r e a s e o f 4 p e r c e n t .  43  DEATH OF CALVES IN WINTER  A number o f s t u d i e s o f o t h e r c e r v i d s show t h a t t h e young may snows a r e deep.  Caribou  s t a r v e when  i n Newfoundland must a l s o contend w i t h g r e a t snow-  f a l l s (see F i g . 6) and f r e q u e n t i c e c r u s t s .  The w i n t e r s o f 1958-59 and  61 were two o f t h e s e v e r e s t w i n t e r s ever r e c o r d e d  i n Newfoundland and  1960-  provided  an o p p o r t u n i t y t o a s s e s s the impact o f maximum snow depths and i c e c r u s t s on the s u r v i v a l of c a l v e s .  D u r i n g t h e w i n t e r o f 1958-59 t h e I n t e r i o r Herd  o b s e r v e d from 3 t o 22 March. difficulty.  was  The a n i m a l s were g e t t i n g f o r a g e w i t h extreme  I found two dead c a l v e s and n o t e d f o u r weak ones ( F i g . 1 1 ) .  T h i r t y - s i x o t h e r s appeared e q u a l t o a d u l t s i n p h y s i c a l c o n d i t i o n and v i g o r . I n 1961  W i l d l i f e O f f i c e r Stephen H a l l v i s i t e d the w i n t e r range from March .22  t o A p r i l 13.  The c a r i b o u were emaciated and spent l o n g hours f e e d i n g and  stand-  ing... However, none o f t h e 69 c a l v e s he observed appeared weak and none were found dead. I n d i r e c t e v i d e n c e i n d i c a t e d t h a t i n most w i n t e r s few c a l v e s d i e d .  For  example, t h e ages o f 85 c a l v e s found dead from n a t u r a l causes showed t h a t o n l y 6 <(7 per c e n t ) had d i e d o v e r w i n t e r  (Table 19).  F u r t h e r , m o r t a l i t y i n the f i r s t  y e a r o f l i f e , based on t h e ages o f 132 dead c a r i b o u was however, a n o t h e r m o r t a l i t y i n d e x , October c o m p o s i t i o n  68 per cent (Table  c o u n t s , suggested t h a t  69 per c e n t o f t h e c a l v e s were a l r e a d y dead by o n l y 6-months-of-age ( T a b l e The  s i m i l a r i t y o f t h e s e two  19),  estimates i s c o n s i s t e n t w i t h the view of  20).  little  winter loss. Another approach was Herd i n f a l l and  spring.  t o compare t h e p e r c e n t a g e o f c a l v e s i n t h e  Interior  S e v e r a l o f t h e s p r i n g c o u n t s were made a f t e r  s o u t h s l o p e s were f r e e o f snow and t h e worst o f w i n t e r had passed. p a r i s o n o f t h e p e r c e n t a g e o f c a l v e s i n t h e herd i n October and  the  T h i s com-  i n March-April  44  F i g . 11.  A weak c a l f observed i n March 1959.  45 f a i l e d t o demonstrate t h a t c a l v e s were d y i n g a t a r a t e d i f f e r e n t t h a n a d u l t s :  Winter  C a l v e s a s P e r c e n t a g e o f Herd ± .95 C L .  Season  October  1956-57  4.4±2.9  7.612.5  1957-58  5.511.0  ' 5.312.3  1958-59  15.Oil.5  14.413.1  1959-60  19.013,1  27.416.7  1960-61  15,113.4  18. -614.0  1962-63  9.412.7  8.812.0  1963-64  8.411.3  .9.-411.6  10.810.7  11. O i l . 0  T h i s comparison i s p r o b a b l y  March-April  l e a s t v a l i d f o r t h e w i n t e r o f 1958-59 c o h o r t  t h a t s p r i n g count was made m o s t l y i n t h e f i r s t two weeks o f March. c o u l d have r e s u l t e d i n l a t e March and A p r i l .  since  Mortality  A l l t h e o t h e r comparisons l i s t e d  above were based on s a m p l i n g done i n t h e l a s t o f March o r i n e a r l y A p r i l . As a n o t h e r e v a l u a t i o n o f w i n t e r l o s s I p l o t t e d y e a r l i n g p e r 100 doe s t a tistics  secured  i n June ( T a b l e 21) a g a i n s t t h e p e r c e n t a g e o f c a l v e s i n t h e  herd t h e p r e v i o u s autumn ( F i g . 1 2 ) .  The y e a r l i n g - c a l f r e g r e s s i o n was h i g h l y  s i g n i f i c a n t ( F i g . -12) and suggested t h a t a n n u a l v a r i a t i o n s i n s u r v i v a l o c c u r r e d p r i o r t o w i n t e r o r t h a t t h e magnitude o f w i n t e r m o r t a l i t y v a r i e d d i r e c t l y w i t h summer l o s s . did  The r e g r e s s i o n showed t h a t t h e v a l u e f o r t h e w i n t e r o f 1958-59  d e p a r t f u r t h e r from t h e r e g r e s s i o n l i n e t h a n any o f t h e . o t h e r  i n t h e comparison.  This departure  9 winters  i s c o n s i s t e n t w i t h my f i e l d o b s e r v a t i o n s o f  a few dead and weak c a l v e s i n e a r l y March 1959.  46  50 H  BY C A L V I N G  GROUNDS  r = 0.727 cr  u  P< 0 . 0 0 1  40-  CQ  n = 24  o  O 30 •  H  O O  z  20-  5 O  _i _j  o  Y= - 0 - 8 2 + 1 ^ 8 x 10 -  Ll UJ  I  1-  10  LU  o Q  30-1  BY  YEARS  O O  r =0.867  cr  P<0.01  LU  °-  20-  59-60  n = 10  60-61  o _J CE < UJ  10-  63-64  >-  '64-65 '62-63  57-58  PER CENT A POT  HILL  • BUCHANS O GREY  F i g . 12.  CALVES  PLATEAU  RIVER  I— 20  i  10 IN  15 HERD  IN  OCTOBER  O MIDDLE  RIDGE  • SANDY  LAKE  * LA  —r 25  POILE  RIVER  The r e g r e s s i o n o f r e c r u i t m e n t o f y e a r l i n g (12-month-old) on r e c r u i t m e n t o f c a l v e s (6-months-old). The r e g r e s s i o n l i n e by y e a r s e x c l u d e d 1964-65 and 1958-59. June samples 1965 d i d not i n c l u d e c a r i b o u from t h e western c a l v i n g grounds. W i n t e r m o r t a l i t y i s b e l i e v e d t o have o c c u r r e d i n 1958-59.  • 47 A f i n a l i n d e x i n v o l v e d comparing t h e p e r c e n t a g e o f c a l v e s i n t h e  Interior  Herd a t 6-months-of-age and t h e p e r c e n t a g e o f the same c o h o r t a t 24-months-ofage  ( c o r r e c t e d f o r new  recruitment).  This t e s t should detect  differential  m o r t a l i t y o f a c o h o r t r e l a t i v e t o a d u l t s any t i m e between 6 and age.  The  assumption was  24-months-of-  t h a t any d i f f e r e n c e s n o t e d would a p p l y t o t h e  during the f i r s t winter of l i f e .  survival  T h i s comparison f a i l e d t o demonstrate d i f f e r -  e n t i a l m o r t a l i t y o f young v s . a d u l t s i n e i g h t w i n t e r s ( T a b l e 22).  But  again  i t appeared a g r e a t e r p r o p o r t i o n o f c a l v e s t h a n a d u l t s d i e d i n the w i n t e r 1958-59 ( T a b l e  or  22).  B o t h t h e i n d i c e s t h a t suggested an i n c r e a s e l o s s o f c a l v e s i n t h e  winter  o f 1958-59 a r e not independent and presume t h a t t h e c a l f count i n O c t o b e r November 1958  d i d not o v e r e s t i m a t e  p e r c e n t a g e o f c a l v e s i n f a l l 1958 c u r e d i n 12 y e a r s (n=2253) and (Table  the percentage o f c a l v e s i n the herd. was  The  based on t h e l a r g e s t autumn sample se-  i n c l u d e d a n i m a l s from a l l the  populations  12).  I n b r i e f , t h e e v i d e n c e s u g g e s t s t h a t more c a l v e s d i e d t h a n a d u l t s i n t h e w i n t e r o f 1958-59, but t h a t c a l v e s s u r v i v e d e q u a l l y as w e l l as a d u l t s i n -9 other winters.  I n t h i s paper r e c r u i t m e n t  month-old a n i m a l s i n t h e . t o t a l p o p u l a t i o n .  i s based on t h e p e r c e n t a g e o f  6-  48 EARLY MORTALITY OF CALVES S i n c e t h e b i r t h r a t e was h i g h and t h e m o r t a l i t y o f a d u l t s and 6-montho l d c a l v e s was l o w , we a r e l e f t w i t h t h e m o r t a l i t y o f c a l v e s i n t h e i r summer o f l i f e as t h e main cause f o r t h e s l o w growth o f t h e herds.  first  Detailed  i n v e s t i g a t i o n s o f t h e c a r i b o u herds i n A l a s k a and Northwest T e r r i t o r i e s • s h o w e d t h a t many c a l v e s d i e d d u r i n g t h e f i r s t summer (Skoog 1968 and K e l s a l l 1968). To i n v e s t i g a t e t h e e a r l y m o r t a l i t y o f c a l v e s t h e y were observed and c l a s s i f i e d i n each s p r i n g 1957 t o 1967.  I n t h i s s e c t i o n on c a l f m o r t a l i t y I d i s c u s s t h e  t i m e and amount o f c a l f l o s s e s and t h e n c o n s i d e r t h r e e p o s s i b l e causes o f m o r t a l i t y , d i s e a s e , p r e d a t i o n , and adverse weather.  Time and Amount  I n t h e y e a r s 1957 t o 1967 l a r g e numbers o f new born c a l v e s o f t h e I n t e r i o r Herd were dead by t h e m i d d l e o f June ( T a b l e 2 3 ) . The m o r t a l i t y v a r i e d from 6 per.cent  a t t h e M i d d l e Ridge c a l v i n g ground i n 1959 t o 65 p e r cent a t t h e  Pot H i l l c a l v i n g ground i n 1964 ( T a b l e 2 3 ) . M o r t a l i t y was s u f f i c i e n t i n a l l y e a r s , except 1959, t o r e d u c e t h e number o f c a l v e s f a r below t h a t expected on t h e b a s i s o f counts o f parous does. C a l f m o r t a l i t y i n t h e i n t e r i o r c o n t i n u e d h i g h i n J u l y and August but declined  by September-October ( F i g . 13 and T a b l e 2 4 ) . The 1 0 - y e a r (1958-67)  mean m o r t a l i t y o f i n t e r i o r c a l v e s between b i r t h and 6-months was 69 p e r cent ( T a b l e 2 0 ) . The extreme v a l u e s were 35 p e r cent i n 1967 and 85 p e r cent i n 1963.  C a l v e s b o r n on t h e two w e s t e r n c a l v i n g g r o u n d s , t h e L a P o i l e R i v e r and  Buchans Plateau-, g e n e r a l l y had b e t t e r s u r v i v a l r a t e s t h a n t h o s e r e a r e d i n c e n t r a l and e a s t e r n Newfoundland ( T a b l e 1 2 ) . The number o f c a l v e s i n f a l l was c o r r e l a t e d w i t h c a l f m o r t a l i t y by June  49  012345678 AGE  IN  9101112  MONTHS  F i g . 13. C a l f s u r v i v a l t o l l - m o n t h s - o f - a g e i n t h r e e c o h o r t s i n t h e I n t e r i o r Herd. The two low counts i n 1957 were from t h e Grey R i v e r and Sandy Lake p o p u l a t i o n s t h a t l o s t a g r e a t e r number o f c a l v e s than p o p u l a t i o n s a t Buchans P l a t e a u and M i d d l e Ridge.  50 ( F i g . 14).  These c o r r e l a t i o n s might have been more p r e c i s e i f the d e t e r m i n a -  t i o n o f e a r l y m o r t a l i t y c o u l d have been made on the same d a t e s on each c a l v i n g ground (see METHODS).  However c a l f m o r t a l i t y had t o be measured i m m e d i a t e l y  p o s t - c a l v i n g b e f o r e the udders o f parous does i n v o l u t e d (Bergerud 1964a).  The  c o r r e l a t i o n o f numbers i n f a l l w i t h m o r t a l i t y by "mid-June s u g g e s t s t h a t v a r i a t i o n s i n a n n u a l m o r t a l i t y o f c a l v e s were e s t a b l i s h e d i n J u n e , and t h a t heavy c o n t i n u e d  the  l o s s e s i n J u l y and August ( F i g . 13) v a r i e d d i r e c t l y w i t h deaths  i n June. I t appeared t h a t more male c a l v e s d i e d i n t h e s p r i n g t h a n f e m a l e s . 1-4  weeks-of-age t h e male:female r a t i o was  was  the r e v e r s e , 52:48 (Table 16).  48:52, whereas t h e r a t i o a t  By October t h e sex r a t i o was  unbalanced f a v o r i n g females (Table 16).  At birth  significantly  C l e a r l y , male c a l v e s d i e d a t  higher  r a t e s t h a n female d u r i n g the p e r i o d o f h i g h e a r l y m o r t a l i t y . Annual s u r v i v a l o f c a l v e s t o 6-months-of-age i n the i n t e r i o r showed from 1951  t o 1967  ( F i g . 15 and T a b l e s .12 and  from 1951  t o 1956  (5 y e a r s ) , i n c r e a s e d 1957  t o 1963  (3 y e a r s ) , and  (5 y e a r s ) .  25).  trends  S u r v i v a l d e c r e a s e d each y e a r  t o 1959  (3 y e a r s ) , d e c l i n e d  showed improvement w i t h each a n n u a l c o h o r t 1963  1961 to  1967  T h i s s e r i e s o f r u n s i s a s i g n i f i c a n t d e p a r t u r e from random ( S i e g e l  1956). On t h e A v a l o n P e n i n s u l a more c a l v e s s u r v i v e d t h a n i n . t h e i n t e r i o r . 10-year mean m o r t a l i t y t o 6 months-of-age was o f 2 per c e n t i n 1959  and  73 i n 1965  30 p e r cent w i t h extreme  (Table 17).  The values  A l s o , s u r v i v a l on the A v a l o n  showed some s y n c h r o n i z a t i o n w i t h t h e p a t t e r n d e s c r i b e d f o r t h e I n t e r i o r Herd ( F i g s . 15 and  16).  Both herds r e a c h e d a peak i n s u r v i v a l i n 1959  Humber R i v e r Herd) f o l l o w e d by s e v e r a l y e a r s o f d e c l i n e ( F i g . 1 6 ) .  (as d i d  the  These d a t a  suggest a common cause o f m o r t a l i t y i n b o t h herds but a d i f f e r e n c e i n degree  51  O1  1  0  - i  10 CALF APOT  20  1  1  1  1  30  40  50  60  MEAN  DATE  MORTALITY  AS OF  HILL  • BUCHANS  • PLATEAU ALA  ROIL E  OMIDDLE • GREY  1  r  70  80  J U N E 16 RIDGE RIVER  RIVER  F i g . 14. The s u r v i v a l o f c a l v e s u n t i l October i n r e l a t i o n t o m o r t a l i t y i n June.  52  FOLLOWING LYNX REMOVAL  58  59  60  61  NTERIOR HERD  62  63  64  65  66  67  • AVALON PEN. HERD  F i g . 15. C a l f s u r v i v a l i n t h e I n t e r i o r and A v a l o n P e n i n s u l a herds u n t i l 6-months-of-age.  53  5 0  cn  40  Q  cr  LU IE Z  cr  LU  3  H U M B E R RIVER HERD AVALON PENINSULA HERD  0 -  I— 2  0  Ps  / / /  -  LU  3  < o  V  cr  o . 1 0  H  A  A A/ / /•  -\\  \b/ ^ A'  LU O i  0  X / D  cont  ROL  D  N TERIOR HERD  cr  LU Q_ 56  57  58  5&  60  61  62  63  64  65  66  67  YEARS CLASSIFIED F i g . 16. The p e r c e n t a g e o f c a l v e s i n f a l l i n t h e I n t e r i o r , A v a l o n , and Humber R i v e r h e r d s , 1956 t o 1967.  54 on t h e A v a l o n .  Weather M o r t a l i t y o f C a l v e s  I n barren-ground c a r i b o u , c a l f s u r v i v a l v a r i e d between y e a r s i n t h e N o r t h west T e r r i t o r i e s ( K e l s a l l 1960  and 1 9 6 8 ) .  M o r t a l i t y from a d v e r s e c h i l l i n g o f  n e o n a t a l young was c i t e d a t a major d e c i m a t i n g f a c t o r .  In t h i s study, c a l f  s u r v i v a l t o t h e f a l l showed t h r e e p r o g r e s s i v e t r e n d s over 3 t o 5 y e a r s ( T a b l e 25).  I f c a l f s u r v i v a l was p r i m a r i l y a f u n c t i o n o f weather I would expect e a r l y  m o r t a l i t y t o v a r y w i t h weather and more o r l e s s a t random.  As n o t e d , t h e s e  were r u n s i n t h e m o r t a l i t y r a t e o f c a l v e s and t h e s e were not a t random.  This  does not suggest e a r l y m o r t a l i t y was caused by f a c t o r s v a r y i n g a t random such as  weather. The Buchans P l a t e a u c a l v i n g ground had t h e c o l d e s t s p r i n g . w e a t h e r o f any  y e t . s u r v i v a l was h i g h e r here t h a n e l s e w h e r e , except a t La P o i l e R i v e r ( T a b l e 12).  I n 1958  on t h e P l a t e a u . i t r a i n e d h e a v i l y a l l day and n i g h t on t h e peak  day o f c a l v i n g .  Winds were 4 0 mph.  No dead c a l v e s were found.  The maximum  d a i l y w i n d c h i l l f i g u r e s , t a b u l a t e d from w e a t h e r . s t a t i s t i c s a t Buchans a i r p o r t , were l e s s t h a n t h o s e l i s t e d by K e l s a l l (1960) and H a r t e t . a l . ' (1961) as c a u s ing m o r t a l i t y i n the T e r r i t o r i e s .  F u r t h e r , Newfoundland c a l v e s were h e a v i e r  a t b i r t h t h a n barren-ground a n i m a l s and might t h e r e f o r e w i t h s t a n d g r e a t e r exposure t o i n c l e m e n t weather. D u r i n g t h e 11 y e a r s t h a t f i e l d p a r t i e s were w i t h t h e c a r i b o u i n J u n e , o n l y two c a l v e s were found w i t h congested l u n g s . pneumonia i n d e p e n d e n t l y o f weather.  These young c o u l d have developed  Thus t h e r e was no e v i d e n c e t h a t c a l v e s  d i e d from exposure o v e r t h e p e r i o d 1957 t o  1967.  The d e p t h and hardness o f snow c o v e r c o u l d m o d i f y t h e abundance o f f o r a g e i n f l u e n c e t h r o u g h t h e doe t h e i n t r i n s i c v i a b i l i t y o f c a l v e s a t b i r t h ( c f .  .55 D o b r o t v o r s k y e t a l . 1938).  I n t h i s s t u d y t h e r e were s i g n i f i c a n t d i f f e r e n c e s  between y e a r s i n t h e mean weight o f c a l v e s a t b i r t h ( F i g . 1 7 ) . However, t h e s e a n n u a l d i f f e r e n c e s were o n l y weakly c o r r e l a t e d w i t h w i n t e r s n o w f a l l (r= 0.673).  R e g a r d l e s s o f t h e i r cause t h e s e a n n u a l v a r i a t i o n s do i n d i c a t e d i f f e r -  ences between y e a r s i n p h e n o t y p i c v i a b i l i t y a t b i r t h . However t h e r e was no s i g n i f i c a n t c o r r e l a t i o n between n e o n a t a l w e i g h t s o f c a l v e s from d i f f e r e n t c a l v i n g grounds and m o r t a l i t y by June (r= 0.120, n = 8 ) . Nor were t h e mean a n n u a l b i r t h w e i g h t s i n 8 y e a r s c o r r e l a t e d w i t h t h e e x t e n t o f e a r l y c a l f m o r t a l i t y ; i n 1961 c a l v e s a t b i r t h averaged o n l y 14.9 pounds, 2 pounds below t h e weight o f young i n 7 o t h e r seasons ( F i g . 1 7 ) . But 'the s u r v i v a l o f t h e s e c a l v e s exceeded t h a t o f t h e 1957, 1962, and 1963 ( T a b l e s 1 2 and 2 0 ) .  I conclude t h a t t h e a v a i l a b i l i t y o f winter forage d i d not i n f l u e n c e  calf survival i n spring.  I t may have i n f l u e n c e d weight o f c a l v e s a t b i r t h .  D i s e a s e and P r e d a t i o n  Each y e a r dead and moribund  n e o n a t a l c a l v e s were found w i t h c e r v i c a l ab-  s c e s s e s ( F i g . 1 8 ) . The d a t e s when t h e f i r s t d i s e a s e d c a l v e s were f o u n d , 195764 were:  June 1, May 3 1 , June 4,4,6,10,1, and May 29. A h e a l t h y newborn c a l f  was tagged on May 31 and r e c o v e r e d dead w i t h a b s c e s s e s on June 4. The a b s c e s s e d c a l v e s d i e d from s e p t i c e m i a r e s u l t i n g from t h e p a t h o g e n i c organism P a s t e u r e l l a m u l t o c i d a mucoid t y p e A.  P a s t e u r e l l a i d e n t i f i c a t i o n was  p r o v i d e d by t h r e e d i f f e r e n t Canadian l a b o r a t o r i e s . . A t o t a l of-84 abscessed c a l v e s were found on c a l v i n g grounds i n 11 y e a r s ( T a b l e 2 6 ) .  R e j e c t e d Hypotheses  of Pasteurella Etiology  S e v e r a l w o r k i n g hypotheses o f t h e e t i o l o g y o f t h e P a s t e u r e l l a i n f e c t i o n s were t e s t e d and r e j e c t e d .  T h i s n e g a t i v e i n f o r m a t i o n i s b r i e f l y mentioned  since  56  F i g . 17.  1958  1959  1960  1961  1962  1963  1964  1966  (7)  (30)  (82)  (51)  (52)  (54)  (44)  (12)  The mean w e i g h t o f c a l v e s (+ 1 S.E.) s i z e s g i v e n below y e a r s .  at b i r t h .  Sample  F i g . 18.  C a l v e s b i t t e n by l y n x t h a t developed  abscesses.  58 some o f t h e t h e o r i e s are s t i l l c u r r e n t i n Newfoundland and may  occur to.the  reader. The  t h e o r y t h a t t h e i n f e c t i o n was  c o n g e n i t a l was r e j e c t e d s i n c e none o f  117 newborn c a l v e s s u c c e s s f u l l y h e l d i n c a p t i v i t y f o r a minimum o f 3 weeks developed t h e i n f e c t i o n . on B r u n e t t e  A g a i n , t h e d i s e a s e was  not found i n 59 c a l v e s b o r n  I s l a n d from p a r e n t s t o c k i n t r o d u c e d from r a n g e s where abscessed  c a l v e s were f r e q u e n t . The was  t h e o r y t h a t t h e i n f e c t i o n was  rejected.  caused by nose b o t s o r by a r t h r o p o d s  None o f the b o t s h e l d i n c o n t a i n e r s s t r a p p e d  calves penetrated  the f l e s h of the animals.  t o t h e necks o f  None o f t h e s i x c a l v e s h e l d on a  wooden p l a t f o r m on t h e Pot H i l l c a l v i n g ground ( F i g . 1 9 ) , f r e e o f c r a w l i n g i n s e c t s or s p i d e r s , d e v e l o p e d the i n f e c t i o n i n the adjacent  ground e x c l o s u r e .  But  nor d i d t h e seven c a l v e s housed  65 per c e n t o f t h e f r e e - r a n g i n g  i n t h e herd f r e q u e n t i n g t h e bog where t h e p l a t f o r m was  calves  constructed died  by  June 19 ( T a b l e 23) and many a b s c e s s e d c a l v e s were found. E x p e r i m e n t s w i t h Lynx t o I s o l a t e P a s t e u r e l l a  Dr. John M. K i n g ( p a t h o l o g i s t ) and Dr. Las K a r s t a d came t o Newfoundland i n June 196^  (epidemiologist)  t o study t h e e t i o l o g y o f t h e c e r v i c a l  s c e s s e s o f the P a s t e u r e l l a syndrome.  They c o n c l u d e d a f t e r a u t o p s y i n g  ab-  a  number o f c a l v e s t h a t t h e i n f e c t i o n r e s u l t e d from trauma. Subsequent t o t h i s h y p o t h e s i s , a dead c a l f was but no a b s c e s s e s . present  The  on t h e neck.  l o c a t e d w i t h neck l e s i o n s  c a l f had d i e d from a broken neck. The  Four l e s i o n s were  s p a c i n g o f t h e f o u r h o l e s and t h e deep p e n e t r a t i o n  suggested t h e b i t e o f a l y n x .  The  jaws o f a l y n x s k u l l were p l a c e d o v e r the  neck and t h e c a n i n e t e e t h matched t h e f o u r l e s i o n s ( F i g . 20).  I n many c a l v e s  examined p r e v i o u s l y , t h e l o c a t i o n o f t h e l e s i o n s had been d i s t o r t e d by p o c k e t s  59  F i g . 19.  The P o t H i l l C a l v i n g Ground.  60  Fig.  20.  The canine t e e t h o f a s k u l l o f a l y n x i n s e r t e d i n t o f o u r l e s i o n s on the neck o f a c a l f .  61 o f pus.  L a t e r , a more c a r e f u l e x a m i n a t i o n o f o t h e r c a l v e s r e v e a l e d a c a l f  w i t h a l o n g s c r a t c h on t h e h i n d q u a r t e r , a c a l f w i t h a s c r a t c h on t h e r i b - c a s e , and a neonate w i t h a t o r n e a r . Next t h e s a l i v a was secured showed P a s t e u r e l l a m u l t o c i d a  from t h r e e w i l d l y n x .  t y p e A.".  N e x t , t h r e e c a l v e s were p r e s e n t e d pen.  C u l t u r e o f the. s a l i v a  i n d i v i d u a l l y t o a l y n x i n a 9x5 f o o t  The l y n x s t a l k e d . t h e c a l v e s w i t h a slow p u r s u i t i n w h i c h i t remained t o  t h e s i d e and r e a r o f t h e c a l v e s .  The s t a l k s l a s t e d 15, 25, and 55 m i n u t e s .  When t h e l y n x sprang i t spread i t s f o r e f e e t and s t r u c k t h e c a l v e s i n t h e shoulder.region,.knocking  them o f f b a l a n c e .  I n two i n s t a n c e s t h e l y n x grasped  t h e c a l f by t h e neck; once t h e l y n x and c a l f jumped s i m u l t a n e o u s l y , l y n x m i s s e d and b i t t h e c a l f on t h e s h o u l d e r . seconds a f t e r b e i n g b i t t e n . tilt  and t h e  A l l c a l v e s g o t up w i t h i n 30  One c a l f d e v e l o p e d neck p a r a l y s i s and c o u l d n o t  i t s head upward; i t would have been u n a b l e t o n u r s e i n t h e w i l d . A l l  developed a b s c e s s e s near t h e wounds from which P a s t e u r e l l a m u l t o c i d a t y p e A was c u l t u r e d . The  c a l v e s d i e d as f o l l o w s : Sex  Age When B i t t e n  Male  17 days  Male  12 days  Female  14 days  Autopsies w i l d animals.  Days S u r v i v e d A f t e r A t t a c k 15  • 4%  o f t h e c a l v e s showed b i t e l e s i o n s t h a t resembled t h o s e seen on The e v i d e n c e was c o n c l u s i v e ; t h e a b s c e s s syndrome was caused by  b i t e s o f l y n x i n w h i c h t h e c a l f escaped t h e p r e d a t o r .  62 P r e d a t i o n o f Lynx on C a l v e s C e r v i c a l l e s i o n s o c c u r r e d on a l l t h e 84 a b s c e s s e d c a l v e s t h a t were located.  W i l d l i f e o f f i c e r s r e p o r t e d t h a t when l y n x k i l l domestic lambs  t h e y b i t e them on t h e neck.  This k i n d o f attack:; i s c h a r a c t e r i s t i c o f l y n x  p r e d a t i o n on c e r v i d s i n Sweden.(Boag 1956 and Haglund 1966). i s a common t e c h n i q u e  The neck g r a s p  o f s e v e r a l o t h e r members o f t h e F e l i d a e ( G r i n n e l l e t  a l . 1937, Marston 1942,  Young 1958, R o s e n b l a t t  and S c h n e i r l a 1962, Van Wormer  1964,. P e r r y 1964, and S c h a l l e r 1967). Some o f t h e c a l v e s t h a t developed a b s c e s s e s may have escaped from t h e l y n x t h r o u g h t h e d e f e n s i v e t a c t i c s o f t h e doe. charged by a doe t h a t had a young c a l f .  On two o c c a s i o n s ,  One o f t h e does sprang and l a n d e d ,  a l l f o u r f e e t , on t h e p r e c i s e spot where I had been. c h a s i n g a s e t t e r dog and a f o x .  Other does were seen  One f e m a l e ' r a n s t r a i g h t a t a bear and s h i e d  t o one s i d e a t 1 0 f e e t t o r e t r i e v e h e r c a l f . w i l d l i f e o f f i c e r s captured  t h e i r young.  Does were q u i t e f e a r l e s s when  Two dams approached so t h a t t h e y  c o u l d be touched and most f e m a l e s came w i t h i n 25-50 f e e t . r e p l e t e w i t h r e f e r e n c e s t o female u n g u l a t e s d e f e n d i n g predators  ( D a r l i n g 1937, E i n a r s e n 1948, M u i r e 1951,  Tomich 1953, P e t e r s o n The  I was  The l i t e r a t u r e i s  t h e i r young a g a i n s t  Roe 1 9 5 1 ,  L i n s d a l e and  1955, and Cowan 1956).  c a l v e s known t o have d i e d from P a s t e u r e l l a i n f e c t i o n accounted f o r  o n l y a minor p o r t i o n o f t h o s e t h a t d i e d i n June. H i l l c a l v i n g ground i n 1958, a p p r o x i m a t e l y  F o r example, a t t h e P o t  478 c a l v e s were b o r n ; 75 does had  l o s t t h e i r young by June 11-17, b u t o n l y 10 a b s c e s s e d c a l v e s were l o c a t e d . A g a i n , a t P o t H i l l i n 1964, about 256 does gave b i r t h ; 14 i n f e c t e d c a l v e s were found and 12 were removed from t h e i r dams f o r r e a r i n g . m i d d l e o f June 140 c a l v e s were m i s s i n g .  Y e t by t h e  63 A s e a r c h f o r t h e m i s s i n g c a l v e s was made i n June 1958 and 1964 by d a i l y h e l i c o p t e r f l i g h t s over t h e M i d d l e Ridge and P o t H i l l c a l v i n g grounds ( F i g . 19).  The s e a r c h was made a t l o w a l t i t u d e s and reduced speeds.  grounds c o u l d be e f f e c t i v e l y t r a v e r s e d i n 1-hour's f l y i n g t i m e .  Both c a l v i n g For instance,  t h e a r e a where p o s t p a r t u r i e n t does aggregated a t P o t H i l l measured 8x10 square miles.  F r e q u e n t l y a l l t h e major d o e - c a l f g r o u p s were t o g e t h e r  m i l e s e c t i o n o f l a r g e sedge bogs.  S e a r c h was c o n c e n t r a t e d  i n a 4-square  i n the v i c i n i t y of  does t h a t f a i l e d t o show normal f l i g h t b e h a v i o u r when buzzed by t h e h e l i c o p t e r . Many o f t h e s e does r a n i n c i r c l e s , g r u n t i n g and n e a r l y always we l o c a t e d a dead or s i c k c a l f n e a r them.  These f a i t h f u l , c o n s p i c u o u s does h e l p e d us t o l o c a t e  n e a r l y a l l t h e dead c a l v e s t h a t were v i s i b l e . Where were t h e m i s s i n g c a l v e s ?  The ground was s u f f i c i e n t l y f i r m t h a t c a l f  remains c o u l d n o t have sunk o u t - o f - s i g h t . many c a l v e s wandered i n t o s u r r o u n d i n g  A l s o t h e r e was no p o s s i b i l i t y t h a t  timber.  C a l v e s always accompanied t h e i r  dams i n t r a v e l l i n g and t h e does d i d n o t use f o r e s t c o v e r u n t i l l a t e i n June. At t i m e s c a l v e s l e f t t h e i r dams on s h o r t s p u r t s o f e x p l o r a t o r y a c t i v i t y o r r u n n i n g d a s h e s , b u t t h e y s t a y e d m o s t l y i n t h e open.  The m i s s i n g c a l v e s were  a p p a r e n t l y dragged from t h e open h a b i t a t s i n t o t h e t a n g l e d , s t u n t e d on bog p e r i p h e r i e s t h a t was i m p o s s i b l e t o s e a r c h .  vegetation  I n the course o f the study,  f o u r b a d l y decayed c a l v e s were stumbled upon i n f o r e s t c o v e r a t P o t H i l l . B e a r s c o u l d d r a g c a l v e s i n t o t h e dense c o v e r .  A few b e a r s were observed  l u m b e r i n g a f t e r c a l v e s each J u n e , y e t no s u c c e s s f u l chase was seen. a b l y a few young c a l v e s were c a p t u r e d .  Presum-  Bears appeared on t h e grounds a f t e r  some c a l v e s had d i e d from t h e p a s t e u r e l l o s i s , . They scavenged dead c a l v e s and f e m a l e s t h a t had d i e d i n p a r t u r i t i o n .  No b e a r s were seen d r a g g i n g  carcasses;  however, t h e y a t e them where found. The  only other predator  i n Newfoundland t h a t c o u l d d r a g a dead c a l f i s  64 the  lynx.  A 16-pound c a l f c o u l d be h a u l e d by a 19-pound female o r 24-pound  male l y n x .  I have found no r e c o r d s i n t h e l i t e r a t u r e o f l y n x d r a g g i n g p r e y .  T h i s i s n o t s u r p r i s i n g s i n c e t h e f o o d s r e p o r t e d f o r l y n x a r e snowshoe hare (Lepus americanus) and f o r e s t g r o u s e , t h a t would be t a k e n i n c o n c e a l i n g f o r e s t h a b i t a t s o r l i g h t enough t o c a r r y , and r o e deer ( C a p r e o l u s c a p r e o l u s ) and r e i n d e e r ( R a n g i f e r t a r a n d u s ) , w h i c h a r e t o o l a r g e t o be p u l l e d ( I u r g e n s o n 1955, Saunders 1963a, Van Z y l l de Jong 1966, and Haglund 1966).  Presumably i t  would be advantageous f o r a l y n x t o d r a g t h e c a l f o u t - o f - s i g h t o f t h e dam. S e v e r a l members o f t h e F e l i d a e a r e r e p o r t e d t o s h i f t t h e i r p r e y t o overhead c o v e r t s , even when t h e p r e y exceeds t h e i r own weight (Young and Goldman 1946, Young 1958, R o s e n b l a t t and S c h n e i r l a 1962, P e r r y 1964, and S c h a l l e r 1 9 6 7 ) .  E x p e r i m e n t a l Removal o f Lynx Lynx t r a p p i n g was u n d e r t a k e n i n t h e w i n t e r o f 1964^65 t o o b t a i n e s t i m a t e s of  l y n x d e n s i t i e s on c a l v i n g grounds and t o a s c e r t a i n whether removal o f l y n x  c o u l d improve c a l f s u r v i v a l . region.  Four t r a p p e r s worked t h e M i d d l e Ridge c a l v i n g  As a c o n t r o l , l y n x on t h e P o t H i l l c a l v i n g ground, 26 m i l e s d i s t a n t ,  were l e f t u n d i s t u r b e d . T r a p p e r s remained a t M i d d l e Ridge u n t i l June.attempt-. ing  t o g e t a l l t h e l y n x ; 44 a n i m a l s were s e c u r e d ( T a b l e -27) o r about 1 l y n x  per  5 square m i l e s ( F i g . 2 1 ) . F o l l o w i n g t h e r e m o v a l program t h e c a l f  incre-  ment was g r e a t e r a t M i d d l e Ridge t h a n a t P o t H i l l : Population  Pot H i l l  M i d d l e Ridge  Statistics  l y n x n o t removed  ( l y n x removed)  C a l f s u r v i v a l i n June 1965 Per  c e n t c a l v e s i n pop. i n O c t .  49% ( 8 9 ) *  85% (98)  . 2.7% .(299)  16.3% (-92)  Y e a r l i n g s p e r 100 does, June 1966  4.7  (190)  -27.5 (109)  2-yr.  2.9  (172)  10.2  does/100 a d u l t does, June 1967 " a d u l t does i n sample  (167)  65  F i g . 21.  Lynx t r a p p e d . a t M i d d l e Ridge i n t h e w i n t e r o f 1964-65 and 1965-66. Note t h e c o n c e n t r a t i o n n e a r L i t t l e Gander Pond.  66 S u r v i v a l o f c a l v e s on t h e A v a l o n P e n i n s u l a exceeded t h a t o f t h e I n t e r i o r Herd-in  8 o f 10 y e a r s ( F i g . 15).  snared i n 1965-66.  To i n v e s t i g a t e l y n x d e n s i t y , l y n x were  N i n e t e e n lynx.were h a r v e s t e d  about 1 l y n x p e r 10 s q u a r e - m i l e s — h a l f in  1964-65.  which provided a d e n s i t y o f  the d e n s i t y recorded  a t Middle  The y e a r p r i o r t o t h e l y n x removal program o n l y 27 p e r c e n t o f  t h e young on t h e A v a l o n P e n i n s u l a l i v e d t i l l a f t e r t h e s n a r i n g 85 p e r . c e n t  October^ ( F i g . 1 5 ) .  o f the calves survived t i l l  The y e a r  October.  l i k e l y t h a t t h e removal o f l y n x was r e s p o n s i b l e f o r t h e i n c r e a s e d The  Ridge  I t seems survival.  t r a p p i n g program showed t h a t l y n x were common i n t h e w i n t e r on t h e  c a l v i n g grounds b u t d i d n o t demonstrate c o n c l u s i v e l y t h a t t h e y were common a t p o s t - c a l v i n g time.  Saunders' (1963b) s t u d i e s o f movement o f Newfoundland l y n x  suggested t h a t t h e a n i m a l s were q u i t e sedentary.  H i s t r a c k i n g s t u d i e s gave  home r a n g e s o f t h r e e a d u l t s a s 6, 7, and 8 square m i l e s . d i s t a n c e f o r 14 tagged a n i m a l s was 3.3. m i l e s .  The mean r e c a p t u r e  H i s d a t a were c o l l e c t e d  a p e r i o d when snowshoe h a r e s were i n c r e a s i n g (Dodds 1965). when h a r e s a r e s c a r c e ( I u r g e n s o n 1955).  during  Lynx range f a r t h e r  S t i l l , no d i e - o f f o f h a r e s was noted  d u r i n g t h e w i n t e r t r a p p i n g n o r a r e r e g u l a r e x t e n s i v e w i n t e r - s p r i n g movements o f l y n x known f o r Newfoundland.  I conclude'that  l y n x d e n s i t i e s on c a l v i n g  grounds i n t h e s p r i n g were a t l e a s t e q u a l t o t h a t i n w i n t e r . Our t r a p p i n g showed t h a t t h e home r a n g e s o f l y n x were n o t m u t u a l l y s i v e ( c f . Haglund 1966). one  F i v e a d u l t a n i m a l s were t a k e n w i t h i n a few weeks a t  snaring s i t e , four a t another.  The l y n x a t M i d d l e Ridge were  around L i t t l e Gander Pond ( F i g . 2 1 ) , p r o b a b l y  concentrated  because o f t h e abundance o f h a r e s .  S i m i l a r l y , i t i s q u i t e p o s s i b l e t h a t l y n x c o u l d aggregate i n t h e s p r i n g to calving  areas.  exclu-  adjacent  67  Sex V u l n e r a b i l i t y  o f Male C a l v e s t o Lynx P r e d a t i o n  More male t h a n female c a l v e s d i e d between b i r t h and 6-months-of-age but t h e r e was no s i g n i f i c a n t change i n t h e sex r a t i o from 5- t o (Table 16).  12-months-of-age  'When I combined a l l samples 5- t o 12-moriths-of-age,^ t h e male:  female p e r c e n t a g e s were 40.2 and 59.8, n = 1 2 8 5 ( T a b l e 1 6 ) .  Hence i n . t h e  f i r s t 6 months o f l i f e 1.3 males were l o s t f o r each female t h a t d i e d , based on t h e assumption t h a t t h e sex r a t i o a t b i r t h was 52:48 ( c f . K e l s a l l 1968). Male c a l v e s may have been more v u l n e r a b l e t o l y n x because some wandered f a r t h e r from t h e i r dams t h a n f e m a l e s .  There was a h i g h l y s i g n i f i c a n t  ence between t h e sexes i n t h i s b e h a v i o u r ( F i g . 2 2 ) . stalking  s o l i t a r y calves.  differ-  A l y n x might be b o l d e r i n  F u r t h e r , l y n x move u n o b t r u s i v e l y about a home range  r e y l i n g on s i g h t and sound t o d e t e c t p r e y (Saunders 1963b and Haglund  1966).  An a c t i v e , c u r i o u s c a l f , t r a v e l l i n g a wide r a d i u s might a t t r a c t more a t t e n t i o n t h a n a more s e d e n t a r y i n d i v i d u a l .  Then t o o , a s t r a y i n g c a l f would l i k e l y  be  l e s s a b l e t o o b s e r v e warning s i g n a l s from a d u l t s . The p r o p o r t i o n o f male c a l v e s a l i v e a t 1- t o 4-weeks-of-age was i n y e a r s o f good c a l f s u r v i v a l  greater  ( F i g . 2 3 ) , which i s to.be e x p e c t e d i f males a r e  more prone t o p r e d a t i o n t h a n f e m a l e s , but t h e p e r c e n t a g e o f males i n t h e r e c r u i t m e n t a t 12-months-of-age  was l e s s w i t h improved c a l f s u r v i v a l  ( F i g . 24).  T h i s l a t t e r r e s u l t would not be e x p e c t e d i f male s u s c e p t i b i l i t y t o d e a t h i n creased p r o p o r t i o n a l l y with t o t a l c a l f m o r t a l i t y . losses, individual  Perhaps i n y e a r s w i t h l a r g e  s u s c e p t i b i l i t y m a t t e r s l e s s ; p r e d a t i o n i s so s e v e r e t h a t  few a n i m a l s a r e u l t i m a t e l y e x c l u d e d . V a r i a t i o n i n Lynx P r e d a t i o n Between Areas  The s u p e r i o r s u r v i v a l o f c a l v e s born on t h e La P o i l e R i v e r and Buchans  DISTANCE OBSERVED  OBSERVED  OF  dd  CHI  OBSERVATIONS  EXPECED  ON  SO,  BASIS 99  YDS.  41  5 9.7  5.9  > 5 £ 10 Y D S .  24  2 7.7  0-5  < 5  40  NUMBER  >10< 2 0 Y D S .  38  33.5  0.6  >20< 5 0 Y D S .  32  24.7  0.3  >50YDS.  18  7.3  15.7  1  <5  >5<10  DISTANCE  OF  >10< CALF  20  >20< 5 0  FROM  DAM  >50 (YDS.)  F i g . 22. Male c a l v e s s t r a y e d f a r t h e r t h a n f e m a l e . c a l v e s from t h e i r dams.  69  F i g . 23.  The r e g r e s s i o n o f t h e p e r c e n t a g e o f c a l v e s i n t h e I n t e r i o r Herd i n O c t o b e r on t h e s e x r a t i o o f c a l v e s 1-4- weeks-of-age.  70  70  CALVING  r =- 0.546  LU  3  P< 0 . 0 2  •  POT  n=21  •  BUCHANS  A  GREY  O  MIDDLE  •  SANDY  60-  cr  <  POPULATIONS HILL PLATEAU  RIVER RIDGE LAKE  °  5  LU > LU _l <  40-  LU O  30'  Y=  52.29-0.87x  cr  LU CL  20  - —r 1  —r 10  -  -I—  —T—  15  20  25  30  YEARLINGS PER 100 DOES IN JUNE  F i g . 24-.  The r e g r e s s i o n o f t h e p e r cent male y e a r l i n g s on t h e r e c r u i t m e n t i n June f o r t h e I n t e r i o r Herd.  71 P l a t e a u c a l v i n g grounds r e l a t i v e t o t h e o t h e r c a l v i n g s i t e s ( T a b l e .12) maybe due t o lower d e n s i t i e s o f l y n x . Buchans i n e i g h t s p r i n g s .  Only f o u r b i t t e n c a l v e s were found on  the  Both t h e La P o i l e and Buchans P l a t e a u c a l v i n g  grounds a r e i n the s u b a l p i n e and a l p i n e v e g e t a t i v e zones (below) where c o n i f e r s a r e s t u n t e d and f r e q u e n t l y p r o s t r a t e .  Such stands c a t c h snow and a r e l e s s  s u i t a b l e t o snowshoe h a r e s (Lepus americanus) and t h u s l y n x .  The  remaining  c a l v i n g grounds have more f o r e s t c o v e r . Calving  Mean  Ground  Per Cent C a l v e s i n  Elevation ( f t . )  P o p u l a t i o n i n the Fall±95 C l .  La P o i l e R i v e r  1400-1600 f t .  19.8+2.1 •C6)*  Buchans P l a t e a u  1500  15.211.4 (10)  ft.  Grey R i v e r  1000-1100 f t .  Sandy Lake  900-1000 f t .  Middle  700-800  Pot  Ridge  700  Hill  ll.-3±1.2 (9) .9.'911.0 (10)  ft.  10.311.5 (6)  ft.  11.111.3 (6)  * herd c l a s s i f i e d i n 6 y e a r s  V a r i a t i o n i n Lynx P r e d a t i o n Between Y e a r s The  s u r v i v a l o f c a l v e s u n t i l October i n t h e I n t e r i o r Herd showed nonrandom  t r e n d s f o r a t l e a s t 16 y e a r s ( T a b l e 25).  S u r v i v a l on t h e A v a l o n P e n i n s u l a  showed a s i m i l a r p a t t e r n f o r 10 y e a r s and i n t h e Humber R i v e r Herd f o r 7 y e a r s o f data (Table 18).  These s u r v i v a l t r e n d s o f 3 t o 5 y e a r s c o u l d r e f l e c t  cyclic  changes i n t h e amount o f l y n x p r e d a t i o n . The magnitude o f l y n x p r e d a t i o n c o u l d depend on t h e number o f l y n x t h e i r search f o r caribou.  C a l f s u r v i v a l i n t h e i n t e r i o r was  and  correlated with  numbers o f l y n x t r a p p e d of l y n x trapped  ( F i g . 25).  But i t i s a moot p o i n t whether t h e number  r e f l e c t e d p o p u l a t i o n changes.  Iurgenson (1955) showed t h a t  l y n x n e a r l y d o u b l e d t h e i r c r u i s i n g r a d i u s when hares d e c l i n e d ; i n c r e a s e d movement would i n c r e a s e t r a p p i n g v u l n e r a b i l i t y and d i s t o r t f u r r e t u r n s as i n d i c e s o f abundance. Lynx depend on snowshoe h a r e s f o r f o o d i n Newfoundland (Saunders 1963a). Their "searching  image" (sensu o f T i n b e r g e n 1960)  can be e a s i l y f o u n d .  Dodds (I960 and 1965)  Newfoundland i n 1960-61.  be f o r hares when hares  r e p o r t e d a h i g h i n hare numbers i n  A high i n c a l f s u r v i v a l i n the Avalon,  Humber R i v e r herds o c c u r r e d herd may  may  i n 1959  (Fig. 16).  Interior,  and  C a l f s u r v i v a l i n t h e Humber  have been c o r r e l a t e d w i t h t h e abundance o f snowshoe h a r e s i n t h a t  r e g i o n ( F i g . 26). D u r i n g a d e c l i n e o f h a r e s l y n x p r e d a t i o n on c a r i b o u might i n c r e a s e . t h e o r y , t h e r e i s a l a g . i n numbers between p r e d a t o r s ' a n d  prey; predators  In do  not r e s p o n d i m m e d i a t e l y t o t h e p r e y d e c l i n e and c o n t i n u e t o i n c r e a s e w h i l e prey i s decreasing  ( r e v i e w s by H o l l i n g 1961  and S a l t 1967).  the  Iurgenson's (1955)  d a t a from the U.S.S.R. show t h a t l y n x d i d i n c r e a s e a f t e r hares d e c l i n e d :  Winter  Number o f V a r y i n g  Season  Hares Per 10 km.  1931- 32  -44.2  6-9  8.6  1932- 33  11.3  13-16  7.7  31+  6.3  16-18  14.3  1934- 35  10.4  12-14  11.4  1933-  Number o f Lynx A l i v e i n National Forest  Average Length D a i l y T r a v e l o f Lynx  K e i t h ' s (1963) r e v i e w o f N o r t h American hare and l y n x c y c l e s i n d i c a t e s t h a t l y n x a t t i m e s r e m a i n h i g h f o r a few y e a r s a f t e r h a r e s d e c l i n e . d a t a a r e based on t r a p p i n g .  However, h i s  A p r i o r i one c o u l d r e a s o n t h a t t h e numbers o f a  km.  73  F i g . 25.  The s u r v i v a l o f c a l v e s i n e a s t e r n and c e n t r a l on t h e t o t a l l y n x h a r v e s t e d f o r t h e i s l a n d .  Newfoundland  74  cr >  4  0  1  o LU  ^  0-| 50  —  ,  60  1  1  1  70  80  90  P E R - C E N T JUVENILE SNOWSHOE HARES IN HUMERI SAMPLES, HUMBER RIVER F i g . 26. S u r v i v a l o f c a l v e s i n t h e Humber R i v e r Herd and p r o d u c t i o n o f snowshoe h a r e s (snowshoe hare d a t a from Dodds 1965).  m o b i l e , l o n g - l i v e d p r e d a t o r as t h e l y n x would not respond decrease o f i t s p r e y .  immediately t o the  A judgement on t h e r e l a t i v e r o l e s o f p r e d a t o r and  t h e abundance o f a l t e r n a t i v e p r e y on c a l f l o s s e s r e q u i r e s  further  study.  76  FACTORS LIMITING POPULATION GROWTH 1900 t o  1967  Rate o f P o p u l a t i o n Growth  The t h e o r e t i c a l growth i n numbers o f a p o p u l a t i o n i n t h e absence o f  mor-  t rm  . t a l i t y i s p r e d i c t e d from t h e f o r m u l a N^ = N^ rate of increase.  The  , where r ^ e q u a l s t h e  intrinsic  i n t r i n s i c r a t e o f i n c r e a s e i s a measure o f t h e i n n a t e  c a p a c i t y o f t h e s p e c i e s t o i n c r e a s e under optimum c o n d i t i o n s . ( A n d r e w a r t h a B i r c h 1954).  If r  and  can be c a l c u l a t e d , i t p r o v i d e s a means by.which t h e a c t u a l  r a t e o f i n c r e a s e ( r ) o f p o p u l a t i o n s can be compared i n a s s e s s i n g t h e i r growth and t h e s e v e r i t y o f f a c t o r s a f f e c t i n g growth. The growth o f t h e c a r i b o u herd on B r u n e t t e I s l a n d may mate e s t i m a t e o f r  f o r Newfoundland c a r i b o u .  p r o v i d e an a p p r o x i -  The a n i m a l s were i n t r o d u c e d  m i n t o t h i s new i n 5 years.  environment and i n c r e a s e d e x p o n e n t i a l l y from 17 t o 100  animals  No a n i m a l s a r e known t o have d i e d and some females reached p u b e r i t y  as y e a r l i n g s , s u g g e s t i v e o f good c o n d i t i o n s . The r a t e - o f - i n c r e a s e f o r t h e B r u n e t t e I s l a n d a n i m a l s over 5 y e a r s 0.352 young p e r i n d i v i d u a l per y e a r .  was  T h i s r a t e r e s u l t e d from t h e a t y p i c a l  sex  r a t i o o f 3 males and 14- females and s h o u l d be a d j u s t e d t o t h e a c t u a l sex r a t i o expected  i n u n d i s t u r b e d Newfoundland p o p u l a t i o n s .  I t h i n k t h e b e s t e s t i m a t e o f t h e sex r a t i o o f a d u l t s i n a p o p u l a t i o n not s u b j e c t t o s e l e c t i v e h u n t i n g o f s t a g s i s 36 males t o 64 f e m a l e s . i s midway between t h e percentage  This value  o f s t a g s i n t h e I n t e r i o r Herd i n 1957,  32 per  c e n t ( T a b l e 9 ) , and t h e f i g u r e secured f o r t h e A v a l o n Herd o f 40:60 (n = 518). T h i s f i g u r e i s s i m i l a r t o t h e p r o p o r t i o n o f males and females  (36:44) i n a  complete c l a s s i f i c a t i o n I made o f a s m a l l p r o t e c t e d herd a t Mt. A l b e r t , Quebec i n 1959  (unpublished).  77 I f we a d j u s t t h e number o f a n i m a l s i n t r o d u c e d t o B r u n e t t e I s l a n d on t h e b a s i s o f a m a l e r f e m a l e r a t i o o f 8:14 to  105 a n i m a l s .  t h e n t h e i n c r e a s e i n 5 y e a r s i s from  These f i g u r e s g i v e a r ^ v a l u e o f 0.312  young p e r  22  individual  per y e a r . The a e r i a l census r e s u l t s p r o v i d e d t o t a l s o f 4600 a n i m a l s f o r t h e I n t e r i o r Herd ( e x c l u d i n g t h e La P o i l e p o p u l a t i o n ) i n 1957 and 6200 i n 1966 These f i g u r e s g i v e an r v a l u e o f 0.044. c r e a s e 1956 t o 1958 From 1961 t o 1967  (Table 5).  (Table 5).  The A v a l o n Herd p r o b a b l y d i d not i n -  Census f i g u r e s i n 1959  and 1960 a r e u n r e l i a b l e .  t h e A v a l o n Herd i n c r e a s e d from 350 t o 720 a n i m a l s o r r 0.120.  The t a l l i e s o f t h e Humber Herd suggested no i n c r e a s e from 1956 t o 1964 5).  The two w i n t e r c o u n t s o f t h e N o r t h e r n P e n i n s u l a Herd i n 1958 and  showed no p o p u l a t i o n t r e n d .  (Table 1961  These d a t a i n d i c a t e t h a t a l l t h e herds were  s e v e r e l y l i m i t e d i n growth compared t o t h a t o f a n i m a l s i n t r o d u c e d t o B r u n e t t e Island. The a c c u r a c y o f t h e census r e s u l t s i n p r e d i c t i n g r a t e s - o f - i n c r e a s e can be p a r t i a l l y checked f o r t h e I n t e r i o r and A v a l o n Herds by c a l c u l a t i n g t h e r a t e s - o f - i n c r e a s e from h e r d c o m p o s i t i o n d a t a t h a t a r e independent  of  tallies.  animals  I n t h e I n t e r i o r Herd t h e r e were 55.3 does f o r e v e r y 100  (Table 13). 14.5  These does gave b i r t h t o 46.6  of these calves l i v e d t i l l  fall  census  c a l v e s (55.3 x 0.843, T a b l e 20) and  (46.6 x 0.310, T a b l e -20).  The a d u l t  m o r t a l i t y r a t e was 11 p e r c e n t — t h e d i f f e r e n c e ; t h e r a t e - o f - i n c r e a s e was per cent.  F o r t h e A v a l o n Herd, 39.2 does i n 100 a n i m a l s ( T a b l e 13)  produced  29.2 c a l v e s (39.2 x 0.745, T a b l e 1 7 ) , and 20.4 c a l v e s l i v e d t i l l t h e (29.2 x 0.699, T a b l e 1 7 ) ; a g a i n o f 12.0  3.5  per c e n t , 20.4 per cent - 8.4  fall per  cent . t t o t a l • m o r t a l i t y ( T a b l e 1 1 ) . A c t u a l l y t h e I n t e r i o r Herd d i d not i n c r e a s e each ..year"at "the - c a l c u - - . . l a t e d r a t e o f 4 per c e n t .  Counts o f c a l v e s i n t h e f a l l suggest t h a t r e c r u i t -  78  ment was  i n s u f f i c i e n t t o b a l a n c e m o r t a l i t y l o s s e s i n 1957,  P r i o r t o t h i s study the annual increments m o r t a l i t y i n 1952  t o 1956  (Table  25).  may  196-2, and  1963.  have f a i l e d t o compensate f o r  Thus t h e herd c o u l d have d e c l i n e d i n 8  o f 17 y e a r s .  Reproduction  i n P o p u l a t i o n Growth  A n n u a l v a r i a t i o n s i n t h e r e p r o d u c t i v e r a t e o f f e m a l e s appeared due change i n t h e p e r c e n t a g e o f n u l l i p a r o u s 2 - y e a r - o l d s  i n the p o p u l a t i o n .  to The  f e c u n d i t y o f mature does seemed c o n s t a n t even though t h e r e were g r e a t extremes between y e a r s i n t h e r e l a t i v e abundance o f w i n t e r f o r a g e .  I n a sample o f 18  nonparous does 6 were 3 - y e a r s - o l d t h a t had never o v u l a t e d .  I t seems l i k e l y  t h a t t h e p r o p o r t i o n o f f e m a l e s r e a c h i n g p u b e r t y a t 2\ y e a r s c o u l d v a r y w i t h nutrition. The number o f f e m a l e s p r e g n a n t , 84-.5 per c e n t , was  s i m i l a r to that r e -  p o r t e d f o r t h e Northwest T e r r i t o r i e s ( K e l s a l l 1968), A l a s k a (Skoog 1 9 6 8 ) , and O n t a r i o (Simkin  1965).  The l i c h e n range o f t h e O n t a r i o herd was  largely  un-  d i s t u r b e d , w h i l e many o f t h e ranges a v a i l a b l e t o t h e a n i m a l s i n t h e Northwest T e r r i t o r i e s had been d e s t r o y e d by f i r e s ( S i m k i n 1965  and S c o t t e r 1964).  Two  o f t h e h e r d s were i n c r e a s i n g when sampled, and one was p o s s i b l y s t a b l e o r  de-  c l i n i n g y e t t h e r e p r o d u c t i v e r a t e s o f a l l t h e p o p u l a t i o n s were s i m i l a r . I n Sweden, t h e numbers o f mature pregnant r e i n d e e r i n a s m a l l herd averaged 84 p e r c e n t o v e r 7 y e a r s (Skunke p e r s . comm.). f e d on v e r y o v e r g r a z e d  I n some w i n t e r s t h e  animals  p a s t u r e s and i n o t h e r s on r a n g e s w i t h more abundant  s u p p l i e s o f l i c h e n (Skunke p e r s . comm.).  Snow depths i n t h e 7 y e a r s ranged  w i d e l y and t h e a n i m a l s r e c e i v e d supplementary r a t i o n s o f 1 kg. per day i n 5 seasons.  I c o u l d see no apparent c o r r e l a t i o n between f r e q u e n c i e s each y e a r  and t h e extremes i n t h e a v a i l a b i l i t y o f w i n t e r f o r a g e .  79 K l e i n (1968) c o l l e c t e d female r e i n d e e r f r o m . S t . Matthew I s l a n d , A l a s k a j u s t p r i o r t o a c r a s h from w i n t e r s t a r v a t i o n on an o v e r - g r a z e d  range.  a l s o c o l l e c t e d from t h e s u r v i v i n g herd a f t e r t h e mass m o r t a l i t y .  He  Females i n  b o t h samples had c o n t i n u e d t o o v u l a t e . It  seems t h a t c a r i b o u , u n l i k e N o r t h American deer and moose, have l i t t l e  phenotypic  p l a s t i c i t y i n t h e i r r e p r o d u c t i v e a d a p t i v e . s t r a t e g y t h a t might v a r y  and a f f e c t p o p u l a t i o n growth.  This finding i s consistent with  the view of  D a v i d Lack (1966) t h a t s p e c i e s have e v o l v e d t h e r e p r o d u c t i v e r a t e t h a t  provides  t h e maximum number o f s u r v i v i n g young but i s a t odds w i t h the t h e o r y o f WynneEdwards (1962) t h a t a n i m a l s  can r e g u l a t e t h e i r numbers by c o n t r o l l i n g  r a t e s through s o c i a l behaviour.  birth  I n c a r i b o u t h e v a r i a b l e parameter l i m i t i n g  p o p u l a t i o n growth i s m o r t a l i t y .  Natural M o r t a l i t y of  Calves  The major n a t u r a l l o s s from t h e p o p u l a t i o n s was i n t h e i r f i r s t summer o f l i f e .  a high m o r t a l i t y of calves  The r a t e s - o f - g a i n o f t h e . A v a l o n  and  Interior  herds were c o r r e l a t e d w i t h t h e s u r v i v a l o f c a l v e s u n t i l 6-months-of-age ( F i g . 27).  Therefore  e a r l y m o r t a l i t y determined p o p u l a t i o n growth.  Over 10 y e a r s , an average o f -69 p e r cent o f t h e c a l v e s b o r n i n t h e  interior  were dead by O c t o b e r , and 30 per c e n t o f the c a l v e s on the A v a l o n P e n i n s u l a d i e d by autumn.  C a l v e s began t o d i s a p p e a r  immediately  after calving.  had  I n the  I n t e r i o r H e r d , '27 per cent o f t h e c a l v e s born were m i s s i n g from the open c a l v ing  grounds b e f o r e J u l y ( T a b l e 23).  Yet behaviour  s t u d i e s showed t h a t does and  c a l v e s d i d not l e a v e the open c a l v i n g a r e a s f o r the woods u n t i l J u l y , when f l i e s became bothersome.  My i n t e r p r e t a t i o n i s t h a t c a l v e s were k i l l e d and  from t h e c a l v i n g a r e a s .  dragged  S i n c e 84 o f 114 dead o r morbid c a l v e s found were b i t t e n  80  -.10 I 0  I  10  1  20  1  1  1  1  30  40  50  60  :  1  1  1  70  80  90  PER CENT CALF SURVIVAL UNTIL  6 MO.  F i g . 27. The r e g r e s s i o n o f t h e r a t e - o f - i n c r e a s e on s u r v i v a l o f c a l v e s u n t i l 6-months-of-age.  81 by l y n x t h i s p r e d a t o r was most l i k e l y r e s p o n s i b l e f o r t h e h i g h l o s s e s o f calves. C a l f m o r t a l i t y remained h i g h i n J u l y and August b u t had l a r g e l y ceased by l a t e September.  T h i s p a t t e r n can be e x p l a i n e d by l y n x p r e d a t i o n .  Young c a l v e s  a r e more v u l n e r a b l e t o l y n x because o f t h e i r s m a l l s i z e , u n w a r i n e s s , and t h e i r a l t e r n a t i n g p e r i o d s o f e x p l o r a t o r y a c t i v i t y and s l e e p .  C a l v e s become more  s e l f - s u f f i c i e n t and a l e r t i n J u l y and A u g u s t , b u t d u r i n g t h e s e two months some d o e - c a l f herds disband  and d i s p e r s e i n t o f o r e s t c o v e r t o escape f l i e s .  the s t a l k i n g o p p o r t u n i t i e s f o r l y n x would be enhanced.  Also the small s i z e  o f bands o f c a r i b o u i n t h e f o r e s t would r e d u c e t h e a l a r m d i s t a n c e 1961a).  Thus  Heavy p r e d a t i o n ceased i n l a t e September p r o b a b l y  (Bergerud  because t h e c a r i b o u  l e a v e t h e f o r e s t , a f t e r t h e f l y - s e a s o n and congregate on open h a b i t a t s p r i o r to the r u t . The  hypothesis  o f p r e d a t i o n by l y n x was t e s t e d by removal o f l y n x on t h e  A v a l o n P e n i n s u l a and t h e M i d d l e Ridge c a l v i n g ground o f t h e I n t e r i o r Herd. C a l f s u r v i v a l showed a marked improvement i n b o t h a r e a s f o l l o w i n g t h e r e d u c t i o n s of l y n x . The  p a t t e r n o f p r e d a t i o n by l y n x i s c o n s i s t e n t w i t h t h e f i n d i n g t h a t c a l f  s u r v i v a l f o l l o w s 3- t o 5-year i n c r e a s i n g o r d e c r e a s i n g  trends that could r e -  l a t e t o approximate 10-years c y c l e s o f abundance o f l y n x .  The h y p o t h e s i s i s  a l s o c o n s i s t e n t w i t h t h e f a c t t h a t t h e I n t e r i o r , A v a l o n , and Humber R i v e r herds showed some s y n c h r o n i z a t i o n i n s u r v i v a l o f c a l v e s .  Moreover, i t p r o v i d e s an  e x p l a i n a t i o n f o r a g r e a t e r l o s s o f male t h a n female c a l v e s .  Male c a l v e s may  wander f a r t h e r from t h e i r dams t h a n f e m a l e s and be more s u s c e p t i b l e t o p r e d a t i o n by l y n x . L a s t l y t h e r a t e s - o f - g a i n o f t h r e e herds were a l s o c o r r e l a t e d w i t h t h e abundance o f l y n x :  Brunette  I s l a n d r =0.352 and no l y n x , A v a l o n  Peninsula  82 r = 0.120 and 1 l y n x p e r 10 square m i l e s i n 1965-66, and t h e I n t e r i o r Herd r = 0.044 and 1 l y n x p e r 5 square m i l e s i n 1964^65. I c o n c l u d e t h a t l y n x p r e d a t i o n was t h e f a c t o r l i m i t i n g growth o f t h e A v a l o n and I n t e r i o r . herds.  The importance o f l y n x can be t e s t e d f u r t h e r by  i n t r o d u c i n g them t o B r u n e t t e I s l a n d .  I p r e d i c t t h a t c a l f s u r v i v a l w i l l de-  c r e a s e and p o p u l a t i o n growth w i l l d e c l i n e f o l l o w i n g t h e i n t r o d u c t i o n .  For a  v a l i d t e s t snowshoe h a r e s would a l s o have t o be i n t r o d u c e d . The g r e a t e r s u r v i v a l o f c a l v e s on B r u n e t t e  I s l a n d and t h e A v a l o n P e n i n -  s u l a i n d i c a t e s t h a t many o f t h e i n t e r i o r c a l v e s would n o t have d i e d from o t h e r causes i n t h e absence o f p r e d a t i o n .  The l o s t c a l v e s were n o t a s u r p l u s and  doomed t o d i e and l y n x r e d u c e d t h e amount o f increment. The numbers o f c a l v e s r e c o r d e d  i n the f a l l o r winter i n other  caribou  herds i n N o r t h America l i v i n g w i t h i n t h e range o f l y n x a r e s i m i l a r t o those found i n t h i s i n v e s t i g a t i o n . The mean increment o f c a l v e s i n t h e Mealy Mount a i n Herd i n s o u t h e r n L a b r a d o r i n 6 y e a r s was 11 p e r c e n t (Bergerud  1967a),  on t h e Gaspe P e n i n s u l a i n 6 autumns 16 p e r cent (Moisan 1958 and.pers. comm.), and O n t a r i o 17 p e r cent i n 7 w i n t e r s ( S i m k i n 1965 and p e r s . comm.).  These  f i g u r e s i m p l y a heavy l o s s between b i r t h and f a l l and p r e d a t i o n by l y n x i s a possibility.  P r e d a t i o n by Lynx on Male The  Calves  l o s s o f more male t h a n female c a l v e s t o p r e d a t i o n by l y n x would  a c c e l e r a t e t h e r a t e - o f - i n c r e a s e o f t h e herd i f i t r e s u l t e d i n a lower age o f s t a g s . (cf.  percent-  T h i s would r e s u l t because c a r i b o u a r e f u n c t i o n a l l y polygynous  Buechner 1960). However, t h e g r e a t e r p r e d a t i o n o f male c a l v e s by l y n x appears i n s u f f i c i e n t  to  e x p l a i n i n g t h e sex r a t i o s o f a d u l t s f a v o u r i n g f e m a l e s .  The sex r a t i o o f  83 t h e a d u l t p o p u l a t i o n i n 1957,  p r i o r t o h u n t i n g o f males o n l y , was  32:68  (Table 9).  I n the A v a l o n and Humber h e r d , the a d u l t p r o p o r t i o n o f males and  f e m a l e s was  33:67 (n = 680), n e a r l y t h e same as t h e i n t e r i o r , y e t t h e  sex  r a t i o of t h e r e c r u i t s i n autumn f o r b o t h o f t h e s e herds was -50:-50 (n = 1 4 7 ) . I n b a r r e n - g r o u n d c a r i b o u not s u b j e c t e d t o s i g n i f i c a n t l y n x p r e d a t i o n , t h e  sex  r a t i o o f a d u l t s was-34:66 ( K e l s a l l 1 9 6 8 ) . The  changes i n sex r a t i o between r e c r u i t s and a d u l t s . suggest t h a t male  c a l v e s died at g r e a t e r r a t e s than females r e g a r d l e s s of p r e d a t i o n .  The  diffi-  c u l t y i n t h e s e comparisons i s t h a t t h e sex r a t i o o f a d u l t s i n c l u d e s males o f a l l ages and r e f l e c t s a d u l t m o r t a l i t y as w e l l as d i f f e r e n t numbers o f r e c r u i t s o f each sex.  The m o r t a l i t y o f a d u l t s appears t o be t h e dominant f a c t o r i n t h e  imbalance o f t h e sex r a t i o o f a d u l t s s i n c e t h e r e was  no e v i d e n c e o f  winter  m o r t a l i t y i n e i t h e r the A v a l o n o r Humber herds t h a t might a l t e r t h e i r 50:50 r a t i o o f r e c r u i t s and b r i n g i t c l o s e t o the 40:60 f i g u r e i n t h e i n t e r i o r . c o n c l u s i o n i s t h a t sex r a t i o o f a d u l t s i n a l l herds w h i c h had d i f f e r e n t  My  levels  o f c a l f m o r t a l i t y would have been s i m i l a r i n t h e absence o f h u n t i n g o f males.  The  Decline of Caribou  1915-1930  I b e l i e v e t h a t the g r e a t d e c l i n e o f Newfoundland c a r i b o u . b e t w e e n 1915  and  •1930 r e s u l t e d from i n c r e a s e d p r e d a t i o n by l y n x and a heavy a n n u a l h a r v e s t 6000 t o 8000 a d u l t s by h u n t e r s .  There was  no h i s t o r i c a l e v i d e n c e t h a t  d i e d d u r i n g the d e c l i n e from w i n t e r s t a r v a t i o n o r an e p i z o o t i c . i n t h a t p e r i o d were not s e v e r e .  The  I n s i x w i n t e r s i n t h e c u r r e n t study  caribou  winters there  were g r e a t e r s n o w f a l l s a t S t . John's t h a n t h e y e a r o f maximum•snowfall d u r i n g t h e p e r i o d o f d e c l i n e , 1915 o f Newfoundland was  t o 1930.  t r a v e l l e d by t r a p p e r s who  D u r i n g t h e s e y e a r s the  of  recorded  interior  r e l i e d on c a r i b o u f o r food  and  f o x b a i t ; a mass m o r t a l i t y would have been n o t i c e d and mentioned i n t h e news-  84 papers o f t h a t p e r i o d . Lynx P r e d a t i o n and the  Decline  I n t h e e a r l y 1800's l y n x were e x c e e d i n g l y r a r e i n Newfoundland. i t i e s have even d i s a g r e e d on whether t h e l y n x i s i n d i g e n e o u s 1958,  Dodds 1960,  and Saunders 1961).  They became e x c e e d i n g l y  abundant when h a r e s r e a c h e d h i g h d e n s i t i e s about 1896.  Many newspaper a c c o u n t s  mentioned t h e abundance o f l y n x and a b i l l t o e x t e r m i n a t e  The  t a i n e d on t h e I s l a n d .  t o 1915  introduced  (Dodds 4 9 6 0 ) .  the g r e a t e s t d e n s i t y o f h a r e s ever a t -  The p o p u l a t i o n d e c l i n e d a f t e r 1915  abundant l y n x p o p u l a t i o n p a r t l y w i t h o u t f o o d . i n Newfoundland (Bergerud  l y n x was  (Dodds 1960).  f i r s t h i g h i n numbers o f hare l a s t e d from 1896  Dodds f e l t t h a t t h i s i n i t i a l peak was  (Cameron  A f t e r snowshoe hares were i n t r o d u c e d  t o Newfoundland l y n x began t o i n c r e a s e (Dodds I 9 6 0 ) .  i n t h e Newfoundland Assembly i n 1900  o r not  Author-  and l i k e l y l e f t  an  There a r e o n l y 14 n a t i v e mammals  1963b) and no n a t i v e f o r e s t grouse s p e c i e s .  p r o b a b l y t o o k some a r c t i c h a r e s , Lepus a r c t i c u s (Bergerud  Lynx  1967b), beaver  ( C a s t o r c a n a d e n s i s ) , mice ( M i c r o t u s p e n n s y l v a n i c u s ) , and p t a r m i g a n (Lagopus spp.).  I n a d d i t i o n , t h e y l i k e l y p r e y e d h e a v i l y on c a r i b o u c a l v e s .  I t might be argued t h a t l y n x would not g r e a t l y r e d u c e c a r i b o u numbers during  a hare d e c l i n e s i n c e l y n x s h o u l d a l s o d e c l i n e ,  The a v a i l a b l e e v i d e n c e  suggests t h a t l y n x d i d d e c l i n e f o l l o w i n g the h i g h i n hare abundance.  This  s u p p o r t s t h e v i e w t h a t a l t e r n a t e f o o d s i n c l u d i n g c a r i b o u were u n s a t i s f a c t o r y to maintain l y n x .  However, an abundant p o p u l a t i o n o f l y n x , even i f d e c l i n i n g ,  c o u l d k i l l many c a l v e s when h a r e s were s c a r c e .  They need p r e y h e a v i l y on  c a l v e s f o r o n l y 3 t o 5 y e a r s and w i t h a heavy human h a r v e s t numbers o f c a r i b o u would be d r a s t i c a l l y r e d u c e d . year 1951  t o 1957  R e c e n t l y t h e p e r c e n t a g e o f c a l v e s d e c l i n e d each  ( T a b l e 25) and 1959  t o 1962  (Table 12).  Hence l y n x  apparently  85 d i d c o n t i n u e t o t a k e l a r g e numbers o f c a l v e s f o r s e v e r a l c o n s e c u t i v e  years  when h a r e s d e c l i n e d ( c f . Dodds 1965 r e l a t i v e t o hare f l u c t u a t i o n s ) . I c a n o n l y s p e c u l a t e a s t o t h e p l a s t i c i t y l y n x have t o s u r v i v e l o w numbers o f hares and t h e l a c k o f an adequate w i n t e r d i e t .  Lynx may have c o n s i d e r a b l e  p l a s t i c i t y i n f e c u n d i t y r e l a t i v e t o hare numbers.  Saunders (1961) examined  l y n x r e p r o d u c t i v e t r a c t s . secured  d u r i n g a hare l o w i n 1956 and 1957.  He •  suggested t h a t -24 p e r c e n t o f t h e a d u l t f e m a l e s might n o t have b r e d i n t h e y e a r collected.  I n 14 female t r a c t s t h a t had v i a b l e young he counted 41 v i a b l e  embryos, 6 p l a c e n t a l s c a r s , and -77 c o r p o r a l u t e a .  Another t r a c t had 5 embryos  t h a t were c l e a r l y b e i n g reabsorbed. These d a t a suggest t h a t t h e r e p r o d u c t i v e r a t e may be r e d u c e d i f f o o d i s s c a r c e .  I t i s possible that the declines of  l y n x r e p o r t e d i n t h e l i t e r a t u r e a r e m o s t l y due t o a r e d u c t i o n i n b i r t h r a t e s (possibly postparturient mortality of kittens also).  Seton (1929) i s t h e o n l y  a u t h o r i t y I have l o c a t e d t h a t a c t u a l l y r e p o r t e d he found dead a d u l t l y n x t h a t may have s t a r v e d t o d e a t h . A g a i n l y n x c o u l d show p l a s t i c i t y i n t h e i r h u n t i n g h a b i t s f o r h a r e s i n t h e c o u r s e o f hare f l u c t u a t i o n s . distances searching.  When h a r e s were l o w l y n x would t r a v e l  Lynx don't appear t o have m u t u a l l y  greater  e x c l u s i v e home r a n g e s ;  t h i s b e h a v i o u r i s m would p e r m i t h u n t i n g l y n x t o l o c a t e and u t i l i z e . l o c a l popul a t i o n s o f h a r e s t h a t remained common d u r i n g a p e r i o d o f g e n e r a l A g a i n N e l l i s and K e i t h (1968) p r o v i d e d  scarcity.  e v i d e n c e t h a t t h e r e were between y e a r  d i f f e r e n c e s i n t h e e f f o r t expended by l y n x i n c h a s i n g h a r e s , i n c a t c h i n g and  food,  i nv i s i t s to carrion. D u r i n g a l o w i n h a r e s i n 1957 on t h e A v a l o n P e n i n s u l a , I n o t e d t h a t h a r e s  were s t i l l common i n s m a l l d i s c o n t i n u o u s  p o c k e t s ( c f . K e i t h 1966).  Dodds  (1965) was a b l e t o s e c u r e a s m a l l sample o f 911 humeri bones o f h a r e s from r e s i d e n t s on t h e West Coast when t h e p o p u l a t i o n was l o w i n 1957.  Newfoundland  86 r e s i d e n t s continue  t o have some s u c c e s s s n a r i n g h a r e s , . e v e n when numbers a r e  down, e s p e c i a l l y a t t h e b e g i n n i n g  o f t h e open season f o r s n a r i n g .  Dodds (1960 and 1965) i n d i c a t e d h i g h p o p u l a t i o n s l a n d i n 1940, 1952, and 1960-61. p o i n t s f o r c a r i b o u numbers. that lynx switched  o f h a r e s i n Newfound-  These a r e p e r i o d s t h a t appear t o be h i g h  These c o r r e l a t i o n s a r e c o n s i s t e n t w i t h t h e t h e s i s  t o c a r i b o u a f t e r h a r e s had d e c l i n e d .  Such a s w i t c h  seems  p l a u s i b l e f o r a l o n g - l i v e d and v e r s a t i l e a n i m a l such as t h e l y n x .  H u n t i n g and t h e D e c l i n e  The l o s s o f c a l v e s from 1915 t o 1930 would n o t have been g r e a t enough t o reduce t h e i s l a n d ' s c a r i b o u herds from perhaps 40,000 t o 2,000 a n i m a l s i n 15 years.  A d u l t s a l s o must have d i e d a t h i g h r a t e s t o e x p l a i n a d e c l i n e o f t h i s  magnitude.  P r e s e n t e d below i s a t h e o r e t i c a l d e c l i n e o f 40,000 c a r i b o u based  on t h e f o l l o w i n g assumptions:  (1) an a n n u a l h a r v e s t  o f 7,000 a n i m a l s ,  n a t u r a l m o r t a l i t y r a t e o f a d u l t s o f 5 p e r c e n t , and ( 3 ) c a l f s i m i l a r t o t h a t which o c c u r r e d  (2) a  recruitment  from 1951 t o 1957 (Table 25) when t h e I n t e r i o r  Herd d e c l i n e d ( F i g . '9).  Year i n  Total  Decline  Population  1  40,000  2  Population A f t e r H u n t i n g Loss  Natural  Per cent  Total  Mortality  Calves i n Oct.  Recruitment  33,000  1,650  .11.2  3,973  35,473  28,473  1,424  8.2  2,416  3  29,465  ' 20,465  1,023  7.3  1,531  4  20,973  13,973  697  5.6  788  5  14,064  7,064  . 353  5.5  . 391  6  7,102  102  5  5.4  6  7  .' 103  -  87 These c a l c u l a t i o n s i n d i c a t e t h a t t h e c a r i b o u h e r d c o u l d have been d e s t r o y e d i n a few y e a r s i f h u n t i n g m o r t a l i t y remained h i g h and t h e r e were s e v e r a l y e a r s o f low c a l f s u r v i v a l . Such a t h e o r e t i c a l d e c l i n e c o u l d o n l y have r e s u l t e d i f t h e l a w - o f d i m i n i s h i n g r e t u r n s was  an i n e f f e c t i v e check on e x p l o i t a t i o n .  C a r i b o u are  h i g h l y v u l n e r a b l e t o h u n t i n g because o f a g r e g a r i o u s h e r d s t r u c t u r e , l a c k o f w a r i n e s s , use o f open h a b i t a t s , and m i g r a t o r y h a b i t s .  The c o n t i n u a l wander-  i n g o f t h e bands g r e a t l y i n c r e a s e s t h e p o s s i b i l i t y o f p e o p l e from some s e t t l e ment making c o n t a c t w i t h t h e a n i m a l s .  A g a i n the c a r i b o u were a p r i m a r y source  o f f r e s h meat f o r t h e Newfoundland p e o p l e i n t h e e a r l y 1900's; i t i s c l e a r from t h e i n t e r v i e w s w i t h former h u n t e r s t h a t t h e s e men  travelled farther  s t a y e d i n t h e c o u n t r y l o n g e r s e a r c h i n g f o r a n i m a l s as t h e herds  and  declined.  Even as l a t e as 1959 h u n t e r s t r a v e l l e d i n t o some o f t h e r o u g h e s t t e r r a i n i n Newfoundland on t h e N o r t h e r n P e n i n s u l a and h a r v e s t e d a r e p o r t e d 150 o f t h e e s t i m a t e d 500 a n i m a l s r e m a i n i n g i n the h e r d .  These a n i m a l s c o u l d have been  anywhere i n an a r e a o f 3,000 square m i l e s , 1 c a r i b o u p e r 6 square m i l e s . The d e n s i t y o f c a r i b o u i n Newfoundland i n y e a r 6 o f t h e h y p o t h e t i c a l p o p u l a t i o n d e c l i n e would have been 1 c a r i b o u p e r 6 square m i l e s .  F o r t h e s e reasons  i t seems p o s s i b l e f o r t h e h u n t e r s o f Newfoundland t o d e s t r o y t h e herds i n a m a t t e r o f 10 t o 15 y e a r s i n t h e absence o f s a t i s f a c t o r y a n n u a l i n c r e m e n t s .  88  EVOLUTIONARY IMPORTANCE OF PREDATION  I n my v i e w , s p e c i e s u s u a l l y f l u c t u a t e w i t h i n n a r r o w e r l i m i t s than t i a l l y p o s s i b l e because t h e y are the p r o d u c t o f p a s t D a r w i n i a n  poten-  selection  and  have o n l y s u r v i v e d because they have e v o l v e d e f f e c t i v e s t r a t e g i e s t o cope w i t h past contingencies.  There i s v a l u e i n a s s e s s i n g the r o l e o f f a c t o r s such as  p r e d a t i o n i n the n a t u r a l s e l e c t i o n o f i n d i v i d u a l s .  Such.study p r o v i d e s  insight  i n t o t h e ' a d a p t a t i o n s t h a t p e r m i t i n d i v i d u a l s , and thus c o l l e c t i v e l y p o p u l a t i o n s , to prosper.  The  f u t u r e o f a s p e c i e s depends on how  e f f e c t i v e the  present  a d a p t a t i o n s , f o r g e d i n t h e p a s t , are i n c o p i n g w i t h a dynamic p r e s e n t  and  f u t u r e environment.  P o p u l a t i o n L i m i t a t i o n from Wolf P r e d a t i o n  The Newfoundland c a r i b o u a p p a r e n t l y e v o l v e d i n a r e l a t i v e l y s i m p l e  insular  environment i n the presence o f p r e d a t i o n by the Newfoundland w o l f and i n more r e c e n t c e n t u r i e s the p r e d a t i o n o f the B e o t h i c I n d i a n s . e x t i n c t i n t h e e a r l y 1800's and the l a s t w o l f was  The B e o t h i c s became  killed in  1911.  I b e l i e v e t h a t the s t r u g g l e between c a r i b o u and w o l f f o r s u r v i v a l i n t h e s i m p l e Newfoundland ecosystem r u l e d out the e v o l u t i o n o f a system o f s e l f regulation i n caribou.  P i m l o t t (1967:275) i n d i s c u s s i n g why  d e e r , moose and  c a r i b o u a p p a r e n t l y have not e v o l v e d i n t r i n s i c p o p u l a t i o n c o n t r o l s s t a t e d : " I t seems r e a s o n a b l e  t o p o s t u l a t e t h a t . i t may  be because they have had  very  e f f i c i e n t p r e d a t o r s , and the f o r c e s o f s e l e c t i o n have k e p t them busy e v o l v i n g ways and means not o f l i m i t i n g t h e i r own mortality  numbers but o f k e e p i n g a b r e a s t  of  factors".  The w o l f appears t o have the t r a i t s n e c e s s a r y t o l i m i t the numbers o f caribou.  The p o t e n t i a l r e p r o d u c t i v e r a t e o f wolves i s g r e a t e r than c a r i b o u  89 ( c f . Rausch 1967).  Wolves a r e v e r s a t i l e , m o b i l e p r e d a t o r s t h a t s h o u l d be  t o ^ s e a - r c f i ^ u t c a r i b o u i n most h a b i t a t s .  The f o o t - l o a d i n g s o f wolves and  i n snow a r e r e a s o n a b l y  s i m i l a r (Nasimovich  s o f t snows ( N a s i m o v i c h  1955).  1955).  caribou  Both s p e c i e s a v o i d deep,  Wolves s h o u l d be a b l e t o f o l l o w c a r i b o u a t a l l  seasons e x c e p t i n t h e s p r i n g when t h e y pup. f e l t t h a t c a n i d p r e d a t i o n on u n g u l a t e s t h a t p r e d a t o r s took m o s t l y  able."  was  E r r i n g t o n (1946, 1956, an-:.exception  1967)  to his generalization  s u r p l u s a n i m a l s and d i d not l i m i t numbers.  E v i d e n c e t h a t wolves may  be a b l e t o l i m i t a c a r i b o u p o p u l a t i o n i s p r o -  v i d e d by t h e growth o f a c a r i b o u herd and a w o l f p o p u l a t i o n i n c e n t r a l A l a s k a . From 1956  t o 1963  t h e N e l c h i n a Herd i n c r e a s e d from 40,000 t o 71,000 a n i m a l s  a t a r a t e o f 9 per cent per y e a r (Skoog 1968). herd i n c r e a s e d from an e s t i m a t e d 1965  (Rausch 1967)  12 a n i m a l s  The wolves p r e y i n g on  i n 1953  this  t o perhaps 400 a n i m a l s  o r a t a r a t e o f 27 per cent per y e a r .  Burkholder  r e p o r t e d t h a t a pack o f 10 wolves i n t h i s p o p u l a t i o n d i v i d e d t h e i r  in  (1959) hunting  t i m e about e q u a l l y between moose and c a r i b o u and i n a p e r i o d o f 6 weeks k i l l e d 14 c a r i b o u .  Skoog (1968) e s t i m a t e d t h a t t h i s pack would k i l l 12 c a r i b o u per  w o l f per y e a r .  At t h i s m o r t a l i t y r a t e the w o l f p o p u l a t i o n i n 1955  a t 35 a n i m a l s , Rausch 1967) 1965  would have t a k e n 1.5.per c e n t o f the h e r d .  t h e w o l f p o p u l a t i o n would have t a k e n a p p r o x i m a t e l y  c a r i b o u , and i n c r e a s e o f 200 p e r cent i n 10 y e a r s . 1965  was  (estimated  about 1 a n i m a l per 50 square m i l e s .  In  5 per cent o f the  The w o l f p o p u l a t i o n i n  P i m l o t t (1967) i n d i c a t e d t h a t a  maximum d e n s i t y o f wolves i n N o r t h America might be 1 w o l f per 10 square m i l e s . At t h i s d e n s i t y the wolves c o u l d have k i l l e d 24,000 c a r i b o u a n n u a l l y . These c a l c u l a t i o n s a r e based on a c o n s t a n t r a t e o f p r e d a t i o n ; however as p o p u l a t i o n s o f b o t h p r e y and p r e d a t o r expanded, wolves might t a k e more c a r i b o u per w o l f .  Rausch (1967) r e p o r t e d an i n c r e a s e i n pack s i z e w i t h i n c r e a s e d den-  s i t i e s of wolves.  L a r g e r packs might i n c r e a s e k i l l i n g e f f i c i e n c y . ; - .  As  caribou  90 i n c r e a s e d , t h e s e a r c h i n g t i m e o f wolves would be .reduced.  A d d i t i o n a l l y , there  i s e v i d e n c e t h a t c a r i b o u become more v u l n e r a b l e t o p r e d a t i o n i n v e r y l a r g e herds d u r i n g stampedes ( C r i s l e r 1956  and K e l s a l l  I960).  E l s e w h e r e i n N o r t h America M u r i e (194'4) and Mech (1966) r e p o r t t h a t w o l f p r e d a t i o n appeared t o have s t a b i l i z e d t h e numbers o f a mountain sheep ( O v i s d a l l i ) and a moose p o p u l a t i o n d u r i n g . s h o r t i n t e r v a l s o f study.  Both s p e c i e s  produce t w i n c a l v e s and l i k e l y have b i r t h r a t e s h i g h e r t h a n c a r i b o u ( c f . Buechner 1960  and P i m l o t t 1 9 5 9 ) .  I f w o l f p r e d a t i o n l i m i t e d t h e numbers o f Newfoundland c a r i b o u i n t h e p a s t , what d e t e r m i n e d t h e upper l i m i t i n numbers o f c a r i b o u b e f o r e t h e i r growth halted?  For t h i s d i s c u s s i o n one assumes t h a t t h e w o l f - c a r i b o u  populations  were not s t a b i l i z e d and c a r i b o u were i n c r e a s i n g .  Such an unbalance c o u l d  r e s u l t because t h e p r e d a t o r - p r e y  imperfectly  ent ( M i l n e 1957)  r e l a t i o n s h i p was  was  density-depend-  w i t h both species subject t o c a t a s t r o p h i c m o r t a l i t y f a c t o r s  such as d i s e a s e i n wolves or mass s t a r v a t i o n i n c a r i b o u .  The p o p u l a t i o n  t h a t c a r i b o u would r e a c h b e f o r e p r e d a t i o n h a l t e d growth would depend on,  level (1)  the i n i t i a l numbers o f c a r i b o u when r became p o s i t i v e , ' .(2) t h e v a l u e o f r ( w o l f d e n s i t i e s i n v o l v e d ) , and  (3) t h e l e n g t h o f t i m e t h a t r remained p o s i t i v e .  T h i s model i s t h a t o f the Andrewartha and B i r c h s c h o o l o f p o p u l a t i o n t i o n (see Andrewartha and B i r c h 1954:656). i n the past reached v a r i o u s u n p r e d i c t a b l e  Thus I b e l i e v e t h a t  have been a major peak f o r the  F o r example, Cormack.(1822), the f i r s t w h i t e man  Newfoundland, t r a v e l l e d v a s t s e c t i o n s o f the i n t e r i o r w i t h o u t numbers o f a n i m a l s .  populations  levels.  The numbers o f c a r i b o u about 1890-1900 may Newfoundland herds.  limita-  The abundant p o p u l a t i o n o f 1900  to cross  seeing l a r g e  o c c u r r e d between t h e  dis-  appearance o f the I n d i a n s and n e a r l y a l l t h e w o l v e s , and a t t h e s t a r t o f the increase of lynx.  A l s o i n t h i s t i m e the main herds were l i g h t l y hunted because  91 t h e Newfoundland r a i l w a y was not completed u n t i l about 1898  ( D a v i s 1895).  The herds p r o b a b l y had a h i g h p o s i t i v e r a t e - o f - i n c r e a s e f o r many y e a r s tween t h e d i s a p p e a r a n c e  be-  o f wolves and t h e i n c r e a s e o f l y n x p r i o r t o heavy  hunting. Lynx P r e d a t i o n i n N a t u r a l S e l e c t i o n  The a d a p t a t i o n s o f c a r i b o u e f f e c t i v e a g a i n s t wolves may a disadvantage  when t h e y e n c o u n t e r l y n x .  place caribou at  T h i s would h e l p e x p l a i n t h e h i g h  c a l f l o s s e s caused by l y n x i n t h i s i n v e s t i g a t i o n .  L i n d r o t h (1963) c o n c l u d e d  t h a t t h e r e was no p o s t - g l a c i a l l a n d b r i d g e between Newfoundland and Thus c a r i b o u may  Labrador.  have been w i t h wolves but w i t h few o r no l y n x f o r many t h o u -  sands o f y e a r s . E l s e w h e r e I have suggested  (Bergerud 1961a) t h a t the c o m b i n a t i o n  of a  s y n c h r o n i z e d c a l v i n g season i n Newfoundland and t h e p o s t p a r t u r i e n t aggregat i o n s o f does w i t h c a l v e s was an e f f e c t i v e d e f e n s e a g a i n s t t h e open approach o f wolves.  This behaviour  i s of l i t t l e defense a g a i n s t l y n x .  bushes p r e y and t r a v e l s most a t n i g h t .  The l y n x  am-  In general a dispersed d i s t r i b u t i o n  i s more e f f e c t i v e a g a i n s t p r e d a t o r s t h a n c l u m p i n g , u n l e s s t h e c o o p e r a t i o n tween members i s s u f f i c i e n t l y e f f e c t i v e t o overcome t h e d i s a d v a n t a g e s c e n t r a t i o n ( H o l l i n g 1961  be-  o f con-  and S a l t 1967).  A g a i n , c a r i b o u a p p a r e n t l y a r e adapted t o p e r c e i v e m o t i o n ; a f e a t u r e important  i n d e t e c t i n g t h e approach' o f a t e s t i n g w o l f .  not show a l a r m r e a c t i o n s t o a man be  C a r i b o u u s u a l l y do  s t a n d i n g s t i l l and a crouched l y n x may  not  avoided. The  s e l e c t i o n by wolves t a k e s p l a c e most o f t e n d u r i n g a chase where.the  s i c k , young, s e n i l e , and c r i p p l e d , become conspicuous 1956,  and Mech 1966).  ( M u r i e 1944,  With l y n x , t h i s k i n d o f c u l l i n g i s l a r g e l y  Crisler absent.  92 Lynx p r e d a t i o n i s f o c u s e d almost e x c l u s i v e l y on t h e young.  The  conspicuous  prey f o r lynx i s the a c t i v e c u r i o u s c a l f that frequents t e r r a i n n e a r . s t a l k i n g • cover. Lynx p r e d a t i o n , i n t h e absence o f w o l v e s , has l i k e l y s t a r t e d t h e n a t u r a l s e l e c t i o n o f Newfoundland c a r i b o u i n a new d i r e c t i o n .  S e l e c t i o n may  now  f a v o r t h e h i d i n g o f c a l v e s and w i l l l i k e l y s t r e n g t h e n t h e m a t e r n a l bond. d i s t a n c e between t h e dam  and c a l f and t h e defense o f t h e c a l f w i l l now  t a k e on more importance t h a n r u n n i n g away.  A g a i n i t may  The  likely  be advantageous  to  have a l o n g e r c a l v i n g season w i t h w i d e l y d i s p e r s e d a n i m a l s r a t h e r t h a n congregations at calving.  Caribou that c a l f i n bleak t r e e l e s s habitats  likely  now have an advantage.  To c a l v e i n t h e open on t h e edge between bog  and  f o r e s t , i s to court disaster. However, t h e s t r u g g l e between l y n x and c a r i b o u i s not l i k e l y as e q u a l as t h a t between w o l f and c a r i b o u .  The l y n x s t i l l depends on t h e hare and i t s  a d a p t a t i o n s cannot d e p a r t t o o f a r from those which a r e e f f e c t i v e i n c a t c h i n g them.  Thus t h e c o n s t r a i n t s t o a d a p t i o n seem l e s s f o r c a r i b o u t h a n l y n x . C a r i b o u on t h e A v a l o n P e n i n s u l a show t h r e e b e h a v i o u r i s m s l a c k i n g • i n t h e  i n t e r i o r a n i m a l s t h a t seem a d a p t i o n s t o l y n x and s u p p o r t t h e i d e a o f such selection pressure.  The A v a l o n Herd has no s p e c i f i c c a l v i n g ground - t h e  a n i m a l s a r e w e l l d i s p e r s e d , t h e f e m a l e s do not form l a r g e p o s t - c a l v i n g aggreg a t i o n s , and c a l v i n g i s spread o v e r . t h r e e weeks r a t h e r t h a n two weeks as i n the i n t e r i o r (Bergerud 1961a). sembles t h e i n t e r i o r b a r r e n s .  P h y s i o g r a p h i c a l l y the Avalon Peninsula r e There i s a h i s t o r y o f wolves on t h e A v a l o n  P e n i n s u l a s i m i l a r to the i n t e r i o r .  One d i f f e r e n c e i s t h a t t h e c l i m a t e on t h e  A v a l o n i s more o c e a n i c t h a n i n t h e i n t e r i o r (Hare 1 9 5 2 ) . Gene flow.between t h e A v a l o n and I n t e r i o r herds has l i k e l y been s l i g h t s i n c e t h e c o n n e c t i n g isthmus became w e l l t r a v e l l e d by p e o p l e — p e r h a p s  100 t o  150 y e a r s ago.  I n t h i s I n t e r v a l t h e herd was reduced t o l e s s t h a n 100  f o r many-years. 10.  animals  The number o f e f f e c t i v e b r e e d i n g : s t a g s was l i k e l y o n l y 5 t o  N a t u r a l s e l e c t i o n i n s m a l l p o p u l a t i o n s can pro.ceed v e r y r a p i d l y ( F o r d  1 9 6 5 ) , and i t i s c o n c e i v a b l e t h a t t h i s has i n f l u e n c e d t h e r a t e o f a d a p t i o n o f t h e herd t o l y n x .  The d i f f e r e n c e s i n b e h a v i o u r between t h e two herds might  p a r t i a l l y e x p l a i n the 12 per cent r a t e - o f - i n c r e a s e of the Avalon p o p u l a t i o n :  v s . t h e 4 per c e n t a n n u a l g a i n f o r t h e I n t e r i o r Herd. L a s t l y , I b e l i e v e t h a t t h i s s t u d y i s a n o t h e r reminder o f t h e f r a g i l e b a l a n c e between p r e d a t o r and p r e y i n i n s u l a r f a u n a s .  I t i l l u s t r a t e s the long-  d e l a y e d but f a r - r e a c h i n g e f f e c t o f t h e i n t r o d u c t i o n o f snowshoe h a r e s , a p r e y s p e c i e s , i n t o a r e l a t i v e l y s i m p l e ecosystem.  new  94 SUMMARY  1.  The p o p u l a t i o n dynamics o f t h e c a r i b o u on t h e i s l a n d o f Newfoundland were i n v e s t i g a t e d 1957 t o 1967.  H i s t o r i c a l i n f o r m a t i o n on p o p u l a t i o n  s t a t u s was s e c u r e d 1900 t o 1956.  2.  Four c a r i b o u herds were r e c o g n i z e d and censused:  the Northern Peninsula -  450 a n i m a l s i n 1958 and 400 a n i m a l s i n 1966, t h e A v a l o n P e n i n s u l a Herd 125 a n i m a l s i n 1957 and 720 a n i m a l s i n 1967, t h e Humber R i v e r Herd 130 a n i m a l s i n 1956 and 115 a n i m a l s i n 1964, and t h e I n t e r i o r Herd 4600 i n 1957 and 6200 a n i m a l s i n 1966.  3.  The p o p u l a t i o n o f c a r i b o u was e s t i m a t e d a t 40,000 i n 19§0 and d e c l i n e d t o perhaps  4.  1000 t o 2000 a n i m a l s by 1930.  The p e r c e n t a g e o f does, 2 - y e a r s and o l d e r , t h a t gave b i r t h t o s i n g l e c a l v e s was 84.5 p e r c e n t (n = 6657).  E x c l u d i n g 2 - y e a r o l d does,  94 p e r cent o f t h e females were p r e g n a n t . 5.  N a t u r a l m o r t a l i t y o f a d u l t s , i n c l u d i n g a l l a n i m a l s o l d e r t h a n 6 months, was e s t i m a t e d a t 6 p e r cent f o r t h e A v a l o n P e n i n s u l a Herd.  6.  N a t u r a l m o r t a l i t y o f a d u l t s f o r t h e I n t e r i o r Herd was e s t i m a t e d a t 4 p e r c e n t f o r does, y e a r l i n g s , and 6 month - o l d c a l v e s , and 9 p e r cent f o r s t a g s .  7.  The m o r t a l i t y o f t h e t o t a l p o p u l a t i o n was 5 p e r c e n t .  H u n t i n g m o r t a l i t y o f a d u l t s i n t h e I n t e r i o r Herd was e s t i m a t e d . a t 11 p e r c e n t f o r . s t a g s and 3 p e r cent f o r does.  8.  The I n t e r i o r Herd i n c r e a s e d when t h e percentage o f c a l v e s i n t h e h e r d i n October exceeded.11 p e r cent f o r s e v e r a l c o n s e c u t i v e y e a r s .  95 9.  D u r i n g 9 y e a r s t h e r e was no e v i d e n c e t h a t c a l v e s d i e d d u r i n g t h e w i n t e r a t g r e a t e r r a t e s t h a n a d u l t s i n t h e w i n t e r o f 1958-59 c a l v e s may have died a t a greater r a t e than a d u l t s .  10.  Many c a l v e s d i e d i n t h e f i r s t summer o f l i f e , 30 p e r c e n t i n t h e A v a l o n P e n i n s u l a Herd and 69 p e r c e n t i n t h e I n t e r i o r Herd.  The  a v a i l a b l e e v i d e n c e s u g g e s t e d t h a t l y n x k i l l e d most o f t h e s e c a l v e s . 11.  The two major m o r t a l i t y f a c t o r s t h a t appear t o have l i m i t e d  population  growth o f c a r i b o u i n Newfoundland 1900 t o 1967 a r e l y n x p r e d a t i o n o f c a l v e s and h u n t i n g m o r t a l i t y o f a d u l t s . recruitment  A c o m b i n a t i o n o f poor  and h i g h h u n t i n g m o r t a l i t y p r o b a b l y  caused t h e d e c l i n e o f  t h e h e r d s 1915 t o 1930. The p r i m a r y l i m i t i n g f a c t o r o f t h e a n i m a l s i n t h e I n t e r i o r and A v a l o n h e r d s , 1957 t o 1967 appeared t o be l y n x p r e d a t i o n o f c a l v e s i n t h e i r f i r s t summer o f l i f e . was p r o b a b l y  an i m p o r t a n t  Illegal  hunting  check on p o p u l a t i o n growth o f t h e N o r t h e r n  P e n i n s u l a and Humber R i v e r h e r d s 1957 t o 1967.  LITERATURE CITED  Andrewartha, H.G. £ L.C. B i r c h . of animals.  Univ. o f Chicago P r e s s , C h i c a g o , 111. 782 p.  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Mgmt.  1946.- The puma m y s t e r i o u s American c a t .  I n s t i t u t e , Washington, D.C.  358 p.  APPENDIX I  TABLES  T a b l e 1.  105  Sex and age c a t e g o r i e s used d u r i n g t h e s t u d y  Sex and Age C a t e g o r i e s  Spring  Summer  Fall  Winter  C l a s s i f i c a t i o n s from Ground Stags Adult  X  Large  X  Medium  X  Small  X  Senile 2-year o l d Does Adult  x  Non-parous Pregnant With udder and c a l f With udder no c a l f Yearlings Male  X  Female  X  Sex unknown  x  X  X  Calves Male  X  Female Sex unknown  X X  C l a s s i f i c a t i o n s from h e l i c o p t e r  Spring  Adult  Summer x  Fall  Winter  X  Stag Yearling  X  Doe  X  Calf  X  X  Adult  X  X  Stag  X  C l a s s i f i c a t i o n s from f i x e d - w i n g aircraft  Yearling Doe Calf  X  X  107  T a b l e 2.  Age c o m p o s i t i o n o f t h e I n t e r i o r Herd based on t h e lower mandibles  Age i n  of  stags •  Number o f mandibles  years  2  3  1951-53*  6  1956-58  Total  4-6  7-9  10+  15  17  7  1  46  7  21  37  19  6  90  1961  . 13  23  29  34  12  111  1962  8  52  56  37  16  169  1963  6  10  65  19  17  117  1964  4  29  40  •5  9  87  1965  8  11  44  6  4  73  52  161  127  65  693  Totals  288  * i n c l u d e s some f e m a l e s , remainder  o f c o l l e c t i o n stags  T a b l e 3.  The age c o m p o s i t i o n o f c a r i b o u k i l l e d by h u n t e r s 1961-63,' from counts o f a n n u l i i n i n c i s o r s .  Number o f . s t a g s k i l l e d  Age (years)  1961  1962  1963  Total  13  8  6  27  15  41  13  69  7  24  23  54  11  .11  28  50  6  11  7  24  Ik  6  5  10  21  8k  14  6  9  29  • 4  11  6  21  4  4  3  .11  2  4  -  6  2  4  -  6  13k  -  -  -  -  142g  -  -  1  1  15%  -  -  -  -  16k  -  -  1  1  84  . 129  107  320  3k  '  5h  10^ nk  Totals  109 T a b l e 4.  C a r i b o u k i l l e d from t h e I n t e r i o r Herd d u r i n g l e g a l h u n t i n g seasons 1935 t o 1966.  Hunting  Caribou  Hunting  Sold  Killed  Season  1935  33  6  1951  8669  369  1936  65  14  1952  6523  270  1937  82  14  1953  5196  266  1938  80  11  1954  5754  158  1939  100  20  1955  6696  183  1940  100  20  1956  8654  193  1941  234  45  1957  8797  205  1942  220  24  1958  102*  56  1943  294  35  1959  164  82  1944  296  24  1960  200  128  1945  2475  113  1961  300  185  1946  3846  159  1962  '354  243  1947  5048  177  1963  358  203  1948  5159  232  1964  336  161  1949  5930  221  1965  384  196  1950  7200  234  1966  763  366+  Season  Licenses  * 1935' t o 1957 one b i g game h u n t i n g l i c e n s e s  Licenses Sold  Caribou Killed  v a l i d f o r e i t h e r one  moose o r one c a r i b o u , 1959 t o 1966 h u n t i n g a l l o w e d f o r s t a g s o n l y  T a b l e 5.  Numbers o f c a r i b o u from a e r i a l and t r a c k census  Total caribou Year  Avalon Peninsula  Humber  Northern  River  Peninsula  1956  . 71**  130  1957  86**  100  1958  86**  105  1959  HI**  100  1960  206**  130  1961  350  1962  409-  1963  —  1964  508  1965  51.8  1966  650  1967  720  Interior  Brunette  Herd*  Island  4600 450 4800  6100 114  17  99  27  115  54 400  6200  78 100  * La P o i l e p o p u l a t i o n n o t i n c l u d e d , e s t i m a t e d 1300 animals  40  5700  and 1966 a t 1500  ** b e l i e v e d t o be undercounted  1964 a t  in  Total Caribou Year  La P o i l e  Buchans  Grey  Sandy  Pot  River  Plateau  River  Lake  450+  1200  75  250  200  ?  Hill  Middle Ridge  Mount Peyton  1960  500  1962  650  1000  1300  73  544  502  178  1963  692  643  1800  212  420  265  165  1964  ?  1341  1772  123  275  358  257  1965  800  892  2400  161  333  560  253  112  T a b l e 7.  Age o f females c o l l e c t e d i n :June and -reproductive condition  T o t a l Sample Nonparous Age i n  Pregnant  years  Ovulated  Never  prior f a l l  ovulated  2  1  8  3  2  H-6  8  2  1  7-9  1  1  —  10+  5  5  1  6  113  T a b l e 8.  Parous does i n t h e I n t e r i o r Herd i n p e r cent based on udder counts i n June  Parous f e m a l e s ( 2 - y e a r s and o l d e r ) Year  T o t a l sample size  Buchans  Grey  Pot  Middle  Other  Plateau  River  Hill  Ridge  pop.  85.5  Total all  pop.  91.4  1957  245  94.2  93.2  1958  464  81.9  84.7  1959  932  92.1  92.4  1960  654  76.6  79.6  1961  362  76.3  1962  742  76.3  1963  878  93.6  1964  286  88.8  1965  534  84.2  95.7  79.0  1966  772  79.1  92.6  85.3  1967  788  80.4  89.5  77.7  88.2***  83.2  83.1  91.0  83.6  83.6  84.5  (768)  (378)  (6657)  Weighted Means sample s i z e * Sandy Lake ** L a P o i l e s'cftj't Mt.  Peyton  85.2 (2085)  83.2 88.4  91.1 78.1  91.4*  76.8 66.2  72.1  70.8  82.6  77.2  89.1  90.4  91.7  94.8  91.3  (1681) (1750)  .  .81.3**  85.0 83.7  114  T a b l e 9.  The sex  r a t i o o f a d u l t s i n t h e I n t e r i o r Herd .i n October and November  Percentage of.stags  Total sample  "La P o i l e  Buchans  Grey-  Pot  Middle  size  River  Plateau  River  Lake  Hill  Ridge  ± .95 c.1.  1957  1265  33  32  31  25  23  30  32.2± 2. 6  1958  1306  —  —  31  37  28  —  31.9± 2. 5  1959  437  —  —  —  . 34  15  —  27.9± 4. 2  1960  266  —  —  27  30  —  —  28.6± 5. 4  1961  101  —  —  -— '  30  —  —  29.7± 8. 9  1962  425  —  —  36  29  —  —  30.8± 4. 4  1963  1152  28  26  29  18  21  29  24.3± 2. 5  1964*  597  31  34  35  27  28  40  31.7± 3. 7  1965  748  28  25  27  21  —  36  25.8± 3. 1  1966  780  19  .21  28  23  —  —  22.8± 2. 9  Year  Sandy  Total  * b i a s e d towards s t a g s s i n c e count made on t h e peak days o f r u t : R e g r e s s i o n o f s t a g p e r c e n t a g e s on y e a r s ( e x c l u d e s 1964) was: Y = 8 3 . 9 0 - 0.910 X where X e q u a l s t h e l a s t two d i g i t s o f t h e y e a r  T a b l e 10.  115  Age c o m p o s i t i o n o f c a r i b o u i n t h e Buchans P l a t e a u p o p u l a t i o n c a p t u r e d a t Lake V i c t o r i a i n November 1963 and 1964  Age (Years)  T o t a l Animals Stags  P e r c e n t a g e o f Animals  Does  Total  Stags  Does  Total  k  12  15  •27  28.8  15.2  19.2  ik  4  •5  9  9.5  5.1  6.4  2k  2  4  6  4.8  4.0  4.3  3k  9  14  23  21.4  14.2  16.3  ±k  3  16  . 19  7.1  16.2  13.5  5k  4  9  13  9.5  9.1  9.2  6k  3  9  . 12  7.1  9.1  8.5  ik  -  4  4  4.0  2.8  8k  1  6  7  6.1  5.0  9k  -  1  1  1.0  0.7  iok  -  1  .' 1 '  1.0  0.7  uk  -  3  . 3  3.0  2.1  12k  -  -  -  13k  -  1  1  1.0  0.7  mk  -  1  1  •1.0  0.7  4  10  14  10.1  9.9  42  99.  141  unknown Totals  mean age 3g-14Jg y e a r s :  2.4  9.5 . 100.1  s t a g s 3 .0 y e a r s and does 4. 7 y e a r s  mean age 3%-14lg* y e a r s :  s t a g s 4.8 y e a r s and does 6.0 y e a r s  * c a l c u l a t e d t o reduce h u n t e r '.b i a s o f n o t s h o o t i n g year-old stags  100.0  k-2k  99.9  T a b l e . 11.  C a l c u l a t i o n o f m o r t a l i t y rates f o r the Avalon  116  P e n i n s u l a Herd  Total  Per c e n t  Total  Population  Natural  caribou i n  calves i n  number o f  minus  mortality  October  October  calves  calves  1961  350  21.3  75  275  1962  409  19.6  80  329  14.5  —  Year  .  1963  per  cent  6.0(21/350)  1964  508  17.7  99  409  1965  518  9.8  51  467  8.1(41/508)  1966  '650+27*  26.1  170  507  2.1(11/518)  1967  720+26+25*'*  19.4  140  631  6.8(46/677)  5.8(119/2053)  N a t u r a l M o r t a l i t y Rate 1966  650***  26.1  170  480  7.3(38/518)  1967  720***  19.4  140  580  10.8(70/650)  M o r t a l i t y Rate  8.4(170/2026)****  * p l u s 27 k i l l e d i n September 1966 ** p l u s 26 k i l l e d i ni September 1967 and 25 k i l l e d i n September 1966 (27-C27 x .06) *** These f i g u r e s used i n comparison w i t h r a t e - o f - i n c r e a s e s t a t i s t i c s based on a h e r d i n c r e a s e from 350 i n 1961 t o 720 i n 1967 and include hunting m o r t a l i t y **** i n c l u d e s f i g u r e s from 1962 and 1965 (above)  117  T a b l e 12.  P e r c e n t a g e o f c a l v e s a t 6-months-of-age  Per Cent C a l v e s  Total Year  Caribou in  i n t h e I n t e r i o r Herd  La  Buch-  Grey  Weighted  Eastern  Central  Western  Sandy  Middle  Pot  means ± .95 conf. l i m i t s  River  Lake  Ridge  Hill  8.3  4.4  3.8  9.0  7.2  5.5 ±  1.0  *  16.7  13.0  10.5  16.0  15.0 ±  1.5  20.1  19.0 ±  3.1  12.6 ±  2.0  10.6 ±  3.3  3.3  7.8 ±  1.6  A  4.3  8.4 ±  1.4  12.3  51  6.3  8.3  10.8  A  21.8  10.8  11.6  27.1  26.4  20.2  Weighted Means  . 19.8  15.2  11.3  Sample S i z e s  (1418)  Sample  Poile  ans  1957  2057  6.3  1958  2253  A  1959  621  1960  1057  15.1  9.9  10.8  1961  331  *  13.0  4.4  1962  1025  10.9  5.7  8.5  1963  1567  13.0  8.2  8.9  13.6  1964  725  17.3  17.6  9.2  1965  893  25.7  15.8  1966  1126  :22.6  1967  839  17.5 A  '  9.9  (2457) (2529) (3397)  11.6 ± 2.3 15.1 ±  2.3  17.6 ±  2.2  24.7 ± 2.9  —-  10.3  11.1  (564)  (2129)  * p e r c e n t a g e s n o t shown f o r samples l e s s t h a n 100 a n i m a l s  13.4 ±  0.6  (12 ,494)  T a b l e 13.  118 C o m p o s i t i o n o f t h e I n t e r i o r and A v a l o n P e n i n s u l a herds i n October - November based on t h e assumption t h a t  calf  m o r t a l i t y beyond 6-months-of-age i s s i m i l a r t o t h a t o f a d u l t s  Composition o f the herd i n p e r cent Year  Interior  Avalon Peninsula Does  Yrs.  Calves  28,.3  42..7  11.,6  17.,4  15. 0  26.,7  40,.5  14..2  18.,6  12..2  19. 0  23.,6  35,,7  13.,6  27.,1  50..0  16.,6  12. 6  22,.2  33,.5  20..7  23..7  22..2  55..9  11.,3  10. 6  23,,9  36,.2  18,.6  21,,3  1962  22..3  60.,1  9.,8  7. 8  25,.4  38,.3  17..3  19..6  1963  22.,5  62,.0  7.,1  8. 4  27,.3  41,.4  16,.8  14,.5  1964  20..8  60..2  7.,4  11. 6  28,,2  42,.6  12,.0  17,,7  1965  18..6  • 56,.5  9..8  15. 1  29,.5  44,.7  16..0  9,.8  1966  16.,7  53,.3  12..4  17. 6  26,.5  40,.1  7,.2  26,.1  1967  14..2 • 47,.8  13,,3  24. 7  23,.7  35,.8  21,.0  19,.5  55..3  10..3  13. 4  25,.9  39,.2  15..4 . 19,.6  Stags*  Does  1957  28.,0  59..3  7.,2  5. 5  1958  25..0  55..3  4.,7  1959,  20.,8  48..0  1960  20..8  1961  Means  .21..1  Yrs.  Calves  Sta£  * sex r a t i o o f t h e I n t e r i o r Herd based on t h e r e g r e s s i o n Y =83.90 0.91 X, T a b l e 9:  sex r a t i o o f t h e A v a l o n Herd based on 39.8 p e r  c e n t m a l e s , counts made i n 1956, 1958, 1959, 1960, 1961, and 1964, n = 518.  T a b l e 14.  Causes o f n a t u r a l . m o r t a l i t y o f a d u l t s , 1957  Mortality factor  t o 1967  Number d y i n g females  males  —  4  Interactions Locked A n t l e r s Gored  1  2  Broken neck  —  3  Unknown  —  6  Died i n p a r t u r i t i o n  6  Senility  1  2  Accidents Drowned  2  Crippled front legs  1  2  Nose-bots i n c r a n i a l c a v i t y  -  1  Predation Lynx  1  Bear  -  1  120  T a b l e 15. Common p a r a s i t e s o f Newfoundland  Common  Scientific  name  name  caribou  Number o f C a r i b o u  Minimum  examined  frequency  Warble F l y  Oedemagena t a r a n d i  51  100  Roundworm  Ostertagia  14  86  Nose B o t  Cephenomyia trompe  60  83  Roundworm  Ostertagia  gruhneri  9  78  Rumen F l u k e  P aramph i s t omum s p .  26  69  Roundworm  Elaphostrongylus sp.  9  55  Roundworm  Pneumostrongylus s p .  5  40  Lungworm  Dictyocaulis 37  38  35  47  mossi  (Micrurocaulus) e c k e r t i Roundworm  Nematodirus  filicollis  and o r N e m a t o d i e r e l l a longissimespiculata  121 T a b l e 16.  The p r o p o r t i o n o f males from b i r t h t o 12 months o f age i n a n n u a l c o h o r t s i n t h e I n t e r i o r Herd  Per Cent Male Year  1957  1-4  At  5-6  birth  weeks  months  —  —  • —  10  12  months  months  —  1958  54(35)*  50(121)  35(204)  1959  50(34)  49(273)  36(58)  1960  52(86)  49(197)  **(19)  1961  56(57)  45(40)  **C5)  —  39(108)  1962  49(67)  44(251)  **(19)  —  41(74)  1963  43(35)  46(424)  40(52)  —  **(13)  1964  51(76)  42(102)  40(30)  —  60(43)  1965  —  50(265)  —  —  46(142)  1966  ft*(12)  55(351)  —  —  48(109)  1967  —  47(261)  —  —  —  48±2(2285)  38±5(387)  42±12(81)  T o t a l s ± 95% C L . 52±5(402)  * sample s i z e s i n p a r e n t h e s e s ** p e r c e n t a g e s n o t l i s t e d f o r l e s s t h a n 20 a n i m a l s  35(23)  44(43)  — 45(58)  35(69) 33(91) 32(122)  41±3(814)  T a b l e 17.  C a l c u l a t i o n of s u r v i v a l o f calves i n the Avalon Peninsula Herd t o  Year  P e r Cent  6-months-of-age  P e r Cent o f Herd  Newborn  Per cent of  % s  of x  calves born  parous  Adult  2-Year  calves/100  c a l v e s i n Herd  calves  doesCl)  doe(2)  doe(3)  caribou(4)  J u n e ( 5 ) Nov.(6) 6 mo.(7)  1958  80.3  42.7  6.1  39.2  28.2  18.6  56.4  1959  75.8  40.5  7.5  36.4  26.7  •27.1  98.9  1960  74.1  35.7  7.2  31.8  24.1  23.7  94.9  1961  62.2  33.5  11.0  27.7  21.7  21.3  94.7  1962  67.0  36.2  9.8  30.8  23.5  19.6  77.0  1963  70.3  38.3  9.2  33.4  25.0  14.5  • 49.4  1964  73.5  41.7  8.6  37.0  27.0  17.7  56.4  1965  79.8  42.6  6.3  39.0  28.1  9.8  27.0  1966  76.0  44.8  8.3  40.4  28.8  26.1  84.7  1967  86.4  40.1  3.8  37.9  27.5  . 19.5  '61.9  Means  74.5  39.6  7.8  35.4  26.7  19.8  70.1  Calculations: .Cl) c a l c u l a t e d from t h e r e g r e s s i o n Y = 100.12 - 1.40X  (Figs.- -7)  assumed t h a t t h e f e r t i l i t y o f does on t h e A v a l o n P e n i n s u l a i s s i m i l a r t o t h a t i n t h e I n t e r i o r Herd. (2) and C6) from T a b l e 13, (6) based on October-November  c a l f counts  (3) from y e a r l i n g s i n T a b l e 13 c o r r e c t e d f o r females on b a s i s o f sex r a t i o o f calves i n October (4) ( a d u l t does + 2-year does) x ( p e r c e n t parous does) (5) (newborn c a l v e s ) / (newborn c a l v e s + (7) sample c a l c u l a t i o n s 1958:  100)  s^ = (18.6 x 71.8 x 97.0) / (28.2 x 8 1 . 4 ) ,  81.4 = 100.0 - 18.6,.71.8 = 100.0 - 28.2, 97.0 = a d u l t s u r v i v a l \ y e a r  T a b l e 19.  The age c o m p o s i t i o n o f c a r i b o u d y i n g from n a t u r a l causes  Age  Number found*  Percentage  < 1 Month  47  52  1-3 Months  19  21  3-6 Months  13  14  6-12 Months  6  6  C a l f Unknown  6  6  91  99  1-2 Years  0  —  2-3 Years  6  14  3-4 Years  5  12  4-6 Years  16  38  7-9 Years  9  21  10+ Years  6  14  42  99  Calf Total  Adult Total  * does n o t i n c l u d e c a l v e s l i s t e d i n T a b l e 26  124  T a b l e 18.  P e r cent c a l v e s i n t h e Humber R i v e r Herd i n t h e F a l l and W i n t e r  Year  Total  born  caribou  Classified  1957  100  80  • 5.0 ± 2 . 1  1958  105  80  - 21.6 ± 4.4  1959  100  70  1960  130  T o t a l Caribou  P e r Cent C a l v e s ± 95 % C.L.*  35.7  130  10.0  65  10.8  1961  + 6.1  ±4.8  1962  114  74  6.8 ± 3.4  1963  99  87  12.3 ± 2.4  108  84  14.6  Means  * 95 p e r cent C L . = (1.96/ p x q / n) (/ N-n / N) ** h e r d e s t i m a t e d a t 108 a n i m a l s  T a b l e 20.  125  C a l c u l a t i o n o f s u r v i v a l o f c a l v e s o f t h e I n t e r i o r Herd u n t i l 6-months-of-age  Year calves born  P e r Cent parous does(l)  A d u l t Does per  100  caribou(2)  2 Y r . Does per  100  Newborn calves/100  caribou(3)  Per Cent o f  % s  calves i n herd  of X  calves  c a r i b o u ( 4 ) J u n e ( 5 ) Nov.(6) 6 mo.(7)  1958  89.5  59.3  4.3  56.0  36.2  . 15.0  29.4  1959  92.4  55.3  2.6  53.5  34.8  19.0  41.5  1960  79.1  48.0  7.9  44.2  30.7  12.6  30.8  1961  73.5  50.0  10.9  44.8  30.9  10.6  25.1  1962  82.5  55.9  7.0  51.9  34.2  7.8  15.4  1963  85.3  60.1  6.0  56.4  36.1  8.4  15.3  1964  89.2  62.0  4.1  60.0  37.5  11.6  20.7  1965  88.4  60.2  4.3  •57.0  36.3  15.1  29.5  1966  83.9  56.5  4.7  51.3  33.9  16.7  36.9  1967  79.0  53.3  6.6  47.3  32.1  24.7  65.6  Means  84.3  56.1  5.8  52.3  34.3  14.2  31.0  Calculations: (1) c a l c u l a t e d from t h e r e g r e s s i o n Y = 100.12 - 14.40X ( F i g s .  7)  (2) from T a b l e 13 (3) from y e a r l i n g s T a b l e 13, sex r a t i o s from T a b l e 16 (4) ( a d u l t does + 2-year does) x ( p e r c e n t parous does) (5) (newborn c a l v e s ) / (newborn c a l v e s +  100)  (6) October-November c o m p o s i t i o n counts T a b l e 12 (7) sample c a l c u l a t i o n s f o r 1958: 63.8 = 100.0  s  - 36.2, 85.0 = 100.0  = (15.0 x 63.8 x 94.5)  / (36.2 x  85.0)  - 15.0, 94.5 = a d u l t s u r v i v a l \ y e a r  126  T a b l e 21.  Comparison o f o b s e r v a t i o n s  o f y e a r l i n g c a r i b o u made by  the w i l d l i f e s t a f f i n May and June on v a r i o u s  calving  grounds o f t h e I n t e r i o r Herd  Total Year  Y e a r l i n g P e r 100 Does  sample  Buchans  Grey  Pot  Middle  Other  Weighted  size  Plateau  River  Hill  Ridge  Areas  Means*  1957  1322  4.5  —  2.2  0.5  1958  1917  9.5  —  3.6  2.5  1959  2331  10.9  7.5  14.6  8.9  1960  2788  22.7  17.1  22.6  28.6  47.5  28.7  1961  1846  • 21.6  —  10.6  —  23.9  21.0  1962  1656  14.0  11.9  4.3  13.4  17.5  12.3  1963  1675  7.3  11.5  1.0  6.6  6.3  7.4  1964  370  7.1  A  2.6  —  —  6.6  1965  806  —  6.2  —  7.3  —  6.4  1966  927  —  10.6  4.7  27.5  35.2  19.9  1967  863  —  14.1  14.7  21.2  12.2  12.1  8.1  12.9  (4895)  (3113)  Weighted Means Sample S i z e s  (3372) (2713)  2.9  —  5.4 10.1  18.5  —  12.7  (2409) (16,501)  * f i g u r e s n o t shown f o r samples o f l e s s t h a n 100 a n i m a l s  T a b l e 22.  Year  The p e r c e n t a g e o f young c a r i b o u a t 6 and 24-months-of-age  Animals  Does C l a s s i f i e d  Counted  2 Years L a t e r  a t 6 Mo.*  Adult  2 Years  W i n t e r Exposed to  Mortality  As C a l v e s  As Y r s .  127  P e r Cent o f population  6 Mo.**  24  6.9 ± 1.8**  1957  796  908  24  1957-58  1958-59  5.0  1958  1443  584  35  1958-59  1959-60  16.3 ± 1.9  1959  239  320  41  1959-60  1960-61  21.3 ± 5.2 .' 18.3  1960  677  427  34  1960-61  1961-62  13.1 ± 2 . 5  12.9  1961  216  211  19  1961-62  1962-63  13.0 ± 4 . 5  14.8  1962  526  273  13  1962-63  1963-64  7.8 ± 2.3  8.9  1963  912  512  22  1963-64  1964-65  6.9 ± 1.6  8.1  1964  339  487  18  1964-65  1965-66  6.8 ± 2.7  8.6  1965  255  750  38  1965-66  1966-67  9.4 ± 3.6  10.5  9.5  * i n c l u d e s o n l y t h o s e p o p u l a t i o n s i n which b o t h June counts o f does and October c a l f counts were a v a i l a b l e . ** 95 p e r c e n t c o n f i d e n c e l i m i t s *** a d u l t s t a g s c a l c u l a t e d on t h e b a s i s o r t h e r e g r e s s i o n Y = 8 3 . 9 0 0.910 X ( T a b l e '9), 2 y e a r - o l d s t a g s c a l c u l a t e d on t h e b a s i s o f t h e p e r c e n t a g e o f males i n c o h o r t s 5-12 months-of-age ( T a b l e 1 6 ) , and 2-year-old-does c o r r e c t e d on t h e assumption t h a t 38.45 p e r c e n t o f t h e young does were n o t r e c o g n i z e d  T a b l e 23.  M o r t a l i t y o f c a l v e s by 2-4 weeks o f age based on counts o f does w i t h udders w i t h and w i t h o u t c a l v e s  Year  Females  calves  in  Buchans  Grey  Pot  Middle  born  sample  Plateau  River  Hill  Ridge  1957  165  33  —  35  —  34  1958  183  —  —  16  —  16  1959  581  9  —  —  6  8  1960  249  —  33  37  —  35  1961  245  14  —  19  —  16  1962  481  18  49  26  —  32  1963  328  27  —  44  —  37  1964  261  17  —  65  —  37  1965  454  —  . 38  51  15  . 35  1966  339  —  49  27  1967  589  —  30  21  17  24  17 •  38  32  11  27  (953)  (934)  (1502)  Weighted Means Sample S i z e s  C a l f M o r t a l i t y i n P e r Cent Weighted Means  37  (486)  (3875)  129  T a b l e 24.  Loss o f c a l v e s u n t i l 6-months -of-age i n 1957 ;  Month  C a l v e s observed p e r 100 does  and  Buchans  Grey  Week  Plateau  River  B i r t h , May 4  94  June 1  72  Pot H i l l and  Middle  Sandy Lake  Ridge  93  86  67  53  June 2  73  59  —  June 3  —  57  48  June 4  60  —  —  July 4  41  31  —  7  —  —  6  6  —  August 4 September  3-4  October 1  27  7*  —  October 2  —  6*  —  October 3  —  9*  —  October 4 November 3  13  November 4  .13  Total  c a r i b o u c l a s s i f i e d 1449  g ft  —  16  8*  —  13  —  —  2758  769  703  * The apparent i n c r e a s e i n t h e number o f calves; p e r 100 does from t h a t shown f o r e a r l i e r counts l i k e l y r e s u l t e d from sampling e r r o r s  T a b l e 25.  Percentage  o f c a l v e s i n t h e I n t e r i o r Herd i n f a l l  based on h u n t e r l i c e n s e r e t u r n s  Hunting  Caribou  P e r Cent C a l v e s  Season  i n Sample  ' ± .95 Conf. L i m i t s  1951  653  1952  440  8.2  + 2.6  1953  862  7.3  + 1.7  1954  499  5.6  + 2.0  1955  290  5.5 + 2.6  1956  434  5.4  + 2.1\  1957  681  6.9  + 1.9  1958  217  11.1  + 4.2  1959  567  13.5  + 2.8  1960  1002  13.7  + 2.1.,.  1961  1646  12.2  + 1.6  1962  1699  10.0  +  1963  1399  10.9  + 1.6  1964  1193  13.4  + 1.9  1965  1389  13.4  + 1.8  1641  14.9  +  1966  N  11.5 + 2.4  1.7  * t h e r e are f o u r runs i n t h e above s e r i e s which i s a s i g n i f i c a n t d e p a r t u r e from a random s e r i e s a t t h e 95 p e r cent c o n f i d e n c e level (Siegel  1956)  T a b l e 26.  Causes o f n a t u r a l m o r t a l i t y o f c a l v e s 1957 t o 1967 131 Number o f C a l v e s  Causes o f Mortality  Females  Males  Sex Unknown  D i s e a s e and i n f e c t i o n s 27  30  27  abscesses  2  —  1  Infected u m b i l i c a l cord  2  —  1  —  1  1  —  —  6  S t i l l b i r t h (cause unknown)*  2  2  1  P a r a l y s i s carpus  1  —  —  1  —  —  —  1  —  1  —  —  —  —  1  1  1  —  Drowned  —  —  2  Trampled  —  1  —  M i r e d bog h o l e  —  1  —  3  1  —  Bear .  —  —  1  Possible winter starvation  —  —  2  Totals  40  38  P a s t e u r e l l a multocidav. Brain or lung  Pneumonia Birth  anomalies  Breach  birth  extensor  Blind Legs deformed Subaortic septal defect Cleft l i p Accidents A n t l e r stab  Predation Lynx  43  * 26 a n i m a l s t e s t e d f o r B r u c e l l o s i s , a l l n e g a t i v e ( P e t e r s ' £• •' K i n g 1959)  T a b l e 27.  D e c l i n e o f t h e l y n x p o p u l a t i o n from t r a p p i n g a t M i d d l e R i d g e , 1965.  T o t a l lynx trapped  Date Males  Females  Total  10  2  12  3  1  4  March 15-31  8  6  14  April  1-14  1  2  3  April  15-30  -  -  -  February March  15-28  1-14  May  1-14  2  "i  3  May  15-31  1  2  3  1-14  1  -  1  26  .' 14  June Totals  * 4 l y n x t r a p p e d date unknown  40*  APPENDIX I I  REPRODUCTIVE HISTORY OF THE CARIBOU AS REFLECTED IN THE ANATOMY AND HISTOLOGY OF THE OVARIES AND UTERUS  by  H . T . G i e r and G.B. Marion  Kansas S t a t e  University.  A l l o v a r i e s r e c e i v e d have been weighed, measured, and hand s l i c e d i n t o s e c t i o n s o f 2 t o 2.5  mm.  thickness.  Corpora l u t e a , corpora  and f o l l i c l e s were measured and t a b u l a t e d .  Representative  s e c t i o n s from  each ovary were embedded i n p a r a f f i n , s e c t i o n e d a t 8p, and one from each was  s t a i n e d i n each o f (1) h a e m a t o x y l i n - a c i d  rubra,  slide  fuchsin,  (2) M a l l o r y ' s t r i p l e s t a i n , and (3) p e r i o d i c a c i d S c h i f f (P.A.S.) S e c t i o n s were s t u d i e d c o n c u r r e n t l y by Dr. G.B.  Marion and me,  and  s i g n i f i c a n t s t r u c t u r e s a n a l y z e d and n o t e d . The  u t e r i were weighed a f t e r r e m o v a l o f excess m e s e n t e r i e s ,  measurements were t a k e n on c e r v i x , body, and b o t h h o r n s .  The  were s p l i t a l o n g t h e d o r s a l w a l l and opened f o r e x a m i n a t i o n ment o f c a r u n c l e s .  Representative  a g a i n a f t e r t h e d o r s a l w a l l was  and  horns  and measure-  t r a c t s were photographed i n t a c t  removed.  and  H i s t o l o g i c a l s e c t i o n s were  t a k e n t h r o u g h one u t e r i n e h o r n , and i n s e v e r a l specimen, from t h e vagina.  RESULTS  O v a r i e s from 58 c a r i b o u were examined. 16-20 The  mm  ovary  l o n g , 10-15  mm b r o a d , 6-12  mm  T h e \ n o r m a l . o v a r i e s were  t h i c k , and weighed 0.5  t o 1.2  c o n t a i n i n g t h e corpus luteum o f pregnancy weighed 1.1  Each ovary was  to 2  a t t a c h e d at b o t h ends i n the o v a r i a n l i g a m e n t , and  the a n t e r i o r - v e n t r a l b o r d e r by the mesovarium.  The  gm. gm.  along  oviducal funnel  a t t a c h e s t o t h e l a t e r a l end o f the ovary and i s i n l o o s e c o n t a c t w i t h the a n t e r i o - d o r s a l surface of the Ovaries  ovary.  c o n t a i n e d . f o l l i c l e s a t a l l seasons o f t h e ..year, r e g a r d l e s s  o f the s t a t e o f r e p r o d u c t i o n .  Even the o v a r i e s from two-year o l d does  c o n t a i n e d s e v e r a l f o l l i c l e s from 2 t o 5 mm  d i a m e t e r i n J u n e , a l l the  . 135 l a r g e r ones b e i n g a t r e t i c .  I n October and November, a l l non-pregnant  does had one t o f o u r f o l l i c l e s 3 t o 7 mm  diameter which appeared' t o be  h e a l t h y , f u n c t i o n a l s t r u c t u r e s . F o l l i c l e s o f 6 t o 8 mm may  ovulate.  A corpus luteum, formed a f t e r o v u l a t i o n , r e g u l a r l y e n l a r g e s t o 10-12 and i s lemon y e l l o w t o orange i n f o r m a l i n - f i x e d specimens.  mm  Such t r e a t -  ment does not s e r i o u s l y change t h e c o l o r o f c o r p o r a l u t e a i n dogs and cows, so p r o b a b l y does not i n c a r i b o u . A corpus luteum reaches maximum s i z e , i n a few days ( p r o b a b l y  5-8)  and m a i n t a i n s f u l l f u n c t i o n a l c o n d i t i o n u n t i l two o r t h r e e days b e f o r e the next o v u l a t i o n - b a r r i n g conception. t h e corpus  I n t h e event o f pregnancy,  luteum remains f u l l s i z e , and a p p a r e n t l y f u l l y  functional  u n t i l a f t e r p a r t u r i t i o n , t h e n r e g r e s s e s over a two month p e r i o d t o a mass o f b l o o d v e s s e l s w i t h s m a l l c l u s t e r s o f " r u b r a " c e l l s between. The  " r u b r a " c e l l s are r a t h e r l a r g e , f a t t y c e l l s t h a t c o n t a i n c o n s i d e r a b l e  q u a n t i t i e s o f a red-brown pigment t h a t g i v e s t h e c o r p o r a r u b r a t h e i r c h a r a c t e r i s t i c reddish color.  Corpora r u b r a r e g r e s s t o a  mass a p p r o x i m a t e l y 2x3x4 mm mm  i n a year.  They may  reddish-brown  i n about 6 months, and t o a s t r i n g about 1x2x4  remain g r o s s l y v i s i b l e and  histologically  d e t e c t a b l e f o r s e v e r a l y e a r s , a c c o u n t i n g f o r 8 t o 12 c o r p o r a i n o l d does.  E s t r o u s c y c l e s o f t h e p a s t season were d e t e r m i n a b l e by t h e s i z e  o f t h e c o r p o r a r u b r a ( o v e r 2 mm  i n t h e l e s s e r dimension) and t h e l o o s e  mass o f b l o o d v e s s e l s w i t h s m a l l lumena and t h i c k w a l l s .  The  blood  v e s s e l s were n e a r l y gone w i t h i n a y e a r . R e g r e s s i n g f o l l i c l e s were n e v e r found t o l u t e i n i z e o r produce "accessory corpora l u t e a . "  Rather, the t y p i c a l process of a t r e s i a ,  found i n f o l l i c l e s o f a l l s i z e s a t a l l s e a s o n s . c o n s i s t e d o f (1) l o o s e n i n g and d e g e n e r a t i o n o f t h e c e l l s o f t h e s t r a t u m granulosum, (2) aedema  o f t h e t h e c a i n t e r n a , (3) g r a d u a l , i r r e g u l a r c o l l a p s e o f t h e  follicle,  and (4) h y a l i n i z a t i o n o f t h e r e m a i n i n g t h e c a , l e a v i n g a s m a l l w h i t i s h s t r e a k b a r e l y v i s i b l e w i t h t h e u n a i d e d eye, but r e a d i l y  distinguishable  i n h i s t o l o g i c a l p r e p a r a t i o n s as u n i f o r m l y . s t a i n e d masses w i t h few n u c l e i . These h y a l i n e remnants p e r s i s t f o r months o r even y e a r s - t h e r e were always l a r g e numbers i n t h e o v a r i e s o f o l d does.  These  follicular  remnants a t times appear y e l l o w i s h t o y e l l o w - o r a n g e and may be m i s t a k e n for o l d corpora rubra.  We have been a b l e t o p o s i t i v e l y  differentiate  between h y a l i n i z e d f o l l i c l e s and o l d c o r p o r a r u b r a o n l y by h i s t o l o g i c a l sections. About h a l f o f t h e pregnant o r r e c e n t p o s t p a r t u m does had c o n c e i v e d d u r i n g t h e i r f i r s t e s t r u s - t h e r e was no l a r g e corpus rub rum p r e s e n t . Twelve does had p a s s e d one heat p e r i o d , and c o n c e i v e d d u r i n g t h e second. None o f t h o s e examined had c o n c e i v e d d u r i n g a t h i r d e s t r u s , as e v i d e n c e d by t h e presence o f a s i n g l e r e g r e s s i n g corpus l u t e a d u r i n g e a r l y or a l a r g e corpus r u b r a d u r i n g l a t e pregnancy.  pregnancy  Only h a l f o f t h e does  t h a t were s p e c i f i c a l l y marked " l a t e c a l v i n g " had f a i l e d t o c o n c e i v e during the f i r s t e s t r u s .  C a l v i n g time i n d i c a t e s e i t h e r an e a r l y  loss  o f t h e conceptus and r e t u r n t o heat about the t i m e f o r t h e t h i r d e s t r o u s p e r i o d , o r a slowness i n coming i n t o h e a t , thus p a s s i n g the f i r s t  period,  then p o s s i b l y f a i l i n g t o conceive at t h e i r " f i r s t " p e r i o d at the time of n o r m a l second p e r i o d s .  Many cows ( B o v i n e ) (up t o 15% o f a l l c o n c e p t i o n s )  l o s e t h e i r embryos between 16 and 30 days, t h e n r e t u r n t o e s t r u s i n another 5 t o 10 days.  Why  n o t e x p l a i n some o f t h e s e l a t e c a l v e s t h e same way  when a s i n g l e corpus rubrum i s p r e s e n t ? No case o f two f u n c t i o n a l c o r p o r a l u t e a was  found;  newly formed corpus luteum o f 1 o r 2 days age (6x5x5 mm)  I n two  ovaries,  was.found-with  a  r e g r e s s i n g corpus luteum o f 4x4x3 mm,  cases t h a t c o u l d be confused by-  g r o s s o b s e r v a t i o n as two c o r p o r a l u t e a . "corpus luteum o f pregnancy" was  I n two mid p r e g n a n c i e s , t h e l a r g e  accompanied  by a s m a l l e r c o r p u s , i n t e r -  p r e t e d t o be t h e corpus luteum o f t h e p r e v i o u s c y c l e , saved from complete r e g r e s s i o n by t h e f a c t o r s t h a t s t i m u l a t e d f o r m a t i o n o f t h e new luteum.  corpus  A second o v u l a t i o n , a f t e r c o n c e p t i o n , as r e p o r t e d by H a l a z o n  i n t h e e l k i s not i n d i c a t e d .  I n f a c t , the o c c u r r e n c e o f t e n cases i n  w h i c h t h e r e was no corpus rubrum accompanying  t h e f u n c t i o n a l corpus  luteum i n pregnant does d e f i n i t e l y c o n t r a - i n d i c a t e s such p r o c e d u r e i n caribou. The s i z e and c o n d i t i o n o f t h e u t e r u s p r o v i d e s c o n c l u s i v e e v i d e n c e as t o p r e v i o u s pregnancy.  There a r e f o u r c r i t e r i a , any one o f which can be  used d e c i s i v e l y . 1.  Weight.  The non-parous  t r a c t , s e v e r e d from t h e v a g i n a i m m e d i a t e l y  p o s t e r i o r t o t h e c e r v i x and f r e e d from excess f a t and mesometria,  weighs  between 15 and 35 grams; t h e p r e v i o u s l y parous t r a c t weighs o v e r 60 grams.  I t i s p r o b a b l e t h a t a non-parous  animal i n or approaching estrus  would have a u t e r u s a p p r o a c h i n g o r even s u r p a s s i n g t h e 60 gram l i m i t . A p o s t p a r t u m u t e r u s r e g r e s s e s t o about 100 grams i n two months a f t e r parturition. 2.  Diameter o f u t e r i n e h o r n .  The never-pregnant u t e r i n e h o r n i s  round i n c r o s s s e c t i o n and was n e v e r found t o exceed 10 mm at t h e a n t e r i o r c u r v a t u r e . 5 t o 7 mm.  Once a  I n J u n e , the'..average non-parous  i n diameter horn  was  u t e r u s has expanded t o . c a r r y a c o n c e p t u s , i t . n e v e r  r e t u r n s t o t h e o r i g i n a l roundness; r a t h e r i t i s d i s t i n c t l y  flattened,  a p p e a r i n g as a t h i c k e n e d e x t e n s i o n o f the mesometrium o v e r 12 mm and o n e - h a l f t o t w o - t h i r d s as t h i c k .  broad  138 3.  Size of caruncles.  When a u t e r i n e horn i s s p l i t  along i t s  d o r s a l s u r f a c e and l a y e d open, a s e r i e s o f 2 t o 4 ( u s u a l l y 3) c a r uncles  can be seen e x t e n d i n g i n t o the u t e r i n e lumen from t h e meso-  m e t r i a l border.  I n the n e v e r pregnant u t e r u s , t h e s e c a r u n c l e s  t h i n b l a d e s about 1 mm  t h i c k , 2 t o 2.5  frequently overlapping  so t h a t a c r o s s s e c t i o n o f the u t e r u s may  t h r o u g h the main p o r t i o n o f one another.  In t h e p r e g n a n t • t r a c t ,  mm  wide and  are  20 to.60 mm  long, cut  and t h r o u g h a t h i n n e r e l o n g a t i o n the c a r u n c l e s  enlarge  of  t o many t i m e s  t h e i r o r i g i n a l s i z e , f o r m i n g t h e cores o f t h e "placentomes" (maybe you  c a l l them " c o t y l e d o n s " ) .  A f t e r p a r t u r i t i o n , the c a r u n c l e s  shrink  r a p i d l y but n e v e r r e t u r n t o p r e - p r e g n a n t s i z e , u s u a l l y t o no l e s s t h a n 2 mm  t h i c k and 6 o r 7 mm 4.  uncles  V a s c u l a r bed.  broad. D u r i n g pregnancy, the. v a s c u l a r i t y o f t h e  and the u t e r i n e w a l l i n g e n e r a l i s i n c r e a s e d t o p o s s i b l y  t i m e s what i t was  i n the v i r g i n u t e r u s .  v e s s e l s c o n s t i t u t e t h e mass t h a t keeps t h e c a r u n c l e s  by e n l a r g e d ,  Apparently  c o n d i t i o n o f the v a s c u l a r bed i s i n d i c a t e d surface,  from h i s t o l o g i c a l s e c t i o n s .  b a r r e n does t a k e n d u r i n g the. summer months a c t u a l l y  be p o s t p a r t u r i e n t a n i m a l s , w i t h  l a r g e remnants o f c o r p o r a  t y p i c a l expanded b l o o d v e s s e l s i n the c a r u n c l e s does had  blood  from s h r i n k i n g  sometimes almost " v a r i c o s e v e i n " c o n d i t i o n on the  but i s b e s t a n a l y z e d  may  The  500  The b l o o d v e s s e l s , once  expanded, n e v e r s h r i n k t o p r e - p r e g n a n t s i z e , and the r e m a i n i n g  t o pre-pregnant s i z e .  car-  and u t e r i n e w a l l .  c a r r i e d calves t o or nearly t o term, then l o s t  a c t u a l l y t h e y were not l a c t a t i n g a t the t i m e o f  l u t e a and These  them.—if  collection.  C o r p o r a l u t e a are m a i n t a i n e d at 10-12'mm d i a m e t e r . u n t i l p a r t u r i t i o n ,  t h e n r e g r e s s t o 5-6 mm t o about 1.5x2x4 mm  i n about two months, t h e n p r o g r e s s i v e l y s l o w e r  a t one y e a r , and 1x1x3 mm.at two y e a r s .  s i z e . i s m a i n t a i n e d , as a y e l l o w i s h t o brownish I n t h e s e c t i o n i n g procedure  The  latter  streak f o r several years.  used i n t h i s s u r v e y , a t h i r d t o a h a l f o f  t h e s m a l l c o r p o r a r u b r a were m i s s e d , but few o f t h e one-year c o r p o r a would have been l e f t i n t a c t .  The  c o l o r i s i n t e n s e enough t h a t t h e y  would be i n f r e q u e n t l y o v e r l o o k e d .  At l e a s t f i v e o f t h e "parous b u t  non-pregnant" does had formed a t l e a s t one corpus luteum t h e p r e v i o u s fall.  They e i t h e r d i d not c o n c e i v e o r a b o r t e d b e f o r e t h e f e t u s  developed  very f a r . U t e r i are much more e l u c i d a t i v e o f r e p r o d u c t i v e performance t h a n are the o v a r i e s .  As p o i n t e d out p r e v i o u s l y , t h e never-pregnant  uterus i s  s m a l l , r o u n d , and r e l a t i v e l y n o n - v a s c u l a r , w i t h . a c t u a l weight o f t h e u t e r u s ( l e s s o v a r i e s and mesometrium) o f o n l y 10-20 u n c l e s as t h i n b l a d e s 15-40  mm  grams, and c a r -  l o n g , 1 mm t h i c k and 1-2.5  mm  broad.  D u r i n g pregnancy, t h e u t e r u s i n c r e a s e s t o about 2kg, expands l a r g e r t h a n t h e c a l f , and the c a r u n c l e s ( p l u s f e t a l c o t y l e d o n s ) e n l a r g e t o as much as 125 mm  l o n g and 60 mm t h i c k .  A l l t h e u t e r i n e w a l l and  c a r u n c l e are b o u n t i f u l l y s u p p l i e d w i t h l a r g e b l o o d v e s s e l s .  the  After  p a r t u r i t i o n , t h e u t e r i n e w a l l s h r i n k s r a p i d l y , t o about 350 grams i n 15 days and 100 grams i n 60 days. c l o s e r e s t i m a t e s are not  Without d e f i n i t e l y d a t e d specimens,  practical.  The placentomes c o n t r a c t a f t e r p a r t u r i t i o n , becoming n e c r o t i c and s l o u g h i n g a l l o f t h e c a r u n c u l a r m a t e r i a l t h a t had been d i r e c t l y i n v o l v e d w i t h embryonic t i s s u e i n the. p l a c e n t a .  As n e a r l y as we  t e l l , t h e s l o u g h i n g o c c u r s between 6 and 10 days p o s t p a r t u m ,  can  repair  140 proceeds r a p i d l y , and t h e c a r u n c l e s are r e - c o v e r e d by e p i t h e l i u m by about 20 days.  There a r e r e g u l a r l y 3 (sometimes 2 o r 4) c a r u n c l e s ,  hence placentomes d u r i n g pregnancy, i n each u t e r i n e h o r n , and a t times 1, 2, 3, o r 4 s m a l l placentomes i n t h e body o f t h e u t e r u s .  B e r g e r u d , A.T.  1964. R e l a t i o n s h i p o f mandible l e n g t h t o s e x i n New-  foundland caribou. B e r g e r u d , A.T.  J . W i l d l . Mgmt.  54-56.  1964. A f i e l d method t o determine a n n u a l p a r t u r i t i o n  f o r Newfoundland c a r i b o u . B e r g e r u d , A.T.  28(1):  J . W i l d l . Mgmt.  rates  2 8 ( 3 ) : 477-480.  1964. Newfoundland w i l d l i f e management r e p o r t .  Ann.  Rep. o f Dept. o f M i n e s , A g r i . and Res. 68-128 pp. B e r g e r u d , A.T.  1967. The d i s t r i b u t i o n and abundance o f A r c t i c h a r e s i n  Newfoundland. B e r g e r u d , A.T. 30(4):  Can. F i e l d Nat. 8 1 ( 4 ) :  242-248.  1967. Management o f L a b r a d o r c a r i b o u .  J . W i l d l . Mgmt.  621-642.  B e r g e r u d , A.T.  1968. Numbers and D e n s i t y —  a chapter i n the I n t e r n a t i o n  B i o l o g i c a l Handbook ( i n p r e s s ) . B e r g e r u d , A.T.  1969. S t a t u s o f Newfoundland p i n e marten.  Can. F i e l d - N a t .  (in press). B e r g e r u d , A.T., F. Manuel £ H. Whalen. C e n t r a l Newfoundland.  N.E. W i l d l . Conf.  B e r g e r u d , A.T. £ L. R u s s e l l . Newfoundland c a r i b o u .  1962. Moose management s t u d i e s i n  1964. E v a l u a t i o n o f rumen f o o d a n a l y s i s f o r J . W i l d l . Mgmt.  B e r g e r u d , A.T., S.S. P e t e r s , £ R. McGrath. of w i l l o w ptarmigan.  809-814.  2 7 ( 4 ) : 700-711.  1964. W i l d l i f e management.  o f M i n e s , A g r i . and Res. B e r g e r u d , A.T. £ W.E. Mercer.  Ann. Rep. Dept.  73-93 pp. 1965. Census o f w i l l o w p t a r m i g a n i n s o u t h -  J . W i l d l . Mgmt.  B e r g e r u d , A.T. and H.L. R u s s e l l . foundland caribou.  28(4):  1964. D e t e r m i n i n g sex and age  J . W i l d l . Mgmt.  B e r g e r u d , A.T. £ F. Manuel.  e a s t e r n Newfoundland.  49 pp.  3 0 ( 1 ) : 101-113.  1966. E x t r a c t i o n o f i n c i s o r s o f New-  J . W i l d l . Mgmt.  30(4):  842-843.  B e r g e r u d , A.T., F. Manuel £ H. Whalen.  1968. The h a r v e s t r e d u c t i o n o f  a moose p o p u l a t i o n i n Newfoundland. B e r g e r u d , A.T. £ F. Manuel.  J . W i l d l . Mgmt.  32(4):  722-728.  1968. Moose damage t o balsam f i r - w h i t e  f o r e s t s i n c e n t r a l Newfoundland.  J . W i l d l . Mgmt. 3 2 ( 4 ) :  birch  729-746.  Bergerud, A.T.  1964. Relationship of mandible length t o sex i n New-  foundland caribou. Bergerud, A.T.  J . W i l d l . Mgmt.  1964. A f i e l d method t o determine annual p a r t u r i t i o n rates  f o r Newfoundland caribou. Bergerud, A.T.  28(1): 54-56.  J . W i l d l . Mgmt.  28(3): 477-4-80.  1964. Newfoundland w i l d l i f e management report. Ann.  Rep. of Dept. of Mines, A g r i . and Res. 68-128 pp. Bergerud, A.T.  1967. The d i s t r i b u t i o n and abundance of A r c t i c hares i n  Newfoundland. Bergerud, A.T.  Can. F i e l d Nat. 81(4): 242-248.  1967. Management of Labrador caribou.  J . W i l d l . Mgmt.  30(4): 621-642. Bergerud, A.T.  1968. Numbers and Density — a chapter i n the Internation  B i o l o g i c a l Handbook ( i n p r e s s ) . Bergerud, A.T.  1969. Status of Newfoundland pine marten.  Can. Field-Nat.  ( i n press). Bergerud, A.T., F. Manuel £ H. Whalen. Central Newfoundland.  N.E. W i l d l . Conf.  Bergerud, A.T. £ L. R u s s e l l . Newfoundland caribou.  1962. Moose management studies i n  1964. Evaluation o f rumen food analysis f o r J . W i l d l . Mgmt.  Bergerud, A.T., S.S. P e t e r s , £ R. McGrath.  Bergerud, A.T. £ F. Manuel.  27(4): 700-711.  1964.. W i l d l i f e management.  of Mines, A g r i . and Res. Bergerud, A.T. £ W.E. Mercer.  Ann. Rep. Dept.  73-93 pp. 1965. Census o f willow ptarmigan i n south-  J . W i l d l . Mgmt.  Bergerud, A.T. and H.L. R u s s e l l . foundland caribou.  28(4): 809-814. 1964. Determining sex and age  of willow ptarmigan. J . W i l d l . Mgmt.  eastern Newfoundland.  49 pp.  30(1): 101-113.  1966. E x t r a c t i o n o f i n c i s o r s o f New-  J . W i l d l . Mgmt.  30(4): 842-843.  

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