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UBC Theses and Dissertations

Population regulation and annual cycles of activity and dispersal in Arctic ground squirrels Green, Jeffrey Emil 1977

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POPULATION PECULATION AND ANNUAL C ¥ CLE'S OF ACTIVITY AND DISPERSAL IN THE ARCTIC GROUND SQUIRREL by JEFFREY E MIL GREEN B . S c , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1974 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS EOR THE DEGREE OF Be 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 r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA JULY, 1977 (^cT) J e f f r e y Srail Green MASTER OF SCIENCE i n t h e Department o f Z o o l o g y In presenting th is thes is in pa r t i a l fu l f i lment o f the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the L ibrary s h a l l make i t f ree ly ava i lab le for reference and study. I fur ther agree that permission for extensive copying of th is thes is for scho la r ly purposes may be granted by the Head of my Department or by h is representat ives . It is understood that copying or p u b l i c a t i o n of th is thes is for f inanc ia l gain shal l not be allowed without my wri t ten permission. Department of ZOOLOGY  The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date July 29,1977. i A b s t r a c t D i s p e r s a l has been i m p l i c a t e d as one o f t h e p o t e n t i a l l y i m p o r t a n t f a c t o r s o f p o p u l a t i o n r e g u l a t i o n . I n t e r a c t i v e b e h a v i o u r s , p a r t i c u l a r l y a g g r e s s i o n , have b e e n s u q g e s t e d as t h e u l t i m a t e c a u s e of d i s p e r s a l . To d e t e r m i n e i f s o c i a l b e h a v i o u r i s r e l a t e d t o d i s p e r s a l and t o p o p u l a t i o n r e g u l a t i o n , I c o n d u c t e d a s t u d y o f t h e p o p u l a t i o n c h a n g e s and b e h a v i o u r o f two p o p u l a t i o n s o f A r c t i c g r o u n d s q u i r r e l s , S p e r a o p h i l u s o n d u l a t u s , i n K l u a n e N a t i o n a l P a r k , Yukon T e r r i t o r y , Canada. W i t h i n e a c h s t u d y s i t e , I e s t a b l i s h e d a c o n t r o l a r e a and one e x p e r i m e n t a l a r e a i n which r e s i d e n t a n i m a l s were removed a t r e g u l a r i n t e r v a l s . On one s i t e , I c o n d u c t e d two a d d i t i o n a l e x p e r i m e n t s . One i n v o l v e d t h e p r o v i s i o n o f an a d d i t i o n a l f o o d s u p p l y and t h e o t h e r , a c o n t i n u o u s r e m o v a l o f a l l a d u l t m a l e s . The a n n u a l a c t i v i t y p a t t e r n o f A r c t i c g r o u n d s q u i r r e l s i n t h e K l u a n e r e g i o n was c h a r a c t e r i z e d by a 7 - 8 month p e r i o d o f h i b e r n a t i o n , emergence, e s t a b l i s h m e n t o f t e r r i t o r i e s , a s h o r t b r e e d i n g p e r i o d , d e v e l o p m e n t and emergence c f young, r e s t o r a t i o n o f f a t d e p o s i t s , e s t a b l i s h m e n t o f f a l l t e r r i t o r i e s and e n t r y i n t o h i b e r n a t i o n . Two p eaks o f a g g r e s s i v e b e h a v i o u r , a s e v i d e n c e d by i n t e r a c t i o n r a t e s and wounding o c c u r r e d , b o t h c o i n c i d e n t w i t h the e s t a b l i s h m e n t o f t e r r i t o r i e s . The number o f r e s i d e n t b r e e d i n g a d u l t s c h a n g e d l i t t l e d u r i n g t h e two and a h a l f y e a r s o f t h i s s t u d y . Some f l u c t u a t i o n s i n t h e t o t a l p o p u l a t i o n o c c u r r e d a s a r e s u l t o f mature a n i m a l and j u v e n i l e d i s p e r s a l and r e c r u i t m e n t o f y o u n g . F o u r p o s s i b l e s o u r c e s o f i n s i t u l o s s were i n v e s t i g a t e d ; p r e d a t i o n , d i s e a s e . i i s t a r v a t i o n and d i s p e r s a l . L o s s due t o d i s e a s e o r s t a r v a t i o n was n e g l i g i b l e . I n t e r s p e c i f i c p r e d a t i o n a c c o u n t e d f o r an e s t i m a t e d 10-15% o f the t o t a l a n n u a l l o s s . The t h r e e measures o f d i s p e r s a l ; i m m i g r a t i o n t o r e m o v a l and c o n t r o l a r e a s and e m i g r a t i o n t c c o n t r o l a r e a s showed s i m i l a r s e a s o n a l peaks. The c o r r e l a t i o n between t h e t h r e e measures i n d i c a t e s t h a t d i s p e r s a l i s t h e major c a u s e o f i n s i t u l o s s . Mature f e m a l e s d i s p e r s e d roost i n flay and J u n e . D i s p e r s a l o f mature f e m a l e s was r e l a t e d t o r e p r o d u c t i v e s u c c e s s . J u v e n i l e male and f e m a l e d i s p e r s a l was h i g h e s t i n A u g u s t . J u v e n i l e male d i s p e r s a l was r e l a t e d t o body s i z e . L a r g e r j u v e n i l e males t e n d e d t o d i s p e r s e f i r s t . A h y p o t h e s i s i s p r o p o s e d s u q q e s t i n q t h a t body s i z e i s r e l a t e d t o the i n i t i a t i o n o f a d u l t : j u v e n i l e a q q r e s s i o n and t h e s u b s e q u e n t d i s p e r s a l o f j u v e n i l e s . B e h a v i o u r a l c o m p a r i s o n s o f d i s p e r s i n g and r e s i d e n t a n i m a l s i n d i c a t e d few d i f f e r e n c e s . O v e r a l l , d i s p e r s i n g a n i m a l s t e n d e d t o i n i t i a t e f e w e r and r e c e i v e more a g o n i s t i c b e h a v i o u r s t h a n r e s i d e n t a n i m a l s . A n i m a l s o f one c l a s s r e c e i v e d and i n i t i a t e d most a g o n i s t i c b e h a v i o u r s w i t h a n i m a l s o f t h e same age a n d / o r s e x . T h i s s u g g e s t s t h a t a q q r e s s i o n among a n i m a l s o f t h e same c l a s s may be an i m p o r t a n t c a u s e o f d i s p e r s a l , p a r t i c u l a r l y i n j u v e n i l e s . F u r t h e r , r e l a t e d a n i m a l s t e n d e d t o show h i g h e r r a t e s o f a m i c a b l e b e h a v i o u r and lower l e v e l s o f p h y s i c a l a q q r e s s i o n t h a n u n r e l a t e d a n i m a l s . A q r a p h i c a l model o f p o p u l a t i o n r e g u l a t i o n i n A r c t i c g r o u n d s q u i r r e l s b a s e d on b e h a v i o u r a l and d e m o q r a p h i c r e l a t i o n s h i p s o b s e r v e d i n t h i s s t u d y , i s p r o p o s e d . i i i T a b l e Of C o n t e n t s A b s t r a c t 1 TABLE OF CONTENTS i i i L I S T OF FIGURES v i L I S T OF TABLES v i i i ACKNOWLEDGEMENTS i x INTRODUCTION 1 MATERIALS AND METHODS 3 T r a p p i n g T e c h n i q u e s 11 B e h a v i o u r a l O b s e r v a t i o n T e c h n i q u e s 15 E x p e r i m e n t a l A r e a s 19 Removal A r e a s 19 The F e e d i n g A r e a (CCF) 21 A d u l t Male Removal Area (CCM) 23 Aqe C l a s s i f i c a t i o n 24 S t a t i s t i c a l A n a l y s e s 24 RESULTS: PART I 25 Ann u a l P a t t e r n s Of A c t i v i t y And Weiqht G a i n 25 Emergence 28 The E s t a b l i s h m e n t Of S p r i n g T e r r i t o r i e s 31 E r e e d i n q 38 L i t t e r S i z e 49 S e a s o n a l Sex R a t i o s 49 S e a s o n a l Chanqes I n Body Weiqht . . . . . . . . . . . . . . . . . . . . . . . 52 O v e r - w i n t e r Weiqht L o s s 53 P a t t e r n s o f Weiqht Change D u r i n g the A c t i v e S e a s o n .... 55 Weight G a i n O ver The A c t i v e P e r i o d . . . . . . . . . . . . . . . . . . . . 61 i v E s t a b l i s h m e n t Of F a l l T e r r i t o r i e s 62 E n t r y I n t o H i b e r n a t i o n 62 DISCUSSION: PART I 66 H i b e r n a t i o n and Emergence 66 T e r r i t o r i a l i t y And B r e e d i n g 67 Female R e p r o d u c t i v e S u c c e s s 69 Changes I n Sex R a t i o With Aqe 70 P a t t e r n s Of Weight G a i n 71 S e c t i o n Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 RESULTS : DEMOGRAPHY 74 P o p u l a t i o n Changes 75 S u r v i v a l 78 C o h o r t S u r v i v a l 84 O r i g i n s o f R e s i d e n t A n i m a l s 87 L o s s Frcm The C o n t r o l P o p u l a t i o n s 90 M o r t a l i t y D u r i n g H i b e r n a t i o n 91 L o s s D u r i n g The A c t i v e P e r i o d 92 Pre da t i o n 92 D i s e a s e And P r e d a t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 D i s p e r s a l 101 D i s p e r s a l Of Mature Males 102 D i s p e r s a l Of Mat u r e Females 109 D i s p e r s a l Of J u v e n i l e M a l e s 109 D i s p e r s a l Of J u v e n i l e Females 110 Q u a l i t a t i v e D i f f e r e n c e s And D i s p e r s a l . . . . . . . . . . . . . . . . . . . 111 M o r p h o l o g i c a l D i f f e r e n c e s 111 J u v e n i l e D i s p e r s a l and L a r q e r Body S i z e . . . . . . . . . . . . . . . 113 B r e e d i n g C o n d i t i o n Of D i s p e r s i n g Mature A n i m a l s . . . . . . . . . 119 V RESULTS : BEHAVIOURAL CHANGES AND DISPERSAL 124 Seasonal Chanqes In Behaviour Budgets 129 Behaviour Of D i s p e r s i n g Animals ......................... 131 Behaviour Budgets Of D i s p e r s i n g Animals 132 S o c i a l Behaviours And D i s p e r s a l 134 Amicable And A g o n i s t i c I n t e r a c t i o n Rates 135 I n i t i a t o r s And R e c i p i e n t s Of A g o n i s t i c Behaviour 139 Genetic Relatedness And Rates Of I n t e r a c t i o n s 150 DISCUSSION: PART I I 155 Do A r c t i c Ground S q u i r r e l P o p u l a t i o n s Remain Constant? .. 155 Loss During H i b e r n a t i o n 156 Loss During The A c t i v e P e r i o d 158 Loss Due To P r e d a t i o n 158 Seasonal Trends Of D i s p e r s a l 161 Which Animals Disperse? 162 Morphological D i f f e r e n c e s 162 Reproductive C o n d i t i o n And D i s p e r s a l 164 Are D i s p e r s i n g Animals B e h a v i o u r a l l y D i f f e r e n t ? ......... 166 Behavioural D i f f e r e n c e s 167 Which Animals Most I n f l u e n c e D i s p e r s a l ? 168 Genetic Relatedness And S o c i a l Behaviour 170 Popul a t i o n R e g u l a t i o n and D i s p e r s a l 174 A Model Of P o p u l a t i o n Regulation In A r c t i c Ground S q u i r r e l s 179 CONCLUSIONS 185 LITERATURE CITED 187 v i L I S T OF FIGURES F i g u r e 1 : L o c a t i o n Of The S t u d y a r e a . 4 F i g u r e 2 : L o c a t i o n Of SRC And SRR 6 F i g u r e 3 : L o c a t i o n Of CCC, CCR, CCF, And CCMR 8 F i g u r e 4 : C o n s t r u c t i o n Of The C o l o u r E a r Tag . . . . . . . . . . . . . 13 F i g u r e 5 : C o n s t r u c t i o n Of The F e e d i n g S t a t i o n 22 F i g u r e 6 : A n n u a l P a t t e r n Of A c t i v i t y And W e i g h t G a i n .....27 F i g u r e 7 : Changes I n R a t e s Of A g o n i s t i c I n t e r a c t i o n s .....32 F i g u r e 8 : P r o p o r t i o n s C f I n t e r a c t i o n s I n v o l v i n g A d u l t s Of Each Sex 34 F i g u r e 9 : B i w e e k l y Changes I n The Number Of Wounds Per A n i m a l ..........................36 F i g u r e 10 : R e p r o d u c t i v e C o n d i t i o n Of Mature M a l e s ........39 F i g u r e 11 : R e p r o d u c t i v e C o n d i t i o n Of Mature F e m a l e s ......41 F i g u r e 12 : M a t u r e Female L a c t a t i o n ........44 F i g u r e 13 : B i w e e k l y Changes In S k u l l l B r e a d t h . . . . . . . . . . . . 57 F i g u r e 14 : R e g r e s s i o n Of J u v e n i l e S k u l l B r e a d t h On Body Weight .......60 F i g u r e 15. S e a s o n a l Changes I n P o p u l a t i o n S i z e ............76 F i g u r e 16. S e a s o n a l S u r v i v a l R a t e s 80 F i g u r e 17. B i w e e k l y S u r v i v a l R a t e s 82 F i g u r e 18. C o h o r t S u r v i v a l .....85 F i g u r e 19. O r i g i n Of C o n t r o l A r e a R e s i d e n t s ..........88 F i g u r e 20. Minimum Number A l i v e On The Removal A r e a s ......103 F i g u r e 21. Number Of I m m i g r a n t s To The C o n t r o l A r e a .......105 F i g u r e 22. Number Of E m i g r a n t s From The C o n t r o l A r e a s .....107 F i g u r e 23. J u v e n i l e Male And Female Growth 115 F i g u r e 24. Number Of E m i g r a n t s From CCF ...........117 F i g u r e 25. S e a s o n a l Changes I n B e h a v i o u r B u d g e t s On CCC ...126 F i g u r e 26. S e a s o n a l Changes I n B e h a v i o u r B u d g e t s On CCB ...133 F i g u r e 27. R e c i p i e n t s Of A g o n i s t i c B e h a v i o u r s ........143 F i g u r e 28. I n t i a t o r s Of A g o n i s t i c B e h a v i o u r s ..148 F i g u r e 29. G e n e t i c B e l a t e d n e s s And I n t e r a c t i o n B a t e s ......152 F i g u r e 30. Model Of P o p u l a t i o n R e g u l a t i o n Of A r c t i c Ground S q u i r r e l P o p u l a t i o n s ........180 M H OF 2 AJ3£ES Table 1. Behavioural Groups And Behaviours ........16 Table 2. Dates Of Emergence From H i b e r n a t i o n .............. 29 Table 3. Reproductive Success Of Mature Females 47 Table Seasonal Sex Ratio s .50 Table 5. Percentage Over-winter Height Loss .......54 Table 6. Dates Of Entry Into H i b e r n a t i o n .................. 64 Table 8. Number Of Burrows Excavated By G r i z z l y Bear .94 Table 7. Predator S i g h t i n g s On SRC And CCC ....97 Tabl e 9. Reproductive C o n d i t i o n Of D i s p e r s i n g And Resident Females 121 Table 10. I n t e r a c t i o n Bates Of Resident And D i s p e r s i n g Animals 136 Table 11. R e c i p i e n t s Of A g o n i s t i c Behaviour .141 Table 12. I n i t i a t o r s Of A g o n i s t i c Behaviour ......146 i x ACKNOWLEDGEMENTS I owe much t o my s u p e r v i s o r , Dr. C . J . K r e b s f o r h i s u n f a i l i n q s u p p o r t , w i l l i n g n e s s t o h e l p , f r i e n d s h i p and g e n e r o u s f i n a n c i a l s u p p o r t . I am i n d e b t e d t o Drs. C L . G a s s and J.N.M. S m i t h f o r t h e i r g u i d a n c e and comments t h r o u g h o u t t h i s s t u d y . D r s . B. B o c n s t r a and H. H i l b o r n g e n e r o u s l y o f f e r e d t h e i r t i m e and e x p e r t i s e t c t e a c h me t h e b a s i c s o f c o m p u t e r programming. L a s t l y , I would l i k e t o t h a n k t h e f a c u l t y , s t a f f a n d ay f e l l o w s t u d e n t s a t t h e I n s t i t u t e o f A n i m a l R e s o u r c e E c o l o g y f o r t h e i r v e r y e n j o y a b l e and s t i m u l a t i n g company. D u r i n g my f i e l d s e a s o n s i n t h e Yukon, many p e o p l e made t h i s p r o j e c t p o s s i b l e . N a t i o n a l P a r k s o f Canada k i n d l y p e r m i t t e d me t o work w i t h i n K l u a n e N a t i o n a l Park. I owe s p e c i a l t h a n k s t o s e v e r a l o f t h e i r p e r s o n n e l ; L. H a r b r i d g e , J . M a c l n t y r e and J . Hasyck. I aa i n d e b t e d t o t h e A r c t i c I n s t i t u t e o f N o r t h A m e r i c a f o r t h e i r f i n a n c i a l s u p p o r t and e s p e c i a l l y t o Mr. and Mrs. A. W i l l i a m s and t h e i r f a i i l y as w e l l a s P. Dpton f o r t h e i r h o s p i t a l i t y a nd s u p p o r t . Mr. K. O l s e n v e r y k i n d l y a l l o w e d me t o use h i s c a b i n f o r t h e d u r a t i o n o f t h e s t u d y . I c a n n o t t h a n k R. C a r l s o n and B. Wolf enough f o r t h e i r t h o u g h t f u l n e s s and f r i e n d s h i p . C. P e r r i n , B. M u l l e r , G. M a c l s a a c and I . W i n g a t e , a l l w i l l i n g l y gave up t i m e t o h e l p me when ne e d e d . To my p a r e n t s , Mr. and Mrs. G. G r e e n , I o f f e r a v e r y s p e c i a l t h a n k s f o r t h e i r e n d l e s s p a t i e n c e , t h e i r w i l l i n g n e s s t o h e l p a t a l l t i m e s and t h e i r c o n t i n u a l s u p p o r t and e n c o u r a g e m e n t . The N a t i o n a l R e s e a r c h C o u n c i l o f Canada g e n e r o u s l y p r o v i d e d me w i t h a g r a d u a t e s c h o l a r s h i p i n 1975 and 1976. The Computing X C e n t r e o f U.B.C. o f f e r e d ample computer s u p p o r t . I would e s p e c i a l l y l i k e t o thank t h e k e y p u n c h i n g s t a f f f o r t h e i r s e r v i c e . W i t h o u t t h e s e p e o p l e , t h i s s t u d y would n o t have been p o s s i b l e , nor would i t have been t h e v e r y e n j o y a b l e and r e w a r d i n g e x p e r i e n c e i t was. To a l l I am v e r y t h a n k f u l . 1 INTRODUCTION D i s p e r s a l has been i m p l i c a t e d as one o f t h e p o t e n t i a l l y i m p o r t a n t r e g u l a t i n g f a c t o r s o f p o p u l a t i o n numbers (see K r e b s and Myers 1974 f o r a r e v i e w ) . The d e t e r m i n a t i o n o f w hich a n i m a l s a r e most l i k e l y t o d i s p e r s e and when s u c h d i s p e r s a l i s l i k e l y t o o c c u r a r e p e r h a p s two o f t h e major p r o b l e m s o f p o p u l a t i o n e c o l o g y t o d a y . Of t h e f a c t o r s which have been s u g g e s t e d a s b e i n g i m p o r t a n t t o t h e i n i t i a t i o n o f d i s p e r s a l , t h e r e s u l t s o f s t u d i e s o f t h e r e l a t i o n s h i p between s o c i a l b e h a v i o u r and d i s p e r s a l have been most e n c o u r a g i n g ( i e . B a r a s h 1974, B e k o f f 1977a, 1977b, and » a tscn and Moss 1970). O v e r a l l t h e main p u r p o s e o f t h i s s t u d y was t o d e t e r m i n e i f s o c i a l b e h a v i o u r i s r e l a t e d t o d i s p e r s a l and i f d i s p e r s a l i s a s i g n i f i c a n t f a c t o r i n p o p u l a t i o n r e g u l a t i o n . I c h o s e t o s t u d y t h e A r c t i c ground s g u i r r e l , ( S p e r m o p h i l u s u n d u l a t u s p l e s i u s ) , which i s commonly f o u n d t h r o u g h o u t t h e s o u t h e r n r e g i o n o f t h e Yukon T e r r i t o r y , Canada. The A r c t i c g r o u n d s q u i r r e l d i s p l a y s a v a r i e t y o f s o c i a l b e h a v i o u r s and i s r e l a t i v e l y e a s y t o o b s e r v e . In a d d i t i o n t h e y o c c u r i n l a r g e numbers and a r e e a s i l y enouqh t r a p p e d t o o b t a i n s u f f i c i e n t d e m o q r a p h i c i n f o r m a t i o n . L i t t l e q u a n t i t a t i v e i n f o r m a t i o n c o n c e r n i n q t h e e c o l o q y o f t h e A r c t i c g round s g u i r r e l i s a v a i l a b l e at p r e s e n t . C a r l (1971) p r e s e n t e d a d e t a i l e d b u t p r i m a r i l y q u a l i t a t i v e d e s c r i p t i o n o f t h e p o p u l a t i o n e c o l o q y o f A r c t i c g r o u n d s q u i r r e l s i n t h e r e q i o n o f P t . Barrow, A l a s k a . Based on h i s o b s e r v a t i o n s o v e r a two y e a r p e r i o d , he d i s c u s s e d t h e o c c u r r e n c e o f b e h a v i o u r a l c h a n q e s i n d i f f e r e n t aqe and s e x c l a s s e s d u r i n q t h e a c t i v e p e r i o d o f t h e 2 y e a r and a t t r i b u t e d i n c r e a s e s i n d i s p e r s a l i n c e r t a i n aqe g r o u p s , p a r t i c u l a r l y j u v e n i l e s , t o t h e s e b e h a v i o u r a l c h a n g e s . He c o n c l u d e d t h a t b o t h i n t r i n s i c and e x t r i n i s i c f a c t o r s were i m p o r t a n t t o t h e r e g u l a t i o n o f p o p u l a t i o n s i z e i n A r c t i c q r o u n d s q u i r r e l s . Based on p r o p o s a l s s e t f o r t h i n C a r l ' s work, I p l a n n e d a s t u d y c f t h e c h a n g e s i n t h e demography and b e h a v i o u r of two p o p u l a t i o n s o f A r c t i c g r o u n d s q u i r r e l s . I n p a r t i c u l a r I c o n s i d e r e d t h e f o l l o w i n g q u e s t i o n s : 1. Do A r c t i c g r o u n d s q u i r r e l p o p u l a t i o n s r e m a i n r e l a t i v e l y c o n s t a n t from y e a r t o y e a r ? I f s o , how i s t h i s a c c o m p l i s h e d ? 2. Do d i f f e r e n t q r o u p s of a n i m a l s t e n d t o d i s p e r s e a t d i f f e r e n t t i m e s o f t h e y e a r ? 3. Which a n i m a l s a r e most l i k e l y t o d i s p e r s e ( i e . m o r p h o l o q i c a l o r b e h a v i o u r a l a t t r i b u t e s ) d u r i n q t h e s e p e a k s ? 4. Do c h a n q e s i n a m i c a b l e and a g o n i s t i c b e h a v i o u r s o c c u r and a r e t h e s e c h a n q e s i n s o c i a l b e h a v i o u r r e l a t e d t o d i s p e r s a l ? 5. I f s o c i a l b e h a v i o u r i s i m p o r t a n t , w h i c h q r o u p o f a n i m a l s i s most l i k e l y t o i n f l u e n c e t h e d i s p e r s a l o f a n i m a l s o f d i f f e r e n t a g e s ? 6. Which t y p e s o f b e h a v i o u r between d i f f e r e n t age g r o u p s a r e most i m p o r t a n t t o t h e i n i t i a t i o n o f d i s p e r s a l ? D u r i n g t h e t e r m o f t h i s s t u d y , i n f o r m a t i o n c o n c e r n i n g t h e a n n u a l c y c l e s o f a c t i v i t y , r e p r o d u c t i o n and growth o f A r c t i c g r o u n d s q u i r r e l s was a l s o o b t a i n e d . I w i l l p r e s e n t some o f t h i s d a t a and d i s c u s s i t i n r e l a t i o n t o p a t t e r n s o f d i s p e r s a l and s o c i a l b e h a v i o u r . 3 I 1 J J H I A L S AND METHODS P o p u l a t i o n s o f A r c t i c q r o u n d s q u i r r e l s were s t u d i e d i n t h e S l i m s E i v e r V a l l e y , i n K l u a n e N a t i o n a l P a r k , s o u t h w e s t e r n Yukon T e r r i t o r y ( F i q . 1 ) o v e r a two and a h a l f y e a r p e r i o d f r o m A p r i l 1975 t o June 1977. F i e l d r e s e a r c h i n 1975 beqan on A p r i l 25 and ended September 28. I n 1976 work beqan A p r i l 9 and e n d e d O c t o b e r 13. I n 1977 t h e f i e l d s e a s o n was s h o r t ( A p r i l 15 - May 29) a s t h e main i n t e r e s t was t o c o l l e c t i n f o r m a t i o n on o v e r - w i n t e r s u r v i v a l and t h e s p r i n g b r e e d i n q p e r i o d . S q u i r r e l s were s t u d i e d i n two main a r e a s . The f i r s t , t h e S l i m s R i v e r A r e a ( e l e v a t i o n 800m), was l o c a t e d on d r y open h i l l s i d e s l a r q e l y d o m i n a t e d by A r t e m e s i a f r i q i d a , C a r e x sj>. , A ^ r o n j r o n yukonense and Penstemmon g o r m a n i . White s p r u c e ( P i c e a q l a u c a ) f o r e s t s b o r d e r t h e a r e a on t h r e e s i d e s w h i l e c l i f f s f a l l i n q t o a sed g e marsh o f t h e S l i m s R i v e r D e l t a f o r m t h e b o u n d a r y on t h e r e r a a i n i n q s i d e . The n o r t h - e a s t e r n p o r t i o n o f t h e a r e a was d e s i q n a t e d a s the c o n t r o l a r e a ( t o be r e f e r r e d t o as SRC) whereas t h e s o u t h - w e s t e r n a r e a was u s e d as t h e e x p e r i m e n t a l r e m o v a l a r e a (SRR) ( F i q . 2 ) . The SRC c o m p r i s e d an a r e a o f 18.3 ha, t h e SRR an a r e a o f 10.6 ha. The s e c o n d s t u d y s i t e was s i t u a t e d on a s u b - a l p i n e p l a t e a u ( e l e v a t i o n 1525m) r e f e r r e d t o l o c a l l y a s C o i n C r e e k t u n d r a , a p p r o x i m a t e l y 9 km w e s t - n o r t h - w e s t o f t h e f i r s t a r e a ( F i q . 3 ) . The main s t u d y a r e a was made up o f a m o s a i c o f s o u t h - f a c i n q h i l l s i d e s d o m i n a t e d by A r t e m e s i a f r i q i d a and d i s t i n c t a r e a s o f 4 F i g u r e 1 : L o c a t i o n o f t h e S l i m s E i v e r V a l l e y , K l u a n e r e g i o n , Yukon T e r r i t o r y . 5 6 F i g u r e 2: L o c a t i o n o f SRC and SRR w i t h i n t h e S l i m s R i v e r a r e a . 7 8 F i g u r e 3; L o c a t i o n o f CCC, CCR, CCF, and CCMR on C o i n C r e e k p l a t e a u . { 10 s h r u b s c o n s i s t i n g m a i n l y o f S a l i x •- s j _ . , Be t u l a g l a n d u l o sa and P o t e n t i l i a f r u i t i c o s a . The a r e a was b r o k e n up i n t o f o u r s t u d y a r e a s , s e p a r a t e d f r o m e a c h o t h e r by a t l e a s t 150m. The 4.5 ha c o n t r o l a r e a ( t o be r e f e r r e d t o as CCC) was s i t u a t e d i n t h e n o r t h e a s t e r n c o r n e r o f t h e a r e a . T h e 3.7 ha r e m o v a l a r e a (CCS) was i n t h e s o u t h w e s t e r n c o r n e r , ft s e c o n d e x p e r i m e n t a l a r e a (2.8 ha) i n w h i c h f e e d i n g s t a t i o n s were m a i n t a i n e d ( CCF ) was l o c a t e d mid-way between t h e c o n t r o l and t h e r e m o v a l a r e a s . F i n a l l y a s m a l l a r e a ( CCM8 ) {2.5 ha) l o c a t e d below t h e r o a d , s o u t h w e s t o f t h e f e e d i n g a r e a , was u s e d a s an a d u l t male r e m o v a l a r e a . D e t a i l e d d e s c r i p t i o n s o f t h e v e g e t a t i o n o f t h e g e n e r a l a r e a a r e g i v e n by D o u g l a s ( 1 9 7 4 ) and H o e f s ( 1 9 7 6 ) . The g e o l o g y o f t h e a r e a has been summarized by M u l l e r { 1 9 6 7 ) . B o s t o c k (1948) has d e s c r i b e d t h e p h y s i o g r a p h y o f t h e K l u a n e r e g i o n . The c l i m a t e o f t h e K l u a n e r e g i o n i s c o n t i n e n t a l , t h e mean a n n u a l t e m p e r a t u r e b e i n g - 4 ° C . The r e g i o n l i e s i n t h e r a i n shadow o f t h e S t . E l i a s M o u n t a i n s and s o i s g u i t e d r y ( t h e a v e r a g e a n n u a l p r e c i p i t a t i o n r a r e l y e x c e e d s 25 cm) ( T a y l o r - B a r g e 1 9 6 9). D u r i n g t h e t h r e e y e a r s o f t h e s t u d y , m e l t o f f u s u a l l y o c c u r r e d i n l a t e A p r i l t o e a r l y May and a l l a r e a s r e m a i n e d s n o w - f r e e u n t i l mid- t o l a t e September a l t h o u g h s n o w f a l l s d i d o c c u r i n most months e x c e p t J u l y . H e a t h e r i n f o r m a t i o n f o r t h e S l i m s B i v e r a r e a and t h e C o i n C r e e k a r e a i s a v a i l a b l e f r o m E n v i r o n m e n t Canada ( W h i t e h o r s e ) . 11 T r a p p i n g T e c h n i q u e s At t h e b e g i n n i n q o f a t r a p p i n g s e a s o n , I s e a r c h e d e a c h a r e a a t l e a s t e v e r y o t h e r d a y f o r . i n d i r e c t - s i g n s o f s q u i r r e l a c t i v i t y s u c h as t r a c k s , d i g q i n g i n t h e snow and d i g g i n g on burrow mounds a s w e l l a s a c t u a l s i g b t i n q s o f s q u i r r e l s . Once s q u i r r e l s were s e e n , I o b s e r v e d and t r a p p e d t h e a r e a f o r a t l e a s t t h r e e d a y s b e f o r e b e q i n n i n g t h e r e g u l a r b i w e e k l y s c h e d u l e o f t r a p p i n q . I n t h i s way I o b t a i n e d an a c c u r a t e a s s e s s m e n t o f emergence i n 1976 and 1977. I t r a p p e d a l l s t u d y a r e a s f o r two d a y s e v e r y two weeks e x c e p t t h e two r e m o v a l a r e a s w h i c h I t r a p p e d f o r t h r e e d a y s e v e r y two weeks i n 1975. N a t i o n a l l i v e t r a p s {15cm x 15cm x 48cm - s i n g l e d oor c o l l a p s i b l e model) were s e t a t s u n r i s e e a c h day o f t r a p p i n g and b a i t e d w i t h a s l i c e o f a p p l e and p e a n u t b u t t e r . A f t e r t h r e e t o f o u r h o u r s , a l l t r a p s were c h e c k e d t h e n c l o s e d . On t h e l a s t day, t r a p s were removed and s t o r e d n e a r b y . D u r i n q peak p o p u l a t i o n p e r i o d s ( f o r example a t t h e t i m e o f t h e emergence o f young) a s e c o n d c h e c k was made on t h e f i r s t t r a p p i n q day. N o r m a l l y one c h e c k e a c h t r a p p i n g day was s u f f i c i e n t t o c a t c h most o f t h e a n i m a l s known (from b e h a v i o u r a l o b s e r v a t i o n s ) t o be i n t h e a r e a . A f t e r t h e f i r s t month o f t r a p p i n q and b e h a v i o u r a l o b s e r v a t i o n s i n 1975, permanent t r a p p i n g s t a t i o n s were e s t a b l i s h e d a t s i t e s a t w h i c h c a p t u r e o f known a n i m a l s was most s u c c e s s f u l . T h e s e were marked w i t h a numbered wooden s t a k e and were used t h r o u g h o u t t h e s t u d y . When f i r s t c a p t u r e d e a c h s g u i r r e l w a s . t a g g e d i n one e a r w i t h a nionel m e t a l .tag ( s i z e 1, s t y l e 4-1005 N a t i o n a l Band and 12 Tag Co., Newport, K e n t u c k y ) . Each a n i m a l was a l s o c o l o u r t a g g e d s o t h a t i t c o u l d be i d e n t i f i e d d u r i n g b e h a v i o u r a l o b s e r v a t i o n s . Two c o l o u r e d p i e c e s o f p l a s t i c {Dymo L a b e l Tape 1/4" s i z e ) , one 2 cm l o n g , t h e o t h e r 1 cm l o n g , were a t t a c h e d t o t h e o t h e r e a r by means o f t h e same t y p e o f m e t a l t a g ( F i g . 4 ) s u c h t h a t t h e s h o r t p i e c e o v e r l a p p e d t h e l o n g p i e c e . Thus b o t h c o l o u r s were v i s i b l e . To f u r t h e r p r e v e n t m i s - i d e n t i f i c a t i o n , e a c h a n i m a l was g i v e n a b l a c k dye mark on p a r t o f t h e body ( i e . paws, s h o u l d e r , s i d e o f t h e h e a d , e t c . ) u s i n g N y a n z o l A dye (Nyanza Dye and C h e m i c a l Co., Lawrence,Mass.) ( s e e M e l c h i o r and Iwen 1965 f o r methods) s u c h t h a t no two a n i m a l s had t h e same c o l o u r t a g and dye c o m b i n a t i o n . L a s t l y e a c h a n i m a l was t o e c l i p p e d t o c o r r e s p o n d t o t h e l a s t two d i g i t s o f i t s t a g number. At e a c h c a p t u r e , I r e c o r d e d t h e l o c a t i o n o f c a p t u r e , s e x , r e p r o d u c t i v e c o n d i t i o n , w e i g h t ( g ) , s k u l l w i d t h ( z y g o m a t i c b r e a d t h ) ( c m ) and t h e number o f wounds on t h e p o s t e r i o r body . I f t h e dye mark had f a d e d t h e a n i m a l was a l s o r e d y e d . ,. The r e p r o d u c t i v e c o n d i t i o n s n o t e d were as f o l l o w s : f o r m a l e s , t e s t e s s c r o t a l o r a b d o m i n a l ; f o r f e m a l e s , b r e e d i n g ( v a g i n a l p a p i l l a e s w o l l e n and p i n k ) o r n o n - b r e e d i n g ( v a g i n a l p a p i l l a e s m a l l and l i g h t l y c o l o u r e d ) , l a c t a t i o n ( s m a l l , medium, o r l a r g e n i p p l e s i z e ) and e x t e r n a l s i g n s o f p r e g n a n c y . A l l a n i m a l s were r e l e a s e d i m m e d i a t e l y a f t e r p r o c e s s i n g e x c e p t on t h e e x p e r i m e n t a l a r e a s d u r i n g r e m o v a l p e r i o d s . u r e 4: C o n s t r u c t i o n o f t h e c o l o u r e d e a r t a g . E a c h p i e c e o f p l a s t i c t a p e was o f d o u b l e t h i c k n e s s and had a 0.3 cm h o l e punched i n one end. a monel m e t a l t a g was i n s e r t e d t h r o u g h t h e h o l e s and t h e t a g was a t t a c h e d t o t h e e a r . The s h o r t p i e c e o f p l a s t i c was p o s i t i o n e d o v e r t h e l a r g e r p i e c e s u c h t h a t b o t h were v i s i b l e when a t t a c h e d t o t h e s q u i r r e l * s e a r . 15 B e h a v i o u r a l O b s e r v a t i o n t e c h n i q u e s I o b s e r v e d s g u i r r e l s i n t h r e e o f t h e s t u d y a r e a s e v e r y two weeks. A n i m a l s were i n i t i a l l y i d e n t i f i e d u s i n g a s p o t t i n g s c o p e ( B u s h n e l l S p a c e m a s t e r I I {60mm) w i t h 20^-401 zoom eye p i e c e ) . S u b s e q u e n t l y t h e a n i m a l s were u s u a l l y o b s e r v e d t h r o u g h 7x35 b i n o c u l a r s . A d i f f e r e n t method o f r e c o r d i n g b e h a v i o u r was u s e d i n t h e f i r s t s e a s o n t h a n i n t h e s e c o n d . I n t h e 1975 f i e l d s e a s o n , I o n l y o b s e r v e d a n i m a l s OB SRC and CCC . E a c h a r e a was o b s e r v e d f o r 3 d a y s e v e r y two weeks. A d a y ' s o b s e r v a t i o n i n v o l v e d f o u r 2-hour s e s s i o n s from 0700-0900, 1000-1200, 1300-1500 and 1600-1800 h o u r s . Each two hour s e s s i o n was d i v i d e d i n t o t w e l v e 10 minute s a m p l i n g p e r i o d s . , ! o b s e r v e d s i n q l e a n i m a l s f o r 10 m i n u t e s a s f o l l o w s : d u r i n q e a c h 30 s e c o n d i n t e r v a l I o b s e r v e d t h e a n i m a l f o r t h e f i r s t 20 s e c o n d s and c o d e d t h e o b s e r v e d b e h a v i o u r ( s ) on s h e e t s d u r i n q t h e l a s t 10 s e c o n d s . I f a a n i m a l went o u t o f s i q h t f o r more t h a n two m i n u t e s and a n o t h e r a n i m a l was i n s i q h t , I beqan o b s e r v a t i o n o f t h e new a n i m a l . T h i s i s s i m i l a r t o t h e f o c a l a n i m a l s a m p l i n g scheme d e s c r i b e d by Altmann (1974). A t o t a l o f *i3 b e h a v i o u r s ( b a s e d l a r g e l y on t h o s e d e s c r i b e d by S h e p p a r d and Y o s h i d a 1971) were r e c o g n i z e d and c l a s s i f i e d u nder 10 major g r o u p s o f b e h a v i o u r s ( T a b l e 1 ) . I n t h e c a s e o f i n t e r a c t i v e b e h a v i o u r s , t h e t a g number o f t h e a n i m a l i n t e r a c t i n g w i t h t h e a n i m a l u n d e r o b s e r v a t i o n was a l s o r e c o r d e d . The l o c a t i o n o f an a n i m a l d u r i n g e a c h b e h a v i o u r was r e c o r d e d i n o r d e r t o o b t a i n e s t i m a t e s o f d a i l y movements. I marked o u t e a c h o b s e r v e d a r e a i n a g r i d o f 30 meter s q u a r e s . 16 T a b l e 1: B e h a v i o u r a l g r o u p s and i n d i v i d u a l b e h a v i o u r s r e c o g n i z e d d u r i n g b e h a v i o u r a l o b s e r v a t i o n s . I n t e r a c t i v e b e h a v i o u r s a r e b a s e d cn t h e c l a s s i f i c a t i o n s o f S h e p p a r d and Y o s h i d a (1971). V o c a l i z a t i o n s were n o t e d b u t were n o t i n c l u d e d i n t h e t i m e b u d g e t s , a s a n i m a l s were a l w a y s a c t i v e i n some o t h e r b e h a v i o u r when v o c a l i z i n g . RECOGNITIVE BEHAVIOUR nose-nose nose-body nose-anus nose-genital approach COHESIVE BEHAVIOUR social grooming rubbing/crawling crawling under mounting AGONISTIC BEHAVIOUR threat arching warding sparring attack/pounce fight chase INTERACTIVE AVOIDANCE BEHAVIOUR avoidance mutual avoidance recoil ing submissive posture VOCALIZATIONS single chatter double chatter t r ip le chatter squeal growl FEEDING BEHAVIOUR mouth only paw manipulation nest gathering feed search POSTURING BEHAVIOUR s i t t i n g low crouch high crouch semi-erect low erect high erect l i e MAINTENANCE GROOMING BEHAVIOUR l icking paw wash scratch . dust, r o l l MOVEMENT normal fast run hop DIGGING — 18 C o l o u r e d s t a k e s marked t h e c o r n e r s o f e a c h s q u a r e . I n a d d i t i o n t h e l o c a t i o n o f a l l b u r r o w s , runways, t r e e s , s h r u b s and o t h e r r e a d i l y i d e n t i f i a b l e o b j e c t s was mapped on a s c a l e o f 1 cm:2.5ra. I r e c o r d e d t h e c o o r d i n a t e s o f e a c h new p o s i t i o n o f an a n i m a l u n d e r o b s e r v a t i o n t o t h e n e a r e s t meter, u s i n g e i t h e r g r i d c o o r d i n a t e s c r s p e c i f i e d map l o c a t i o n s I n t h e 1976 s e a s o n , I o b s e r v e d a n i m a l s on CCC and CCS f o r 2-3 d a y s e v e r y two weeks, whereas t h o s e on SEC were o b s e r v e d f o r o n l y one day e v e r y two weeks. I u s e d t h e same f o u r 2-hour p e r i o d s b u t each p e r i o d was d i v i d e d i n t o two 1-hour s a m p l i n g i n t e r v a l s . F o r e a c h h o u r , I s e l e c t e d a g r o u p o f 10 a n i m a l s i n a s p e c i f i c o r d e r f r o m t h e a n i m a l s v i s i b l e a t t h a t t i m e . C h o i c e was b a s e d on, t h e e x t e n t o f p r e v i o u s s i g h t i n g s { a n i m a l s n o t y e t o b s e r v e d d u r i n g t h e b i w e e k l y s a m p l i n g p e r i o d were g i v e n p r i o r i t y t o t h o s e a l r e a d y o b s e r v e d ) and age {young a n i m a l s were p r e f e r e n t i a l l y o b s e r v e d o v e r a d u l t a n i m a l s ) . U s i n q an e l e c t r o n i c metronome ( E i e n s e t . ajL 1970) s e t a t a s i x s e c o n d i n t e r v a l , I o b s e r v e d e a c h s u c c e s s i v e a n i m a l i n t h e q r o u p a t e a c h s o u n d i n q o f t h e metronome, s u c h t h a t e a c h o f t h e 10 a n i m a l s i n t h e f i e l d was o b s e r v e d o n c e e v e r y m i n u t e . As e a c h i n d i v i d u a l was o b s e r v e d , I r e c o r d e d t h e t y p e o f b e h a v i o u r s e e n {at t h e s o u n d i n q o f t h e metronome), t h e i n t e r a c t i v e p a r t n e r { i f a p p l i c a b l e ) and t h e l o c a t i o n o f t h e a n i m a l { i f new) on a c a s e t t e t a p e u s i n q a p o r t a b l e t a p e r e c o r d e r { P h i l l i p s 3/60 r e c o r d e r ) w i t h a hand c o n t r o l l e d o n - o f f m i c r o p h o n e s w i t c h . The l a t t e r a l l o w e d c o n t i n u o u s s c a n n i n g and l o c a t i o n o f a n i m a l s w h i l e r e c o r d i n g t h e d a t a . The method o f b e h a v i o u r a l o b s e r v a t i o n u s e d i n 1976 i s c o m p a r a b l e t o A l t m a n n * s (1974) i n s t a n t a n e o u s s a m p l i n g t e c h n i q u e . 19 The f o c a l a n i m a l s a m p l i n g method u s e d i n 1975 and t h e i n s t a n t a n e o u s s a m p l i n g method u s e d i n 1976 a r e b o t h c a p a b l e o f c o l l e c t i n g d a t a s u i t a b l e f o r t h e c a l c u l a t i o n o f p e r c e n t a g e b e h a v i o u r b u d g e t s . The f o c a l a n i m a l s a m p l i n g method a l l o w e d me t o o b t a i n d e t a i l e d i n f o r m a t i o n on o n l y a s m a l l number o f a n i m a l s . F u r t h e r , a c t i v e a n i m a l s t e n d e d t o be o b s e r v e d more t h a n l e s s a c t i v e a n i m a l s . The i n s t a n t a n e o u s s a m p l i n g method o n t h e o t h e r hand a l l o w e d me t o o b s e r v e a w i d e r r a n g e o f a n i m a l s a t t h e same t i m e and s o s a m p l i n g t i m e s f o r i n d i v i d u a l a n i m a l s were more e g u a l t h a n i n t h e f o c a l a n i m a l s a m p l i n g method. U n f o r t u n a t e l y t h e i n s t a n t a n e o u s s a m p l i n g method d o e s n o t a l l o w f o r t h e c a l c u l a t i o n o f i n t e r a c t i o n r a t e s . The a d v a n t a g e o f i n c r e a s e d s ample s i z e s was t h o u g h t t o be more i m p o r t a n t . E x p e r i m e n t a l A r e a s Removal A r e a s i n 1975 a r e m o v a l scheme s i m i l a r t o t h e c o n t i n u o u s r e m o v a l e x p e r i m e n t o f Myers and K r e b s (1971) and K r e b s e t . a l (1976) was u s e d . By c r e a t i n g an a r e a o f v e r y low a n i m a l d e n s i t y i t was hoped t h a t any d i s p e r s i n g a n i m a l e n c o u n t e r i n g t h e a r e a would become a r e s i d e n t . Thus i t was assumed t h a t new a n i m a l s whose home r a n g e s were p r i m a r i l y w i t h i n t h e b o u n d a r i e s o f t h e r e m o v a l a r e a were d i s p e r s i n g a n i m a l s and would be c h a r a c t e r i s t i c o f d i s p e r s i n g s g u i r r e l s . On b o t h CCR and SRS, a l l a n i m a l s were t a g g e d , p r o c e s s e d and 20 r e l e a s e d when f i r s t c a u g h t . I removed an a n i m a l o n l y when i t had been c a p t u r e d i n 3 c o n s e c u t i v e t r a p p i n g s e s s i o n s . F o r example, an a n i m a l c a p t u r e d on a l l t h r e e d a y s of one t r a p p i n g p e r i o d was removed on t h e l a s t t r a p p i n g day, as was an a n i m a l c a u g h t t w i c e i n one t r a p p i n g week and on t h e f i r s t t r a p p i n g day o f t h e n e x t week. T h i s l e s s e n e d t h e c h a n c e s o f my a c c i d e n t a l l y r e m o v i n g a r e s i d e n t a n i m a l f r o m a n e a r b y a r e a which may have moved o n t o t h e r e m o v a l a r e a . o n . a . s i n g l e d a y , . w h i l e i n c r e a s i n g t h e p r o b a b i l i t y o f r e m o v i n g a n i m a l s r e s i d e n t on t h e r e m o v a l a r e a . A n i m a l s removed i n 1975 were a u t o p s i e d . F o r e a c h a n i m a l a u t o p s i e d I r e c o r d e d t h e same i n f o r m a t i o n as f o r a l i v e - t r a p p i n g c a p t u r e as w e l l as t o t a l l e n g t h i n c l u d i n g t h e t a i l ( f u l l y e x t e n d e d ) , t a i l l e n g t h , t h e amount o f f a t d e p o s i t e d i n t h e a b d o m i n a l m e s e n t e r y (based on an i n d e x where 1=no f a t t o 5=heavy f a t d e p o s i t s ) and i n t e r n a l r e p r o d u c t i v e c o n d i t i o n . I n t e r n a l r e p r o d u c t i v e c o n d i t i o n was n o t e d a s f e l l o w s : f o r m a l e s , t e s t e s w e i g h t ; f o r f e m a l e s u t e r u s s i z e ( t h r e a d - l i k e , n o r m a l o r e n l a r g e d ) , u t e r u s w e i g h t , number o f p l a c e n t a l s c a r s , number o f embryos ( i f p r e s e n t ) and p r e v i o u s b r e e d i n g c o n d i t i o n ( n u l l i p a r o u s , p r i m i p a r o u s o r m u i t i p a r o u s ) . A u t o p s y i n f o r m a t i o n was u s e d m a i n l y t o v e r i f y e x t e r n a l i n d i c a t o r s o f b r e e d i n g c o n d i t i o n . I n 1976 a p u l s e d r e m o v a l scheme r a t h e r t h a n a c o n t i n u o u s r e m o v a l scheme was u s e d . T h i s e n a b l e d o b s e r v a t i o n s o f t h e s g u i r r e l s c o m i n g o n t o and i n h a b i t i n g t h e r e m o v a l a r e a s o v e r a l o n g e r t i m e p e r i o d . B e h a v i o u r a l o b s e r v a t i o n s were c o m p l e t e d on CCB o n l y . A n i m a l s on b o t h SBK and CCH when c a u g h t were t a g g e d , p r o c e s s e d and r e l e a s e d . Then once e v e r y t h r e e t r a p p i n g p e r i o d s 21 ( s i x c a l e n d a r w e e k s ) , a l l a n i m a l s c a u g h t a t l e a s t o n c e e v e r y t r a p p i n g p e r i o d were removed. I n a d d i t i o n on CCR, any r e s i d e n t a n i m a l o b s e r v e d on t h e a r e a , b u t n o t n e c e s s a r i l y t r a p p e d i n e a c h p e r i o d was a l s o removed, a n i m a l s removed were t r a n s f e r e d t o a s m a l l i s l a n d i n t h e s o u t h w e s t e r n end o f K l u a n e L a k e . The F e e d i n g A r e a fCCF) My t r a p p i n g and b e h a v i o u r a l r e s u l t s from 1975 s u g g e s t e d t h a t j u v e n i l e growth and t h e t i m e a t which a j u v e n i l e r e a c h e d a d u l t s i z e were i m p o r t a n t f a c t o r s l e a d i n g t o d i s p e r s a l . To t e s t t h e p r e d i c t i o n s o f t h i s h y p o t h e s i s , I a t t e m p t e d t o i n c r e a s e j u v e n i l e growth by p r o v i d i n g a d d i t i o n a l f o o d . I c o n s t r u c t e d t h r e e f e e d i n g s t a t i o n s ( F i g . 5 ) and i n s t a l l e d t h e s e by t h r e e o f t h e main burrow s y s t e m s w i t h i n t h e CCF a r e a . Each was s u p p l i e d w i t h 9-10 kg o f o a t s a week f r o m May 1 t o O c t o b e r 9,1976 and f r o m A p r i l 18 t o May 18,1977. CCF was t r a p p e d b i w e e k l y t h r o u g h o u t t h e 1976 and 1977 s e a s o n . A d u l t Male Removal Area (CCM) S e v e r a l s t u d i e s have shown t h a t a d u l t male a g g r e s s i o n i s i m p o r t a n t i n t h e d i s p e r s a l o f j u v e n i l e a n i m a l s ( A r m i t a g e 1974, B a r a s h 1975, D o n a l d s o n 1 9 7 7 ) . My r e s u l t s f r o m t h e 1975 f i e l d s e a s o n a l s o s u g g e s t e d t h i s i n A r c t i c g r o u n d s q u i r r e l s . To d e t e r m i n e i f t h e p r e s e n c e o f a d u l t males a f f e c t e d j u v e n i l e d i s p e r s a l , I removed a l l a d u l t males c a u g h t i n two s u c c e s s i v e t r a p p i n g p e r i o d s on the a r e a . I f a d u l t male a g g r e s s i o n i s u r e 5: C o n s t r u c t i o n o f t h e f e e d i n g s t a t i o n s . F i v e g a l l o n p l a s t i c p a i l s w i t h t o p s were u s e d f o r t h e o u t e r c a s i n g . T h r e e o p e n i n g s , 8 cm i n d i a m e t e r were c u t a b o u t 16 cm from t h e bottom o f t h e p a i l s . The p a i l s were t h e n i n s e r t e d i n t o t h e g r o u n d up t o t h e b o t t o m o f t h e o p e n i n g s . A f u n n e l , c o n s t r u c t e d f r o m t h e t o p o f a m e t a l 5 - g a l l o n drum was i n s e r t e d i n t h e t o p o f t h e p a i l . O a t s were t h e n p l a c e d i n t h e f u n n e l and a l l o w e d t o f e e d c u t i n t o t h e chamber below. 23 metal drum grain plastic pail 24 i m p o r t a n t t o t h e i n i t i a t i o n o f j u v e n i l e d i s p e r s a l , one would e x p e c t more j u v e n i l e s t o r e m a i n on t h e a r e a t h a n on t h e n e a r b y c o n t r o l a r e a . S u c c e s s o f t h i s e x p e r i m e n t was l i m i t e d b e c a u s e o f t h e v e r y p o o r p r o d u c t i o n o f young i n t h a t a r e a , a n i m a l s were t r a p p e d b i w e e k l y from Hay 3 t o O c t o b e r 9,1976. Age C l a s s i f i c a t i o n T h r o u g h o u t t h e r e m a i n d e r o f t h e R e s u l t s and D i s c u s s i o n , I w i l l u s e t h e t e r m s a d u l t , y e a r l i n g and j u v e n i l e a n i m a l s o n l y f o r a n i m a l s o f known h i s t o r y . A d u l t s a r e a n i m a l s g r e a t e r t h a n 2 y e a r s o f age. Y e a r l i n g s a r e a n i m a l s i n t h e i r s e c o n d s p r i n g and summer. The t e r m mature a n i m a l s w i l l be used t o t o r e f e r t o t h e co m b i n e d a d u l t and y e a r l i n g age c l a s s e s and w i l l be us e d p r i m a r i l y where t h e r e i s some d o u b t a s t o t h e a c t u a l age o f some a n i m a l s . J u v e n i l e s a r e a n i m a l s b o r n t h a t y e a r . On a l l t r a p p i n g a r e a s I r e c o g n i z e d f o u r major c l a s s e s o f a n i m a l s ; mature m a l e s , mature f e m a l e s , j u v e n i l e m a l e s and j u v e n i l e f e m a l e s . S t a t i s t i c a l A n a l y s e s I t e s t e d t h e s i g n i f i c a n c e o f c o m p a r i o n s o f two d a t a s e t s u s i n g a S t u d e n t * s t - t e s t , which i s s u i t a b l e f o r s a m p l e s s i z e s s m a l l e r t h a n 50 ( E l l i o t 1 9 7 1). C o m p a r i s o n s f o u n d t o be s t a t i s t i c a l l y s i g n i f i c a n t a r e s i g n i f i c a n t a t t h e 0.05 l e v e l o f s i g n i f i c a n c e . I n a l l e t h e r c a s e s when d i f f e r e n t s t a t i s t i c a l t e s t s were employed, d e t a i l s a r e g i v e n i n t h e t e x t . The te r m X ± Y r e f e r s t o t h e 95% c o n f i d e n c e l i m i t s o f X. 25 RESULTS: PART I I w i l l p r e s e n t t h e r e s u l t s i n two s e c t i o n s , t h e f i r s t d e s c r i b e s i m p o r t a n t e v e n t s i n t h e a n n u a l c y c l e o f a c t i v i t y and w e i g h t g a i n and t h e s e c o n d , t h e demography and b e h a v i o u r o f t h e c o n t r o l and e x p e r i m e n t a l p o p u l a t i o n s . A d i s c u s s i o n w i l l d i r e c t l y f o l l o w b o t h s e c t i o n s c f t h e R e s u l t s . To c o n c l u d e t h e f i n a l d i s c u s s i o n I w i l l p r e s e n t a g r a p h i c a l model o f p o p u l a t i o n r e g u l a t i o n i n A r c t i c g r o u n d s g u i r r e l s , i n c o r p o r a t i n g i n f o r m a t i o n o b t a i n e d d u r i n g t h i s s t u d y on a c t i v i t y p a t t e r n s , demography and s o c i a l b e h a v i o u r . A n n u a l P a t t e r n s Of A c t i v i t y And We i q h t G a i n The e c o l o g y o f many o f t h e s o u t h e r n s p e c i e s o f g r o u n d s g u i r r e l s has been e x t e n s i v e l y s t u d i e d ( i e . F i t c h 1948, M i c h e n e r and M i c h e n e r 1977, Sherman 1976, S l a d e and B a l p h 1974). L i t t l e i n f o r m a t i o n i s a v a i l a b l e on t h e more n o r t h e r n s p e c i e s , S. u n d u l a t u s and S. c o l u m b i a n u s however. To u n d e r s t a n d t h e d e m o g r a p h i c mechanisms o f a p o p u l a t i o n , one must know s o m e t h i n g o f t h e b a s i c r e p r o d u c t i v e , d e v e l o p m e n t a l and s o c i a l b i o l o g y . S o c i a l i n t e r a c t i o n s f o r example would l i k e l y d i f f e r between the b r e e d i n g p e r i o d and t h e n o n - b r e e d i n g p e r i o d . C a r l (1971) and Mayer (1953) have p r e s e n t e d a g u a l i t a t i v e r e v i e w o f some of t h e common e v e n t s i n t h e a n n u a l a c t i v i t y p a t t e r n o f t h e A r c t i c g r o u n d s g u i r r e l w h i l e o t h e r s ( M i t c h e l l 1959, S t e i n e r j 1972, • • ' i L i n c o l n 1972) h a v e d i s c u s s e d more d e t a i l e d a s p e c t s o f t h e b i o l o g y o f S. u n d u l a t u s . V e r y l i m i t e d g u a n t i t a t i v e i n f o r m a t i o n 26 i s a v a i l a b l e however. I w i l l f i r s t p r e s e n t some o f t h e r e l e v a n t d a t a on a c t i v i t y p a t t e r n s , r e p r o d u c t i o n , g r o w t h and b e h a v i o u r o b t a i n e d i n t h i s s t u d y and d i s c u s s t h e s e i n t e r m s o f t h e i r s i g n i f i c a n c e t o t h e demography as w e l l a s t h e i r s i m i l a r i t y t o o t h e r g r o u n d s g u i r r e l s p e c i e s . A g e n e r a l i z e d a c t i v i t y p a t t e r n and w e i g h t g a i n c y c l e o v e r a y e a r f o r mature a n d j u v e n i l e a n i m a l s on SBC i s shown i n F i g . 6 (a s i m i l a r p a t t e r n was a l s o o b s e r v e d on C C C ) . Emergence S q u i r r e l s began t o emerge from h i b e r n a t i o n i n t h e t h i r d t o f o u r t h week o f A p r i l i n t h e K l u a n e r e g i o n . The d a t e s o f f i r s t e m ergence on SRC were A p r i l 24, A p r i l 19 and A p r i l 14 i n 1975, 1976, and 1977 r e s p e c t i v e l y . On CCC d a t e s o f f i r s t emergence were A p r i l 28 i n 1976 and A p r i l 18 i n 1977. Emergence d a t a f o r a n i m a l s on SRC i n 1975 a r e l i m i t e d due t o p r o b l e m s a s s o c i a t e d w i t h t h e e s t a b l i s h m e n t o f t r a p p i n g and o b s e r v a t i o n a l a r e a s . No d a t a was o b t a i n e d f o r a n i m a l s on CCC i n 1975 a s t h e a r e a was n o t t r a p p e d u n t i l J u n e . Mean d a t e s o f f i r s t emergence f o r mature, a d u l t , and j u v e n i l e , m ales and f e m a l e s f o r 1975-1977 a r e g i v e n i n T a b l e 2. M a l e s and f e m a l e s emerged a t t h e same t i m e . O n l y on CCC i n 1977 was t h e r e . a s e p a r a t i o n between t h e emergence d a t e s o f a d u l t s and y e a r l i n g s o f t h e same s e x . M a t u r e males t e n d e d t o emerge f i r s t , f o l l o w e d by mature f e m a l e s , j u v e n i l e m ales and j u v e n i l e f e m a l e s i n t h a t o r d e r . A n i m a l s on t h e S l i m s B i v e r a r e a began t o emerge from h i b e r n a t i o n b e f o r e a n i m a l s on t h e C o i n 27 F i g u r e 6: A n n u a l p a t t e r n o f a c t i v i t y and w e i g h t g a i n on SSC. Ave r a g e body w e i g h t s were c a l c u l a t e d f o r e a c h c l a s s . 95% c o n f i d e n c e l i m i t s a r e i n d i c a t e d . Sample r a n g e s f o r e a c h c l a s s were as f o l l o w s : mature males 2<N<17, mature f e m a l e s 1<N<22, j u v e n i l e males 2<N<9, j u v e n i l e f e m a l e s 2<N<10. Means a r e f o r 1975-1977 s a m p l e s . T h e r e were no 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 . Emergence, b r e e d i n g and h i b e r n a t i o n e n t r y i n d i c a t o r s a r e f o r t h e maximum r a n g e s o b s e r v e d . A M a t u r e M a l e s • , Mature F e m a l e s A J u v e n i l e M a l e s H J u v e n i l e F e m a l e s 28 29 T a b l e 2: D a t e s o f emergence. The mean d a t e o f emergence , r a n g e o f emergence d a t e s and t h e number o f a n i m a l s i n e a c h sample a r e shown f o r mature males and f e m a l e s . Where p o s s i b l e , means, r a n g e s and sample s i z e s a r e i n c l u d e d f o r a n i m a l s o f known a g e s f r o m t h e mature a n i m a l s ample. D a t e s a r e shown f o r t h e s p r i n g o f 1975, 1976 and 1977. AREA i CLASS 1975 1976 1977 MEAN DATE RANGE N MEAN DATE RANGE N MEAN DATE RANGE - - I N MATURE MALES April 26 Apr.24-Apr.28 8 April 24 Apr.20-May2 3 April 18 Apr.15-Apr.20 6 ADULT MALES April 20 Apr.20 1 April 16 Apr.15-Apr.17 2 SLIMS RIVER YRLNG. MALES April 25 Apr.20-May 2 2 April 19 Apr.17-Apr.20 4 CONTROL MAT. FEMALES April 28 Apr.27-Apr.28 3 April 27 Apr.20-May 2 4 April 27 Apr.15-May 4 9 AD. FEMALES April 25 Apr.20-May 2 2 April 27 Apr.15-May 3 6 YRLNG.FEMALES April 28 Apr.19-May 2 2 May 3 May 3- May 4 3 MATURE MALES April 29 Apr.28-May 1 4 April 30 Apr.18-Mayl3 7 COIN CREEK CONTROL ADULT MALES YRLNG. MALES April 30 April 28 Apr.29-May April 28 1 2 2 April 20 May 13 Apr.18-Apr.22 May 13 4 3 MAT. FEMALES April 29 Apr.28-May 5 15 April 28 Apr.l8-May 13 15 AD. FEMALES „ April 29 Apr.28-May 5 10 April 25 Apr.18-Apr.30 11 YRLNG.FEMALES April 28 April 28 5 May 7 May 5-May 13 4 _ i 3 1 Creek area but animals on both areas had s i m i l a r ranges of emergence dates. The Establishment Of S p r i n g T e r r i t o r i e s The establishment o f s p r i n g t e r r i t o r i e s began s h o r t l y a f t e r emergence from h i b e r n a t i o n and based on measures of wounding and i n t e r a c t i o n r a t e s f o r animals on both SRC and CCC, i n v o l v e d r e l a t i v e l y high l e v e l s of a g g r e s s i o n . ,  I n t e r a c t i o n r a t e s (the mean number of i n t e r a c t i o n s per day) f o r a g o n i s t i c behaviours were c a l c u l a t e d f o r each biweekly p e r i o d o f b e h a v i o u r a l o b s e r v a t i o n s ( F i g . 7 ) . Behavioural i n f o r m a t i o n f o r the s p r i n g p e r i o d was on l y a v a i l a b l e f o r 1976 on both areas. S i m i l a r l y , the average number of wounds f o r each c l a s s was c a l c u l a t e d f o r the animals caught i n l i v e t r a p s d u r i n g each biweekly t r a p p i n g p e r i o d . a g o n i s t i c i n t e r a c t i o n s reached a peak two to three weeks a f t e r f i r s t emergence . ;, On SRC, mature male: mature male a g o n i s t i c i n t e r a c t i o n s were most common s h o r t l y a f t e r emergence ( F i g . 8). On CCC a s i m i l a r p a t t e r n was not e v i d e n t i n 1976 as onl y one mature male was present d u r i n g the f i r s t two weeks Mature female:mature female and mature male:mature female a g o n i s t i c i n t e r a c t i o n s became more common two to f i v e weeks a f t e r emergence. Whereas mature male i n t e r a c t i o n s l a r g e l y i n v o l v e d chases and prolonged f i g h t s , mature female i n t e r a c t i o n s were most o f t e n b r i e f s k i r m i s h e s or t h r e a t s . Mature males showed the hi g h e s t number of wounds s h o r t l y a f t e r emergence ( F i g . 9). Wounds v a r i e d from s m a l l puncture 3 2 F i g u r e 7 : B i w e e k l y c h a n g e s i n t h e r a t e o f a g o n i s t i c i n t e r a c t i o n s . The t o t a l number o f a g o n i s t i c i n t e r a c t i o n s o b s e r v e d d u r i n g e a c h week o f o b s e r v a t i o n s was d i v i d e d by t h e number o f a n i m a l s o b s e r v e d on t h e a r e a d u r i n g t h e same p e r i o d and was d i v i d e d by t h e number o f o b s e r v a t i o n a l d a y s (8 h o u r s / d a y ) f o r t h e p e r i o d t o o b t a i n t h e number o f i n t e r a c t i o n s / a n i m a l / d a y . A S B C (1976) • C C C (1976) 33 A 9.0- \ = = A 3.0H 34 Figure 8: P r o p o r t i o n of i n t e r a c t i o n s i n v o l v i n g a d u l t s of each sex. Mature Males:Mature Males Mature Males:Mature Female Mature Female:Mature female A) SRC 36 F i g u r e 9: S e a s o n a l c h a n g e s i n t h e number o f wounds per a n i m a l . The mean number o f wounds f o r e a c h c l a s s d u r i n g e a c h t r a p p i n g p e r i o d was b a s e d on t h e number o f wounds c o u n t e d on t h e p o s t e r i o r h a l f o f t h e body. C o u n t s o f wounds were not begun u n t i l m i d - A u g u s t 1975. i & M a t u r e M a l e s # Mature F e m a l e s A J u v e n i l e M a l e s J u v e n i l e F e m a l e s 37 SRC 6-* 1975 1976 1977 38 wounds t o l a r g e (1-2cm 2) g a s h e s on t h e rump and f l a n k s . O c c a s i o n a l l y wounding was f o u n d on t h e head and neck and i n t h r e e i n s t a n c e s bones were b r o k e n o r e x p o s e d . No a n i m a l s were known t o d i e as a r e s u l t o f wounding. Mature f e m a l e s on t h e o t h e r hand showed a v e r y low number o f wounds d u r i n g t h e same p e r i o d . M a t u r e f e m a l e wounding was p r i m a r i l y s m a l l p u n c t u r e s on t h e p o s t e r i o r r e g i o n o f t h e body. B r e e d i n g A l l mature males c a u g h t w i t h i n t h e f i r s t week a f t e r emergence had d e s c e n d e d t e s t e s and were i n b r e e d i n g c o n d i t i o n . By t h e t h i r d week a f t e r emergence however, t h e number o f males s t i l l i n b r e e d i n g c o n d i t i o n d e c r e a s e d and by t h e f i f t h week a f t e r emergence no s c r o t a l males were c a p t u r e d { F i g . 10). Most y e a r l i n g males were s c r o t a l when f i r s t c a p t u r e d and were assumed t o . be c a p a b l e o f b r e e d i n g , a l l y e a r l i n g males on SRC i n 1976 and 1977 were s c r o t a l a t t h e t i m e o f f i r s t c a p t u r e b u t none o f t h e y e a r l i n g males on CCC i n 1976 were i n b r e e d i n g c o n d i t i o n and i n 1977 o n l y UQ% o f t h e y e a r l i n g m ales were s c r o t a l . a l l b r e e d i n g y e a r l i n g males on CCC emerged a t t h e same t i m e as a d u l t males whereas t h e n o n - b r e e d i n g y e a r l i n g s d i d n o t emerge u n t i l t h e t h i r d t o f i f t h week a f t e r f i r s t e mergence. I t w o u l d a p p e a r t h e n , t h a t o n l y t h e e a r l y e m e r g i n g y e a r l i n g males a r e s c r o t a l a t emergence. , a l l mature f e m a l e s showed e x t e r n a l s i g n s o f b r e e d i n g ( e n l a r g e d v a g i n a l p a p i l l a e ) i n t h e s p r i n g ( F i g . , 1 1 ) . Some f e m a l e s were not i n b r e e d i n g c o n d i t i o n when f i r s t c a p t u r e d b u t u r e 10: R e p r o d u c t i v e c o n d i t i o n o f mature males. The mean p e r c e n t a g e o f t h e r e s i d e n t mature male p o p u l a t i o n w i t h s c r o t a l t e s t e s i n e a c h t r a p p i n g p e r i o d d u r i n g t h e s p r i n g and e a r l y summer o f 1975-1977 a r e shown f o r b o t h c o n t r o l a r e a s . The t i m e a x i s i s b a s e d on t h e number o f d a y s a f t e r f i r s t emergence f r o m h i b e r n a t i o n . A M a t u r e males SRC 6 M a t u r e males CCC 40 100-(A 80-Jj) u 2 60-O 40-20-Weeks after first Emergence 41 F i g u r e 11: R e p r o d u c t i v e c o n d i t i o n o f mature f e m a l e s . The mean p e r c e n t a g e o f r e s i d e n t mature f e m a l e s i n b r e e d i n g c o n d i t i o n d u r i n g e a c h t r a p p i n g p e r i o d f r o m A p r i l t o September o f 1975-1977 a r e shown f o r e a c h a r e a . The t i m e a x i s i s b a s e d on t h e number o f weeks f r o m t h e t i m e o f f i r s t emergence. A mature f e m a l e s SRC 0 mature f e m a l e s CCC 42 43 a l l were b r e e d i n g a t most t h r e e weeks l a t e r . Some males were s t i l l s c r o t a l a t t h i s t i m e and s o a l l e s t r o u s f e m a l e s s h o u l d a t l e a s t have had t h e o p p o r t u n i t y t o b r e e d . No c o p u l a t i o n s were s e e n d u r i n g t h e s p r i n g p e r i o d s o I c o u l d n o t e s t i m a t e t h e number o f f e m a l e s t h a t s u c c e s s f u l l y b r e d . F o u r f e m a l e s were f o u n d t o have v a g i n a l p l u g s , 3 on A p r i l 29 and one on May 5 i n 1977. W h i t t e n <1956) used t h e p r e s c e n c e o f v a g i n a l p l u g s i n l a b o r a t o r y m i c e t o d e t e r m i n e when c o p u l a t i o n o c c u r r e d . A l l f o u r f e m a l e s were c a p t u r e d t h e f o l l o w i n g day and none r e t a i n e d t h e v a g i n a l p l u g . T h i s s u g g e s t s t h a t s u c c e s s f u l c o p u l a t i o n s do o c c u r up t o a t l e a s t t h r e e weeks a f t e r f i r s t emergence. The e x t e r n a l i n d i c e s o f f e m a l e b r e e d i n g c o n d i t i o n u s e d t h r o u g h o u t t h i s s t u d y a p p e a r e d t o be more c l o s e l y r e l a t e d t o p r e g n a n c y and l a c t a t i o n t h a n t o t h e p e r i o d o f e s t r o u s (assuming t h e p e r i o d o f e s t r o u s i n S. u n d u l a t u s i s s i m i l a r t o t h e 4-6 hour e s t r o u s p e r i o d o f S. b e l d i n g i (Sherman 1976)}. T h i s was e v i d e n c e d by t h e s h a r p d e c l i n e i n t h e number o f b r e e d i n g f e m a l e s i n t h e t e n t h week a f t e r f i r s t e mergence, c o i n c i d e n t w i t h t h e emergence o f young on b o t h a r e a s . S i m i l a r l y a d e c l i n e i n t h e p e r c e n t a g e o f f e m a l e s s h o w i n g medium t o l a r g e s i z e d mammae a l s o o c c u r r e d w i t h i n t h e same p e r i o d ( F i g . 1 2 ) . A l t h o u g h a l l mature f e m a l e s a p p e a r e d t o be c a p a b l e o f b r e e d i n g , n o t a l l became p r e g n a n t o r r a i s e d l i t t e r s . P r e g n a n c y was d e t e r m i n e d on t h e b a s i s o f e x t e r n a l s i g n s ( v i s i b l e s w e l l i n g o f t h e abdomen, d e p o s i t i o n o f f a t t y t i s s u e a r o u n d t h e b a s e o f and e n l a r g e m e n t o f t h e mammae, a n d / o r a r a p i d d r o p i n w e i g h t i n t h e t h i r d o r f o u r t h week o f M a y 1 ) . The p r o p o r t i o n o f f e m a l e s p r e g n a n t was c a l c u l a t e d by d i v i d i n g t h e number o f f e m a l e s 44 f i g u r e 12 : M a t u r e f e m a l e l a c t a t i o n . N i p p l e s i z e was c l a s s i f i e d as s m a l l , medium o r l a r g e . Sample s i z e s a r e shown f o r e a c h w e e k l y p e r i o d . Time a x i s i s b a s e d on t h e number o f weeks from t h e t i m e o f f i r s t e m ergence. S m a l l n i p p l e s i z e Medium n i p p l e s i z e L a r g e n i p p l e s i z e c) 5 R C 46 s h o w i n g s i g n s o f p r e g n a n c y by t h e t o t a l number o f f e m a l e s p r e s e n t on t h e a r e a f r o m May 1 to J u n e 12 2 . The number o f f e m a l e s s u c c e s s f u l l y r a i s i n g l i t t e r s t o p o s t w e a n i n g was d e t e r m i n e d by o b s e r v i n g and t r a p p i n g young a s t h e y emerged f r o m t h e burrow and a t t r i b u t i n g t h e young t o t h e f e m a l e t h a t had been a c t i v e l y u s i n g t h a t burrow complex f o r t h e p r e v i o u s two weeks o r more. I n no c a s e d u r i n g t h e two y e a r s o f t h e s t u d y d i d two f e m a l e s o c c u p y a s i n g l e burrow complex as t h e i r main c e n t r e o f a c t i v i t y d u r i n g t h e p e r i o d o f d e v e l o p m e n t and weaning o f young. I am c o n f i d e n t a l l mother:young a s s o c i a t i o n s were c o r r e c t . The p r o p o r t i o n o f f e m a l e s on SRc w h i c h became p r e g n a n t was .55 (N=24) whereas 0.73 <N=22) o f t h e mature f e m a l e s on CCC became p r e g n a n t . An a v e r a g e o f 0.40 and 0.55 o f t h e mature f e m a l e s on SEC and CCC s u c c e s s f u l l y r a i s e d l e t t e r s to t h e p o s t - w e a n i n g s t a g e . Female r e p r o d u c t i v e s u c c e s s f o r e a c h a r e a and y e a r i s summarized i n T a b l e 3. 1. Mayer (1953) gave a f i g u r e o f 25 d a y s f o r t h e t i m e o f d e v e l o p m e n t o f young, from b i r t h t o emergence from t h e n a t a l b u r r o w . The p r o b a b l e t i m e o f b i r t h and o b v i o u s w e i g h t l o s s was c a l c u l a t e d by s u b t r a c t i n g 25 days from t h e d a t e s o f t h e emergence o f young. 2. T h e s e d a t e s were used t o span t h e p e r i o d f r o m b r e e d i n g t o e s t i m a t e d b i r t h o f young. Females n o t r e m a i n i n g on t h e a r e a d u r i n g t h i s p e r i o d were n o t i n c l u d e d a s i t was d i f f i c u l t t o d e t e r m i n e i f t h e a n i m a l was p r e g n a n t o r n o t , e x c e p t n e a r t h e end o f p r g n a n c y . F e m a l e s e n t e r i n g t h e a r e a and r e m a i n i n g p a s t t h e t i m e o f b i r t h were i n c l u d e d . 47 f a b l e 3: R e p r o d u c t i v e s u c c e s s o f mature f e m a l e s . Only females which remained on t h e a r e a f o r a t l e a s t f o u r t r a p p i n g p e r i o d s i n t h e p e r i o d from May 1 - J u l y 1 were i n c l u d e d . Preganancy was based on v i s u a l s i g n s and/or a r a p i d change i n weight i n mid-May. C o i n Creek was f i r s t t r a p p e d i n J u l y 1975 and as a r e s u l t no pregnancy d a t a was o b t a i n e d t h a t y e a r . S i m i l a r l y , t r a p p i n g on both SRC and CCC ended i n June 1977 and so data on t h e number of s u c c e s s f u l l i t t e r s was not o b t a i n e d . 48 AREA TOTAL // ^PREGNANT N % SUCCESSFUL LITTERS N SLIMS - RIVER CONTROL 1975 7 85 6 43 3 1976 8 63 5 38 3 1977 9 100 9 - -COIN CREEK CONTROL 1975 7 - - 86 6 1976 11 55 6 55 6 1977 11 91 t \ 49 L i t t e r S i z e P l a c e n t a l s c a r c o u n t s and embryo c o u n t s were u s e d t o e s t i m a t e t h e a v e r a g e l i t t e r s i z e a t b i r t h . O n l y d a t a from f e m a l e s removed d u r i n g t h e i n i t i a l t r a p - o u t o f r e s i d e n t a n i m a l s on t h e r e m o v a l a r e a s were i n c l u d e d . The mean number o f p l a c e n t a l s c a r s o f f e m a l e s f r o m SBR and CCR were 5.2 and 4.6 r e s p e c t i v e l y . T h e r e were no s i g n i f i c a n t d i f f e r e n c e s between a r e a s . Embryo c o u n t s were o n l y p o s s i b l e on SBR a s f e m a l e s had a l r e a d y g i v e n b i r t h when CCB was e s t a b l i s h e d . The mean embryo c o u n t f o r SRB was 5.0. T h i s was n o t s i g n i f i c a n t l y d i f f e r e n t f r o m t h e p l a c e n t a l s c a r c o u n t s f o r e i t h e r r e m o v a l a r e a . The t h r e e c o u n t s were combined t o g i v e an a v e r a g e l i t t e r s i z e a t b i r t h o f 4.9 ± 1.6. Mean l i t t e r s i z e a t emergence f r o m t h e n a t a l burrow on SRC and CCC were 3.5 and 3.6 r e s p e c t i v e l y . S e a s o n a l Sex R a t i o s S e a s o n a l sex r a t i o s were b a s e d on t h e minimum number a l i v e f o r e a c h t i m e p e r i o d . S p r i n g and l a t e summer s e x r a t i o s f o r mature a n i m a l s a s w e l l as s e x r a t i o s f o r j u v e n i l e s i n t h e f i r s t two weeks a f t e r emergence, a t one month and a t two months a f t e r emergence from t h e n a t a l b u rrow a r e g i v e n i n T a b l e 4. I n a l l y e a r s on SRC t h e s e x r a t i o o f mature a n i m a l s was 1:1 i n t h e s p r i n g ( a t b r e e d i n g ) and i n l a t e summer j u s t p r i o r t o h i b e r n a t i o n . On CCC t h e mature s e x r a t i o was skewed t o w a r d s f e m a l e s i n t h e s p r i n g ( x 2 = 4.00,1df) and thou g h n o t s i g n i f i c a n t was a l s o s u g g e s t e d i n t h e f a l l ( x 2 = 3.57, 1 d f , i n 1975 and x 2 = 50 f a b l e 4: S e a s o n a l s e x r a t i o s . Sex r a t i o s a r e e x p r e s s e d as t h e p r o p o r t i o n o f males. B a t i o s a r e b a s e d on t h e minimum number a l i v e d u r i n g t h e s p e c i f i e d p e r i o d s . Y e a r l i n g r a t i o s i n c l u d e o n l y a n i m a l s o f known o r i g i n . B a t i o s s i g n i f i c a n t l y d i f f e r e n t f r o m e q u a l i t y a r e marked w i t h an * ( 0 . 0 5 ) . 51 1975 j 1976 1977 SLIMS RIVER CONTROL Prop. Males ' N Prop. Males N Prop. Males N ADULTS (mid-May) 0.56 18 0.31 13 0 .47 17 ADULTS (mid-August) 0.44 9 0.33 9 - -YEARLINGS (mid-May) - - 0.38 8 0.44 9 YEARLINGS (mid-August) - - 0.25 4 -JUVENILES (July) 0.18 11 0.70 10 " - -JUVENILES (August) * 0.13 8 0.56 9 - -JUVENILES (September) 0.60 . 10 0.57 7 — — COIN CREEK CONTROL ADULTS (mid-May) - - 0.25* 16 0.38 21 ADULT (mid-August) 0.14 7 0.22 9 - - . YEARLING (mid-May) - - 0.38 8 0.50 8 YEARLINGS (mid-August) - - 0.25 4 - -JUVENILES (July) 0.46 24 0.50 16 - -JUVENILES (August) . 0.37 19 0.50 12 - -JUVENILES (September) 0.40 15 0.50 10 — — 2.77, 1df, i n 1S76) . J u v e n i l e sex r a t i o s were 1:1 a t emergence, and a t one and two months a f t e r emergence, e x c e p t i n 1975 on SBC. T h e r e , j u v e n i l e f e m a l e s were more abundant t h a n j u v e n i l e m ales o n l y a t b i r t h ( x 2 = 4.46, 1df) and one month a f t e r n a t a l emergence ( x 2 = 4.5, 1 d f ) , but by two months a f t e r n a t a l emergence t h e s e x r a t i o was 1:1 { x 2 = 0.4, 1df) . The e g u a l j u v e n i l e s e x r a t i o s b u t skewed mature s e x r a t i o s on CCC s u g g e s t t h a t t h e c h a n g e between j u v e n i l e and mature s e x r a t i o s may be due t o l o s s i n t h e l a t e f a l l , d u r i n g h i b e r n a t i o n a n d e a r l y s p r i n g . I f s o , i t s h o u l d be r e f l e c t e d i n t h e s e x r a t i o o f y e a r l i n g a n i m a l s t h e n e x t s p r i n g . U n f o r t u n a t e l y , t h e number o f known y e a r l i n g a n i m a l s s u r v i v i n g t o t h e n e x t s p r i n g i s low and d o e s n o t a l l o w s t a t i s t i c a l c o m p a r i s o n . The d a t a s u g g e s t s t h a t t h e r e i s no s i g n i f i c a n t change i n sex r a t i o o v e r - w i n t e r ( T a b l e 4 ) . B y l a t e summer t h e r e was a t r e n d t o w a r d s a s e x r a t i o f a v o u r i n g f e m a l e s . I do n o t f e e l t h i s i m p l i e s t h a t t h e major l o s s o f young males which r e s u l t s i n skewed a d u l t s e x r a t i o s o c c u r s a t t h i s t i m e . R a t h e r young males a r e g r a d u a l l y l o s t o v e r a l o n g p e r i o d (1-1/2 y e a r s ) a t a r a t e h i g h e r t h a n t h a t f o r young f e m a l e s . The c h a n g e i n s e x r a t i o i s n o t s i g n i f i c a n t a s a r e s u l t , u n t i l t h e end o f t h i s p e r i o d . S e a s o n a l Changes I n Bo dy H e i g h t Two d i s t i n c t p e r i o d s o f w e i g h t change a r e a p p a r e n t i n A r c t i c ground s g u i r r e l s . D u r i n g t h e a c t i v e p e r i o d o f t h e y e a r , m u s c l e t i s s u e and f a t s t o r e s d e p l e t e d d u r i n g h i b e r n a t i o n a r e 53 r e s t o r e d . C o n v e r s e l y , i n t h e h i b e r n a t i o n p e r i o d , f a t s t o r e s a r e u t i l i z e d a s an e n e r g y s o u r c e and some m u s c l e t i s s u e may a l s o be m e t a b o l i z e d { M o r r i s o n and G a l s t e r 1976). F o r c o n v e n i e n c e , w e i g h t c h a n g e s w i l l be. d i s c u s s e d i n t e r m s o f o v e r - w i n t e r and a c t i v e p e r i o d w e i g h t c h a n g e s . O v e r - w i n t e r Weight L o s s O v e r - w i n t e r w e i g h t l o s s was c a l c u l a t e d by s u b t r a c t i n g t h e w e i g h t o f an t a n i m a l a t f i r s t c a p t u r e a f t e r emergence f r o m h i b e r n a t i o n , f r o m i t s w e i g h t a t l a s t c a p t u r e p r i o r t o h i b e r n a t i o n and was e x p r e s s e d as a p e r c e n t a g e o f t h e l a t t e r . As a n i m a l s were t r a p p e d a t b i w e e k l y p e r i o d s t h r o u g h o u t most of t h e s e a s o n , a n i m a l s may have been a c t i v e up t o two weeks a f t e r t h e l a s t c a p t u r e i n t h e f a l l . S i m i l a r l y , a n i m a l s c a u g h t a f t e r t h e day o f emergence may have g a i n e d w e i g h t by t h e t i m e o f f i r s t c a p t u r e . P e r c e n t a g e w e i g h t l o s s e s p r e s e n t e d h e r e r e p r e s e n t minimum e s t i m a t e s . Mature males showed l i t t l e w e i g h t l o s s o v e r w i n t e r {2%-"\3%) ( T a b l e 5 ) . Mature f e m a l e s showed t h e h i g h e s t w e i g h t l o s s o v e r w i n t e r o f any c l a s s ( 2 2 - 3 7 $ ) . J u v e n i l e males and f e m a l e s l o s t s i m i l a r amounts o f w e i g h t ( 7-29% f o r j u v e n i l e m ales v e r s u s 19-32% f o r j u v e n i l e f e m a l e s ) . P a t t e r n s o f Weight Change D u r i n g t h e A c t i v e S e a s o n Mature males ( F i g . 6) s t e a d i l y l o s t w e i g h t d u r i n g t h e b r e e d i n g s e a s o n . I n t h e t h i r d t o f o u r t h week a f t e r f i r s t e 5: P e r c e n t a g e o v e r - s i n t e r w e i g h t l o s s . The mean p e r c e n t a g e w e i g h t l o s s f r o m t h e t i m e o f e n t r y i n t o h i b e r n a t i o n u n t i l emergence f o r e a c h c l a s s i s shown. The number o f a n i m a l s i n e a c h c l a s s and t h e 95% c o n f i d e n c e l i m i t s a r e a l s o i n i d i c a t e d . 55 % OVER-WINTER WEIGHT LOSS AREA MATURE MALES MATURE FEMALES JUVENILE MALES JUVENILE FEMALES SRC 1975-1976 13% 1 22 ± 19.0 3 7 + 7 3 22 ± 27 5 SRC 1976-1977 3% ± 2% 2 32% ± 31 6 12.6 ± 1 3 19.0 ± 21 3 CCC 1975-1976 - 32 ± 8 6 25 ± 11 3 32 ± 10 4 CCC 1976-1977 2 ± 3 2 37 ± 8 7 29 ± 20 4 26 ± 3 2 56 emergence (mid-May) mature males began t o g a i n w e i g h t and c o n t i n u e d t o do so t h r o u g h o u t t h e s e a s o n u n t i l t h e t i m e o f e n t r y i n t o h i b e r n a t i o n . M ature f e m a l e s g a i n e d weight f r o m t h e t i m e o f emergence t o t h e m i d d l e o f May. A s l i g h t d e c l i n e i n t h e mean body w e i g h t o f mature f e m a l e s a c c o m p a n i e d t h e b i r t h o f t h e young and f r o m t h e n u n t i l m i d - J u l y mature f e m a l e s g a i n e d l i t t l e w e i g h t , l i m i t e d w e i g h t g a i n d u r i n g t h i s p e r i o d was p r o b a b l y due t o t h e e n e r g e t i c c o s t s o f weaning t h e young. I n J u l y , j u s t a f t e r weaning and t h e emergence o f t h e young, mature f e m a l e s showed a s t e a d y i n c r e a s e i n body w e i g h t t o h i b e r n a t i o n . Mature males and f e m a l e s showed s i m i l a r body w e i g h t s j u s t p r i o r t o h i b e r n a t i o n i n b o t h a r e a s a l t h o u g h t h e mean body w e i g h t o f mature males was c o n s i s t e n t l y g r e a t e r . J u v e n i l e males were s i g n f i c a n t l y h e a v i e r t h a n j u v e n i l e f e m a l e s t h r o u g h o u t most o f t h e y e a r on b o t h a r e a s . Both j u v e n i l e males and j u v e n i l e f e m a l e s grew r a p i d l y t h r o u g h o u t t h e a c t i v e p e r i o d u n t i l h i b e r n a t i o n . On SRC, j u v e n i l e m a l e s e n t e r e d h i b e r n a t i o n a t h e a v i e r body w e i g h t s . S k u l l b r e a d t h was a l s o r e c o r d e d a t e a c h c a p t u r e a s a s e c o n d i n d e x o f g r o w t h . M a t u r e m a l e s and f e m a l e s showed l i t t l e c h a n g e i n s k u l l b r e a d t h o v e r t h e a c t i v e s e a s o n ( F i g . . 1 3 ) , i n d i c a t i n g s x u l l growth i s c o m p l e t e i n mature a n i m a l s . I n j u v e n i l e males and f e m a l e s , t h e change i n s k u l l b r e a d t h o v e r t h e summer was s i m i l a r t o t h a t f o r body w e i g h t . Body w e i g h t and s k u l l b r e a d t h o f j u v e n i l e a n i m a l s were s i g n i f i c a n t l y c o r r e l a t e d ( F i g . 1 4 ) . 57 f i g u r e 13; P a t t e r n s o f s k u l l growth on SRC. S k u l l s i z e ( z y g o m a t i c b r e a d t h ) was measured f o r a l l a n i m a l s c a p t u r e d d u r i n g e a c h t r a p p i n g p e r i o d . T h e r e were no 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 so a l l s a m p l e s f o r e a c h a r e a were combined., Mean v a l u e s shown a r e f o r 1975, 1976 and 1977 combined and 9 5% c o n f i d e n c e l i m i t s a r e i n d i c a t e d . Range o f sample s i z e s f o r e a c h c l a s s a r e t h e same a s i n F i g u r e 6. a s i m i l a r p a t t e r n was a l s o o b s e r v e d on CCC. A M a t u r e M a l e s Mature F e m a l e s A J u v e n i l e M a l e s J u v e n i l e F e m a l e s 59 F i g u r e 14: Regression of j u v e n i l e s k u l l s i z e on j u v e n i l e body ueight. A l l r e g r e s s i o n s were s i g n i f i c a n t (P=0.05}. R 2 v a l u e s f o r each r e g r e s s i o n a n a l y s i s were as f o l l o w s : J u v e n i l e males SRC r 2=Q.836 J u v e n i l e males CCC r 2=0.912 J u v e n i l e females SRC r 2=0.752 J u v e n i l e females CCC r 2=0.817 SRC M a l e s CCC 4.0-t 1 Body Weiqht (q) 61 Weiqht G a i n Over T.he A c t i v e P e r i o d Weight g a i n o v e r t h e a c t i v e s e a s o n was c a l c u l a t e d o n l y f o r a n i m a l s which r e m a i n e d on t h e c o n t r o l a r e a s from t h e t i m e o f emergence from h i b e r n a t i o n ( o r i n t h e c a s e o f j u v e n i l e s , f r o m t h e n a t a l burrow) t o t h e p e r i o d o f h i b e r n a t i o n e n t r y f o r t h e a p p r o p r i a t e c l a s s . Maximum w e i g h t g a i n was e s t i m a t e d u s i n g t h e l o w e s t and t h e h i g h e s t w e i g h t s f o r e a c h a n i m a l d u r i n g t h e a c t i v e p e r i o d . Sample s i z e s a r e low i n a l l c a s e s due t o t h e s m a l l number o f a n i m a l s i n e a c h c l a s s r e m a i n i n g on t h e c o n t r o l a r e a s t h r o u g h o u t t h e a c t i v e p e r i o d . No s i g n i f i c a n t d i f f e r e n c e s i n t h e p e r c e n t a g e w e i g h t g a i n o v e r t h e a c t i v e p e r i o d were a p p a r e n t between y e a r s f o r any a g e / s e x c l a s s and s a m p l e s f o r 1975 and 1976 were c o m b i n e d . M a t u r e males on SSC g a i n e d an a v e r a g e o f 43 ± 18% (N=7) o f t h e i r emergence w e i g h t . ; One mature male r e m a i n e d on CCC t h e e n t i r e s e a s o n i n 1976 (no emergence d a t a f o r 1975 on CCC) and showed a g a i n o f 64%. , Mature f e m a l e s on SEC and CCC r e s p e c t i v e l y g a i n e d 46 ± 46% (N=11) and 73 ± 32% (N=7) (1976 o n l y ) o f t h e i r emergence w e i g h t . J u v e n i l e males showed an a v e r a g e w e i g h t g a i n o f 166 ± 10% (N=2) on SBC and 134 ± 109% (N=10)on CCC, whereas j u v e n i l e f e m a l e s g a i n e d an a v e r a g e o f 94 ± 19% (N=8) and 91 ± 71% (N=12) on SBC and CCC r e s p e c t i v e l y . J u v e n i l e males g a i n e d t h e most w e i g h t d u r i n g t h e a c t i v e p e r i o d , f o l l o w e d by j u v e n i l e f e m a l e s and mature f e m a l e s and males i n t h a t o r d e r . , 62 E s t a b l i s h m e n t Of F a l l T e r r i t o r i e s P r i o r t o e n t r y i n t o h i b e r n a t i o n , s g u i r r e l s began t o d e f e n d s m a l l a r e a s a r o u n d s p e c i f i c b u r r o w s , p r e s u m a b l y t h e i r h i b e r n a c u l u m . , A g r e s s i v e e n c o u n t e r s i n c r e a s e d i n e a r l y A u g u s t and r e m a i n e d r e l a t i v e l y h i g h ( F i g . 7 ) . A n i m a l s o f a l l c l a s s e s i n t e r a c t e d ; a d u l t r a d u l t , a d u l t : j u v e n i l e , and j u v e n i l e : j u v e n i l e i n t e r a c t i o n s were common. A l l c l a s s e s , most n o t i c e a b l y j u v e n i l e m a l e s , showed i n c r e a s e d wounding i n mid- t o l a t e A u g u s t { F i g . 9 ) . The m a j o r i t y o f t h e wounds were s m a l l p u n c t u r e wounds i n d i c a t i n g t h a t i n t e r a c t i o n s were n o t as p h y s i c a l l y a g g r e s s i v e a s i n t h e s p r i n g . Entry. I n t o H i b e r n a t i o n I t i s d i f f i c u l t t o d e t e r m i n e when an a n i m a l has a c t u a l l y begun h i b e r n a t i o n . J A n i m a l s may d i s a p p e a r t h r o u g h d i s p e r s a l , d e a t h , o r e n t r y i n t o h i b e r n a t i o n . I n d i c a t o r s s u c h as t h e r e s t r i c t i o n o f movement t o t h e v i c i n i t y o f c e r t a i n b u r r o w s ( p r e s u m a b l y h i b e r n a c u l u m ) , d e c r e a s e d w e i g h t g a i n , and v e r y s h o r t d a i l y p e r i o d s o f a c t i v i t y s u g g e s t t h a t an a n i m a l i s c l o s e t o e n t e r i n g h i b e r n a t i o n . Not a l l a n i m a l s d i s a p p e a r i n g i n l a t e summer and e a r l y f a l l and r e a p p e a r i n g t h e f o l l o w i n g s p r i n g d i s p l a y e d t h e s e s i g n s , s o I c a n n o t use t h e s e i n d i c a t o r s t o d e f i n e a l l h i b e r n a t i n g a n i m a l s . The d a t e o f e n t r y i n t o h i b e r n a t i o n f o r each age and sex c l a s s was e s t i m a t e d u s i n g t h e d a t e o f l a s t c a p t u r e o r l a s t o b s e r v a t i o n o f a n i m a l s which s u r v i v e d t h e w i n t e r and emerged t h e 63 f o l l o w i n g s p r i n g . Any a n i m a l d i s a p p e a r i n g d u r i n g t h e p e r i o d o f h i b e r n a t i o n f o r i t s c l a s s was assumed t o have e n t e r e d h i b e r n a t i o n . T h i s method w i l l i n c l u d e some l o s s due t o m o r t a l i t y , p r e d a t i o n o r d i s p e r s a l , as w e l l as e n t r y i n t o h i b e r n a t i o n . The number o f s g u i r r e l s i m m i g r a t i n g o n t o t h e r e m o v a l and c o n t r o l a r e a s a t t h i s t i m e ( t o be d i s c u s s e d i n d e t a i l l a t e r ) was s m a l l however, s u g g e s t i n g l i t t l e d i s p e r s a l o c c u r r e d . S i m i l a r l y , I f o u n d l i t t l e e v i d e n c e o f p r e d a t i o n o f s g u i r r e l s ( i e . g r i z z l y b ear e x c a v a t i o n s ) on t h e c o n t r o l a r e a s o r r e m o v a l a r e a s d u r i n g t h i s p e r i o d . Most a n i m a l s which d i s a p p e a r e d d u r i n g t h e c a l c u l a t e d p e r i o d s o f h i b e r n a t i o n e n t r y were t h o u g h t t o have e n t e r e d h i b e r n a t i o n . As some e r r o r may be i n c l u d e d due t o l e s s by p r e d a t i o n o r d i s p e r s a l , r a n g e s f o r t h e d a t e s o f e n t r y r e p resent.maximum e s t i m a t e s . M ature f e m a l e s began t o e n t e r h i b e r n a t i o n b e f o r e mature males ( T a b l e 6 ) . D i f f e r e n c e s i n t h e r a n g e o f e n t r y d a t e s were s i g n i f i c a n t o n l y i n 1975 and 1976 on CCC. S i m i l a r l y , j u v e n i l e f e m a l e s began t o e n t e r h i b e r n a t i o n b e f o r e j u v e n i l e m a l e s , but r a n g e s o f e n t r y d a t e s were o v e r l a p p i n g i n a l l a r e a s and y e a r s A d u l t s showed a s i g n i f i c a n t t r e n d t o w a r d s e n t e r i n g h i b e r n a t i o n b e f o r e j u v e n i l e s o f t h e same s e x . I n summary, c l a s s e s e n t e r e d h i b e r n a t i o n i n t h e o r d e r ; mature f e m a l e s < ( b e f o r e ) mature males < j u v e n i l e f e m a l e s < j u v e n i l e m a l e s , b u t t h e r e was o v e r l a p i n t h e r a n g e s o f e n t r y d a t e s o f a l l c l a s s e s . 64 T a b l e 6: Dates o f e n t r y i n t o h i b e r n a t i o n . ,The mean d a t e o f e n t r y i n t o h i b e r n a t i o n a s w e l l as t h e r a n g e o f e n t r y d a t e s a r e shown f o r e a c h c l a s s . P r o c e d u r e s f o r t h e c a l c u l a t i o n o f t h e d a t e s a r e o u t l i n e d i n t h e t e x t . Sample s i z e s a r e shown f o r e a c h c l a s s . DATES OF ENTRY INTO HIBERNATION AREA ADULT MALES JUVENILE MALES ADULT FEMALES JUVENILE FEMALES N I N SRC 1975 Aug.28 ± 1 2 Sept.12 ± 0 6 Aug.20 ± 22 5. Sept.7 ± 13 6 (Aug.28-Aug.29) (Sept.12 (Aug.14-Sept.12) (Aug.29-Sept.12) SRC 1976 Sept.8 ± 20 3 Sept.23 ± 18 6 Aug.14 ± 16 6 Sept.10 ± 0 2 (Aug.26-Sept.20) (Sept.10-06) Aug.l2-Sept.9) (Sept.10) CCC 1975 Sept.19 1 Sept.19 ± 1 7 Aug.32 ± 13 7 Sept.16 ± 11 10 (Sept.19) (Sept.18-19) (Aug.21-Sept.5) (Sept.5-14) CCC 1976 Sept.22 ± 0 2 Sept.16 ± 26 8 Aug.24 ± 19 9 Sept.6 ± 1 7 6 (Sept.22) (Sept.7-22) (Aug.9-Sept.8) Aug.27-Sept.22 66 DISCUSSION: PART I The a c t i v i t y p a t t e r n o f A r c t i c g r o u n d s g u i r r e l s i n t h e K l u a n e r e g i o n was c h a r a c t e r i z e d by a l o n g p e r i o d o f h i b e r n a t i o n , emergence, e s t a b l i s h m e n t o f t e r r i t o r i e s , a s h o r t b r e e d i n g p e r i o d , d e v e l o p m e n t and emergence o f young, r e s t o r a t i o n o f f a t d e p o s i t s , e s t a b l i s h m e n t o f f a l l t e r r i t o r i e s and e n t r y i n t o h i b e r n a t i o n . As a r e s u l t o f t h e s h a r p c o n t r a s t i n t h e l e v e l s o f a c t i v i t y between t h e summer and w i n t e r p e r i o d s , t h e f a c t o r s most a f f e c t i n g t h e demography o f g r o u n d s g u i r r e l p o p u l a t i o n s d u r i n g t h e s e p e r i o d s a r e l i k e l y v e r y d i f f e r e n t . H i b e r n a t i o n and Emergence A r c t i c g round s g u i r r e l s i n t h e K l u a n e r e g i o n h i b e r n a t e d f o r 7-8 months e a c h y e a r . M a t u r e f e m a l e s t e n d e d t o h i b e r n a t e f o r t h e l o n g e s t p e r i o d s , f o l l o w e d by mature m a l e s , j u v e n i l e f e m a l e s and j u v e n i l e m a l es. H i b e r n a t i o n i s t h u s i m p o r t a n t i n t e r m s o f t h e t i m e p e r i o d i n v o l v e d y e t few f i e l d s t u d i e s o f h i b e r n a t i o n have been c o n d u c t e d i n any s p e c i e s o f g r o u n d s g u i r r e l s . Most work t o d a t e has i n v o l v e d l a b o r a t o r y s t u d i e s o f p h y s i o l o g i c a l c y c l e s d u r i n g h i b e r n a t i o n ( M o r r i s o n and G a l s t e r 1976, D r e s c h e r 1967). T h e r e i s need f o r a b e t t e r u n d e r s t a n d i n g o f t h e c a u s e s and m a g n i t u d e s o f p o p u l a t i o n l o s s e s d u r i n g h i b e r n a t i o n . Emergence f r o m h i b e r n a t i o n began i n t h e s e c o n d o r t h i r d week o f A p r i l e a c h y e a r and a n i m a l s r a p i d l y came i n t o b r e e d i n g c o n d i t i o n . A r c t i c g r o u n d s g u i r r e l s i n t h i s s t u d y t e n d e d t o emerge e a r l i e s t i n t h e warmest s p r i n g and a p p e a r e a r l i e r a t 67 l o w e r e l e v a t i o n s t h a n a t h i g h e r e l e v a t i o n s . H a l e s t e n d e d t o a p p e a r b e f o r e f e m a l e s , i n b o t h a d u l t and y e a r l i n g c l a s s e s , and mature a n i m a l s t e n d e d t o emerge b e f o r e y e a r l i n g s o f t h e same s e x . S i m i l a r s e q u e n c e s o f emergence f r o m h i b e r n a t i o n have been n o t e d i n S. u n d u l a t u s by C a r l (1971) a s w e l l a s i n S. r i c h a r d s o n i ( M i c h e n e r 1977), S. b e l d i n g i ( H o r t o n 1975, Sherman 1976), S. a r m a t u s C S l a d e and B a l p h 1974), and S. c o l u p b j a n u s (Adams 1961) . D e s p i t e d i f f e r e n c e s i n t h e t i m e o f f i r s t e m ergence, A r c t i c g r ound s q u i r r e l s o f d i f f e r e n t a q e s and a t d i f f e r e n t e l e v a t i o n s r a p i d l y e s t a b l i s h e d b r e e d i n g t e r r i t o r i e s and showed v e r y s i m i l a r p a t t e r n s o f c hange i n b r e e d i n g c o n d i t i o n . T h i s s u g g e s t s t h a t t h e t i m i n g o f r e p r o d u c t i o n i n A r c t i c ground s g u i r r e l s , e s p e c i a l l y i n males may depend on i n t e r n a l r h y t h m s r a t h e r t h a n t h e a c t u a l t i m e o f emergence. T e r r i t o r i a l i t y And B r e e d i n g The e s t a b l i s h m e n t o f s p r i n g b r e e d i n g t e r r i t o r i e s i n v o l v e d some a g g r e s s i o n i n b o t h mature males and f e m a l e s . I n t h i s s t u d y and C a r l ' s (1971) s t u d y , mature males became h i g h l y a g g r e s s i v e t o w a r d s o t h e r males. Whereas C a r l c o n c l u d e d t h a t mature f e m a l e s p a s s i v e l y e s t a b l i s h e d b r e e d i n g t e r r i t o r i e s , f e m a l e s on b o t h my s t u d y a r e a s were a g g r e s s i v e and many s u f f e r e d m i n o r wounding. On t h e b a s i s o f t h e t y p e s o f i n t e r a c t i o n s and t h e d e g r e e o f wounding however, mature f e m a l e s were n o t as p h y s i c a l l y a g g r e s s i v e a s mature,... m a l e s . . A n i m a l s f a i l i n g t o o b t a i n t e r r i t o r i e s a r e l i k e l y f o r c e d t o d i s p e r s e . D u r i n g t h e b r e e d i n g 68 p e r i o d t h e n , d i s p e r s a l o f mature a n i m a l s a p p e a r s t o be c l o s e l y r e l a t e d t o s o c i a l b e h a v i o u r . Mature males were most a g g r e s s i v e i n t h e f i r s t and s e c o n d w e e k . a f t e r e m e r g e n c e , s u g g e s t i n g t h a t c o m p e t i t i o n f o r t e r r i t o r i e s i s most i n t e n s e t h e n . Once t e r r i t o r i e s were e s t a b l i s h e d , b o u n d a r i e s were r e s p e c t e d and few t e r r i t o r i a l d i s p u t e s o c c u r r e d . Mature f e m a l e s were a g g r e s s i v e t o w a r d s o t h e r mature males and f e m a l e s t h r o u g h o u t t h e b r e e d i n g p e r i o d and i n a d d i t i o n became i n c r e a s i n g l y i n t o l e r a n t o f o t h e r s g u i r r e l s t o w a r d s t h e t i m e o f b i r t h c f t h e young. The i n c r e a s e i n mature f e m a l e a g g r e s s i o n d u r i n g t h i s p e r i o d may be a means o f l i m i t i n g i n t r a s p e c i f i c p r e d a t i o n o f j u v e n i l e s (Sherman 1976) r a t h e r t h a n s t r i c t l y a c o n t i n u e d d e f e n c e o f a b r e e d i n g t e r r i t o r y and burrow. There a p p e a r s t o be c o n s i d e r a b l e v a r i a t i o n among s p e c i e s o f g r o u n d s g u i r r e l s i n t h e a b i l i t i e s o f y e a r l i n g a n i m a l s t o b r e e d . I n some, b o t h male and f e m a l e y e a r l i n g s a r e c a p a b l e o f b r e e d i n g IS. u n d u l a t u s ( C a r l 1 971), S. a r m a t u s { S l a d e and B a l p h ) , S. JEic h a r d s o n i ( D o r r a n c e and K e i t h 1974, M i c h e n e r 1974,1977, S h e p p a r d 1972) and S. f r a n k l i n i ( M u r i e 1973). I n o t h e r s p e c i e s , y e a r l i n g f e m a l e s a r e f e r t i l e whereas males a r e n o t (S. b e l d i n q i ( M o r t o n and G a l l u p 1975, Sherman 1976) and i n some s p e c i e s no y e a r l i n g s b r e e d (S. c o l u m b i a n u s ( M i c h e n e r 1 9 7 7 ) . M o s t y e a r l i n g males and a l l y e a r l i n g f e m a l e s came i n t o b r e e d i n g c o n d i t i o n . A l l y e a r l i n g males on SRC become s c r o t a l but on CCC l e s s t h a n h a l f t h e y e a r l i n g males became s c r o t a l . S l a d e and B a l p h (1974) f o u n d t h a t males t h a t emerged l a t e had s m a l l t e s t e s and t h a t i n some c a s e s , l a t e e m e r g i n g m a l e s were n o n - s c r o t a l and showed no s e x u a l b e h a v i o u r . I n t e r e s t i n g l y , d u r i n g a 4 y e a r p e r i o d i n which t h e y 69 e x p e r i m e n t a l l y r e d u c e d t h e p o p u l a t i o n on t h e i r a r e a , t h e y f o u n d t h a t y e a r l i n g males which had p r e v i o u s l y n o t b r e d ( a t h i g h d e n s i t i e s ) became s c r o t a l . T h i s s u g g e s t s t h a t s o c i a l p r e s s u r e may be c a p a b l e o f c a u s i n g d e l a y e d b r e e d i n g i n y e a r l i n g a n i m a l s . H a l e d e n s i t i e s were h i g h e r on CCC i n a l l y e a r s t h a n on SRC and may e x p l a i n some o f t h e i n c i d e n c e s o f n o n - s c r o t a l m a l e s . The l a t e - e m e r g i n g , n o n - s c r o t a l males may, on t h e o t h e r hand, be a r e s u l t o f t e s t e s r e g r e s s i o n p r i o r t o t h e i r emergence. Female R e p r o d u c t i v e S u c c e s s F e m a l e s on SBC and CCC showed s i m i l a r r e p r o d u c t i v e s u c c e s s d e s p i t e a l t i t u d i n a l and d e n s i t y d i f f e r e n c e s . E s t i m a t e s o f l i t t e r s i z e p r i o r t o e mergence, b a s e d on p l a c e n t a l s c a r c o u n t s and embryo c o u n t s were s m a l l e r i n A r c t i c g round s g u i r r e l s i n t h e K l u a n e r e g i o n t h a n t h o s e r e p o r t e d by C a r l f197T) (4.9 v e r s u s 5 . 9 ) . D o r r a n c e and K e i t h (1974) f o u n d t h a t l i t t e r s i z e s i n c r e a s e d i n a n i m a l s g i v e n a d d i t i o n a l f o o d and s u g g e s t e d t h a t d i f f e r i n g f o o d q u a l i t i e s and q u a n t i t i e s c o u l d c a u s e v a r i a t i o n i n l i t t e r s i z e . Q u i t e p o s s i b l y , f o o d r e s o u r c e s c o u l d d i f f e r i n q u a l i t y and g u a n t i t y between C a r l * s s t u d y a r e a and mine. F u r t h e r , t h e s g u i r r e l s C a r l s t u d i e d were o f a d i f f e r e n t s u b s p e c i e s t h a n a n i m a l s i n t h e K l a u n e r e g i o n (S. u n d u l a t u s p a r r y i i v e r s u s S. u n d u l a t u s p l e s i n s ) . N a d l e r and Hoffman (1977) f o u n d t h e s e s u b s p e c i e s t o be g e n e t i c a l l y d i f f e r e n t on t h e b a s i s o f s e v e r a l p o l y m o r p h i c p r o t e i n s and i t i s p o s s i b l e t h e y may a l s o d i f f e r i n t h e i r r e p r o d u c t i v e p o t e n t i a l . 70 C h a n q e s I n Sex B a t i o With Age Mature s e x r a t i o s on CCC were skewed i n f a v o u r o f mature f e m a l e s d e s p i t e t h e f a c t t h a t t h e j u v e n i l e sex r a t i o was 1:1. Sex r a t i o s were e q u a l however on SBC i n b o t h mature and j u v e n i l e age c l a s s e s . S i m i l a r l y i n a number o f g r o u n d s g u i r r e l s p e c i e s , s e x r a t i o s a r e b i a s e d i n f a v o u r o f f e m a l e s among t h e b r e e d i n g p o r t i o n o f t h e p o p u l a t i o n (S. a r m a t u s { S l a d e and B a l p h 1974), S. b e l d i n g i {Sherman 1976), S. r i c h a r d s o n i ( D o r r a n c e and K e i t h 1974, M i c h e n e r and M i c h e n e r 1971 and S h e p p a r d 197 2) , even t h o u g h j u v e n i l e s e x r a t i o s a t b i r t h were e g u a l . I n S . f r a n k l i n i ( M u r i e 1973) and M. f l a v i v e n t r i s { A r m i t a g e 1974) sex r a t i o s were e g u a l i n b o t h j u v e n i l e and mature age c l a s s e s . Sex r a t i o s o f A r c t i c g r o u n d s g u i r r e l s i n C a r l ' s (1971) s t u d y ( c a l c u l a t e d f r o m t h e p o p u l a t i o n numbers i n h i s F i g . 6 ) were not s i g n i f i c a n t l y d i f f e r e n t f r o m e q u a l i t y i n a d u l t a n i m a l s . J u v e n i l e numbers were g r o u p e d s o . j u v e n i l e s e x r a t i o s c o u l d n o t be c a l c u l a t e d . Skewed a d u l t sex r a t i o s - have . been a t r i b u t e d t o d i f f e r e n t i a l m o r t a l i t y { D o r r a n c e and K e i t h 1974, M i c h e n e r 1972, Y e a t o n 1972), d i f f e r e n t i a l d i s p e r s a l { Quanstrom 1971, Y e a t o n 1972, Schmutz 1977} and d i f f e r e n t i a l o v e r - w i n t e r m o r t a l i t y ( C l a r k 1970, M i c h e n e r 1972, Schmutz 1977). The e f f e c t s o f age and s e x s p e c i f i c m o r t a l i t y and d i s p e r s a l and t h e i r e f f e c t s on t h e p o p u l a t i o n s t r u c t u r e o f A r c t i c ground s g u i r r e l s w i l l be c o n s i d e r e d i n a f o l l o w i n g s e c t i o n . 71 P a t t e r n s Of Weight G a i n Most s t u d i e s o f w e i g h t g a i n and l o s s i n g r o u n d s g u i r r e l s h a v e i n d i c a t e d t h a t b o t h a d u l t s and j u v e n i l e s s t e a d i l y g a i n w e i g h t f r o m t h e t i m e o f emergence t o e n t r y i n t o h i b e r n a t i o n (S. f r a n k l i n i ) ( M u r i e 1973), S. r i c h a r d s o n i ( C l a r k 1970, H i c h e n e r 1974), S. t r i d e c e m l i n e a t u s (Hohn and M a r s h a l l 1970) and M. , f l a v i v e n t r i s ( A r m i t a g e 1976) a l t h o u g h i n some s p e c i e s a d e c l i n e i n t h e r a t e o f growth o c c u r r e d j u s t p r i o r t o h i b e r n a t i o n . S. L a t e r a l i s ( S k y r j a and C l a r k 1970) and S. b e l d i n g i ( M o r t o n 1975, Sherman 1976) as w e l l as S. u n d u l a t u s i n t h i s s t u d y were s i m i l a r i n most r e s p e c t s e x c e p t t h a t mature males t e n d e d t o l o s e w e i g h t d u r i n g t h e b r e e d i n g s e a s o n . F o l l o w i n g b r e e d i n g , males r a p i d l y g a i n e d w e i g h t o v e r t h e summer p e r i o d u n t i l j u s t p r i o r t o e n t r y i n t o h i b e r n a t i o n . C o n s i d e r i n g t h e . s h o r t a c t i v e s e a s o n o f g r o u n d s g u i r r e l s and t h e l a r g e e n e r g e t i c demands o f h i b e r n a t i o n , . i t seems u n u s u a l t h a t mature males l o s e w e i g h t d u r i n g t h e s p r i n g . M o r t o n (1975) f o u n d t h a t t h e w e i g h t l o s s o f male S. b e l d i n g i d u r i n g t h e s p r i n g p e r i o d was l a r g e l y due t o t h e l o s s o f t o t a l body l i p i d s . The s i m p l e s t e x p l a n a t i o n t h e n o f t h e o b s e r v e d w e i g h t l o s s m i g h t be t h e l a c k o f s u f f i c i e n t f o o d . A d u l t f e m a l e s , h o w e v e r , showed no s u c h w e i g h t l o s s i n any o f t h e s t u d i e s d u r i n g t h e same p e r i o d , s u g g e s t i n g t h a t a l t h o u g h f o o d may n o t have been a b u n d a n t , s u f f i c i e n t f o o d was a v a i l a b l e t o a l l o w some w e i g h t g a i n . F u r t h e r , I f o u n d t h a t d e s p i t e t h e a d d i t i o n o f 10-12 kg o f whole o a t s . p e r week t o t h e f e e d i n g a r e a i n t h e s p r i n g o f 1977, t h e two m a t u r e males p r e s e n t s t i l l l o s t w e i g h t r a p i d l y up u n t i l t h e 72 f o u r t h week a f t e r e m e rgence. I n s u f f i c i e n t f o o d d o e s n o t a p p e a r t o be a l i k e l y c a u s e o f male w e i g h t l o s s d u r i n g t h e b r e e d i n g p e r i o d * B e h a v i o u r a l o b s e r v a t i o n s on b o t h a r e a s d u r i n g l a t e A p r i l and e a r l y May o f 1976 i n d i c a t e d mature males do n o t spend a s much t i m e f e e d i n g a s mature f e m a l e s . As male r e p r o d u c t i v e s u c c e s s i n A r c t i c g r o u n d s g u i r r e l s i s l a r g e l y d e p e n d e n t on t h e a b i l i t y o f t h e male t o o b t a i n and d e f e n d a b r e e d i n g t e r r i t o r y on a c o l o n y , p e r h a p s t h e a d v a n t a g e o f s u c c e s s f u l l y m a i n t a i n i n g a b r e e d i n g t e r r i t o r y may o u t w e i g h t h e d i s a d v a n t a g e s o f l o s i n g w e i g h t . T h i s i s s u p p o r t e d by t h e g r a d u a l l y i n c r e a s i n g amounts o f time mature m a l e s s p e n t f e e d i n g a s b r e e d i n g t e r r i t o r i e s were e s t a b l i s h e d . Body s i z e has been f o u n d t o be r e l a t e d t o t h e a b i l i t y o f male A r c t i c g r o u n d s g u i r r e l s t o o b t a i n and m a i n t a i n t e r r i t o r i e s f H a t t o n and K e e n l e y s i d e 1971). P e r h a p s one o f t h e a d v a n t a g e s o f l a r g e r body s i z e i s t h e a b i l i t y t o e n d u r e l o n g e r p e r i o d s o f i n s u f f i c i e n t f o o d i n t a k e and so t h e a b i l i t y t o s p e n d more t i m e d e f e n d i n g a b r e e d i n g t e r r i t o r y . Body s i z e may t h u s be an i m p o r t a n t f a c t o r i n male d i s p e r s a l , p a r t i c u l a r l y d u r i n g t h e b r e e d i n g p e r i o d . ( 73 S e c t i o n Summary I n c o n c l u s i o n , i n t r a s p e c i f i c c o m p e t i t i o n i s i n t e n s e d u r i n g two p e r i o d s o f t h e y e a r . The f i r s t i s l a r g e l y r e l a t e d t o b r e e d i n g s u c c e s s , i n t h a t b o t h mature males and f e m a l e s compete f o r b r e e d i n g t e r r i t o r i e s . Male b r e e d i n g s u c c e s s i s l a r g e l y d e p e n d e n t on t h e a c q u i s i t i o n and m a i n t e n a n c e o f a b r e e d i n g t e r r i t o r y . L o s s o f w e i g h t i n mature males d u r i n g t h i s p e r i o d i s i n d i c a t i v e o f t h e e n e r g e t i c c o s t s o f o b t a i n i n g o r d e f e n d i n g a t e r r i t o r y . The q u a l i t y o f mature male t e r r i t o r i e s i s most l i k e l y r e l a t e d t o t h e number o f b r e e d i n g f e m a l e s w i t h i n i t s b o u n d a r i e s . Female b r e e d i n g s u c c e s s on t h e o t h e r hand may be more d e p e n d e n t on v e g e t a t i o n a l q u a l i t y o r g u a n t i t y o r t h e g u a l i t y o f t h e n a t a l b urrow. Much r e m a i n s t o be known o f t h e d e t e r m i n a n t s o f mature male and mature f e m a l e r e p r o d u c t i v e s u c c e s s . ; A l l y e a r l i n g f e m a l e s and some y e a r l i n g males were c a p a b l e o f b r e e d i n g . D e n s i t y may a f f e c t t h e a b i l i t y o f j u v e n i l e m ales t o b r e e d . D i f f e r e n c e s i n t h e j u v e n i l e and a d u l t s e x r a t i o s i n d i c a t e t h a t male l o s s from t h e p o p u l a t i o n i s g r e a t e r t h a n f e m a l e l o s s . Of t h e f a c t o r s c o n s i d e r e d , b o t h body s i z e and s o c i a l b e h a v i o u r a p p e a r t o be i m p o r t a n t f a c t o r s t o d i s p e r s a l d u r i n g t h e s p r i n g and f a l l c o m p e t i t i o n f o r b u r r o w s . B o t h t h e s e f a c t o r s w i l l be c o n s i d e r e d i n t h e f o l l o w i n g s e c t i o n s . 74 RESPITS:DEMOGRAPHY I n t h i s s e c t i o n o f t h e R e s u l t s , I w i l l p r e s e n t i n f o r m a t i o n o b t a i n e d d u r i n g t h e s c h e d u l e o f b i w e e k l y t r a p p i n g p e r i o d s on a l l c o n t r o l and r e m o v a l a r e a s a s w e l l as t h e one f e e d i n g a r e a . The main p u r p o s e o f t r a p p i n g was t o o b t a i n e s t i m a t e s o f p o p u l a t i o n s i z e a s w e l l a s t o d e t e r m i n e which a n i m a l s were most l i k e l y t o d i s p e r s e and i f s e a s o n a l peaks o f d i s p e r s a l were a p p a r e n t . T h e s e f a c t o r s as w e l l as t h e r e l a t i o n s h i p o f body s i z e and r e p r o d u c t i v e c o n d i t i o n t o d i s p e r s a l w i l l a l s o be c o n s i d e r e d . D u r i n g t h e two and h a l f y e a r s p e r i o d o f t h i s s t u d y I t a g g e d a t o t a l o f 654 s g u i r r e l s {171 on a l l S l i m s R i v e r a r e a s , 391 on a l l C o i n C r e e k a r e a s and 92 i n t h e p e r i p h e r a l t r a p p i n g a r e a on C o i n C r e e k ) . E a s e d on t h e number o f a n i m a l s o f e a c h age g r o u p c a u g h t d u r i n g e a c h t r a p p i n g p e r i o d , I c a l c u l a t e d t h e minimum number a l i v e f o r e a c h c l a s s . I n t h e f o l l o w i n g s e c t i o n t h e minimum number a l i v e w i l l be used i n a l l c a l c u l a t i o n s i n v o l v i n g p o p u l a t i o n s i z e . D e c l i n e s d u r i n g t h e p e r i o d o f h i b e r n a t i o n i n e a c h c l a s s a r e b e l i e v e d l a r g e l y due t o t h e l o s s o f a n i m a l s i n t o h i b e r n a t i o n . As a r e s u l t , u n l e s s o t h e r w i s e s t a t e d , I w i l l r e s t r i c t t h e d i s c u s s i o n o f r e s u l t s f o r e a c h c l a s s t o t h e p e r i o d f r o m t h e t i m e o f f i r s t emergence t o t h e t i m e o f f i r s t e n t r y i n t o h i b e r n a t i o n . 75 P o p u l a t i o n Changes The number o f mature males i n e a c h a r e a was low and changed l i t t l e t h r o u g h o u t t h e s e a s o n ( F i g . 1 5 ) . The o n l y l a r g e d e c l i n e i n mature males was i n t h e s p r i n g o f 1975 on SRC (from 12 i n e a r l y May t o 4 i n J u n e ) . The number o f mature f e m a l e s d e c l i n e d d u r i n g May and J u n e t h e n r e m a i n e d r e l a t i v e l y s t a b l e u n t i l h i b e r n a t i o n . C o n s p i c u o u s mature f e m a l e d e c l i n e s o c c u r r e d on SRC i n 1975 and on CCC i n 1976. J u v e n i l e males and f e m a l e s f i r s t a p p e a r e d i n l a t e June and r e a c h e d maximum numbers by m i d - J u l y t o A u g u s t . J u v e n i l e males showed a s t e a d y d e c l i n e i n number t h r o u g h o u t t h e p e r i o d f r o m l a t e J u l y t o e a r l y September a l t h o u g h i n 1975 t h e number o f j u v e n i l e s on b o t h SRC and CCC i n c r e a s e d s l i g h t l y i n mid-September. ,Cn t h e o t h e r hand, t h e number o f j u v e n i l e f e m a l e s c h a n g e d l i t t l e d u r i n g J u l y and A u g u s t . S u r v i v a l Changes i n s u r v i v a l r a t e s a i d i n d e t e r m i n i n g when l o s s o f a n i m a l s i n e a c h c l a s s i s most l i k e l y t o o c c u r . B i w e e k l y s u r v i v a l r a t e s were c a l c u l a t e d f o r mature and j u v e n i l e males and f e m a l e s . From t h e s e , I c a l c u l a t e d s u r v i v a l r a t e s f o r t h e p e r i o d f r o m f i r s t emergence i n t h e s p r i n g ( f o r mature a n i m a l s ) o r f r o m f i r s t e mergence from t h e n a t a l burrow ( f o r j u v e n i l e s ) u n t i l f i r s t e n t r y i n t o h i b e r n a t i o n . O v e r - w i n t e r s u r v i v a l r a t e s c o u l d n o t be c a l c u l a t e d i n t h e ..same manner b e c a u s e a n i m a l s were i n h i b e r n a t i o n . I n s t e a d I u s e d t h e r a t i o o f a n i m a l s e m e r g i n g i n t h e 76 F i g u r e : 1 5 S e a s o n a l c h a n g e s i n t h e minimum number a l i v e . The minimum number a l i v e i n e a c h c l a s s was c a l c u l a t e d f o r each b i w e e k l y p e r i o d . T r a p p i n g was n o t begun on CCC u n t i l e a r l y J u l y i n 1975. & M a t u r e males © M a t u r e f e m a l e s A J u v e n i l e males A J u v e n i l e f e m a l e s 1 SRC Males !5«l 78 CCC 79 s p r i n g o f t h o s e which were presumed t o have e n t e r e d h i b e r n a t i o n t h e p r e v i o u s autumn . As a r e s u l t I c o u l d n o t d e t e r m i n e when d u r i n g t h e p e r i o d o f h i b e r n a t i o n t h e g r e a t e s t l o s s o c c u r r e d . B o t h mature male and mature f e m a l e s u r v i v e d w e l l t h r o u g h o u t t h e a c t i v e p e r i o d { a v e r a g e s o f 0.87 and 0.88 on SBC and 0.85 and 0.83 on CCC f o r mature males and f e m a l e s r e s p e c t i v e l y ) { F i g . 16) . M a t u r e male and f e m a l e b i w e e k l y s u r v i v a l showed few f l u c t u a t i o n s d u r i n g t h e a c t i v e p e r i o d e x c e p t on CCC ( F i g . 1 7 ) . On CCC, mature male s u r v i v a l d e c l i n e d i n b o t h y e a r s . I n 1975 t h i s was l a r g e l y due t o t h e l o s s o f one o f t h e two r e s i d e n t m a l e s . I n 1976, male i m m i g r a t i o n and t u r n - o v e r was h i g h . The s u r v i v a l o f j u v e n i l e males on SBC was l o w e r i n b o t h y e a r s t h a n on CCC (0.63 v s . 0 . 8 0 ) . J u v e n i l e f e m a l e s s u r v i v e d w e l l on b o t h a r e a s (0.83 on SHC and 0.86 on CCC) . On a l l a r e a s , j u v e n i l e males c o n s i s t e n t l y showed a d e c l i n e i n b i w e e k l y s u r v i v a l i n t h e f i r s t two weeks o f A u g u s t . J u v e n i l e f e m a l e s however showed few c h a n g e s i n b i w e e k l y s u r v i v a l t h r o u g h o u t t h e summer p e r i o d . , Matu r e males s u r v i v e d p o o r l y o v e r w i n t e r (mean s u r v i v o r s h i p o f 0.38 and 0.33 on SBC and CCC) { F i g . 16) . Mature f e m a l e s on t h e o t h e r hand s u r v i v e d w e l l (0.73 on SBC and 1.0 on C C C ) . J u v e n i l e males s u f f e r e d h i g h m o r t a l i t y o v e r - w i n t e r on b o t h a r e a s { s u r v i v a l r a t e s o f 0.48 and 0.33 on SBC and CCC) whereas j u v e n i l e f e m a l e s s u r v i v e d w e l l on SBC (0.74) b u t showed p o o r s u r v i v a l on CCC (0.32) . I n g e n e r a l mature males s u r v i v e d p o o r l y o v e r - w i n t e r wheras mature f e m a l e s s u r v i v e d w e l l t h r o u g h o u t t h e y e a r . J u v e n i l e males s u r v i v e d m o d e r a t e l y w e l l i n t h e i r f i r s t summer b u t s u f f e r e d h i g h 80 F i g u r e 16: S e a s o n a l s u r v i v a l . S e a s o n a l s u r v i v a l r a t e s f o r e a c h summer p e r i o d and e a c h h i b e r n a t i o n p e r i o d f o r male and f e m a l e , j u v e n i l e and mature a n i m a l s were c a l c u l a t e d by methods d e s c r i b e d i n t h e t e x t . S u r v i v a l r a t e s f o r t h e a c t i v e p e r i o d a r e t h e means o f b i w e e k l y s u r v i v a l r a t e s f o r t h e s e a s o n . 95% c o n f i d e n c e l i m i t s a r e shown f o r t h e summer means o n l y . A) SRC Summer '75 Winter '75 Summer '76 Winter '76 82 -Figure 17: B i w e e k l y s u r v i v a l were c a l c u l a t e d f o r n a t u r e i n 1975 and 1976, T r a p p i n g CCC i n 1975. r a t e s . B i w e e k l y s u r v i v a l r a t e s and j u v e n i l e males and f e m a l e s was n o t begun u n t i l J u l y on A Mature males M a t u r e f e m a l e s A J u v e n i l e males J u v e n i l e f e m a l e s SRC CCC M a t u r e 1975 19 76 00 CO 84 m o r t a l i t y o v e r - w i n t e r . J u v e n i l e f e m a l e s u r v i v a l was good t h r o u g h o u t t h e summer p e r i o d and o n l y moderate l o s s o c c u r r e d o v e r - w i n t e r . O v e r a l l , male l o s s f r o m t h e c o l o n y was h i g h e r t h a n f e m a l e l o s s . C o h o r t S u r v i v a l D e c r e a s e s i n b i w e e k l y s u r v i v a l r a t e s and o v e r - w i n t e r s u r v i v a l r a t e s would be b u f f e r e d by i m m i g r a t i o n . To d e t e r m i n e what e f f e c t s i m m i g r a t i o n may have on s u r v i v a l , I c o n s i d e r e d o n l y t h e s u r v i v a l o f j u v e n i l e s b o r n on t h e c o n t r o l a r e a . The p r o p o r t i o n o f t h e male and f e m a l e c o h o r t s s u r v i v i n g e a c h s p r i n g and f a l l i s shown i n F i g . 1 8 . Means f o r t h e 1S75 and 1976 c o h o r t s a r e g i v e n f o r t h e f i r s t f a l l and s p r i n g { t h e r e were no 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 p r o p o r t i o n o f m a l e s o r f e m a l e s s u r v i v i n g ) . S u r v i v a l r a t e s i n t h e s e c o n d s p r i n g and f a l l a r e f o r t h e 1975 c o h o r t o n l y . I n b o t h a r e a s , males d i d n o t s u r v i v e as w e l l as f e m a l e s . Male s u r v i v a l t o t h e f i r s t s p r i n g was v e r y low and by t h e s e c o n d s p r i n g , no males b o r n on t h e c o l o n y i n 1975 r e m a i n e d i n t h e p o p u l a t i o n . A l l males p r e s e n t a t t h a t t i m e ( w i t h t h e e x c e p t i o n o f s e v e r a l mature males o f unknown o r i g i n t h a t were p r e s e n t on t h e s t u d y a r e a s i n 1975) had i m m i g r a t e d o n t o t h e a r e a s as j u v e n i l e s o r a d u l t s . T h e r e were no s i g n i f i c a n t d i f f e r e n c e s between a r e a s i n t h e p r o p o r t i o n o f males s u r v i v i n g i n any one t i m e p e r i o d . Female s u r v i v a l was a l s o low t h r o u g h o u t t h e i r f i r s t y e a r o f l i f e b u t s u r v i v a l c h a n g e d l i t t l e i n t h e s e c o n d y e a r . F e m a l e s on 85 F i g u r e 18: C o h o r t s u r v i v a l . The p r o p o r t i o n o f young b o r n on th e a r e a , s t i l l r e s i d e n t i n e a c h s p r i n g and f a l l was c a l c u l a t e d . Means f o r t h e two y e a r s a r e i n d i c a t e d f o r t h e f i r s t f a l l and t h e f i r s t s p r i n g . The r a n g e o f v a l u e s f o r e a c h mean a r e shown f o r t h e two y e a r s . D a t a f o r t h e s e c o n d s p r i n g and f a l l p e r i o d were a v a i l a b l e f o r o n l y t h e 1975 c o h o r t . ( FF= f i r s t f a l l , FS = f i r s t s p r i n g , SF = s e c o n d f a l l , and SS = s e c o n d s p r i n g ) A M a l e s : SBC £ M a l e s : CCC A F e m a l e s : SBC F e m a l e s : CCC 87 SRC s u r v i v e d b e t t e r i n t h e i r f i r s t y e a r t h a n d i d f e m a l e s on CCC b u t t h e 1975 c o h o r t s u g g e s t t h a t t h i s d i f f e r e n c e d i m i n i s h e s i n t h e s e c o n d and s u b s e g u e n t y e a r s . O r i g i n s Of R e s i d e n t A n i m a l s The low r a t e s o f s u r v i v a l o f j u v e n i l e c o h o r t s compared t o t h e o v e r a l l s u r v i v a l r a t e s f o r j u v e n i l e s d u r i n g t h e f i r s t y e a r o f l i f e , i n d i c a t e t h a t some i m m i g r a t i o n must o c c u r . T h i s i s s u p p o r t e d by t h e c o m p o s i t i o n o f e a c h c l a s s b a s e d on t h e o r i g i n s o f t h e r e s i d e n t a n i m a l s ( i e . : , b o r n on t h e c o l o n y v e r s u s i m m i g r a t i o n ) . I d e t e r m i n e d t h i s a s f o l l o w s . F o r e a c h s p r i n g and f a l l p e r i o d , I c a l c u l a t e d t h e p r o p o r t i o n o f a n i m a l s b o r n on t h e a r e a and t h e p r o p o r t i o n o f i m m i g r a n t s o f t h e t o t a l number i n e a c h c l a s s . As t h e o r i g i n o f mature a n i m a l s c a u g h t on t h e c o n t r o l a r e a s i n 1975 was n o t known, t h e y were i n c l u d e d a s a n i m a l s o f unknown o r i g i n * O n l y a n i m a l s r e s i d i n g on t h e c o n t r o l a r e a s f o r a minimum o f two t r a p p i n g p e r i o d s and which were p r e s e n t i n one o f t h e l a s t two t r a p p i n g p e r i o d s i n August were i n c l u d e d i n t h e c a l c u l a t i o n o f f a l l p r o p o r t i o n s . S i m i l a r l y , o n l y t h o s e a n i m a l s p r e s e n t i n t h e f i r s t t h r e e t r a p p i n g p e r i o d s a f t e r f i r s t emergence were i n c l u d e d i n t h e s p r i n g p r o p o r t i o n s . No j u v e n i l e s a r e shown i n t h e s p r i n g p e r i o d , a s s u r v i v i n g young ( i e . y e a r l i n g s ) were i n c l u d e d i n t h e mature a n i m a l c a t e g o r y . On b o t h SRC and CCC s i m i l a r t r e n d s were a p p a r e n t . The m a j o r i t y o f mature males were f r o m n o n - c o l o n y s o u r c e s ( F i g . 1 9 ) . No j u v e n i l e males b o r n on SEC were p r e s e n t a s mature m a l e s . On CCC o n l y a few j u v e n i l e m a l e s r e m a i n e d a s r e s i d e n t s on t h e 88 F i g u r e 19: o r i g i n o f c o n t r o l a r e a r e s i d e n t s The p r o p o r t i o n o f t h e a n i m a l s o f unknown, c o l o n i a l and n o n - c o l o n i a l o r i g i n were c a l c u l a t e d f o r e a c h s p r i n g and f a l l p e r i o d . Unknown a n i m a l s a r e t h o s e a n i m a l s p r e s e n t on t h e a r e a when t h e s t u d y was begun. C o l o n i a l a n i m a l s were t h o s e a n i m a l s b o r n on t h e c o l o n y . N o n - c o l o n i a l a n i m a l s a r e i m m i g r a n t s . Unknown o r i g i n C o l o n i a l o r i g i n N o n - c o l o n i a l o r i g i n CCC l o - i e.5-0 Z "5 jo *o c o a o ft. a. m _LL. 1.0 0.5- S 3 0.5-l.Oi 0.5J 1 t l A M AF JF SRC 0.5 1.0 0.5H l.O-i 0.51 JM l.O 0.5 ra!S Summer" * Fc!! 1975 1976 Summer 1977 •c a 8 8 Fail " Summer " fall * 'Summer* 1975 1976 1977 00 90 c o n t r o l a r e a . Mature f e m a l e s on t h e o t h e r hand were p r e d o m i n a n t l y f e m a l e s t h a t were born on the c o n t r o l a r e a . O n l y a v e r y s m a l l p r o p o r t i o n of r e s i d e n t mature f e m a l e s had e m i g r a t e d from e t h e r a r e a s . J u v e n i l e f e m a l e s were p r e d o m i n a n t l y a n i m a l s t h a t were b o r n on t h e a r e a t o o . I n a l l c a s e s , a l a r g e r p r o p o r t i o n o f j u v e n i l e males than j u v e n i l e f e m a l e s were i m m i g r a n t s . On t h e b a s i s o f c o h o r t s u r v i v a l r a t e s and t h e p r o p o r t i o n o f a n i m a l s of t h e d i f f e r e n t age and sex c l a s s e s born o f f the a r e a , i t would appear t h a t males more o f t e n move between c o l o n i e s than f e m a l e s . L a r g e r numbers o f males d i s a p p e a r e d from t h e c o n t r o l a r e a s as w e l l as im m i g r a t e d t o t h e c o n t r o l a r e a s . More f e m a l e s remained on the c o l o n y and i n many c a s e s s u r v i v e d t o breed s u c c e s s f u l l y as a d u l t s i n t h e c o l o n y of t h e i r b i r t h . , Loss From The C o n t r o l P o p u l a t i o n s The l o s s o f a n i m a l s from each c l a s s may be the r e s u l t o f many f a c t o r s . I was o n l y a b l e t o e s t i m a t e the importance of f o u r o f t h e s e ; p r e d a t i o n ( i n t e r - and i n t r a s p e c i f i c ) , d i s e a s e , s t a r v a t i o n and d i s p e r s a l . At b e s t , o n l y rough e s t i m a t e s can be made o f t h e f i r s t t h r e e f a c t o r s i n t h i s s t u d y . As the a c t i v i t y l e v e l s o f ground s g u i r r e l s d i f f e r g r e a t l y between t h e p e r i o d o f h i b e r n a t i o n and t h e p e r i o d of a c t i v i t y , one might e x p e c t m o r t a l i t y f a c t o r s t o a l s o d i f f e r between seasons. For t h i s r e a s o n , l o s s w i l l be d i s c u s s e d i n terms of t h e two a c t i v i t y l e v e l s each y e a r . 91 M o r t a l i t y D u r i n g H i b e r n a t i o n D u r i n g t h e p e r i o d of h i b e r n a t i o n g r o u n d s g u i r r e l s would be r e l a t i v e l y i n a c c e s s a b l e t o most p r e d a t o r s , a l l a e r i a l p r e d a t o r s and most g r o u n d p r e d a t o r s would be i n a c t i v e ( i e . g r i z z l y b e a r ) , a b s e n t f r o m t h e a r e a ( i e . s e a s o n a l m i g r a t i o n s o f hawks and e a g l e s ) o r u n a b l e t o d i g t h r o u g h t h e f r o z e n g r o u n d to t h e h i b e r n a c u l a . O t h e r g r o u n d s g u i r r e l s ( M u s s a c c h i a 1954) o r s m a l l c a r n i v o r e s s u c h as w e a s e l may k i l l h i b e r n a t i n g s q u i r r e l s . I n g e n e r a l t h o u g h , p r e d a t i o n would seem t o be a m i n o r f a c t o r i n o v e r - w i n t e r l o s s . S t a r v a t i o n , a s a r e s u l t o f an i n s u f f i c i e n t s t o r e o f f a t , i s p r o b a b l y a major c a u s e o f o v e r - w i n t e r m o r t a l i t y . J u v e n i l e a n i m a l s would be more l i k e l y u n a b l e t o s t o r e s u f f i c i e n t f a t a s a r e s u l t o f t h e s h o r t growth p e r i o d . J u v e n i l e o v e r - w i n t e r l e s s may o f t e n be due t o s t a r v a t i o n a s a r e s u l t . However, t h e r e was no i n d i c a t i o n t h a t a n i m a l s s u r v i v i n g t h e w i n t e r e n t e r e d h i b e r n a t i o n a t l a r g e r body w e i g h t s t h a n a n i m a l s n o t s u r v i v i n g . L a r g e body s i z e a t h i b e r n a t i o n d o e s n o t e n s u r e s u r v i v a l . P e r h a p s t h e q u a l i t y o f t h e h i b e r n a c u l a ( i e . p o o r d r a i n a g e o r snow c o v e r o r s h a l l o w depth) i s a l s o i m p o r t a n t . Mature a n i m a l l o s s d u r i n g t h e w i n t e r was h i g h e r t h a n d u r i n g t h e a c t i v e p e r i o d . a l t h o u g h t h e a v e r a g e l i f e e x p e c t a n c y o f a r c t i c g round s g u i r r e l s i s n o t known, Sherman (1976) f o u n d t h e a v e r a g e l i f e e x p e c t a n c y o f B e l d i n g ground s g u i r r e l s t o be 2.1 and 3.4 y e a r s f o r males and f e m a l e s r e s p e c t i v e l y , a n i m a l s o f a t l e a s t t h r e e y e a r s o f age were known on e a c h c o n t r o l a r e a . I f l i f e e x p e c t a n c i e s o f a r c t i c and B e l d i n g g r o u n d s g u i r r e l s a r e 92 s i m i l a r , o v e r - w i n t e r l o s s o f mature a n i m a l s may be t h e r e s u l t o f i n c r e a s e d s u s c e p t i b i l i t y w i t h age t o s t a r v a t i o n ( a s a r e s u l t o f t h e i n a b i l i t y t o s t o r e s u f f i c i e n t f a t ) , e x p o s u r e ( t h r o u g h a p o o r e r c h o i c e o f h i b e r n a c u l u m a s a r e s u l t o f c o m p e t i t i o n i n t h e f a l l ) o r d i s e a s e ( L e c h l e i t n e r e t . a l 1968). D u r i n g h i b e r n a t i o n l i t t l e l o s s t h r o u g h p r e d a t i o n o r d i s p e r s a l i s p o s s i b l e . , H o s t o v e r - w i n t e r l o s s i s b e l i e v e d due t o s t a r v a t i o n o r e x p o s u r e . L o s s D u r i n q The a c t i v e P e r i o d P r e d a t i o n I n t h e two and a h a l f y e a r s o f t h e s t u d y , o n l y 4 i n s t a n c e s o f i n t e r s p e c i f i c p r e d a t i o n were o b s e r v e d i n t h e g e n e r a l l o c a l e o f t h e s t u d y a r e a s . Two k i l l s were a t t r i b u t e d t o g r i z z l y b e a r ( U r s u s a r c t o s h o r r i b i l i s ) . one t o f o x ( V u l p e s v u l p e s ) and one k i l l t o marsh hawk ( C i r c u s c y a n e n s ).,The two k i l l s a t t r i b u t e d t o g r i z z l y b e a r o c c u r r e d on t h e C o i n Creek a r e a i n June 1976. The a d j o i n i n g burrow s y s t e m s o f an a d u l t f e m a l e and h e r y e a r l i n g d a u g h t e r had been e x c a v a t e d and t h e n e s t chambers e x p o s e d . The k i l l by t h e f o x was s e e n a b o u t 0.5 km s o u t h o f CCC i n May 1977. The s g u i r r e l k i l l by a marsh hawk was s e e n i n a w h i t e s p r u c e f o r e s t on t h e r o a d l e a d i n g up t o t h e C o i n C r e e k p l a t e a u on September 1,1976., No p r e d a t i o n was n o t e d on t h e S l i m s R i v e r a r e a . I f I assume t h a t t h e i n c i d e n c e s o f p r e d a t i o n I o b s e r v e d , t o 93 be t y p i c a l o f t h a t which o c c u r r e d when I was n o t p r e s e n t , I can u s e t h e r a t i o o f t h e t i m e I was a c t i v e l y t r a p p i n g o r o b s e r v i n g an a r e a , t o t h e e s t i m a t e d maximum t o t a l t i m e s g u i r r e l s were a c t i v e (12 h o u r s / d a y ) , t o o b t a i n an e s t i m a t e o f p r e d a t i o n . O s i n g t h i s method I o b t a i n e d an e s t i m a t e o f 9 k i l l s p e r s e a s o n f o r a l l a r e a s . T h i s d o e s n o t i n c l u d e p r e d a t i o n by g r i z z l y b e a r . G r i z z l y b e a r h u n t and k i l l g r o u n d s g u i r r e l s by e x c a v a t i n g t h e burrow s y s t e m . Thus i t i s r e l a t i v e l y e a s y t o o b t a i n some e s t i m a t e o f p r e d a t i o n by g r i z z l y by c o u n t i n g e x c a v a t i o n s . No e x c a v a t i o n s were e v e r s e e n on SRC. On CCC e x c a v a t i o n s were n o t e d on e a c h a r e a d u r i n g t h e s t u d y ( T a b l e 7 ) . Most d i g g i n g s o c c u r r e d i n l a t e a u g u s t t o e a r l y September w i t h t h e e x c e p t i o n o f one i n J u n e and one i n J u l y o f 1976. Some e x c a v a t i o n s e x p o s e d o n l y s h o r t segments o f t h e burrow whereas o t h e r s f u l l y e x p o s e d t h e n e s t chamber. I assumed t h a t o n l y e x c a v a t i o n s which e x p o s e d t h e n e s t chamber were s u c c e s s f u l . I f one a t t r i b u t e s a k i l l o f one s g u i r r e l t o e a c h e x c a v a t i o n i n which t h e n e s t chamber was e x p o s e d , a t o t a l o f 5 and 6 s g u i r r e l k i l l s i n 1975 and 1976 on CCC were due t o g r i z z l y b e a r . T h i s r e p r e s e n t s a s u c c e s s r a t e o f a b o u t 65% ( C a r l (1971) e s t i m a t e d a s u c c e s s r a t e o f 5 6 % ) . The number o f t a g g e d s g u i r r e l s c a u g h t one o r more t i m e s on a l l a r e a s t r a p p e d on C o i n C r e e k was 143 and 182 i n 1975 and 1976. G r i z z l y p r e d a t i o n would r e p r e s e n t a l o s s o f a b o u t 3% o f t h e p o p u l a t i o n per y e a r . O t h e r p r e d a t i o n would a c c o u n t f o r 5% o f t h e l o s s . A n n u a l l o s s o f a n i m a l s on CCC ( f r o m one s p r i n g to t h e n e x t ) was 64% i n 1975-1976 and 67% i n 1976-1977. Assuming t h e a n n u a l l o s s o f s g u i r r e l s was s i m i l a r on t h e C o i n C r e e k a r e a i n g e n e r a l , p r e d a t i o n would a c c o u n t f o r o n l y 10-15% o f t h e a n n u a l 94 T a b l e 7: P r e d a t o r s i g h t i n g s on SRC and CCC. The number o f s i g h t i n g s o f e a c h t y p e o f p r e d a t o r d u r i n g e a c h month o f t h e a c t i v e p e r i o d , a r e shown. T o t a l numbers o f s i g h t i n g s of a l l p r e d a t o r s f o r e a c h y e a r a r e a l s o i n d i c a t e d . 95 NUMBER OF SIGHTINGS SPECIES APRIL MAY JUNE • JULY AUGUST SEPTEMBER FOX 0 0 1 3 0 2 GRIZZLY 0 3 6 1 3 5 COYOTE 0 0 1 0 0 0 WEASEL 0 0 0 . 0 0 1 WOLVERINE 0 0 2 1 0 0 LYNX 2 0 0 0 0 0 GOLDEN EAGLE 0 6 3 8 6 8 MARSH HAWK 2 0 0 1 5 4 TOTAL 4 9 13 14 14 20 96 l o s s . T h i s i s f u r t h e r e v i d e n c e d by t h e f a c t t h a t t h e t o t a l number o f p r e d a t o r s i g h t i n g s p e r month showed a g r a d u a l i n c r e a s e t h r o u g h o u t t h e y e a r ( T a b l e 8) y e t h i g h l y s e a s o n a l peaks were o b s e r v e d i n t h e l o s s o f a n i m a l s o f p a r t i c u l a r age c l a s s e s . A l t h o u g h p r e d a t o r s p r o b a b l y k i l l some j u v e n i l e s s h o r t l y a f t e r e m ergence, u n l e s s t h e y a r e a l s o h i g h l y age and sex s p e c i f i c i n t h e s p r i n g and t h e f a l l , i t seems u n l i k e l y t h a t i n t e r s p e c i f i c p r e d a t i o n c o u l d a c c o u n t f o r t h e g r e a t e r p r o p o r t i o n o f t h e s e a s o n a l l o s s e s o b s e r v e d on t h e c o n t r o l a r e a s . P r e d a t i o n on r e s i d e n t a n i m a l s o f e s t a b l i s h e d c o l o n i e s i s p r o b a b l y r e d u c e d by t h e s y s t e m o f w a r n i n g v o c a l i z a t i o n s . A r c t i c g r o u n d s g u i r r e l s have s e v e r a l d i s t i n c t w a r n i n g v o c a l i z a t i o n s s p e c i f i c t o a e r i a l p r e d a t o r s and g r o u n d p r e d a t o r s ( C a r l 1971, H e l c h i o r 1 9 72). S i g h t i n g s o f v a r i o u s p r e d a t o r s i n t h e two a r e a s i n 1976 a r e l i s t e d i n T a b l e 8 and i n a l l b u t 2 c a s e s ( b o t h g r i z z l y b e a r a p p r o a c h e s ) , a p p r o p r i a t e w a r n i n g v o c a l i z a t i o n s were g i v e n . A n i m a l s n o t r e s p o n d i n g t o w a r n i n g v o c a l i z a t i o n s o r u n a b l e t o f i n d s u i t a b l e r e f u g e a r e p r e s u m a b l y more s u s c e p t i b l e t o p r e d a t i o n . J u v e n i l e a n i m a l s a r e n o t w e l l c o o r d i n a t e d when t h e y f i r s t emerge and do n o t a l w a y s r e s p o n d t o w a r n i n g v o c a l i z a t i o n s o r t h e p r e s e n c e o f p r e d a t o r s . On s e v e r a l o c c a s i o n s , when p r e d a t o r s were a p p r o a c h i n g t h e c o l o n y , mothers were s e e n t o c h a s e t h e i r young i n t o b u r r o w s when young f a i l e d t o r e s p o n d t o w a r n i n g v o c a l i z a t i o n s . In a d d i t i o n i n e a r l y J u l y , I was a b l e t o c a t c h v e r y young a n i m a l s by s i m p l y w a i t i n g by t h e burrow mouth u n t i l t h e y emerged. The a p p r o a c h o f most p r e d a t o r s i s r a p i d and t h e f a i l u r e t c r e s p o n d g u i c k l y s h o u l d i n c r e a s e an a n i m a l ' s 97 Table 8: Number of burrows excavated by g r i z z l y bear. The number of burrows which were excavated by g r i z z l y bear on a l l areas of Coin Creek plateau are indicated. No excavations were ever found on SRC. The number of excavations i n which the nest was exposed are also indicated. I assumed that only excavations exposing the nest resulted i n the death of a s q u i r e l . Totals are shown for 1975 and 1976. TOTAL NO. TOTAL NO. AREA OF BURROWS EXCAVATED WHERE NEST WAS EXPOSED CCC 1975 3 2 1976 4 . 3 CCR 1975 3 3 1976 1 0 CCF 1976 3 1 CCM 1976 3 2 TOTAL 1975 6 5 TOTAL 1976 11 6 99 c h a n c e s o f b e i n g t a k e n . Young w o u l d p r o b a b l y be more s u s c e p t i b l e t o p r e d a t i o n t h a n o l d e r j u v e n i l e s o r mature a n i m a l s . As a r e s u l t , I a t t r i b u t e d much o f t h e l o s s o f j u v e n i l e a n i m a l s d u r i n g t h e f i r s t two weeks a f t e r n a t a l emergence t o p r e d a t i o n r a t h e r t h a n t o d i s p e r s a l . D i s p e r s i n g a n i m a l s would p r e s u m a b l y n o t be f a m i l i a r w i t h t h e t e r r a i n and i n some c a s e s may n o t be a b l e t o l o c a t e o r use a b urrow a s a r e f u g e . Thus t h e y may o f t e n be more e x p o s e d t h a n a n i m a l s on t h e c o l o n y . F u r t h e r , l o n e d i s p e r s i n g a n i m a l s may be more s u s c e p t i b l e t o ambush due t o t h e l a c k o f w a r n i n g v o c a l i z a t i o n s . A l t h o u g h a n e c d o t a l , t h e o b s e r v a t i o n o f t h e s g u i r r e l k i l l by t h e marsh hawk, which o c c u r r e d a t l e a s t 0.5 km f r o m t h e n e a r e s t burrow s y s t e m , i s i n a g r e e m e n t w i t h t h i s c o n c l u s i o n . I n t e r s p e c i f i c p r e d a t i o n a c c o u n t s f o r o n l y a s m a l l f r a c t i o n o f t h e t o t a l i n s i t u l o s s . Huch o f t h i s i s l i k e l y due t o t h e l o s s o f v e r y young a n i m a l s . I b e l i e v e however t h a t p r e d a t i o n i s an i m p o r t a n t p r o x i m a t e c a u s e o f a n i m a l l o s s d u r i n g d i s p e r s a l . S t e i n e r (1974) r e p o r t e d some i n s t a n c e s o f i n t r a s p e c i f i c p r e d a t i o n , p a r t i c u l a r l y o f j u v e n i l e s n e a r t h e t i m e o f emergence f r o m t h e n a t a l b urrow, i n a p o p u l a t i o n o f A r c t i c g r o u n d s g u i r r e l s a p p r o x i m a t e l y 60km e a s t o f my a r e a s . Two i n s t a n c e s o f i n t r a s p e c i f i c p r e d a t i o n may have o c c u r r e d on my s t u d y i n 1976. B o t h were v e r y young a n i m a l s (one on SHC and one on CCC) and were f o u n d i n e a r l y J u l y j u s t a f t e r j u v e n i l e s had emerged from t h e n a t a l b u r r o w s . B o t h had l a r g e wounds (1.5-2cm 2) o n t h e i r b a c k s . The young on CCB was d e a d when f o u n d . The young cn SRC was wounded when f i r s t c a p t u r e d and was i n f e s t e d w i t h i n s e c t 100 l a r v a e . The a n i m a l was f o u n d dead o u t s i d e o f one o f t h e b u r r o w s s e v e r a l d a y s l a t e r . When j u v e n i l e s f i r s t emerged , no o v e r t a t t a c k s on j u v e n i l e s g u i r r e l s by mature a n i m a l s were s e e n . Based on t h i s and t h e f a c t t h a t s o few young were wounded o r f o u n d d e a d , I f e e l t h a t i n t r a s p e c i f i c p r e d a t i o n i s o f m i n o r i m p o r t a n c e i n c a u s i n g t h e o b s e r v e d d e c r e a s e i n j u v e n i l e numbers. D i s e a s e And P r e d a t i o n No a n i m a l s c a u g h t showed any v i s i b l e s i g n s o f d i s e a s e , s t a r v a t i o n o r extreme p a r a s i t i s m . E x a m i n a t i o n o f s e v e r a l i n t e s t i n a l t r a c t s i n 1975 r e v e a l e d no l a r g e i n t e s t i n a l p a r a s i t e s . Most i n d i v i d u a l s c a r r i e d t h e f l e a O r o p s v l l a i d a h o e n s i s but none a p p e a r e d b a d l y i n f e s t e d . Wounds sometimes became b a d l y i n f e c t e d b u t a l l a n i m a l s which r e m a i n e d cn t h e c o l o n y w i t h s u c h wounds r e c o v e r e d , w i t h t h e e x c e p t i o n o f t h e one j u v e n i l e a l r e a d y m e n t i o n e d . The a b s c e n c e o f d i s e a s e d a n i m a l s o r a n i m a l s s h o w i n g s i g n s o f s t r e s s , t h e low d e g r e e o f i n t e r n a l o r e x t e r n a l p a r a s i t i s m and t h e good r e c o v e r y o f known wounded a n i m a l s s u g g e s t t h a t n e i t h e r d i s e a s e , p a r a s i t i s m o r s t a r v a t i o n a r e i m p o r t a n t s o u r c e s o f l o s s d u r i n g t h e a c t i v e p e r i o d . 101 D i s p e r s a l T h r e e methods were u s e d t o i n d i c a t e t h e t i m i n g and e x t e n t o f d i s p e r s a l and t h e t y p e o f a n i m a l s most l i k e l y t o d i s p e r s e ; i m m i g r a t i o n t o r e m o v a l a r e a s , i m m i g r a t i o n t o c o n t r o l a r e a s and e m i g r a t i o n f r o m c o n t r o l a r e a s . I f s e a s o n a l peaks o f d i s p e r s a l o c c u r and i f t h e above methods a d e g u a t e l y measure d i s p e r s a l , one s h o u l d o b s e r v e peaks i n e a c h o f t h e above measures o f d i s p e r s a l d u r i n g t h e same p e r i o d . The magn i t u d e o f t h e peaks would n o t n e c e s s a r i l y be t h e same however. On t h e c o n t r o l a r e a s , I assumed t h a t a l l u n t a g g e d a n i m a l s as w e l l as a l l t a g g e d a n i m a l s f r o m o t h e r a r e a s were d i s p e r s i n g a n i m a l s . The o n l y e x c e p t i o n s t o t h i s were young b o r n on t h e a r e a . A f t e r t h e e s t a b l i s h m e n t o f each c o n t r o l a r e a i n 1975, few t a g g e d a n i m a l s which r e m a i n e d on t h e c o n t r o l a r e a were n o t c a u g h t t h e n e x t t r a p p i n g p e r i o d . A t o t a l o f 9 a n i m a l s m i s s e d one t r a p p i n g p e r i o d o u t o f a t o t a l o f 422 f i r s t c a p t u r e s i n 1975-1977 on SBC and on CCC i n 1975-1977, 11 a n i m a l s m i s s e d one t r a p p i n g p e r i o d o u t o f a t o t a l o f 413 f i r s t c a p t u r e s . F u r t h e r a l l u n t a g g e d s g u i r r e l s s e e n d u r i n g b e h a v i o u r a l o b s e r v a t i o n s and which t o o k up r e s i d e n c e were c a u g h t w i t h i n one o r two t r a p p i n g p e r i o d s . I am c o n f i d e n t t h a t I was a b l e t o t r a p a l m o s t a l l a n i m a l s p r e s e n t on t h e c o n t r o l a r e a s d u r i n g e a c h t r a p p i n g p e r i o d . The r e m o v a l a r e a s were u s e d t o c r e a t e an a r e a o f s u i t a b l e h a b i t a t o f low s g u i r r e l d e n s i t y . I assumed t h a t s q u i r r e l s i m m i g r a t i n g t o t h e r e m o v a l a r e a were r e p r e s e n t a t i v e o f d i s p e r s i n g s q u i r r e l s . On b o t h SRB and CCR t h e f i r s t two t r a p p i n g 102 p e r i o d s i n 1975 ( d u r i n g t h e e s t a b l i s h m e n t o f t h e a r e a s ) were u s e d t o remove a l l r e s i d e n t a n i m a l s and so w i l l not be i n c l u d e d i n t h e a n a l y s i s . E m i g r a t i o n f r o m c o n t r o l a r e a s was p e r h a p s t h e most d i f f i c u l t o f t h e t h r e e measures o f d i s p e r s a l t o a s s e s s . The d i s a p p e a r a n c e o f a n i m a l s f r o m t h e c o n t r o l a r e a s c o u l d be a t t r i b u t e d t o p r e d a t i o n , d i s e a s e o r d i s p e r s a l . I b e l i e v e l i t t l e i n s i t u l o s s , p a r t i c u l a r l y t h e l o s s o f j u v e n i l e s , i s due t o p r e d a t i o n o r m o r t a l i t y . I w i l l assume t h a t a n i m a l s d i s a p p e a r i n g f r o m t h e c o n t r o l a r e a s have d i s p e r s e d w i t h t h e u n d e r s t a n d i n g t h a t some e r r o r i s i n c l u d e d due t o a s m a l l number o f d e a t h s due t o p r e d a t i o n and o l d age. D i s p e r s a l Of Mature Males I n b o t h y e a r s on SEE few mature males i m m i g r a t e d o n t o t h e r e m o v a l a r e a ( F i g . 2 0 ) . I n 1975 a low number o f mature males were p r e s e n t d e s p i t e c o n t i n u o u s r e m o v a l . A s i m i l a r t r e n d o c c u r r e d i n 1976 e x c e p t t h a t a s l i g h t i n c r e a s e i n mature male d i s p e r s a l was e v i d e n t i n l a t e J u n e . On CCS mature male i m m i g r a t i o n was low b u t i n b o t h y e a r s , i n c r e a s e d i m m i g r a t i o n o f mature males was s e e n i n l a t e J u l y and e a r l y A u g u s t . The i n c r e a s e d movement o f mature males a t t h i s t i m e may be r e l a t e d t o t h e e s t a b l i s h m e n t o f h i b e r n a t i o n t e r r i t o r i e s w h i c h was o c c u r r i n g a t t h i s t i m e on t h e c o n t r o l a r e a s . M a t u r e male i m m i g r a t i o n t o c o n t r o l a r e a s was low ( F i g . 2 1 ) as was e m i g r a t i o n ( F i g . 22) , b u t s l i g h t i n c r e a s e s i n e m i g r a t i o n were e v i d e n t i n A p r i l and May. 1 0 3 F i g u r e 20: Minimum number a l i v e on t h e r e m o v a l a r e a s . The minimum number a l i v e f o r e a c h t r a p p i n g p e r i o d on SRR and CCH i s shown f o r e a c h age c l a s s . A n i m a l s m e e t i n g c e r t a i n c r i t e r i a ( s e e Methods) were removed d u r i n g e a c h t r a p p i n g p e r i o d i n 1975. Removal p e r i o d s i n 1976 a r e i n d i c a t e d by a r r o w s . A n i m a l s removed d u r i n g t h e i n i t i a l two t r a p p i n g p e r i o d s on b o t h a r e a s were n o t i n c l u d e d . A Mature males • M a t u r e f e m a l e s A J u v e n i l e males J u v e n i l e f e m a l e s 105 f i g u r e 21: Number o f i m m i g r a n t s . The number o f i m m i g r a n t s t o e a c h c o n t r o l a r e a a r e shown f o r 1975 amd 1976. J u v e n i l e s b o r n on t h e a r e a a r e n o t i n c l u d e d . A Mature males 6 Mature f e m a l e s A J u v e n i l e males • J u v e n i l e f e m a l e s 106 a) SRC M J J A S O M J J A S O 1975 1 9 76 107 f i g u r e 22: Number o f e m i g r a n t s . The number o f a n i m a l s d i s a p p e a r i n g f r o m t b e c o n t r o l a r e a s a r e shown f o r e a c h t r a p p i n g p e r i o d . The m a j o r i t y o f t h e a n i m a l s which d i s a p p e a r e d a r e assumed t o have e m i g r a t e d . L o s s d u r i n g t h e p e r i o d o f h i b e r n a t i o n e n t r y was n o t i n l c u d e d . A M a t u r e males • M a t u r e f e m a l e s J u v e n i l e males 9 J u v e n i l e f e m a l e s SRC 108 109 D i s p e r s a l Of M a t u r e F e m a l e s A d u l t f e m a l e s showed i n c r e a s e d i m m i g r a t i o n i n June on a l l r e m o v a l a r e a s . , On SRR a p r o m i n e n t peak o f mature f e m a l e i m m i g r a t i o n was e v i d e n t i n l a t e J u n e , 1 9 7 5 . S i m i l a r l y , f e m a l e i m m i g r a t i o n t o CCE r e m a i n e d h i g h t h r o u g h o u t June and J u l y i n 1976. D u r i n g t h e r e m a i n i n g p o r t i o n o f t h e a c t i v e p e r i o d , mature f e m a l e i m m i g r a t i o n t o r e m o v a l a r e a s was low. Few mature f e m a l e s i m m i g r a t e d t o t h e c o n t r o l a r e a s , e x c e p t on SBC i n e a r l y J u n e , 1975. F o u r mature f e m a l e i m m i g r a t e d o n t o t h e c o n t r o l a r e a d u r i n g t h e f i r s t week o f J u n e . T h i s was j u s t p r i o r t o t h e major i n f l u x o f mature f e m a l e s t o t h e r e m o v a l a r e a i n mid J u n e . L i k e mature m a l e s , few mature f e m a l e s e m i g r a t e d . I n 1975 on SRC a t o t a l o f 3 f e m a l e s e m i g r a t e d i n t h e l a s t week o f J u n e , j u s t p r i o r t o t h e l a r g e i n f l u x o f mature f e m a l e s o n t o t h e r e m o v a l a r e a s . Few f e m a l e s e m i g r a t e d f r o m SBC i n 1976 i n ag r e e m e n t w i t h t h e low e s t i m a t e o f d i s p e r s a l f r o m f e m a l e s i m m i g r a t i n g t o t h e r e m o v a l a r e a * I n 1976 on CCC, e m i g r a t i o n o f mature f e m a l e s from t h e c o n t r o l a r e a was h i g h e s t d u r i n g t h e peak p e r i o d o f i m m i g r a t i o n o f mature f e m a l e s t o CCB. D i s p e r s a l Of J u v e n i l e M a l e s T h e r e was an i n f l u x o f j u v e n i l e s males t o a l l r e m o v a l a r e a s i n A u g u s t o f e a c h y e a r . I n 1975 on SRR a s m a l l i n c r e a s e a l s o o c c u r r e d i n J u l y and was a t t r i b u t e d t o t h e emergence o f young on a d j a c e n t a r e a s . O t h e r w i s e , j u v e n i l e male i m m i g r a t i o n t o t h e 110 r e m o v a l a r e a s was marked by a s i n g l e m a j o r peak o f i n A u g u s t , a p p r o x i m a t e l y 6-8 weeks a f t e r n a t a l S i m i l a r l y , peaks o f j u v e n i l e male i m m i g r a t i o n t o and f r o m t b e c o n t r o l a r e a s were a p p a r e n t i n a u g u s t . . D i s p e r s a l Of J u v e n i l e F e m a l e s J u v e n i l e f e m a l e i m m i g r a t i o n o n t o r e m o v a l a r e a s i n 1S75 was h i g h e r on b o t h SBfi and CCB t h a n j u v e n i l e male i m m i g r a t i o n . The s e x r a t i o o f j u v e n i l e a n i m a l s on t h e c o n t r o l a r e a s were b i a s e d i n f a v o u r o f f e m a l e s and s o may a c c o u n t f o r t h e h i g h e r i m m i g r a t i o n o f j u v e n i l e f e m a l e s . I n 1976, no j u v e n i l e f e m a l e s a p p e a r e d on SBB d u r i n g t h e a c t i v e p e r i o d . On CCR, i n 1976, a h i g h o f 6 j u v e n i l e f e m a l e s i m m i g r a t e d o n t o t h e a r e a i n l a t e J u l y v e r s u s a h i g h o f 12 j u v e n i l e males a t t h e same t i m e . Sex r a t i o s were e g u a l on b o t h c o n t r o l a r e a s i n 1976. I m m i g r a t i o n and e m i g r a t i o n o f j u v e n i l e f e m a l e s was low on a l l a r e a s i n b o t h y e a r s . S l i g h t i n c r e a s e s i n j u v e n i l e f e m a l e e m i g r a t i o n were s u g g e s t e d on CCC i n l a t e A u g u s t . O v e r a l l , i n mature f e m a l e s and a l l j u v e n i l e s t h e r e was a c o r r e l a t i o n between t h e t i m e o f d i s p e r s a l a s i n d i c a t e d by i n c r e a s e s i n i m m i g r a t i o n t o r e m o v a l a r e a s , i m m i g r a t i o n t o c o n t r o l a r e a s and e m i g r a t i o n f r o m c o n t r o l a r e a s . I t i s u n l i k e l y t h a t s u c h a c o r r e l a t i o n would e x i s t : u n l e s s t h e c h a n g e s were due t o movement o f a n i m a l s o v e r a wide a r e a d u r i n g t h e same p e r i o d . T h i s s u p p o r t s my h y p o t h e s i s t h a t l o s s d u r i n g t h e s e p e r i o d s i s m a i n l y due t o d i s p e r s a l . S e a s o n a l c h a n g e s i n e m i g r a t i o n and i m m i g r a t i o n e m ergence, e m i g r a t i o n 111 i m m i g r a t i o n t o a l l a r e a s s u g g e s t ; i ) . M ature male d i s p e r s a l was low t h r o u g h o u t t h e y e a r , i i ) . M a t u r e f e m a l e d i s p e r s a l i n c r e a s e d i n l a t e May and J u n e b u t was low t h e r e m a i n d e r o f t h e a c t i v e s e a s o n , i i i ) . J u v e n i l e males and f e m a l e s a p p e a r e d t o d i s p e r s e most i n A u g u s t . Q u a l i t a t i v e D i f f e r e n c e s And D i s p e r s a l Myers and K r e b s (1971) and K r e b s e t . a l (1976) f o u n d t h a t d i s p e r s i n g a n i m a l s t e n d e d t o d i f f e r m o r p h o l o g i c a l l y (body w e i g h t s ) , b e h a v i o u r a l l y , g e n e t i c a l l y (on t h e b a s i s o f b l o o d serum p r o t e i n s ) a n d i n some c a s e s r e p r o d u c t i v e l y f r o m r e s i d e n t a n i m a l s . To d e t e r m i n e i f d i s p e r s i n g A r c t i c g r o u n d s g u i r r e l s d i f f e r f r o m r e s i d e n t s g u i r r e l s , I compared m o r p h o l o g i c a l and b e h a v i o u r a l d a t a . B e h a v i o u r a l d i f f e r e n c e s w i l l be c o n s i d e r e d i n a f o l l o w i n g s e c t i o n . M o r p h o l o g i c a l D i f f e r e n c e s Body w e i g h t has b e e n shown t o be an i m p o r t a n t f a c t o r i n t h e s u c c e s s o f A r c t i c g r o u n d s g u i r r e l s i n o b t a i n i n g and d e f e n d i n g a t e r r i t o r y ( f l a t t e n a n d K e e n l e y s i d e 1971). The l e n g t h o f r e s i d e n c y was a l s o i m p o r t a n t . I f d i s p e r s i n g a n i m a l s a r e t h e l o s e r s o f most a g g r e s s i v e i n t e r a c t i o n s and a r e n o t s u c c e s s f u l i n o b t a i n i n g t e r r i t o r i e s a s s u g g e s t e d by C a r l ( 1 9 7 1 ) , one might e x p e c t d i s p e r s i n g a n i m a l s t o be o f a s m a l l e r body s i z e t h a n r e s i d e n t a n i m a l s . Two measurements o f body w e i g h t were o b t a i n e d f o r e a c h a n i m a l t r a p p e d ; body w e i g h t and s k u l l b r e a d t h . To d e t e r m i n e i f 1 1 2 d i s p e r s i n g a n i m a l s d i f f e r i n t e r m s o f body s i z e , t b e body w e i g h t s and s k u l l b r e a d t h s o f r e s i d e n t a n i m a l s were compared w i t h t h o s e o f a n i m a l s e m i g r a t i n g f r o m t h e c o n t r o l a r e a s o r i m m i g r a t i n g t o t h e c o n t r o l o r r e m o v a l a r e a s w i t h i n t h e same t r a p p i n g p e r i o d . A n a l y s i s o f c o v a r i a n c e {date o f c a p t u r e as t h e c o v a r i a t e ) was u s e d t o compare t h e body w e i g h t s and s k u l l b r e a d t h s o f a n i m a l s i m m i g r a t i n g t o t h e r e m o v a l a r e a s t o t h o s e o f a n i m a l s o f t h e same c l a s s on t h e c o n t r o l a r e a , w i t h i n t h e same t r a p p i n g p e r i o d . No s i g n i f i c a n t d i f f e r e n c e s between d i s p e r s i n g and r e s i d e n t a n i m a l s o c c u r r e d i n any a r e a o r y e a r . Due t o t h e s m a l l number o f i m m i g r a n t s t o e a c h c o n t r o l a r e a o r e m i g r a n t s from e a c h c o n t r o l a r e a , d i f f e r e n c e s between t h e s e a n i m a l s and r e s i d e n t c o n t r o l a n i m a l s c o u l d n o t be compared u s i n g a s i m i l a r s t a t i s t i c a l d e s i g n . I n s t e a d , d i f f e r e n c e s were compared u s i n g a S i g n T e s t { S i e g e l 1956). Mean w e i g h t s and mean s k u l l b r e a d t h s were c a l c u l a t e d f o r each c l a s s w i t h i n e a c h b i w e e k l y t r a p p i n g p e r i o d . D i s p e r s i n g a n i m a l s were g r o u p e d a c c o r d i n g t o whether t h e i r w e i ght o r s k u l l b r e a d t h was l a r g e r o r s m a l l e r t h a n t h e c o n t r o l a r e a mean f o r t h a t p e r i o d . A n i m a l s w i t h t h e same body w e i g h t o r h a v i n g t h e same s k u l l b r e a d t h as t h e c o n t r o l mean were t r e a t e d as t i e s and s o were n o t i n c l u d e d i n e i t h e r g r o u p . S e a s o n a l t o t a l s f o r e a c h o f t h e two c l a s s e s were c a l c u l a t e d and t h e p r o b a b i l i t y o f o b t a i n i n g t h a t d i s t r i b u t i o n was d e t e r m i n e d . O v e r a l l , t h e t r e n d t o w a r d s d i f f e r e n c e s i n t h e body s i z e o f c o l o n i a l and d i s p e r s i n g a n i m a l s was n o t c l e a r i n any c l a s s e x c e p t j u v e n i l e m a l e s . I n most c a s e s no d i f f e r e n c e s were 113 a p p a r e n t . F u r t h e r , i n o n l y two c a s e s were t h e s i g n i f i c a n t d i f f e r e n c e s i n t h e d i r e c t i o n p r e d i c t e d ; t h a t i s t h a t d i s p e r s i n g a n i m a l s were o f a s m a l l e r body w e i g h t and s k u l l b r e a d t h t h a n r e s i d e n t a n i m a l s on t h e c o n t r o l a r e a i n t h e same t i m e p e r i o d (mature males on CCB i n 1975 and mature f e m a l e s on SRC i n 1975). I n t h e r e m a i n i n g c a s e s , where d i f f e r e n c e s i n body s i z e were s i g n i f i c a n t , d i s p e r s i n g a n i m a l s t e n d e d t o be l a r g e r t h a n r e s i d e n t a n i m a l s ( mature f e m a l e s on CCB i n 1975 and 1976 and j u v e n i l e males i n 1976 on SBC and CCC a s w e l l a s on CCC i n 1975). J u v e n i l e D i s p e r s a l and L a r q e r Body S i z e One o f t h e i m p o r t a n t a s s u m p t i o n s o f t h e c o m p a r i s o n s o f t h e body s i z e s o f d i s p e r s i n g and r e s i d e n t a n i m a l s was t h a t d i s p e r s i n g a n i m a l s would be c o m p e t i n g w i t h a n i m a l s o f t h e same c l a s s . I f however, j u v e n i l e : m a t u r e a n i m a l i n t e r a c t i o n s a r e i m p o r t a n t i n t h e i n i t i a t i o n o f j u v e n i l e d i s p e r s a l , j u v e n i l e s w ould be much s m a l l e r t h a n a d u l t s w i t h i n t h e same p e r i o d . When j u v e n i l e s f i r s t emerged, v e r y few a g o n i s t i c i n t e r a c t i o n s between j u v e n i l e s and mature a n i m a l s were o b s e r v e d . J u v e n i l e s a t t h i s t i m e t e n d e d t o i n t e r a c t m o s t l y w i t h o t h e r j u v e n i l e s and t h e i r m o t h e r s . By m i d - A u g u s t however, j u v e n i l e : m a t u r e a n i m a l i n t e r a c t i o n s became more common. T h i s s u g g e s t s t h a t up t o a c e r t a i n p e r i o d i n t h e y e a r , j u v e n i l e a n i m a l s a r e t r e a t e d d i f f e r e n t l y f r o m mature a n i m a l s b u t a t some p o i n t a r e r e c o g n i z e d and t r e a t e d as mature a n i m a l s by t e r r i t o r i a l m ature s g u i r r e l s on t h e c o l o n y . Body w e i g h t seems a 114 p o s s i b l e f a c t o r i n t h a t j u v e n i l e a n i m a l s below a c e r t a i n s i z e a r e t r e a t e d a s j u v e n i l e s b u t once a t t a i n i n g o r s u r p a s s i n g t h i s s i z e , a r e t r e a t e d a s mature a n i m a l s . I f t h i s i s t h e c a s e , one might e x p e c t t h a t j u v e n i l e a n i m a l s t h a t d i s p e r s e f i r s t a r e t h o s e a n i m a l s t h a t grew f a s t e s t , a t t a i n e d a l a r g e r "mature body s i z e " e a r l i e r and so came i n t o c o m p e t i t i o n w i t h mature a n i m a l s f i r s t . To d e t e r m i n e i f i n c r e a s e d growth and an e a r l i e r a t t a i n m e n t o f a l a r g e body s i z e had any e f f e c t on d i s p e r s a l t e n d e n c i e s , an a d d i t i o n a l f o o d s o u r c e was p r o v i d e d t o a s m a l l g r o u p o f s q u i r r e l s on C o i n C r e e k p l a t e a u . I t was hoped t h a t t h e a d d i t i o n o f f o o d would l e a d t o i n c r e a s e d j u v e n i l e growth and t h a t c h a n g e s i n j u v e n i l e d i s p e r s a l may r e s u l t . Growth c u r v e s f o r j u v e n i l e a n i m a l s on CCF and CCC i n d i c a t e d a p e r i o d o f v e r y r a p i d growth i n J u l y and A u g u s t ( F i g . 2 3 ) . J u v e n i l e a n i m a l s on t h e c o n t r o l a r e a i n p a r t i c u l a r , showed a c h a r a c t e r i s t i c d e c r e a s e i n w e i g h t g a i n i n t h e e a r l y f a l l . A Von B e r t a l a n f f y growth e g u a t i o n b e s t a p p r o x i m a t e s t h i s t y p e o f c u r v e ( H i c k l e f s 1967) . Haximum growth r a t e s and r e g r e s s i o n e g u a t i o n s were d e t e r m i n e d u s i n g t h e method s u g g e s t e d by R i c k l e f s ( 1 S 6 7 ) . A r e g r e s s i o n a n a l y s i s i n d i c a t e d t h a t b o t h j u v e n i l e males (P=0.006) and j u v e n i l e f e m a l e s (P=0.023) grew more r a p i d l y on CCF t h a n a n i m a l s on CCC. The s l o p e o f t h e r e g r e s s i o n l i n e which i s p r o p o r t i o n a l t o t h e g r o w t h r a t e i n d i c a t e d t h a t CCF a n i m a l s grew f a s t e r t h a n CCC a n i m a l s (0.12 and 0.20 f o r j u v e n i l e m ales and 0.06 and 0.28 f o r j u v e n i l e f e m a l e s on CCC and CCF r e s p e c t i v e l y ) . ,• On CCF t h e major i n c r e a s e i n j u v e n i l e male e m i g r a t i o n o c c u r r e d i n m i d - J u l y and by e a r l y A u g u s t , no j u v e n i l e males 115 F i g u r e 23: J u v e n i l e male and f e m a l e g r o w t h . Growth c u r v e s a r e b a s e d on b i w e e k l y body w e i g h t s . Mean w e i g h t s f o r e a c h sex a r e i n d i c a t e d by c l o s e d c i r c l e s . Means and 95% c o n f i d e n c e l i m i t s a r e shown f o r j u v e n i l e s on CCC and CCF. • J u v e n i l e males J u v e n i l e f e m a l e s 117 r e m a i n e d on t h e f e e d i n g a r e a s ( F i g . 2 4) . On CCC t h e peak was n o t r e a c h e d u n t i l m i d - a u g u s t ( F i g . 15). T h e r e a p p e a r e d t o be a c l e a r two-week s e p a r a t i o n i n t h e i n i t i a t i o n o f j u v e n i l e male e m i g r a t i o n on CCF and CCC and a f o u r week s e p a r a t i o n between t h e m a j o r p e a k s o f e m i g r a t i o n . J u v e n i l e f e m a l e e m i g r a t i o n on b o t h a r e a s was m i n i m a l and s o i t i s not p o s s i b l e t o d i s t i n g u i s h s e a s o n a l d i f f e r e n c e s . W e i g h t s o f j u v e n i l e m a l e s j u s t p r i o r t o e m i g r a t i o n were 332 ± 92g (H=8) and 356 ± 195g (N=11) on CCF and CCC r e s p e c t i v e l y . S k u l l b r e a d t h s were 3.34 ± 0.24 cm and 3.46 ± 0 . 4 2 cm f o r t h e two a r e a s . I f o u n d no s i g n i f i c a n t d i f f e r e n c e s i n t h e w e i g h t s o r s k u l l b r e a d t h s o f e m i g r a t i n g a n i m a l s on t h e f e e d i n g a r e a and c o n t r o l a r e a . I n summary, j u v e n i l e a n i m a l s on t h e f e e d i n g a r e a grew f a s t e r t h a n j u v e n i l e s on t h e c o n t r o l a r e a . H i g h e r w e i g h t s were a t t a i n e d e a r l i e r i n t h e s e a s o n and i n j u v e n i l e m a l e s , d i s p e r s a l o c c u r r e d s i g n i f i c a n t l y e a r l i e r on t h e f e e d i n g a r e a t h a n on t h e c o n t r o l a r e a . B r e e d i n g C o n d i t i o n Of D i s p e r s i n g M a t u r e a n i m a l s To d e t e r m i n e i f d i s p e r s i n g a n i m a l s d i f f e r e d f r o m r e s i d e n t c o n t r o l a n i m a l s i n t e r m s o f b r e e d i n g c o n d i t i o n , t h e p r o p o r t i o n o f s c r o t a l males and b r e e d i n g f e m a l e s on e a c h r e m o v a l a r e a was compared t o t h a t on t h e c o n t r o l a r e a . Mature males were o n l y s c r o t a l d u r i n g t h e f i r s t f i v e weeks a f t e r emergence s o o n l y t h i s p e r i o d w i l l be c o n s i d e r e d . , S i m i l a r l y f e m a l e r e p r o d u c t i v e c o n d i t i o n s d u r i n g t h e p e r i o d from May 1 t o J u l y 1 w i l l be 118 f i g u r e 24: Number o f e m i g r a n t s from CCF. The number o f a n i m a l s o f e a c h c l a s s w h i c h d i s a p p e a r e d and were assumed t o have e m i g r a t e d between t r a p p i n g p e r i o d s on CCF a r e shown. L o s s d u r i n g h i b e r n a t i o n was n o t i n l c u d e d . M a t u r e males # M a t u r e f e m a l e s Sk J u v e n i l e males J u v e n i l e f e m a l e s 119 CCF 1 2 0 c o n s i d e r e d . B r e e d i n g s u c c e s s { p r e g n a n c y and p r o d u c t i o n o f a l i t t e r ) was a l s o compared. On SBC i n 1975 and 1976, 100% o f t h e mature males were s c r o t a l whereas o n l y 43% {N=7) o f t h e mature males on SRR i n 1975-1976 were s c r o t a l d u r i n g t h e b r e e d i n g p e r i o d . On CCC i n 1976 o n l y 40% o f t h e mature males were s c r o t a l . On CCB, 50% (N=6) o f t h e mature males p r e s e n t were s c r o t a l . F e w e r . m a t u r e f e m a l e s on SRR were i n b r e e d i n g c o n d i t i o n t h a n on SRC {Table 9 ) . S i m i l a r l y , f e w e r f e m a l e s had medium o r l a r g e s i z e d mammae. F o r t y - s e v e n p e r c e n t o f t h e mature f e m a l e s on SRR had medium t o l a r g e s i z e d mammae whereas a l l f e m a l e s on SRC d i d . F u r t h e r , o n l y 17% o f t h e mature f e m a l e s on SEE showed s i g n s o f p r e g n a n c y whereas 83% o f a l l mature f e m a l e s on SRC d i d . On C o i n C r e e k p l a t e a u , a l l mature f e m a l e s on CCC and CCR were i n b r e e d i n g c o n d i t i o n . More mature f e m a l e s on CCC had l a r g e mammae t h a n on CCR b u t t h e r e was l i t t l e d i f f e r e n c e between t h e number o f f e m a l e s w i t h medium s i z e d mammae. More mature f e m a l e s on CCC showed e x t e r n a l s i g n s o f p r e g n a n c y however t h a n on CCR. D i s p e r s i n g and r e s i d e n t mature males and f e m a l e s showed few d i f f e r e n c e i n t h e number which came i n t o b r e e d i n g c o n d i t i o n . T h e r e were d i f f e r e n c e s however i n t h e b r e e d i n g s u c c e s s o f f e m a l e s . Fewer f e m a l e s on t h e r e m o v a l a r e a s showed s i g n s o f p r e g n a n c y o r i n c r e a s e d mammae s i z e t h a n on t h e c o n t r o l a r e a s . T h i s c o n c l u s i o n was f u r t h e r s u p p o r t e d by t h e d a t a a v a i l a b l e f r o m t h e a u t o p s i e s o f f e m a l e s removed from CCB a n d SRR i n 1975. On SRR 7% o f t h e mature f e m a l e s were n u l l i p a r o u s , 3 6% were p r i m i p a r o u s and 57% were raultiparous (N=14). On CCB 14% were n u l l i p a r o u s , 57% were p r i m i p a r o u s and 29% were m u l t i p a r o u s 121 T a b l e 9: fieproductive c o n d i t i o n o f d i s p e r s i n g and r e s i d e n t mature f e m a l e s . The b r e e d i n g c o n d i t i o n and b r e e d i n g s u c c e s s o f mature f e m a l e s on e a c h c o n t r o l and r e m o v a l a r e a d u r i n g 1975-1S77 a r e i n d i c a t e d . P e r c e n t a g e v a l u e s a r e shown. % LARGE % MEDIUM AREA % BREEDING LACTATION LACTATION N % PREGNANT N SLIMS RIVER REMOVAL . 76 12 35 17 17 6 SLIMS RIVER CONTROL 100 39 61 24 83 20 COIN CREEK REMOVAL 100 12 54 24 24 21 COIN CREEK CONTROL 100 40 60 29 73 16 123 (N=7). The low number o f n u l l i p a r o u s f e m a l e s i n b o t h a r e a s i n d i c a t e s t h a t most d i s p e r s i n g mature f e m a l e s b r e e d . F u r t h e r , a s s u m i n g t h a t most p r i m i p a r o u s f e m a l e s a r e y e a r l i n g s t h a t had b r e d f o r t h e f i r s t t i m e t h a t y e a r , t h e number o f p r i m i p a r o u s v e r s u s m u l t i p a r o u s f e m a l e s on SHE s u g g e s t s t h a t more a d u l t f e m a l e s i m m i g r a t e d t o and t o o k up r e s i d e n c e on t h e r e m o v a l a r e a t h a n d i d y e a r l i n g f e m a l e s . On CCB, t h e o p p o s i t e t r e n d was a p p a r e n t . More y e a r l i n g f e m a l e s s u c c e s s f u l l y i m m i g r a t e d t o t h e r e m o v a l a r e a t h a n a d u l t f e m a l e s . 124 BESUITS X BEHAVIOURAL CHANGES AND DISPERSAL I n t e r a c t i v e behaviours, p a r t i c u l a r l y a g g r e s s i o n , have been suggested as important f a c t o r s i n the i n i t i a t i o n of d i s p e r s a l and p o p u l a t i o n r e g u l a t i o n (King 1971, C h i t t y 1967). Armitage (1975) has a l s o suggested t h a t the l a c k o f a g g r e s s i o n and the degree of amicable s o c i a l c o n t a c t c o u l d be important to the i n i t i a t i o n of d i s p e r s a l of y e a r l i n g marmots. Both amicable and a g o n i s t i c i n t e r a c t i o n s are l i k e l y r e l a t e d t o d i s p e r s a l . As a r e s u l t I undertook a schedule of b e h a v i o u r a l o b s e r v a t i o n s to o b t a i n i n f o r m a t i o n on s e a s o n a l changes i n b e h a v i o u r a l budgets and the r e l a t i v e temporal importance of each type of behaviour, as w e l l as to determine i f d i s p e r s i n g animals d i f f e r e d b e h a v i o u r a l l y frcm n o n - d i s p e r s i n g animals. I conducted o b s e r v a t i o n s only on the two c o n t r o l areas i n 1975 and on the c o n t r o l areas and CCB i n 1976. In a l l years the t o t a l number o f animals observed per week was small d e s p i t e a t o t a l of 111 hours and 104 hours of o b s e r v a t i o n s on SRC and CCC i n 1975 and a t o t a l of 95, 209 and 98 hours of o b s e r v a t i o n s on SBC, CCC and CCB r e s p e c t i v e l y i n 1976. V a r i a t i o n due to the c l a s s i f i c a t i o n of behaviour should be minimal as a l l o b s e r v a t i o n s were done by myself during both years. Behaviour o b s e r v a t i o n s were made by f o c a l animal sampling i n 1975 and instantaneous sampling i n 1976. According to Altmann (1974), the two sampling schemes used give comparable r e s u l t s f o r percentage behaviour budgets and so can be compared between years. I n t e r a c t i o n r a t e s can o n l y be c a l c u l a t e d from data o b t a i n e d with the f o c a l animal sampling t e c h n i q u e . The 125 i n s t a n t a n e o u s s a m p l i n g t e c h n i g u e i s n o t s u i t a b l e f o r t h e c a l c u l a t i o n o f i n t e r a c t i o n r a t e s on a t r u e t i m e s c a l e a s t h e i n t e r v a l p e r i o d between b e h a v i o u r s i s n o t known. B a t e s o f b e h a v i o u r c a l c u l a t e d f o r 1976 w i l l be u s e d o n l y t o g i v e c o m p a r i b l e f i g u r e s f o r a n i m a l s w i t h i n o r between a r e a s and a r e n o t c o m p a r a b l e t o r a t e s i n 1975. A l t h o u g h 43 b e h a v i o u r s were r e c o g n i z e d d u r i n g o b s e r v a t i o n s on t h e s t u d y p o p u l a t i o n s , t h e p r e p o n d e r a n c e o f some b e h a v i o u r a l t y p e s and r a r i t y o f o t h e r s made i t n e c e s s a r y t o combine r e l a t e d b e h a v i o u r s i n t o g r o u p s a s i n d i c a t e d i n T a b l e 1. The p e r c e n t a g e o f t i m e s p e n t i n e a c h t y p e o f b e h a v i o u r was c a l c u l a t e d f o r i n d i v i d u a l a n i m a l s u s i n g t h e f o l l o w i n g f o r m u l a : t o t a l t i m e s p e n t i n t h e b e h a v i o u r s % T i m e / b e h a v i o u r = X 100 g r o u p t o t a l t i m e f o r a l l b e h a v i o u r s I n 1976 a s i m i l a r f o r m u l a was u s e d : t o t a l # t i m e s a b e h a v i o u r s e e n % T i m e / b e h a v i o u r = — — X 100 g r o u p t o t a l # o f t i m e s f o r a l l b e h a v i o u r s Mean b e h a v i o u r b u d g e t s f o r e a c h age c l a s s were c a l c u l a t e d a s f o l l o w s . F i r s t , o n l y a n i m a l s w h i c h were o b s e r v e d f o r 10 m i n u t e s o r more per day ( i n 1975) o r f o r 50 i n s t a n t a n e o u s s a m p l i n g p o i n t s per day ( i n 1976) were i n c l u d e d . A n i m a l s s e e n f o r p e r i o d s s h o r t e r t h a n t h i s t e n d e d t o have a narrow r a n g e o f b e h a v i o u r s and were n o t t h o u g h t t o r e p r e s e n t b e h a v i o u r b u d g e t s . The p e r c e n t a g e b u d g e t s f o r t h e f o u r c l a s s e s on CCC i n 1976 a r e shown i n F i g . 2 5 . B u d g e t s f o r SBC (1975 and 1976) and CCC (1975) showed s i m i l a r t r e n d s . G e n e r a l l y sample s i z e s f o r t h e 126 f i g u r e 25: S e a s o n a l c h a n g e s i n b e h a v i o u r b u d g e t s on CCC. F o r e a c h o b s e r v a t i o n a l p e r i o d t h e mean p e r c e n t t i m e o f t h e t o t a l t i m e f o r a l l b e h a v i o u r s was c a l c u l a t e d f o r e a c h b e h a v i o u r g r o u p i n mature and j u v e n i l e males and f e m a l e s . V a l u e s p l o t t e d as an X on t h e x - a x i s i n d i c a t e t h a t no o b s e r v a t i o n a l d a t a f o r t h e age g r o u p was a v a i l a b l e i n t h a t t i m e p e r i o d . S i m i l a r p a t t e r n s o f c h a n g e were o b s e r v e d i n CCC i n 1975 and on SBC i n b o t h y e a r s . A M a t u r e m a l e s Mature f e m a l e s J u v e n i l e males J u v e n i l e f e m a l e s 100-| 6<H 20H Feeding A A flC I I I E lOO-i C 0) u O 2 0 4 i r Posturing M i i i i Grooming 128 8 i E 4i 0 jo c u O Q . Recognatory T Agonistic I l i Movement Burrowing M J j A S J J A S 129 b i w e e k l y means o f e a c h c l a s s were below 5 a n i m a l s , AS a r e s u l t t h e v a r i a n c e a r o u n d t h e means f o r e a c h b e h a v i o u r g r o u p i n e a c h two week p e r i o d i s g r e a t and few d i f f e r e n c e s between a r e a s , y e a r s , c r c l a s s e s a r e s i g n i f i c a n t . S i m i l a r t r e n d s a r e a p p a r e n t on a l l a r e a s and i n some c a s e s y e a r s . The c o n s i s t e n c y o f t h e s e t r e n d s between a r e a s s u g g e s t s t h e phenomena a r e r e a l . S e a s o n a l Chanqes In B e h a v i o u r B u d g e t s The most o b v i o u s f e a t u r e o f t h e a v e r a g e b e h a v i o u r b u d g e t s f o r e a c h aqe c l a s s was t h a t f e e d i n q and p o s t u r i n g a c t i v i t y a c c o u n t e d f o r 80-90% o f t h e t o t a l above q r o u n d t i m e . I n a d d i t i o n , f e e d i n g and p o s t u r i n g a c t i v i t y a p p e a r t o be i n v e r s e l y c o r r e l a t e d . O t h e r m a i n t e n a n c e b e h a v i o u r s {grooming, movement, and b u r r o w i n g ) a c c o u n t e d f o r 10-15% o f t h e t i m e whereas i n t e r a c t i v e b e h a v i o u r s r a r e l y a c c o u n t e d f o r more t h a n 5% o f t h e t o t a l b u d g e t . The f o l l o w i n g t r e n d s were common t o most c o n t r o l p o p u l a t i o n s e a c h y e a r . M a t u r e a n i m a l s f e d a g r e a t e r amount o f t h e t i m e e a c h s p r i n g t h a n a t o t h e r t i m e s o f t h e y e a r . The p r o p o r t i o n o f t h e t o t a l t i m e budget s p e n t f e e d i n g d e c r e a s e d g r a d u a l l y u n t i l t h e m i d d l e o f J u ne when f e e d i n g a g a i n i n c r e a s e d u n t i l t h e t i m e o f h i b e r n a t i o n . j u v e n i l e a n i m a l s on a l l a r e a s e x c e p t SRC i n 1976 s p e n t r o u g h l y 40% o f t h e i r t o t a l t i m e engaged i n f e e d i n g . L i k e a d u l t s , j u v e n i l e s showed a s l i g h t i n c r e a s e i n f e e d i n g a c t i v i t y t o w a r d s t h e e a r l y f a l l p e r i o d . P o s t u r i n g a c c o u n t e d f o r 45-55% o f t h e a c t i v e t i m e o f mature a n i m a l s i m m e d i a t e l y a f t e r emergence f r o m h i b e r n a t i o n . P o s t u r i n g 130 i n c r e a s e d u n t i l l a t e June and r e m a i n e d r e l a t i v e l y u nchanged u n t i l h i b e r n a t i o n . J u v e n i l e s showed l i t t l e c h a nge i n t h e p r o p o r t i o n o f t i m e s p e n t i n p o s t u r i n g b e h a v i o u r s e x c e p t f o r a s l i g h t i n c r e a s e t o w a r d s t h e l a t e summer. Grooming b e h a v i o u r s a c c o u n t e d f o r o n l y a s m a l l p e r c e n t a g e o f t h e t o t a l t i m e b u d g e t ( 0 - 7 % ) . The h i g h e s t g r o o m i n g r a t e s f o r mature a n i m a l s were o b s e r v e d i n t h e s p r i n g (May) and may be r e l a t e d t o t h e i n c r e a s e d l e v e l s o f i n t r a s p e c i f i c wounding a t t h i s t i m e . J u v e n i l e s showed l i t t l e g rooming a c t i v i t y . B u r r o w i n g a c t i v i t y was r a r e l y o b s e r v e d (maximum o f 4% o f t h e t o t a l t i m e ) . Most b u r r o w i n g a c t i v i t y o c c u r r e d i n t h e s p r i n g i m m e d i a t e l y f o l l o w i n g emergence and i n l a t e summer p r i o r t o h i b e r n a t i o n . Movement a c c o u n t e d f o r between 1 and 18% o f t h e t o t a l a c t i v e t i m e . D u r i n g t h e e a r l y s p r i n g mature m a l e s s p e n t more t i m e moving t h a n a t o t h e r p e r i o d s o f t h e y e a r . Mature male movement d e c l i n e d i n May b u t d u r i n g t h e summer t h e t i m e a c c o u n t e d f o r by movement i n c r e a s e d . . M a t u r e f e m a l e s showed i n c r e a s e d p e r i o d s o f movement i n J u n e and J u l y , d u r i n g t h e p e r i o d when t h e young were j u s t e m e r g i n g . S i m i l a r l y j u v e n i l e s showed i n c r e a s e d p e r i o d s o f movement j u s t a f t e r emergence f r o m t h e n a t a l burrow, a low p e r i o d o f movement i n J u l y and A u g u s t and i n c r e a s e d movement i n t h e l a t e summer and e a r l y f a l l . I n mature m a l e s , a m i c a b l e b e h a v i o u r s ( r e c o g n a t o r y and c o h e s i v e b e h a v i o u r s ) were most common i n e a r l y May. Mat u r e f e m a l e s s p e n t l i t t l e t i m e i n a m i c a b l e b e h a v i o u r s d u r i n g t h e a c t i v e s e a s o n e x c e p t s h o r t l y a f t e r t h e emergence o f t h e young. The i n c r e a s e t h e n was l a r g e l y due t o a h i g h i n c i d e n c e o f 131 m o t h e r : y o u n g g r e e t i n g s . J u v e n i l e a n i m a l s showed a s i m i l a r p a t t e r n t o t h a t of mature f e m a l e s ; low l e v e l s o f a m i c a b l e b e h a v i o u r t h r o u g h o u t t b e a c t i v e p e r i o d e x c e p t s h o r t l y a f t e r emergence Mature males showed i n c r e a s e d p e r i o d s o f a g o n i s t i c b e h a v i o u r i n b o t h the s p r i n g and t h e e a r l y f a l l . A g o n i s t i c b e h a v i o u r s a c c o u n t e d f o r o n l y a s m a l l p o r t i o n o f t h e b e h a v i o u r b u d g e t o f mature f e m a l e s . A s m a l l i n c r e a s e was e v i d e n t i n l a t e J u l y however. B o t h j u v e n i l e m ales and f e m a l e s s p e n t r e l a t i v e l y h i g h p r o p o r t i o n s o f t h e i r t i m e s h o r t l y a f t e r emergence engaged i n a g o n i s t i c i n t e r a c t i o n s . Most i n t e r a c t i o n s a t t h i s t i m e i n v o l v e d p l a y f i g h t s . I n l a t e A u g u st j u v e n i l e s g u i r r e l s showed i n c r e a s e d p e r i o d s o f a g o n i s t i c b e h a v i o u r s which a p p e a r e d t o be a s s o c i a t e d w i t h c o m p e t i t i o n f o r h i b e r n a c u l a . B e h a v i o u r Of D i s p e r s i n g A n i m a l s I f b e h a v i o u r a l f a c t o r s a r e i m p o r t a n t t o t h e i n t i t i a t i o n o f d i s p e r s a l , s e v e r a l q u e s t i o n s a r e o f i n t e r e s t . F i r s t , do d i s p e r s i n g a n i m a l s d i f f e r f r o m r e s i d e n t a n i m a l s i n t e r m s o f t h e i r a l l o t m e n t o f t i m e t o v a r i o u s b e h a v i o u r a l t y p e s , e i t h e r b e f o r e o r a f t e r d i s p e r s a l ? And s e c o n d l y do d i s p e r s i n g a n i m l s d i f f e r from r e s i d e n t a n i m a l s i n t e r m s o f t h e s o c i a l b e h a v i o u r s t h e y i n i t i a t e o r r e c e i v e ? D i f f e r e n c e s i n t h e b e h a v i o u r o f d i s p e r s i n g and r e s i d e n t a n i m a l s can be d e t e r m i n e d by c o m p a r i n g t h e b e h a v i o u r o f r e m o v a l a n i m a l s t o t h e b e h a v i o u r o f r e s i d e n t a n i m a l s on t h e c o n t r o l a r e a . 132 B e h a v i o u r B u d g e t s Of D i s p e r s i n g A n i m a l s A n i m a l s i m m i g r a t i n g t o t h e r e m o v a l a r e a s showed s i m i l a r s e a s o n a l t r e n d s o f b e h a v i o u r t o c o n t r o l a n i m a l s e x c e p t i n s e v e r a l i n s t a n c e s ( F i g . 2 6 ) . J u v e n i l e a n i m a l s on t h e r e m o v a l a r e a s showed i n c r e a s e d p e r c e n t a g e s of t i m e f e e d i n g i n l a t e summer ( l a t e A u g u st and e a r l y September) and l e s s t i m e p o s t u r i n g t h a n a n i m a l s on t h e c o n t r o l a r e a s . B u r r o w i n g o r g r o o m i n g a c t i v i t i e s were r a r e . A l l c l a s s e s e x c e p t j u v e n i l e f e m a l e s showed v e r y low l e v e l s o f b o t h a m i c a b l e and a g o n i s t i c b e h a v i o u r s compared to c o n t r o l a n i m a l s . J u v e n i l e f e m a l e s on t h e r e m o v a l and c o n t r o l a r e a s showed s i m i l a r l e v e l s o f a m i c a b l e b e h a v i o u r s . J u v e n i l e f e m a l e s on t h e r e m o v a l a r e a a l s o showed a a r e l a t i v e l y l a r g e i n c r e a s e i n a g o n i s t i c i n t e r a c t i o n s i n t h e e a r l y f a l l . S o c i a l B e h a v i o u r s And D i s p e r s a l P eaks o f a m i c a b l e and a g o n i s t i c b e h a v i o u r a r e e v i d e n t d u r i n g t h e p e r i o d s o f h i g h mature f e m a l e and j u v e n i l e d i s p e r s a l . I n t e r p r e t a t i o n o f t h e d i f f e r e n t b e h a v i o u r a l t y p e s i s d i f f i c u l t . A m i c a b l e b e h a v i o u r s p r e s u m a b l y i n d i c a t e some s t r e n g t h e n i n g o f s o c i a l t i e s w i t h i n t h e c o l o n y p e r h a p s t h r o u g h a c l e a r e r d e t e r m i n a t i o n o f s o c i a l r a n k . On t h e o t h e r hand, t h e l a c k o f a m i c a b l e b e h a v i o u r a n d / o r i n c r e a s e d a g o n i s t i c a t t a c k s by r e s i d e n t a n i m a l s may l e a d t o a s e v e r i n g o f s o c i a l bonds. I f t h e s e a s s u m p t i o n s a r e c o r r e c t and i f s o c i a l b e h a v i o u r s a r e i m p o r t a n t (as s u g g e s t e d by B e k o f f 1977b) t o t h e i n i t i a t i o n o f 133 F i g u r e 26: S e a s o n a l c h a n g e s i n b e h a v i o u r b u d g e t s on CCB. Mean p e r c e n t a g e t i m e s were c a l c u l a t e d as i n F i g . 25. Data i s f o r t h e 1976 s e a s o n o n l y on CCB. jtk Mature males 4 M a t u r e f e m a l e s J u v e n i l e males • J u v e n i l e f e m a l e s 134 Feedi Grooming 3 2H 1 I \ none seen i i i i i M J J A S 134b Movement A M J J- A S A M J J A S 135 d i s p e r s a l , one would e x p e c t d i s p e r s i n g a n i m a l s t o r e c e i v e more a g o n i s t i c b e h a v i o u r s and f e w e r a m i c a b l e i n t e r a c t i o n s t h a n r e s i d e n t a n i m a l s . They may a l s o t e n d t o i n i t i a t e f e w e r a g o n i s t i c i n t e r a c t i o n s and t e n d t o a v o i d o t h e r a n i m a l s more t h a n r e s i d e n t a n i m a l s { B e k o f f 1977). A m i c a b l e And a g o n i s t i c I n t e r a c t i o n R a t e s To d e t e r m i n e i f d i s p e r s i n g a n i m a l s i n i t i a t e d or r e c e i v e d d i f f e r e n t amounts o f a m i c a b l e o r a g o n i s t i c b e h a v i o u r s , i n t e r a c t i o n r a t e s f o r a n i m a l s o b s e r v e d on SRC and CCC i n 1975 and 1976 were c a l c u l a t e d f o r t h e e n t i r e a c t i v e p e r i o d u s i n g t h e f o l l o w i n g e q u a t i o n s . A d m i t t e d l y i t would have been p r e f e r a b l e t o compare d i s p e r s i n g and r e s i d e n t a n i m a l s on a b i w e e k l y b a s i s b u t due t o t h e low number o f i n t e r a c t i v e s e g u e n c e s s e e n e a c h o b s e r v a t i o n a l week , t h i s was n o t p o s s i b l e . I n 1975 t h e number o f i n t e r a c t i o n s f o r e a c h a n i m a l f o r t h e e n t i r e a c t i v e p e i o d was d e t e r m i n e d . A v e r a g e i n t e r a c t i o n r a t e s ( b o t h f o r i n i t i a t i n g and r e c e i v i n g b e h a v i o u r s ) were c a l c u l a t e d u s i n g t h e f o l l o w i n g e q u a t i o n : # i n t e r a c t i o n s s e e n # o f i n t e r a c t i o n s / h r = X 60 mi n . / h r . # m i n u t e s o b s e r v e d I n 1976 r a t e s were c a l c u l a t e d t o p r o v i d e c o m p a r a b l e r a t e s f o r a l l a n i m a l s but a r e n o t d i r e c t l y c o m p a r a b l e t o t r u e t i m e r a t e s . R a t e s i n 1976 were c a l c u l a t e d a c c o r d i n g t o t h e f o l l o w i n g e q u a t i o n , : # i n t e r a c t i o n s s e e n # i n t e r . / h r . = # h o u r s o b s e r v e d 136 No c l e a r trends were evident i n the r a t e s at which d i s p e r s i n g and r e s i d e n t mature males i n i t i a t e d or r e c e i v e d amicable or a g o n i s t i c behaviours. On SEC d i s p e r s i n g males appeared to i n i t i a t e and r e c e i v e fewer amicable or a g o n i s t i c behaviours whereas on CCC d i s p e r s i n g mature nature males tended t o i n i t i a t e and r e c e i v e more amicable and a g o n i s t i c b e h a v i o u r s ( T a b l e 10). However none of these trends were s t a t i s t i c a l l y s i g n i f i c a n t . Both mature females on SBC and CCC showed opposing t r e n d s i n the i n t e r a c t i v e budgets of r e s i d e n t and d i s p e r s i n g animals. D i s p e r s i n g females on SBC i n i t i a t e d fewer amicable behaviours than r e s i d e n t females whereas e m i g r a t i n g mature females on CCC i n i t i a t e d more amicable behaviours. S i m i l a r l y , d i s p e r s i n g females on. SBC.received s i g n i f i c a n t l y l e s s a g o n i s t i c behaviour than r e s i d e n t females yet on CCC d i s p e r s i n g animals r e c e i v e d s i g n i f i c a n t l y more a g o n i s t i c behaviours than r e s i d e n t s . On both SBC and CCC, j u v e n i l e males tended t o i n i t i a t e more but r e c e i v e fewer amicable behaviours than r e s i d e n t j u v e n i l e males. S i g n i f i c a n t l y fewer a g o n i s t i c i n t e r a c t i o n s were i n i t i a t e d by emigrating j u v e n i l e males on SEC but on CCC, j u v e n i l e males i n i t i a t e d s i g n i f i c a n t l y more a g g r e s s i v e behaviours. D i s p e r s i n g j u v e n i l e males on CCC a l s o tended to r e c e i v e more a g o n i s t i c b ehaviours, U n f o r t u n a t e l y no e m i g r a t i n g j u v e n i l e females on SBC were observed f o r p e r i o d s of s u f f i c i e n t d u r a t i o n f o r i n c l u s i o n . On CCC e m i g r a t i n g j u v e n i l e females r e c e i v e d more and i n i t i a t e d l e s s amicable i n t e r a c t i o n s and i n i t i a t e d fewer and r e c e i v e d more a g o n i s t i c i n t e r a c t i o n s than r e s i d e n t j u v e n i l e females. 137 f a b l e 10: I n t e r a c t i o n s r a t e s o f r e s i d e n t and d i s p e r s i n g a n i m a l s . I n t e r a c t i o n r a t e s »ere c a l c u l a t e d f o r t h e i n i t i a t i o n ( I n i t . ) and r e c e i v i n g (Rec.) o f a m i c a b l e and a g o n i s t i c b e h a v i o u r s i n e a c h c l a s s . Mean r a t e s f o r e a c h c l a s s a r e g i v e n and S5% c o n f i d e n c e l i m i t s a r e i n d i c a t e d . RESIDENT ANIMALS DISPERSING ANIMALS AMICABLE AGONISTIC AMICABLE - AGONISTIC SRC 1975 INIT. REC. INIT . REC. INIT. REC. INIT. REC. Adult Male 1.5 1.7 2.6 1.8 0.610.3 01.10.2 0.711.4 Adult Female 1.0±2.0 2.2±2.7 1.6±0.9 2.4±1.3 0.8 2.3 0.0 0.0 Juvenile Male none none none none none none none none Juvenile Female 2.911.0 2.6±0.3 0.6+1.1 1.4±2.7 none none none none CCC 1975 Adult Male 4.5 4.5 4.9 11.7 none none none none Adult Female 3.9±2.8 5.6±8.6 5.8±5.5 10 . 6 + 7.5 16.3 13.5 13.5 6.7 Juvenile Male 13.5116.4 7.2±9.5 39.3+50.5 34.3±32.7 13.2112.0 13.310.3 73.117.6 77 . 9 1 6.5 Juvenile Female 11.0121.0 9.1±16.0 22.2±27.0 27.6±11.4 o.o 7.3. 7.3 43.9 SRC 1976 Adult Male 0.4±0.2 0.3±0.3 0.3±0.2 0.3±0.5 none none none none Adult Female 0.3±0.3 0.4±0.6 0.1±0.1 0.1±0.1 0.0 0.0 0.1 0.0 Juvenile Male 0.1 0.0 0.3 0.4 0.210.3 0.0 0.210.1 0.210.2 Juvenile Female 0.04 0.0 0.2 0.1 none none none none CCC 1976 Adult Male 0.210.3 0.2±0.2 0.3±0.6 0.1±0.2 .0.410.6 0.510.5 0.4+0.5 0.410.4 Adult Female 0.8±1.3 0.6±0.8 0.5±1.0 0.5±0.6 0.310.3 1.012.8 0.611.9 1.113.5 Juvenile Male 1.6±2.2 0.2±0.0 0.6±1.2 0.7±0.1 1.010.6 0.5+1.0 1 . 7 1 3.0 0.811.3 Juvenile Female 0.2±0.6 0.4±0.4 0.7±0.6 0.8±0.3 0.0 0.0 0.5 0.5 139 Few l a r g e d i f f e r e n c e s between t h e r a t e a t which d i s p e r s i n g and r e s i d e n t a n i m a l s i n i t i a t e and r e c e i v e i n t e r a c t i v e b e h a v i o u r s a r e a p p a r e n t . T r e n d s b a s e d on t h e mean i n t e r a c t i v e r a t e f o r a m i c a b l e and a g o n i s t i c b e h a v i o u r s , i n d i c a t e d t h e r e were no c o n s i s t e n t d i f f e r e n c e s between e m i g r a t i n g a n i m a l s and r e s i d e n t a n i m a l s i n t e r m s o f t h e number o f t i m e s t h e y i n i t i a t e d o r r e c e i v e d a m i c a b l e b e h a v i o u r s . I n most c a s e s however, d i s p e r s i n g a n i m a l s i n i t i a t e d f e w e r a g o n i s t i c b e h a v i o u r s ( w i t h t h e e x c e p t i o n o f j u v e n i l e and mature males on CCC) w h i l e r e c e i v i n g more a g o n i s t i c b e h a v i o u r s t h a n r e s i d e n t a n i m a l s ( w i t h t h e e x c e p t i o n o f mature males and f e m a l e s on SRC)., I n i t i a t o r s and B e c i p i e n t s Of A g o n i s t i c B e h a v i o u r I f d i s p e r s i n g a n i m a l s do d i f f e r f r o m r e s i d e n t a n i m a l s i n t e r m s o f t h e amount o f a g o n i s t i c b e h a v i o u r t h e y i n i t i a t e and r e c e i v e , some i n s i g h t i n t o t h e c a u s e s o f d i s p e r s a l may be g a i n e d by knowing w h i c h c l a s s most o f t e n r e c i e v e d a g o n i s t i c b e h a v i o u r s i n i t i a t e d by a n i m a l s i n e a c h o f t h e f o u r c l a s s e s . I d e t e r m i n e d t h i s by summing t h e t o t a l number o f i n t e r a c t i o n s f o r r e s i d e n t and d i s p e r s i n g a n i m a l s o f e a c h c l a s s . I t h e n c a l c u l a t e d t h e p r o p o r t i o n o f t h e t o t a l i n t e r a c t i o n s i n v o l v i n g r e c i p i e n t s f r o m e a c h o f t h e f o u r c l a s s e s . Mature males a n d mature f e m a l e s on SBC were t h e most common r e c i p i e n t s o f mature male a g g r e s s i o n . On CCC however, mature males i n t e r a c t e d most w i t h j u v e n i l e m a l e s , f o l l o w e d by j u v e n i l e and mature f e m a l e s . A c o m p a r i s o n o f r e s i d e n t males and d i s p e r s i n g m a l e s was n o t p o s s i b l e due t o t h e low number o f 140 i n t e r a c t i o n s i n v o l v i n g d i s p e r s i n g mature males ( T a b l e 1 1 ) . On SBC mature males r e c e i v e d most a g o n i s t i c b e h a v i o u r i n i t i a t e d by e i t h e r r e s i d e n t o r d i s p e r s i n g mature f e m a l e s . I n 1975 on CCC r e s i d e n t mature f e m a l e s more o f t e n i n t i a t e d a g o n i s t i c i n t e r a c t i o n s i n v o l v i n g e i t h e r j u v e n i l e males o r f e m a l e s , b u t i n 1976, o t h e r mature f e m a l e s were more commonly i n v o l v e d . D i s p e r s i n g f e m a l e s however i n t e r a c t e d more w i t h mature males i n 1975 and mature f e m a l e s i n 1976. In b o t h y e a r s t h e numbers o f i n t e r a c t i o n s i n v o l v i n g j u v e n i l e males and f e m a l e s on SRC was t o o low t o e s t i m a t e r e c i p i e n t p r o p o r t i o n s . On CCC, b o t h r e s i d e n t and d i s p e r s i n g j u v e n i l e males a n d f e m a l e s most o f t e n i n i t i a t e d a g o n i s t i c i n t e r a c t i o n s w i t h o t h e r j u v e n i l e males and f e m a l e s . D i s p e r s i n g j u v e n i l e s a l s o i n i t i a t e d s l i g h t l y more a g o n i s t i c b e h a v i o u r s w i t h mature a n i m a l s . With t h e e x c e p t i o n o f mature m a l e s , r e s i d e n t and d i s p e r s i n g a n i m a l s o f one age c l a s s t e n d e d t o i n t e r a c t most w i t h o t h e r a n i m a l s o f t h e same age and s e x c l a s s a s t h e m s e l v e s o r w i t h a n i m a l s o f t h e same age g r o u p a s t h e m s e l v e s ( F i g . 2 7 ) . T h e r e were no c o n s i s t e n t d i f f e r e n c e s between d i s p e r s i n g and r e s i d e n t a n i m a l s i n t e r m s o f i n t e r a c t i v e p a r t n e r s . fin a l t e r n a t e a n a l y s i s o f t h i s d a t a i s from t h e p o i n t o f view o f t h e age c l a s s e s a s r e c i p i e n t s o f i n t e r a c t i o n s i n i t i a t e d by o t h e r a n i m a l s . T h a t i s t h a t g i v e n t h a t a n i m a l s o f a c e r t a i n age c l a s s r e c e i v e d a number o f a g o n i s t i c b e h a v i o u r s , what p r o p o r t i o n s o f t h e t o t a l number o f i n t e r a c t i o n s were i n i t i a t e d by a n i m a l s i n each o f t h e f o u r age and s e x c l a s s e s . R e s u l t s l a r g e l y a g r e e d w i t h t h o s e j u s t d i s c u s s e d . M a t u r e males t e n d e d t o 14.1 T a b l e 1 1 : R e c i p i e n t s o f a g o n i s t i c b e h a v i o u r . F o r e a c h c l a s s , t h e p r o p o r t i o n o f t h e t o t a l number o f a g o n i s t i c i n f l a t e d by t h a t c l a s s t o w a r d s a n i m a l s i n e a c h o f t h e f o u r c l a s s e s was c a l c u l a t e d . P r o p o r t i o n s f o r e a c h a r e a i n e a c h y e a r f o r a l l c l a s s e s a r e shown. The number o f i n t e r a c t i o n s i n i t i a t e d by e a c h c l a s s a r e i n d i c a t e d . PROPORTION OF AGO FISTIC BEHAVIOURS Adult Males SRC 1975 CCC 1975 SRC 1976 CCC 1976 RESIDENT ANIMALS DISPERSING ANIMALS AD.d" AD.9 JU.O* JU.9- N 0.0 0.7 0.1 0.2 18 0.0 0.2 0.5 0.3 101 0.5 0.4 O.'l 0.0 19 0.0 0.3 0.0 0.7 3 AD.O* AD."? JU.O* JU.9 N 0.0 1.0 0.0 0.0 . 4 - none -- none -0.0 0.6 0.0 0.4 5 Adult Females SRC 1975 CCC 1975 SRC 1976 CCC 1976 0.6 0.3 0.0 0.1 21 0.1 0.2 0.4 0.3 87 0.9 0.1 0.0 0.0 16 0.1 0.7 0.1 0.1 37 0.0 0.0 0.0. 0.0 0 0.9 0.0 0.0 0.1 7 1.0 0.0 0.0 0.0 1 0.1 0.9 0.0 0.0 7 Juvenile Males SRC 1975 CCC 1975 SRC 1976 CCC 1976 - none -0.1 01 0.7 0.1 317 0.0 1.0 0.0 0.0 2 0.1 0.1 0.5 0.3 17 - none -0.0 0.0 0.7 0.3 186 0.0 0.0 0.6 0.4 8 0.14 0.14 0.14 0.57 7 Juvenile Females SRC 1975 CCC 1975 SRC 1976 CCC 1976 0.0 0.0 0.2 0.8 15 0.02 0.01 0.79 0.19 121 0.0 0.0 1.0 0.0 4 0.0 0.25 0.42 0.33 12 - none -0.28 0.32 0.0 0.4 25 - none -0.0 0.0 0.5 0.5 2 1 4 3 F i g u r e 27: R e c i p i e n t s o f a g o n i s t i c i n t e r a c t i o n s . F o r e a c h c l a s s , t h e p r o p o r t i o n o f t h e a g o n i s t i c i n t e r a c t i o n s i n i t i a t e d t o w a r d s members o f e a c h o f t h e f o u r c l a s s e s i s shown.,, The l e n g t h o f t h e a r r o w d i r e c t e d t o w a r d s e a c h age c l a s s i n d i c a t e s t h e p r o p o r t i o n o f t h e t o t a l number o f i n t e r a c t i o n s i n i t i a t e d t o w a r d s t h a t c l a s s , e x c e p t i n t h e c a s e o f i n t e r a c t i o n s w i t h a n i m a l s o f t h e same c l a s s . The p r o p o r t i o n e n c l o s e d i n t h e s m a l l e r c i r c l e i n d i c a t e s t h e p r o p o r t i o n o f i n t e r a c t i o n s w i t h a n i m a l s o f t h e same c l a s s . D i s p e r s i n g and r e s i d e n t a n i m a l p r o p o r t i o n s a r e i n d i c a t e d . D i s p e r s i n g a n i m a l s R e s i d e n t a n i m a l s Recipients 144 I 1 I 1 1 i O .4 .8 145 most o f t e n be i n v o l v e d i n i n t e r a c t i o n s i n i t i a t e d by mature f e m a l e s ( T a b l e 12} ., R e s i d e n t mature f e m a l e s were u s u a l l y t h e r e c i p i e n t s o f i n t e r a c t i o n s i n i t i a t e d by o t h e r mature f e m a l e s and mature males whereas d i s p e r s i n g mature f e m a l e s were most o f t e n i n v o l v e d i n i n t e r a c t i o n s i n i t i a t e d by mature and j u v e n i l e m a l e s . J u v e n i l e males and f e m a l e s were commonly t h e r e c i p i e n t s o f j u v e n i l e male and f e m a l e a g g r e s s i o n whereas d i s p e r s i n g j u v e n i l e s were most o f t e n i n v o l v e d i n i n t e r a c t i o n s i n i t i a t e d by j u v e n i l e m ales., O v e r a l l d i f f e r e n c e s between t h e t e n d e n c y o f d i s p e r s i n g and r e s i d e n t a n i m a l s t o be r e c i p i e n t s o f a g o n i s t i c b e h a v i o u r i n i t i a t e d by a n i m a l s o f a p a r t i c u l a r age c l a s s were n o t c l e a r . No p a t t e r n o f i n t e r a c t i o n s was e v i d e n t among mature a n i m a l s b u t i n j u v e n i l e age c l a s s e s , a g o n i s t i c i n t e r a c t i o n s most o f t e n i n v o l v e d o t h e r j u v e n i l e a n i m a l s ( F i g . 2 8 ) . T h i s s u g g e s t s t h a t i f p a t t e r n s o f a g o n i s t i c b e h a v i o u r a r e i m p o r t a n t t o j u v e n i l e d i s p e r s a l , t h a t j u v e n i l e e m i g r a t i o n f r o m t h e c o l o n y may be most i n f l u e n c e d by a g o n i s t i c i n t e r a c t i o n s w i t h o t h e r j u v e n i l e a n i m a l s , p a r t i c u l a r l y j u v e n i l e m a les. 146 Table 12: I n i t i a t o r s of agonis t ic behaviour. For each c la s s the proportion of the t o t a l agonis t ic in te rac t ions received from members of the four classes « a s ca lcula ted for the act ive per iod. The number of in te rac t ions received by each c l a s s i s ind ica ted . PROPORTION OF AGONISTIC BEHAVIOURS RESIDENT ANIMALS DISPERSING ANIMALS Adult Males SRC 1975 CCC 1975 SRC 1976 CCC 1976 AD. O* AD . 9 JU. O* JU . 9 • N 0.0 1.0 0.0 0.0 11 0.0 0.4 0.53 0.07 45 0.38 0.58 0.04 0.0 4 0.0 0.5 0.5 0.0 4 AD . C? AD. 9 JU. d" JU. 9 N - none -- none -- none -0.0 1.0 0.0 0.0 5 Adult Females SRC 1975 CCC 1975 SRC 1976 CCC 1976 0.57 0.43 0.0 0.0 23 0.24 0.24 0.32 0.20 88 0.66 0.17 0.17 0.0 12 0.10 0.70 0.10 0.10 30 - none -1.0 0.0 0.0 0.0 7 - none -0.22 0.78 0.0 0.0 9 Juvenile Males SRC 1975 CCC 1975 SRC 1976 CCC 1976 - none -0.11 0.05 0.71 0.13 300 0.0 0.25 0.75 0.0 12 0.0 0.13 0.63 0.25 16 - none -0.05 0.05 0.69 0.21 270 - none -0.0 0.0 1.0 0.0 3 Juvenile Females SRC 1975 CCC 1975 SRC 1976 CCC 1976 0.22 0.06 0.0 0.72 18 0.12 0.09 0.63 0.16 134 0.0 0.0 1.0 0.0 3 0.14 0.14 0.36 0.36 14 - none -0.1 0.05 0.84 0.0 19 - none -0.0 0.0 0.66 0.34 3 148 F i g u r e 28: I n i t i a t o r s o f a g o n i s t i c i n t e r a c t i o n s . F o r e a c h c l a s s , t h e p r o p o r t i o n o f t h e a g o n i s t i c i n t e r a c t i o n s r e c e i v e d f r o m members o f e a c h o f t h e f o u r c l a s s e s i s shown. The l e n g t h o f t h e arr o w d i r e c t e d t o w a r d s e a c h age c l a s s i n d i c a t e s t h e p r o p o r t i o n o f t h e t o t a l number o f i n t e r a c t i o n s r e c e i v e d f r o m t h a t c l a s s , e x c e p t i n t h e c a s e o f i n t e r a c t i o n s w i t h a n i m a l s o f t h e same c l a s s . The p r o p o r t i o n e n c l o s e d i n t h e s m a l l e r c i r c l e i n d i c a t e s t h e p r o p o r t i o n o f i n t e r a c t i o n s w i t h a n i m a l s o f t h e same c l a s s . D i s p e r s i n g and r e s i d e n t a n i m a l p r o p o r t i o n s a r e i n d i c a t e d . ^ — D i s p e r s i n g a n i m a l s R e s i d e n t a n i m a l s I 1 1 1 1 1 O .4 .8 150 G e n e t i c B e l a t e d n e s s And S a t e s Of I n t e r a c t i o n s D u r i n g t h e a n a l y s i s o f a m i c a b l e and a g o n i s t i c b e h a v i o u r s i t became a p p a r e n t t h a t i n many c a s e s , a n i m a l s a p p e a r e d t o i n t e r a c t more w i t h a n i m a l s r e l a t e d t o them t h a n w i t h u n r e l a t e d a n i m a l s . To d e t e r m i n e i f t h i s was t h e c a s e , I e s t i m a t e d t h e g e n e t i c r e l a t e d n e s s o f e a c h p a i r o f a n i m a l s i n v o l v e d i n an a m i c a b l e o r a g o n i s t i c i n t e r a c t i o n . I t h e n c a l c u l a t e d s e p a r a t e a m i c a b l e and a g o n i s t i c i n t e r a c t i o n r a t e s f o r r e l a t e d and u n r e l a t e d a n i m a l s d u r i n g e a c h b i w e e k l y o b s e r v a t i o n a l p e r i o d . As t h e g e n e t i c r e l a t i o n s h i p s o f i n d i v i d u a l s p r e s e n t on t h e a r e a s when t h e s t u d y was begun i n 1975 were n o t w e l l known , I w i l l r e s t r i c t t h e a n a l y s i s t o t h e 1976 s e a s o n . G e n e t i c r e l a t e d n e s s , as u s e d i n t h i s a n a l y s i s i n c l u d e s t h e r e l a t i o n s h i p s o f b r o t h e r : s i s t e r , mother : young, g r a n d m o t h e r : d a u g h t e r ' s young and s i s t e r : s i s t e r ' s young. The male l i n e a g e was n o t c o n s i d e r e d as no c o p u l a t i o n s were s e e n and hence t h e p r o b a b l e f a t h e r o f most young was n o t known. As a l l mature males on b o t h c o n t r o l s were i m m i g r a n t s o r were presumed t o be i m m i g r a n t s , I assumed t h a t a l l mature males were u n r e l a t e d t o t h e mature f e m a l e s on t h e c o l o n y . A l s o , s e v e r a l mature f e m a l e s p r e s e n t on e a c h c o n t r o l a r e a i n t h e s p r i n g o f 197 5 s t i l l r e m a i n e d on t h e c o n t r o l a r e a s i n t h e s p r i n g o f 1977. On t h e b a s i s o f s o c i a l t i e s , t h e c l o s e p r o x i m i t y o f t h e i r b r e e d i n g b u r r o w s t o o t h e r f e m a l e s and t h e f a c t t h a t so few i m m i g r a t i n g f e m a l e s became r e s i d e n t s , I assumed t h a t t h e s e f e m a l e s o f unknown o r i g i n were i n f a c t r e l a t e d t o o t h e r f e m a l e s w i t h i n t h e same g r o u p i n g of b u r r o w s , e v e n t h o u g h t h e e x a c t n a t u r e o f t h e 151 r e l a t i o n s h i p was n o t known. They were a l s o i n c l u d e d i n t h i s a n a l y s i s . On SRC, r a t e s o f a m i c a b l e b e h a v i o u r s between r e l a t e d and u n r e l a t e d a n i m a l s were s i m i l a r i n t h e e a r l y s p r i n g ( F i g . 2 9 ) . On CCC however, r e l a t e d a d u l t s showed much h i g h e r r a t e s o f a m i c a b l e i n t e r a c t i o n s t h a n u n r e l a t e d a d u l t s . A m i c a b l e i n t e r a c t i o n s i n l a t e A p r i l and e a r l y May were p r i m a r i l y between a d u l t f e m a l e s o r between a d u l t f e m a l e s and mature m a l e s . On b o t h a r e a s , a l m o s t a l l a m i c a b l e b e h a v i o u r s i n J u n e were between r e l a t e d a d u l t f e m a l e s . I n J u l y , m a t u r e : j u v e n i l e i n t e r a c t i o n s were l a r g e l y between r e l a t e d a n i m a l s as were most j u v e n i l e : j u v e n i l e i n t e r a c t i o n s . I n l a t e A u g u s t , a m i c a b l e i n t e r a c t i o n s i n v o l v i n g b o t h r e l a t e d and u n r e l a t e d a n i m a l s i n c r e a s e d . More a g o n i s t i c i n t e r a c t i o n s o c c u r r e d between u n r e l a t e d m a ture a n i m a l s t h a n r e l a t e d a n i m a l s on b o t h SRC and CCC i n l a t e A p r i l and e a r l y May. T h e s e i n v o l v e d m o s t l y mature male : mature f e m a l e i n t e r a c t i o n s . R e l a t e d a n i m a l s ( m o s t l y mature f e m a l e : mature f e m a l e i n t e r a c t i o n s ) showed i n c r e a s e d r a t e s o f a g o n i s t i c b e h a v i o u r i n May and J u n e . I n c r e a s e d l e v e l s o f a g o n i s t i c b e h a v i o u r s i n v o l v i n g r e l a t e d j u v e n i l e s and a d u l t s or r e l a t e d j u v e n i l e s were common i n J u l y and i n v o l v e d m o s t l y p l a y f i g h t i n g . By A u g u s t however, l e v e l s o f p h y s i c a l a g g r e s s i o n i n c r e a s e d . A g o n i s t i c b e h a v i o u r s i n v o l v e d b o t h r e l a t e d and u n r e l a t e d a n i m a l s o f a l l c l a s s e s . T h e s e were presumed t o be a s s o c i a t e d w i t h c o m p e t i t i o n f o r h i b e r n a c u l a . A s i m i l a r i n c r e a s e i n a g o n i s t i c b e h a v i o u r s between u n r e l a t e d a n i m a l s was a l s o e v i d e n t . O v e r a l l , r e l a t e d . a n i m a l s showed, more a m i c a b l e b e h a v i o u r t h a n u n r e l a t e d a n i m a l s . A g o n i s t i c b e h a v i o u r however was common 152 F i g u r e 29: G e n e t i c r e l a t e d n e s s and i n t e r a c t i o n r a t e s . F o r e a c h o b s e r v a t i o n a l p e r i o d , t h e i n t e r a c t i o n r a t e s f o r a m i c a b l e and a g o n i s t i c b e h a v i o u r s i n v o l v i n g r e l a t e d and u n r e l a t e d a n i m a l s were c a l c u l a t e d . R a t e s f o r e a c h p e r i o d a r e shown. Shaded a r e a s i n d i c a t e t h e p r o p o r t i o n o f t h e i n t e r a c t i o n s i n v o l v i n g e a c h o f t h e f o l l o w i n g : i • • «l M a t u r e : m a t u r e a n i m a l s M a t u r e : j u v e n i l e a n i m a l s J u v e n i l e : j u v e n i l e a n i m a l s SRC 81 £ 8 1 0 ^ 0 Sis-0 0 0 o m "CT o i t u y 1111 A MA JN JU 4 4 m m 6 t e s 9 A MA JU AU S CCC 154 between u n r e l a t e d and r e l a t e d a n i m a l s . ' U n r e l a t e d a n i m a l s were more a g o n i s t i c i n t h e e a r l y s p r i n g whereas r e l a t e d a n i m a l s were more a g o n i s t i c i n May and J u n e . As much o f t h e a g o n i s t i c b e h a v i o u r between r e l a t e d a n i m a l s i n J u l y and e a r l y A u g u s t i n v o l v e d p l a y f i g h t i n g , r e l a t e d a n i m a l s do n o t a p p e a r t o be a s p h y s i c a l l y a g g r e s s i v e as u n r e l a t e d a n i m a l s . 155 DISCUSSION: PART I I I n t h e i n t r o d u c t i o n I o u t l i n e d a s e r i e s o f q u e s t i o n s I f e l t were i m p o r t a n t i n d e t e r m i n i n g t h e r e l a t i o n s h i p o f d i s p e r s a l t o p o p u l a t i o n r e g u l a t i o n and t h e f a c t o r s most l i k e l y t o a f f e c t d i s p e r s a l . I w i l l d i s c u s s e a c h o f t h e s e i n t e r m s o f i n f o r m a t i o n o b t a i n e d i n t h i s and o t h e r s t u d i e s . £o M o t i c Ground S q u i r r e l P o p u l a t i o n s Remain C o n s t a n t ? A r c t i c g r o u n d s g u i r r e l p o p u l a t i o n s i n t h e K l u a n e r e g i o n showed r e l a t i v e l y s t a b l e numbers o f r e s i d e n t a d u l t s f o l l o w i n g t h e b r e e d i n g p e r i o d . ,. D e n s i t i e s o f mature males and mature f e m a l e s i n e a r l y J u l y on SRC were 0.27-0.33/ha and 0.38/ha and on CCC were 0.96-0.93/ha and 1.3-2.0/ha. L a r g e f l u c t u a t i o n s i n t o t a l p o p u l a t i o n s i z e d i d o c c u r however. T h e s e were p r i m a r i l y due t o e m i g r a t i o n o f mature f e m a l e s and some mature males i n May and J u n e , t h e r e c r u i t m e n t o f j u v e n i l e s i n J u l y and t h e s u b s e q u e n t d i s p e r s a l o f j u v e n i l e s i n A u g u s t . As i n t h i s s t u d y , t h e l o s s o f a n i m a l s , p a r t i c u l a r l y j u v e n i l e s i s common t o a number o f S c i u r i d s (S. a r m a t u s {Balph and S t o k e s 1963), S . b e e c h e y i ( F i t c h 1 9 4 8 ) , S. r i c h a r d s o n i ( M i c h e n e r and M i c h e n e r 1977, Schmutz 1977, Y e a t o n 1 9 7 2 ) , S. t r i d e c e m l i n e a t u s ( M c C a r l e y 1966), S. u n d u l a t u s ( C a r l 1971), i n marmots (M. monax {deVos and G i l l e s p i e 1960, B r o n s o n 1 9 6 4 ) , M. f l a v i v e n t r i s ( A r m i t a g e 1974) and M. olympus ( B a r a s h 1972)) and i n p r a i r i e dogs (Cynomys l e u c u r u s and Cynomys l u d o v i c i a n u s ) ( T i l e s t o n and L e i c h l e i t n e r 1966). A r m i t a g e ( 1 9 7 4 ) and C a r l {1971} t o o have f o u n d t h a t t h e number o f r e s i d e n t a d u l t s t e n d e d t o 156 r e m a i n c o n s t a n t between y e a r s and t h a t f l u c t u a t i o n s i n p o p u l a t i o n s i z e were l a r g e l y due t o c h a n g e s i n t h e r e c r u i t m e n t and d i s p e r s a l o f j u v e n i l e a n i m a l s . I n many o f t h e s e s p e c i e s , j u v e n i l e males do n o t s u r v i v e a s w e l l as j u v e n i l e f e m a l e s . I t has n o t been p o s s i b l e t o c l e a r l y s e p a r a t e l o s s from t h e c o l o n y due t o d i s p e r s a l f r o m t h a t due t o v a r i o u s m o r t a l i t y f a c t o r s . My d a t a s u g g e s t t h a t d i s p e r s a l i s more i m p o r t a n t than i n s i t u m o r t a l i t y d u r i n g t h e a c t i v e p e r i o d . D u r i n g h i b e r n a t i o n however, d i s p e r s a l i s h i g h l y i m p r o b a b l e and most i f n o t a l l l o s s i n e a c h c l a s s i s due t o m o r t a l i t y f a c t o r s . L o s s D u r i n q H i b e r n a t i o n O v e r - w i n t e r s u r v i v a l o f a r c t i c g r o u n d s g u i r r e l s i n K l u a n e was l o w e r i n males t h a n i n f e m a l e s . G e n e r a l l y a d u l t males s u r v i v e d more p o o r l y t h a n j u v e n i l e males and a d u l t f e m a l e s s u r v i v e d b e t t e r t h a n j u v e n i l e f e m a l e s ( F i g . 1 6 ) . J u v e n i l e o v e r - w i n t e r s u r v i v a l on SRC and CCC was u s u a l l y l o w e r o r i n some c a s e s e g u a l t o t h a t o f mature a n i m a l s . P o o r e r j u v e n i l e t h a n a d u l t s u r v i v a l has a l s o been r e p o r t e d i n S. r i c h a r d s o n i ( M i c h e n e r and M i c h e n e r 1971, 1977, S h e p p a r d and Swanson 1976) and i n M. f l a v i v e n t r i s ( A r m i t a g e 1974). Two f a c t o r s , b o t h r e l a t e d t o t h e e n e r g e t i c c o s t o f h i b e r n a t i o n c o n t r i b u t e t o t h e s e d i f f e r e n c e s i n s u r v i v a l . J u v e n i l e a n i m a l s have a s h o r t e r g r o w t h p e r i o d t h a n mature a n i m a l s and and so may n o t be a b l e t o d e v e l o p s u f f i c i e n t f a t s t o r e s to s u r v i v e h i b e r n a t i o n , a r m i t a g e (1974) f o u n d t h a t t h e s u r v i v a l o f young marmots and t h e d u r a t i o n o f t h e i r f i r s t w i n t e r was i n v e r s e l y 157 c o r r e l a t e d . T h i s s u g g e s t s t h a t t h e " e n e r g e t i c c o s t s " o f h i b e r n a t i o n i n r e l a t i o n t o t h e amount o f s t o r e d f a t may be one o f t h e f a c t o r s d e t e r m i n i n g o v e r - w i n t e r s u r v i v a l . „• D o r r a n c e and K e i t h ( 1 9 7 4 ) have i n f a c t f o u n d t h a t t h e body w e i g h t o f S. r i c h a r d s o n i p r i o r t o h i b e r n a t i o n was r e l a t e d t o t h e p r o b a b i l i t y o f t h e a n i m a l s u r v i v i n g t h e w i n t e r . No s u c h r e l a t i o n s h i p was e v i d e n t i n t h i s s t u d y , but a d m i t t e d l y s a m p l e s f o r e a c h c l a s s were s m a l l . J u v e n i l e s , p a r t i c u l a r l y j u v e n i l e m a les a r e more l i k e l y t o d i s p e r s e and a s s u m i n g d i s p e r s a l i s e n e r g e t i c a l l y s t r e s s f u l , t h i s t o o would add t o t h e l i k e l i h o o d o f i n c r e a s e d o v e r - w i n t e r m o r t a l i t y . The o t h e r f a c t o r which may i n f l u e n c e o v e r - w i n t e r s u r v i v a l i s e x p o s u r e . C a r l (1971) s u g g e s t e d t h a t j u v e n i l e a n i m a l s a r e f o r c e d t o u s e i n f e r i o r h i b e r n a c u l a t o t h o s e u s e d by a d u l t s . As a r e s u l t t h e e n e r g e t i i c c o s t s o f h i b e r n a t i o n may be i n c r e a s e d i n j u v e n i l e s . S i m i l a r l y Shaw (1926) f o u n d t h a t t h e h i b e r n a c u l u a o f a d u l t S. c o l u m b i a n u s were u s u a l l y d e e p e r and more complex t h a n t h o s e o f j u v e n i l e s . A l t h o u g h I d i d n o t a t t e m p t t o o b t a i n measures o f d i f f e r e n c e s i n h i b e r n a c u l a o f j u v e n i l e and a d u l t a n i m a l s , t h e r e l a t i o n s h i p between t h e d e n s i t y o f a n i m a l s on SRC and CCC and o v e r - w i n t e r s u r v i v a l i n f e r t h a t t h e a v a i l a b i l i t y o f h i b e r n a c u l a i s i m p o r t a n t . J u v e n i l e s on SRC s u r v i v e d as w e l l as a d u l t s i n most c a s e s . On CCC, j u v e n i l e s t e n d e d t o s u r v i v e more p o o r l y t h a n mature a n i m a l s . D e n s i t i e s o f a n i m a l s on SRC and CCC i n e a r l y A ugust ( t h e p e r i o d o f o f c o m p e t i t i o n f o r h i b e r n a c u l a ) was 0.92 v e r s u s 5.8 s g u i r r e l s / h a i n 1975 and 1.03 v e r s u s 5.8 s g u i r r e l s / h a i n 1976. I f t h e a v a i l a b i l i t y o f h i b e r n a c u l a i s r e l a t e d t o t h e 158 t o t a l d e n s i t y o f a n i m a l s on an a r e a , s u i t a b l e h i b e r n a c u l a would be more r e a d i l y a v a i l a b l e on SRC t h a n on CCC and s o may e x p l a i n t h e d i f f e r e n c e s i n j u v e n i l e and mature a n i m a l s u r v i v a l o b s e r v e d . O v e r w i n t e r s u r v i v a l a p p e a r s t o be l a r g e l y i n f l u e n c e d by f a c t o r s a f f e c t i n g e n e r g e t i c demands d u r i n g h i b e r n a t i o n as w e l l as t h o s e a f f e c t i n g t h e r a t e and e x t e n t o f f a t d e p o s i t i o n . S t u d i e s o f h i b e r n a t i o n i n g r o u n d s g u i r r e l s ( D a v i s 1976, M o r r i s o n and G a l s t e r 1976, D r e s c h e r 1968} have d e a l t l a r g e l y w i t h t h e p h y s i o l o g i c a l p r o c c e s s e s o f h i b e r n a t i o n . L i t t l e i s known of t h e q u a l i t a t i v e d i f f e r e n c e s between h i b e r n a c u l a o r of t h e d i f f e r e n c e s i n t h e h i b e r n a t i o n p h y s i o l o q y o f i n d i v i d u a l a n i m a l s and t h e i r r e l a t i o n s h i p t o o v e r - w i n t e r s u r v i v a l . Be need s t u d i e s o f t h i s n a t u r e . L o s s D u r i n g The a c t i v e P e r i o d D u r i n g t h e a c t i v e p e r i o d , p r e d a t i o n and d i s p e r s a l have been s u g q e s t e d as t h e major c a u s e s o f l o s s f r o m t h e p o p u l a t i o n . , W h i c h e v e r f a c t o r i s most i m p o r t a n t , i t must be a b l e t o e x p l a i n t h e s e a s o n a l and n u m e r i c a l d i f f e r e n c e s i n l o s s o b s e r v e d i n e a c h c l a s s . L o s s Due To P r e d a t i o n P r e d a t i o n has been s u q q e s t e d as a major f a c t o r i n t h e l o s s o f a n i m a l s . L u t t i c h e t . a l (1970) t h o u q h t t h a t up t o 3355 o f t h e l o s s o f S. r i c h a r d s o n i f r o m t h e i r s t u d y p o p u l a t i o n c o u l d be a c c o u n t e d f o r by r e d - t a i l e d hawk { B u t e o j a m a i c e n s i s ) p r e d a t i o n . S i m i l a r l y , C r a i q h e a d and C r a i q h e a d (1955) c o n s i d e r e d 159 S. r i c h a r d s o n i t o be h i g h l y s u s c e p t i b l e t o r a p t o r p r e d a t i o n . I b e l i e v e p r e d a t i o n i s l a r g e l y an i n f l u e n c e cn o n l y two g r o u p s o f a n i m a l s ; v e r y young and d i s p e r s i n g a n i m a l s . H i g h s u s c e p t i b i l i t y o f j u v e n i l e s t o p r e d a t i o n h a s been s u g g e s t e d as one o f t h e f a c t o r s c o n t r i b u t i n g t o h i g h i n s i t u j u v e n i l e m o r t a l i t y ( S l a d e and B a l p h 1974, Schmutz 1 9 7 7 ) . V e r y young A r c t i c g r o u n d s g u i r r e l s i n t h e K l u a n e r e g i o n were t h o u g h t t o be more s u s c e p t i b l e t o p r e d a t i o n t h a n o l d e r j u v e n i l e s as a r e s u l t o f t h e i r l a c k o f p h y s i c a l c o o r d i n a t i o n and i n some c a s e s , t h e i r f a i l u r e t o r e s p o n d t o a l a r m c a l l s . A r m i t a g e (1974) s i m i l a r l y f o u n d t h a t young M. f l a v i v e n t r i s were more commonly t a k e n by e a g l e s t h a n o t h e r age c l a s s e s . Schmutz {1977) f o u n d t h a t j u v e n i l e S. r i c h a r d s o n i were k i l l e d by hawks more o f t e n t h a n a d u l t s and t h a t j u v e n i l e males were more o f t e n k i l l e d t h a n j u v e n i l e f e m a l e s . L u t t i c h e t . a l {1970) and S h e p p a r d and Swanson (1976) however, f o u n d t h a t t h e p r o p o r t i o n o f young k i l l e d by p r e d a t o r s d i d n o t d i f f e r f r o m t h e p r o p o r t i o n o f young i n t h e p o p u l a t i o n . The r o l e o f p r e d a t i o n as a f a c t o r i n e a r l y j u v e n i l e l o s s i s u n c l e a r and c o n t i n u e d s t u d y i s r e g u i r e d . D i s p e r s i n g a n i m a l s a r e a l s o l i k e l y more s u s c e p t i b l e t o p r e d a t i o n ( A r m i t a g e 1974, C a r l 1971, S l a d e and B a l p h 1974, and H i c h e n e r 1972). P r e s u m a b l y d i s p e r s i n g a n i m a l s would be e x p o s e d f o r l o n g e r p e r i o d s and b e i n g u n f a m i l i a r w i t h t h e t e r r a i n would be u n a b l e t o r e a c h r e f u g e e a s i l y . F u r t h e r , t h e y would be much l e s s l i k e l y t o be warned o f t h e a p p r o a c h o f a p r e d a t o r t h a n c o l o n i a l s g u i r r e l s . S t u d i e s on t h e r e l a t i o n s h i p s between d i s p e r s a l and p r e d a t i o n t o d a t e h a v e been r e s t r i c t e d t o l a b o r a t o r y s i t u a t i o n s . M e t z g a r (1967) f o u n d t h a t mice 160 (Perpmyscus l e u c o p u s ) which had been a l l o w e d t o become f a m i l i a r w i t h an e x p e r i m e n t a l a r e n a , were l e s s l i k e l y t o be t a k e n by a S c r e e c h Owl ( O t u s a s i o ) t h a n mice t h a t had j u s t been e x p o s e d t o t h e e x p e r i m e n t a l a r e n a . M e t z g a r a t t r i b u t e d t h i s to t h e i n c r e a s e d e x p l o r a t o r y b e h a v i o u r o f newly e x p o s e d mice compared t o t h a t o f t h e " r e s i d e n t " m i c e . S i m i l a r l y , S n y d e r (1975) f o u n d t h a t a c t i v e mice were t a k e n more o f t e n by r e d - t a i l e d hawk t h a n i n a c t i v e (drugged) m i c e . B o t h s t u d i e s s u g g e s t e d t h a t an a n i m a l ' s l e v e l o f a c t i v i t y i n f l u e n c e s i t s c h a n c e s o f b e i n g t a k e n by a e r i a l p r e d a t o r s . A s s u m i n g t h e r e s u l t s o f t h e s e s t u d i e s a r e a p p l i c a b l e t o t h e f i e l d s i t u a t i o n , j u v e n i l e male g r o u n d s g u i r r e l s , a s a r e s u l t o f t h e i r g r e a t e r l i k e l i h o o d o f d i s p e r s a l and s o i n c r e a s e d e x p o s u r e , s h o u l d be more s u s c e p t i b l e t o a e r i a l p r e d a t i o n . , Schmutz (1977) i n f a c t f o u n d t h a t j u v e n i l e male S. r i c h a r d s o n i , which showed l a r g e r r a n g e s o f movement and a l o n g e r a c t i v e p e r i o d t h a n j u v e n i l e f e m a l e s , were t a k e n more o f t e n by hawks n e a r h e r s t u d y a r e a s t h a n were j u v e n i l e f e m a l e s . L i t t l e i s known o f t h e s u s c e p t i b i l i t y o f d i s p e r s i n g a n i m a l s t o g r o u n d p r e d a t o r s . With t h e e x c e p t i o n o f g r i z z l y b e a r s , p r e d a t i o n on r e s i d e n t c o l o n i a l a n i m a l s was l i m i t e d by w a r n i n g v o c a l i z a t i o n s . My e s t i m a t e s o f p r e d a t i o n a c c o u n t e d f o r o n l y 10-151 o f the t o t a l a n n u a l l o s s , a l t h o u g h my r e s u l t s a r e o n l y i n f e r e n t i a l , i t seems u n l i k e l y t h a t p r e d a t i o n i s t h e u l t i m a t e c a u s e o f t h e d i s a p p e a r a n c e o f a n i m a l s from t h e c o l o n y ^ B a t h e r i t would seem t h a t p r e d a t i o n i s a v e r y i m p o r t a n t p r o x i m a t e c a u s e o f m o r t a l i t y d u r i n g d i s p e r s a l . , 161 Seasonal Trends Of D i s p e r s a l D i s p e r s a l appeared t o be the major cause of insitu l o s s from both SRC and CCC . The c o r r e l a t i o n between seasonal peaks of immigration to the c o n t r o l and removal areas, with l o s s from the c o n t r o l areas, suggest that much of the l o s s i s due to d i s p e r s a l . Further the s i m i l a r i t y of seasonal d i s p e r s a l peaks on SRC and CCC suggest t h a t s easonal d i s p e r s a l i s a r e g u l a r and i n n a t e component o f the y e a r l y p a t t e r n s of p o p u l a t i o n change i n A r c t i c ground s g u i r r e l s . . Two main peaks of d i s p e r s a l were apparent i n A r c t i c ground s g u i r r e l s i n the Kluane r e g i o n . Mature females showed i n c r e a s e d d i s p e r s a l i n May and e a r l y June and j u v e n i l e s , p a r t i c u l a r l y j u v e n i l e males showed i n c r e a s e d d i s p e r s a l i n August. C a r l (1971) ( i n h i s F i g . 6) i n d i c a t e d t h a t i n A r c t i c ground s g u i r r e l s i n the v i c i n i t y of Pt. Barrow, Alaska, mature males and females s i m i l a r l y showed the g r e a t e s t l o s s of animals (not a t t r i b u t a b l e to h i b e r n a t i o n entry) i n May whereas the l a r g e s t l o s s of j u v e n i l e s from the the colony was i n J u l y and August. Mature and j u v e n i l e S. armatus a l s o showed s i m i l a r p a t t e r n s of s easonal d i s p e r s a l (Slade and Balph 1974). 162 Which J n i m a l s D i s p e r s e ? M o r p h o l o g i c a l D i f f e r e n c e s D i s p e r s i n g A r c t i c g r o u n d s g u i r r e l s showed some m o r p h o l o g i c a l d i f f e r e n c e s f r o m r e s i d e n t a n i m a l s . D i s p e r s i n g j u v e n i l e males t e n d e d t o be h e a v i e r and have l a r g e r s k u l l s i z e s t h a n n o n - d i s p e r s i n g a n i m a l s . D i s p e r s i n g mature f e m a l e s on t h e o t h e r hand o f t e n f a i l e d t o r e p r o d u c e . Few o t h e r s t u d i e s o f d i s p e r s i n g a n i m a l s have been c o n d u c t e d . S l a d e and B a l p h (1974) f o u n d no s i g n i f i c a n t d i f f e r e n c e s i n t h e body w e i g h t o f d i s p e r s i n g and r e s i d e n t S. a r m a t u s . D i s p e r s i n g M i c r o t u s p e n n s y l v a n i c u s however were s m a l l e r t h a n r e s i d e n t a n i m a l s {Myers and K r e b s 1971). T h i s was a t t r i b u t e d t o t h e e m i g r a t i o n o f s u b - a d u l t a n i m a l s j u s t a t t h e t i m e t h e y became r e p r o d u c t i v e l y a c t i v e . Few a d u l t s e m m i g r a t e d . Among j u v e n i l e male A r c t i c g r o u n d s g u i r r e l s , t h e h e a v i e r i n d i v i d u a l s t e n d e d t o d i s p e r s e f i r s t , s u g g e s t i n g t h a t t h e a t t a i n m e n t o f an a d u l t body s i z e and p o s s i b l y i n c r e a s e d c o m p e t i t i o n w i t h a d u l t a n i m a l s may be i m p o r t a n t c a u s e s o f d i s p e r s a l i n j u v e n i l e a n i m a l s . B a r a s h (1974) s u g g e s t e d t h a t i n marmots t h e s o c i a l s y s t e m s have e v o l v e d t o a l l o w j u v e n i l e a n i m a l s t o o b t a i n o p t i m a l s i z e ( f o r s u c c e s s f u l d i s p e r s a l and r e p r o d u c t i o n ) b e f o r e d i s p e r s a l . The two h y p o t h e s e s a r e b a s i c a l l y i n agreement t h a t a n i m a l s r e a c h c e r t a i n t h r e s h o l d s i z e s o r s i z e r a n g e s a t which a n i m a l s a r e t r e a t e d as a d u l t s and so must compete f o r t e r r i t o r i e s w i t h i n t h e c o l o n y . T h i s o p t i m a l s i z e 163 s h o u l d c o i n c i d e w i t h t h e s t a g e o f d e v e l o p m e n t a t w h i c h j u v e n i l e a n i m a l s a r e a b l e t o become t o t a l l y i n d e p e n d e n t f r o m t h e f a m i l y g r o u p . D i s p e r s a l t h e n s h o u l d o c c u r j u s t p r i o r t o t h e t i m e a t w h i c h j u v e n i l e o r young a n i m a l s became r e p r o d u c t i v e l y a c t i v e . I n most g r o u n d s g u i r r e l s , j u v e n i l e s a r e c a p a b l e o f b r e e d i n g t h e s p r i n g f o l l o w i n g t h e i r b i r t h . , S. c o l u m b i a n u s i s t h e one e x c e p t i o n ; most a n i m a l s a r e n o t c a p a b l e o f b r e e d i n g u n t i l t h e i r s e c o n d s p r i n g . I n agreement w i t h t h e t h e o r y , most j u v e n i l e g r o u n d s g u i r r e l s d i s p e r s e b e f o r e t h e i r f i r s t s p r i n g , whereas S. c o l u m b i a n u s do n o t a p p e a r t o d i s p e r s e u n t i l t h e i r s e c o n d summer. B a r a s h (1974) f o u n d t h a t marmots t h a t d i s p e r s e d a s j u v e n i l e s (Marmeta monax), b r e d as y e a r l i n g s , were s o l i t a r y ( e x c e p t f o r mother : young g r o u p s ) and showed l i t t l e s o c i a l b e h a v i o u r . I n s p e c i e s t h a t d i s p e r s e d as y e a r l i n g s o r t w o - y e a r o l d s , a n i m a l s were more s o c i a l and t e n d e d t o show much more a m i c a b l e b e h a v i o u r . B a r a s h s u g g e s t e d t h a t t h e r e was a c o r r e l a t i o n between t h e s o c i a l i t y (amount o f a g o n i s t i c v e r s u s i a m i c a b l e b e h a v i o u r t o w a r d s c o n s p e c i f i c s ) o f a s p e c i e s , t h e l e n g t h o f g r o w i n g s e a s o n and t h e age a t w h i c h a n i m a l s were l i k e l y t o d i s p e r s e . P e r h a p s a s i m i l a r r e l a t i o n s h i p e x i s t s i n S p e r m o p h i l e s . S- c o l u m b i a n u s and S* u n d u l a t u s a p p e a r t o have a v e r y s i m i l a r s o c i a l o r g a n i s a t i o n ( S t e i n e r 1970, M i c h e n e r 1973, C a r l 1971, t h i s s t u d y ) and compared t o most o t h e r g r o u n d s g u i r r e l s a r e g u i t e s o c i a l s p e c i e s . The d i s p e r s a l p a t t e r n s o f S. c o l u m b i a n u s s u p p o r t . B a r a s h ! s . h y p o t h e s i s whereas, a r c t i c g r o u n d s g u i r r e l s m i g h t be e x p e c t e d t o d i s p e r s e as y e a r l i n g s r a t h e r t h a n a s 164 j u v e n i l e s . S. c o l u m b i a n u s p r e d o m i n a n t l y i n h a b i t s a l p i n e meadows and has a s h o r t a c t i v e s e a s o n ( M i c h e n e r 1977) i n c o m p a r i s o n t o A r c t i c g r o u n d s g u i r r e l s . Young a r c t i c g r o u n d s g u i r r e l s may t h u s be a b l e t o r e a c h a s u f f i c i e n t l y l a r g e s i z e i n t h e i r f i r s t summer t o d i s p e r s e whereas j u v e n i l e S* c o l u m b i a n u s c a n n o t . R e p r o d u c t i v e C o n d i t i o n And D i s p e r s a l I n mature f e m a l e A r c t i c g r o u n d s g u i r r e l s , b r e e d i n g s u c c e s s was r e l a t e d t o d i s p e r s a l . D u r i n g t h e b r e e d i n g p e r i o d , most i m m i g r a n t s t o t h e r e m o v a l a r e a s were i n b r e e d i n g c o n d i t i o n a s were a l l mature f e m a l e s e m i g r a t i n g f r o m t h e c o n t r o l a r e a i n May and e a r l y J u n e . However few mature f e m a l e s on t h e r e m o v a l p e r i o d i n May and June showed s i g n s o f becoming p r e g n a n t and fe w e r s t i l l were known t o s u c c e s s f u l l y g i v e b i r t h . D i s p e r s i n g mature f e m a l e s a p p e a r t o be t h o s e f e m a l e s who f o r some r e a s o n f a i l e d t o c o m p l e t e p r e g n a n c y . R e p r o d u c t i v e f a i l u r e i n d i s p e r s i n g mature f e m a l e s has s i m i l a r l y been r e p o r t e d i n s e v e r a l s p e c i e s o f g r o u n d s g u i r r e l s . C a r l (1971) f o u n d t h a t a l l n o n - b r e e d i n g f e m a l e A r c t i c g r o u n d s g u i r r e l s i n t h e main c o l o n y e m i g r a t e d b e f o r e t h e emergence o f t h e young and on an a r e a o f t e m p o r a r y beach r i d g e s , no i m m i g r a t i n g f e m a l e s s u c c e s s f u l l y r e p r o d u c e d . S i m i l a r l y , mature f e m a l e S. armatus w h i c h f a i l e d t o have young, d i s a p p e a r e d f r o m t h e c o l o n y i n t h e s p r i n g b e f o r e young were b o r n ( S l a d e and B a l p h 1974). Sherman (1976) o b s e r v e d t h a t mature f e m a l e S. b e l d i n g i w h ich l o s t l i t t e r s t o p r e d a t i o n o r which p r e s u m a b l y a b o r t e d , a l w a y s e m i g r a t e d t o a n o t h e r a r e a o f t h e l a r g e meadow and, i n 165 some c a s e s , a t t a c k e d and k i l l e d young o f n e i g h b o u r i n g f e m a l e s a t t h e new s i t e . Few e x p l a n a t i o n s have been o f f e r e d f o r t h e e m i g r a t i o n o f n o n - b r e e d i n g f e m a l e s i n t h e s p r i n g . Sherman (1977) s u g g e s t e d t h a t f e m a l e s l e f t t h e a r e a i n s e a r c h o f a s a f e r , more p r e d a t o r - f r e e s i t e and o n c e r e a c h i n g s u c h an a r e a , k i l l e d o f f n e i g h b o u r i n g young t o l i m i t c o m p e t i t i o n i n t h e a r e a i n which t h e y might r e p r o d u c e t h e f o l l o w i n g y e a r . I n t h e K l u a n e r e g i o n , mature f e m a l e : mature f e m a l e a g o n i s t i c i n t e r a c t i o n s i n c r e a s e d d u r i n g t h e p e r i o d o f mature f e m a l e e m i g r a t i o n ( F i g . 22) s u g g e s t i n g t h a t f e m a l e a g g r e s s i o n may be i m p o r t a n t i n t h e i n i t i a t i o n o f mature f e m a l e d i s p e r s a l . T h e r e d i d n o t a p p e a r t o be any r e l a t i o n s h i p however, between t h e number o f a g o n i s t i c o r a m i c a b l e i n t e r a c t i o n s a f e m a l e i n i t i a t e d o r r e c e i v e d and her e v e n t u a l f a t e t h a t s p r i n g ( i e . d i s p e r s a l v e r s u s r e s i d e n c y ) . L i t t l e i s known o f t h e f a c t o r s i n f l u e n c i n g t h e i n i t i a t i o n o f d i s p e r s a l o f mature f e m a l e s i n any g r o u n d s g u i r r e l s p e c i e s , e x c e p t t h a t r e p r o d u c t i v e f a i l u r e i s r e l a t e d t o a t e n d e n c y t o d i s p e r s e . 166 A r e D i s p e r s i n g A n i m a l s B e h a v i o u r a l l v D i f f e r e n t ? S o c i a l i n t e r a c t i o n s have been s u g g e s t e d a s one o f t h e i m p o r t a n t c a u s e s o f d i s p e r s a l ( C h i t t y 1967, K r e b s and Myers 1974, Watson and Moss 1969, Wynne-Edwards 1962, W i l s o n 1975). More s p e c i f i c a l l y , C a r l (1971) s u g g e s t e d t h a t young A r c t i c g r o u n d s g u i r r e l s a r e d r i v e n o u t by, t h e i n c r e a s i n g b e l l i g e r e n c e o f m o t h e r s t o w a r d s t h e i r young. I f s o c i a l b e h a v i o u r s a r e a r e g u l a t i n g f a c t o r , a r e l a t i o n s h i p between p o p u l a t i o n change and t h e r a t e and i n t e n s i t y o f s o c i a l i n t e r a c t i o n s must e x i s t (Watson and Moss 1969, A r m i t a g e 1975). The r e l a t i o n s h i p between s o c i a l b e h a v i o u r and p o p u l a t i o n d e n s i t y i s d i f f i c u l t t o a s s e s s . S e a s o n a l c h a n g e s i n s o c i a l b e h a v i o u r may be due t o a v a r i e t y o f r e s p o n s e s t o d i f f e r e n t s t i m u l i { i e . t h e b r e e d i n g p e r i o d v e r s u s t h e n o n - b r e e d i n g p e r i o d , t h e e s t a b l i s h m e n t o f b r e e d i n g t e r r i t o r i e s v e r s u s t h e e s t a b l i s h m e n t o f f a l l t e r r i t o r i e s e t c . ) . A r m i t a g e (1975) s o l v e d t h i s p r o b l e m t o some e x t e n t by u s i n g t h e mean i n t e r a c t i o n r a t e and t h e mean p o p u l a t i o n d e n s i t y f o r t h e a c t i v e p e r i o d . He f o u n d no c o r r e l a t i o n however, between t h e r a t e s o f a m i c a b l e o r a g o n i s t i c b e h a v i o u r and t h e mean p o p u l a t i o n d e n s i t y o v e r a t e n y e a r s t u d y o f s e v e r a l M. f l a v i y e n t r i s c o l o n i e s . I was n o t a b l e t o d e t e r m i n e i f s o c i a l b e h a v i o u r and p o p u l a t i o n d e n s i t y were c o r r e l a t e d i n A r c t i c g round s g u i r r e l s a s I have o n l y two v a l u e s f o r e a c h a r e a and r a t e s between y e a r s a r e n o t c o m p a r a b l e . I n t e r a c t i o n r a t e s (see T a b l e 12) were h i g h e r on CCC t h a n on SRC. Maximum d e n s i t i e s f o r e a c h y e a r on CCC were c l o s e t o s i x t i m e s t h a t on SRC (mean maximum d e n s i t y o f 6.23 167 a n i m a l s / h a on CCC and 1.04 . a n i m a l s / h a on SBC). T h i s s u g g e s t s t h a t s o c i a l b e h a v i o u r and p o p u l a t i o n d e n s i t y may be p o s i t i v e l y c o r r e l a t e d . T h i s c o u l d s i m p l y be due t o t h e c l o s e p r o x i m i t y o f a n i m a l s on CCC compared t o SBC and s o a h i g h e r i n t e r a c t i o n r a t e due t o t h e i n c r e a s e d p r o b a b i l i t y t h a t a n i m a l s w i l l e n c o u n t e r a n o t h e r a n i m a l , b ut a l t e r n a t i v e l y c o u l d be due t o i n c r e a s e d s o c i a l s t r e s s w i t h i n c r e a s e d d e n s i t i e s . C o n t i n u e d s t u d y o f s o c i a l b e h a v i o u r and p o p u l a t i o n d e n s i t y o f t h e s e p o p u l a t i o n s i s needed. S l a d e and B a l p h (1974) and C a r l (1971) s u g g e s t e d t h a t S. a r m a t u s and S. u n d u l a t u s p o p u l a t i o n s r e s p e c t i v e l y a r e a t l e a s t i n p a r t , i n t r i n s i c a l l y r e g u l a t e d by s o c i a l l y m i t i g a t e d d i s p e r s a l . S i m i l a r l y , B a r a s h (1974) s u g g e s t e d t h a t H. olympus p o p u l a t i o n s were a b l e t o r e g u l a t e t h e p o p u l a t i o n d e n s i t i e s o f c o l o n i e s by a d j u s t i n g t h e d i s p e r s a l r a t e s o f two y e a r o l d s t h r o u g h c h a n g e s i n s o c i a l b e h a v i o u r s . B e h a v i o u r a l D i f f e r e n c e s B e h a v i o u r a l o b s e r v a t i o n s o f a n i m a l s i m m i g r a t i n g t o t h e r e m o v a l a r e a s i n d i c a t e d t h e r e were few d i f f e r e n c e s between t h e b e h a v i o u r b u d g e t s o f r e s i d e n t a n i m a l s and d i s p e r s i n g a n i m a l s . D i s p e r s i n g j u v e n i l e a n i m a l s f e d more i n t h e l a t e summer, s u g g e s t i n g t h a t i n c r e a s e d f e e d i n g i s n e c e s s a r y t o make up f o r t h e e n e r g e t i c c o s t s o f d i s p e r s a l . The most o b v i o u s d i f f e r e n c e s however were t h e l a c k o f a m i c a b l e and a g o n i s t i c b e h a v i o u r s . As a r e s u l t , d i f f e r e n c e s i n t h e s o c i a l b e h a v i o u r s o f d i s p e r s i n g and r e s i d e n t . a n i m a l s .on .the . c o n t r o l a r e a s were more c l o s e l y i n v e s t i g a t e d . 168 D i s p e r s i n g a n i m a l s i n i t i a t e d f e w e r and r e c e i v e d more a g o n i s t i c i n t e r a c t i o n s t h a n r e s i d e n t a n i m a l s . No t r e n d s i n a m i c a b l e b e h a v i o u r were a p p a r e n t . , T h i s s u g g e s t s t h a t a g o n i s t i c b e h a v i o u r may be an i m p o r t a n t c a u s e o f d i s p e r s a l . F u r t h e r e v i d e n c e i s r e q u i r e d . E x p e r i m e n t s m a n i p u l a t i n g t h e l e v e l o f a g g r e s s i o n w i t h i n a c o l o n y may p r o v i d e some i n s i g h t . One c o u l d i n c r e a s e t h e l e v e l o f a g g r e s s i o n as d i d Watson ( 1 9 7 0 ) . They were a b l e t o i n c r e a s e t h e a g g r e s s i v e b e h a v i o u r of male r e d g r o u s e (Lagopus l a g o p u s ) by i n j e c t i n g t h e b i r d s w i t h a n d r o g e n , a l t e r n a t i v e l y , l e v e l s o f a g g r e s s i o n c o u l d be d e c r e a s e d by t h e r e m o v a l o f a d u l t f e m a l e s (Schmutz 1977) o r males ( D o n a l d s o n 1977). S u b s e g u e n t c h a n g e s i n d i s p e r s a l , p a r t i c u l a r l y j u v e n i l e d i s p e r s a l , would s t r o n g l y i m p l i c a t e a g g r e s s i o n as one o f t h e u l t i m a t e f a c t o r s o f d i s p e r s a l . Which A n i m a l s Most I n f l u e n c e D i s p e r s a l ? A g o n i s t i c b e h a v i o u r s a p p e a r t o be an i m p o r t a n t c a u s e o f d i s p e r s a l i n A r c t i c g round s g u i r r e l s . To d e t e r m i n e which a n i m a l s a r e most l i k e l y t o i n f l u e n c e d i s p e r s a l , f o r e a c h c l a s s I d e t e r m i n e d b o t h t h e most common i n i t i a t o r o f a g o n i s t i c i n t e r a c t i o n s t o w a r d s t h e c l a s s as w e l l a s t h e most common r e c i p i e n t s o f t h e a g o n i s t i c i n t e r a c t i o n s i n i t i a t e d by t h e c l a s s . B o t h p r o v i d e some i n d i c a t i o n o f s o c i a l h i e r a r c h i e s w i t h i n t h e c o l o n y . The most common r e c i p i e n t s o f a g o n i s t i c b e h a v i o u r of b o t h r e s i d e n t and d i s p e r s i n g a n i m a l s were a n i m a l s c f t h e same age o r se x { T a b l e 1 1 ) . . T h e r e was a s u g g e s t i o n t h a t d i s p e r s i n g j u v e n i l e 169 a n i m a l s t e n d e d t o a l s o i n t e r a c t more w i t h mature a n i m a l s t h a n r e s i d e n t a n i m a l s . P e r h a p s , r e s i d e n t j u v e n i l e s g u i r r e l s a r e b e t t e r a t a v o i d i n g a d u l t s t h a n d i s p e r s i n g a n i m a l s , a l t e r n a t i v e l y , d i s p e r s i n g j u v e n i l e may s i m p l y be more i n t o l e r a n t o f o t h e r a n i m a l s ( S l a d e and B a l p h 1974}. S i m i l a r l y , a r m i t a g e (1974) has s u g g e s t e d t h a t male y e a r l i n g M. f l a v i v e n t r i s d i s p e r s e t o a v o i d t e r r i t o r i a l a d u l t s , p a r t i c u l a r l y a d u l t m a l e s . D i s p e r s i n g and r e s i d e n t s g u i r r e l s a l s o t e n d e d t o r e c e i v e most a g o n i s t i c b e h a v i o u r from a n i m a l s o f t h e same c l a s s ( T a b l e 1 2 ) . Sample s i z e s f o r d i s p e r s i n g a d u l t a n i m a l s were s m a l l s o l i t t l e c a n be s a i d o f t h e r e l a t i v e i m p o r t a n c e o f i n t e r a c t i o n s i n i t i a t e d by e i t h e r a d u l t males o r f e m a l e s t o w a r d s o t h e r a d u l t s . R e s i d e n t j u v e n i l e s however, r e c e i v e d more a g o n i s t i c i n t e r a c t i o n s i n i t i a t e d by mature a n i m a l s t h a n d i d d i s p e r s i n g j u v e n i l e s . D i s p e r s i n g j u v e n i l e s i n s t e a d were a p p r o a c h e d l a r g e l y by male j u v e n i l e s . I f a l l a g o n i s t i c i n t e r a c t i o n s a r e e g u a l l y i m p o r t a n t , t h i s s u g g e s t s t h a t a d u l t : j u v e n i l e i n t e r a c t i o n s a r e not a s i m p o r t a n t t o j u v e n i l e d i s p e r s a l as j u v e n i l e : j u v e n i l e i n t e r a c t i o n s . W i t h i n one c l a s s , t h e s u b o r d i n a t e i n d i v i d u a l s may t h u s be t h e most l i k e l y a n i m a l s t o i m m i g r a t e , b e i n g l e s s l i k e l y t o be a b l e t o s u c c e s s f u l l y compete w i t h d o m i n a n t i n d i v i d u a l s . C a r l (1971) s u g g e s t e d t h a t h i b e r n a c u l a may be a l i m i t i n g r e s o u r c e . The c h a n c e s o f a j u v e n i l e a n i m a l c o m p e t i n g w i t h a r e s i d e n t a d u l t a n i m a l f o r a f a l l t e r r i t o r y o r h i b e r n a c u l a and s u c c e s s f u l l y o b t a i n i n g a t e r r i t o r y s h o u l d be s m a l l . T hus j u v e n i l e c o m p e t i t i o n f o r t h e r e m a i n i n g v a c a n t h i b e r n a c u l a would be i n t e n s e and so may l e a d t o t h e d i s p e r s a l o f some j u v e n i l e s . , a d u l t : j u v e n i l e 1 7 0 i n t e r a c t i o n s t h e n , may l e a d t o t h e movement o f j u v e n i l e a n i m a l s t o p e r i p h e r a l a r e a s . T h e r e j u v e n i l e : j u v e n i l e i n t e r a c t i o n s a r e l i k e l y i m p o r t a n t i n t h e e s t a b l i s h m e n t o f j u v e n i l e f a l l t e r r i t o r i e s and t h e e v e n t u a l d i s p e r s a l o f d e f e a t e d a n i m a l s . Fewer j u v e n i l e f e m a l e s d i s p e r s e d t h a n j u v e n i l e m a l e s . T h i s may be a r e s u l t o f t h e f o r m a t i o n o f r e l a t e d f e m a l e s o c i a l c o m p l e x e s ( i e . m o t h e r : d a u g h t e r g r o u p i n g s ) which were common on b o t h SBC and CCC. S i m i l a r g r o u p i n g s h a ve been r e p o r t e d i n S. b e l d i n g i (Sherman 1976), S. r i c h a r d s o n i ( Y e a t o n 1972, Qu a n s t r c m 1968) and S. t r i d e c e m l i n e a t u s ( B o n g s t a d 1965, H c C a r l e y 1966). As a r e s u l t , j u v e n i l e f e m a l e s may n o t be s u b j e c t e d t o t h e same l e v e l o f c o m p e t i t i o n f o r h i b e r n a c u l a o r b r e e d i n g s i t e s a s ma l e s . G e n e t i c R e l a t e d n e s s And S o c i a l B e h a v i o u r G e n e t i c r e l a t e d n e s s as w e l l as age and s e x a p p e a r t o be i m p o r t a n t i n d e t e r m i n i n g which a n i m a l s a s g u i r r e l i s most l i k e l y t o i n i t i a t e i n t e r a c t i o n s t o w a r d s o r r e c e i v e i n t e r a c t i o n s f r o m . R e l a t e d a n i m a l s on b o t h my s t u d y a r e a s showed h i g h e r l e v e l s o f a m i c a b l e b e h a v i o u r t h a n u n r e l a t e d a n i m a l s . A m i c a b l e b e h a v i o u r s l a r g e l y o c c u r r e d d u r i n g t h e s p r i n g and e a r l y summer. A d u l t : a d u l t i n t e r a c t i o n s were p r i m a r i l y between r e l a t e d f e m a l e s and i n v o l v e d m o s t l y r e c o g n a t o r y b e h a v i o u r s . S i m i l a r l y , a d u l t : j u v e n i l e i n t e r a c t i o n s o c c u r r e d between mothers and t h e i r young and most o f t e n i n v o l v e d n u z z l i n g o r n o s e - n o s e g r e e t i n g s . A m i c a b l e i n t e r a c t i o n s a r e l i k e l y i m p o r t a n t i n t h e e s t a b l i s h m e n t o f s o c i a l c o n t a c t s and t h e m a i n t e n a n c e o f t h e f a m i l y u n i t 171 f o l l o w i n g t h e emergence o f t h e young f r o m t h e n a t a l burrow. A g o n i s t i c i n t e r a c t i o n s were common between b o t h r e l a t e d and u n r e l a t e d a n i m a l s i n t h e e a r l y s p r i n g . M a l e : f e m a l e c o n t a c t s were more f r e g u e n t t h e n and were p r o b a b l y a s s o c i a t e d w i t h b r e e d i n g w hereas m a l e m a l e and f e m a l e : f e m a l e c o n t a c t s were more l i k e l y a s s o c i a t e d w i t h c o m p e t i t i o n f o r b r e e d i n g t e r r i t o r i e s . S i m i l a r l y i n t h e f a l l , b o t h r e l a t e d and u n r e l a t e d a n i m a l s i n t e r a c t e d . J u v e n i l e : mature a n i m a l c o n t a c t s p r e d o m i n a t e d however, s u p p o r t i n g t h e c o n t e n t i o n t h a t d u r i n g t h e p e r i o d o f c o m p e t i t i o n f o r f a l l t e r r i t o r i e s , mature a n i m a l s p r i m a r i l y r e a s s e r t t h e i r t e r r i t o r i a l " r i g h t s " o v e r j u v e n i l e s r a t h e r t h a n o t h e r t e r r i t o r i a l a n i m a l s . A g o n i s t i c i n t e r a c t i o n s between r e l a t e d a n i m a l s were common i n May, J u n e , and J u l y and i n v o l v e d m o s t l y mature f e m a l e s . L i k e S. b e l d i n g i (Sherman 1977), mature f e m a l e A r c t i c g r o u n d s g u i r r e l s became i n c r e a s i n g l y a g o n i s t i c d u r i n g p r e g n a n c y and t h e weaning o f young, and a p p e a r e d t o d e f e n d t h e a r e a a r o u n d t h e n a t a l burrow from a l l mature a n i m a l s r e g a r d l e s s o f t h e i r r e l a t i o n s h i p . Sherman. (1977) s u g g e s t e d t h a t t h i s may be an a d a p t a t i o n t o m i n i m i z e i n t r a s p e c i f i c p r e d a t i o n . O v e r a l l , r e l a t e d a n i m a l s showed h i g h e r l e v e l s o f a m i c a b l e b e h a v i o u r and s i m i l a r l e v e l s o f a g o n i s t i c b e h a v i o u r t o u n r e l a t e d a n i m a l s . Much o f t h e a g o n i s t i c b e h a v i o u r o f r e l a t e d a n i m a l s i n v o l v e d p l a y f i g h t i n g and s o r e l a t e d a n i m a l s t e n d t o be l e s s p h y s i c a l l y a g g r e s s i v e t h a n r e l a t e d a n i m a l s . S i m i l a r l y , S h e p p a r d and Y o s h i d a (1971) f o u n d t h a t i n S. r i c h a r d s o n i , a m i c a b l e b e h a v i o u r was more common between r e l a t e d a n i m a l s whereas a g o n i s t i c b e h a v i o u r was more common between u n r e l a t e d a n i m a l s . M i c h e n e r and S h e p p a r d (1972) and M i c h e n e r (1973) e x t e n d e d t h i s 172 a p p r o a c h t o t h e i n t e r a c t i o n r e g i m e between a mother and h e r own o r a l i e n young. L i t t l e a g o n i s t i c b e h a v i o u r o c c u r r e d between r e l a t e d a n i m a l s b u t was common between u n r e l a t e d a n i m a l s . F u r t h e r , w i t h i n a l i t t e r , m a les t e n d e d t o r e c e i v e l e s s a m i c a b l e b e h a v i o u r f r o m t h e i r m o t h e r s . The i n f l u e n c e o f t h e mother a p p e a r e d t o have e f f e c t s on t h e e v e n t u a l d i s p e r s a l o f j u v e n i l e s ( M i c h e n e r and M i c h e n e r 1973). J u v e n i l e f e m a l e s a l w a y s o c c u p i e d b u r r o w s c l o s e r t o t h e i r m o thers t h a n j u v e n i l e m a l e s . F u r t h e r , j u v e n i l e males whose mother d i e d , d i d n o t move l o n g d i s t a n c e s away from t h e n a t a l burrow, whereas j u v e n i l e males whose mothers were s t i l l a l i v e , d i d . S i m i l a r l y , C a r l (1971) has s u g g e s t e d t h a t a g o n i s t i c i n t e r a c t i o n s by a mother t o w a r d s h e r young, r e s u l t i n t h e d i s p e r s a l o f young away from h e r f a l l t e r r i t o r y and h i b e r n a c u l u m . In summary, s o c i a l i n t e r a c t i o n s a p p e a r t o be an i m p o r t a n t u l t i m a t e c a u s e o f d i s p e r s a l i n A r c t i c g r o u n d s g u i r r e l s . I n t e r a c t i o n r a t e s a n d maximum p o p u l a t i o n d e n s i t i e s f o r b o t h c o n t r o l a r e a s s u g g e s t t h a t s o c i a l b e h a v i o u r and p o p u l a t i o n c h a n g e s i n A r c t i c g round s g u i r r e l s may be r e l a t e d . S i m i l a r r e l a t i o n s h i p s have been r e p o r t e d i n S. a r m a t u s ( S l a d e and B a l p h 1974) and M. f l a v i v e n t r i s ( A r m i t a g e 1 9 7 4 ) . Age, s e x , and g e n e t i c r e l a t e d n e s s a r e i m p o r t a n t f a c t o r s i n t h e i n i t i a t i o n and r e c e i v i n g o f s o c i a l i n t e r a c t i o n s . R e s i d e n t and d i s p e r s i n g a n i m a l s t e n d e d t o i n t e r a c t l a r g e l y w i t h and r e c e i v e a g o n i s t i c i n t e r a c t i o n s f r o m , a n i m a l s o f a s i m i l a r age and s e x . A m i c a b l e i n t e r a c t i o n s were more common between r e l a t e d a n i m a l s t h a n u n r e l a t e d a n i m a l s , whereas a g o n i s t i c i n t e r a c t i o n s were common between r e l a t e d and u n r e l a t e d a n i m a l s . A g o n i s t i c 173 i n t e r a c t i o n s between u n r e l a t e d a n i m a l s were more p h y s i c a l l y a g g r e s s i v e however. D i s p e r s i n g a d u l t m a l e s a r e most l i k e l y a n i m a l s w h i c h were n o t a b l e t o o b t a i n s p r i n g b r e e d i n g t e r r i t o r i e s o r h i b e r n a c u l a . D i s p e r s i n g mature f e m a l e s on t h e o t h e r hand were o f t e n f e m a l e s t h a t f a i l e d t o s u c c e s s f u l l y r e p r o d u c e . The e x a c t c a u s e o f mature f e m a l e d i s p e r s a l i s n o t known. Mature a n i m a l : j u v e n i l e i n t e r a c t i o n s l i k e l y f o r c e j u v e n i l e s away from t h e n a t a l burrow. O f t e n j u v e n i l e f e m a l e s r e m a i n i n t h e v i c i n i t y o f t h e i r n a t a l b urrow and so r e l a t e d f e m a l e s o c i a l c o m p l e x e s a r e common. D i s p e r s i n g j u v e n i l e males a r e o f t e n l a r g e r t h a n r e s i d e n t j u v e n i l e m ales s u g g e s t i n g t h a t l a r g e r j u v e n i l e s a r e more l i k e l y t o e l i c i t mature a n i m a l a g g r e s s i o n . S m a l l e r a n i m a l s may a v o i d mature a n i m a l a g g r e s s i o n a s a r e s u l t o f mature a n i m a l s e n t e r i n g h i b e r n a t i o n . Most j u v e n i l e males and some j u v e n i l e f e m a l e s a r e f o r c e d t o move t o p e r i p h e r a l a r e a s o f t h e c o l o n y . T h e r e j u v e n i l e : j u v e n i l e c o m p e t i t i o n f o r v a c a n t h i b e r n a c u l u m may be i n t e n s e and so be an i m p o r t a n t c a u s e o f j u v e n i l e d i s p e r s a l i n A u g u s t . 174 P o p u l a t i o n R e g u l a t i o n and D i s p e r s a l C a r l (1971) c o n c l u d e d t h a t " b a s e d on a complex p a t t e r n o f s o c i a l b e h a v i o u r , c o l o n i a l p o p u l a t i o n s o f ( A r c t i c ground) s g u i r r e l s r e c r u i t members by r e p r o d u c t i o n and l o s e by e m i g r a t i o n w h i l e b u f f e r i n g t h e m s e l v e s from i m m i g r a t i o n and l o s s by m o r t a l i t y " . F u r t h e r , he p r o p o s e d t h a t t h e maximum p o p u l a t i o n s i z e was d e t e r m i n e d by t h e number o f s u i t a b l e b r e e d i n g b u r r o w s and s o t h e t h e number o f b r e e d i n g f e m a l e s . A r c t i c g r o u n d s g u i r r e l s i n t h e K l u a n e r e g i o n showed many s i m i l a r i t i e s t o t h o s e s t u d i e d by C a r l (1971) a t P t . Barrow, A l a s k a . R e c r u i t m e n t o f young f o l l o w e d s i m i l a r s e a s o n a l p a t t e r n s as d i d peaks o f e m i g r a t i o n and i m m i g r a t i o n . R e l a t i v e m a g n i t u d e s o f d i s p e r s a l w i t h i n e a c h age and s e x c l a s s were a l s o s i m i l a r . L o s s due t o m o r t a l i t y was g r e a t e s t o v e r - w i n t e r . P r e d a t i o n was an i m p o r t a n t s o u r c e o f l o s s o f v e r y young a n i m a l s a s w e l l as o f d i s p e r s i n g a n i m a l s and a n i m a l s i n t e m p o r a r y h a b i t a t s . I n t h e K l u a n e r e g i o n , h o w e v e r , t h e number o f b r e e d i n g b u r r o w s d i d n o t a p p e a r t o be t h e o n l y l i m i t i n g f a c t o r . L a r g e d i f f e r e n c e s i n d e n s i t y were n o t e d between t h e S l i m s R i v e r and t h e C o i n C r e e k a r e a s , t h e d e n s i t y o f a n i m a l s on t h e l a t t e r b e i n g a p p r o x i m a t e l y s i x t i m e s t h a t on t h e f o r m e r a r e a . On SRC, s e v e r a l o f t h e m a j o r burrow s y s t e m s were v a c a n t a n d were use d l i t t l e t h r o u g h o u t t h e two and a h a l f y e a r p e r i o d o f t h i s s t u d y . On CCC, few b u r r o w s were v a c a n t . B r e e d i n g b u r r o w s as w e l l a s s u i t a b l e h i b e r n a c u l a may be l i m i t i n g f a c t o r s on CCC. I f c o m p e t i t i o n f o r b u r r o w s does l e a d t o d i s p e r s a l , one would e x p e c t few a n i m a l s on SRC t o d i s p e r s e . The low d e n s i t y o f a n i m a l s and 175 t h e f a i l u r e o f a n i m a l s t o o c c u p y v a c a n t b u r r o w s on SBC s u g g e s t t h a t o t h e r f a c t o r s may be i m p o r t a n t . D o r r a n c e and K e i t h (1974) s u g g e s t e d f o o d a s a l i m i t i n g f a c t o r i n S. r i c h a r d s o n i . Food may a l s o be l i m i t i n g on SRC. On SRC, a number o f h e r b i v o r e s a r e p o s s i b l e c o m p e t i t o r s c f A r c t i c g r o u n d s q u i r r e l s . D a l l Sheep ( O v i s d a l l i ) f r e g u e n t t h e v i c i n i t y o f my s t u d y a r e a s ; t h i s a r e a b e i n g an i m p o r t a n t o v e r - w i n t e r i n g r a n g e f o r t h e rams. As t h e d i e t o f D a l l Sheep (M. H o e f s 1976) i n c l u d e s many o f t h e i m p o r t a n t f o o d s p e c i e s o f A r c t i c g r o u n d s g u i r r e l s o b s e r v e d i n t h i s s t u d y ( i e . C a r e x sja., A r t e m e s i a f r i g j d a ) , t h e p o t e n t i a l f o r c o m p e t i t i o n e x i s t s . E u t a m i a s minimus and Peromyscus m a n i c u l a t u s a r e r e l a t i v e l y a b u n d a n t t h r o u g h o u t t h e same a r e a and a r e a l s o p o t e n t i a l c o m p e t i t o r s f o r many o f t h e major f o o d s p e c i e s of A r c t i c g r o u n d s q u i r r e l s . M. H o e u f s ( p e r s . comm.) has s u q q e s t e d t h a t i n r e c e n t y e a r s , t h e S l i m s R i v e r a r e a h a s become o v e r q r a z e d . T h i s , i n i t s e l f , would i n t e n s i f y any c o m p e t i t i o n between t h e s e h e r b i v o r e s . I s u q q e s t t h e n t h a t on S E C , f o o d r e s o u r c e s have s e t an upper l i m i t t o t h e p o p u l a t i o n s i z e . On CCC, however, s h e e p q r a z i n q was m i n i m a l compared to t h a t o b s e r v e d on SEC and i n q e n e r a l , t h e v e g e t a t i o n i s much more dense on CCC t h a n on SRC. Some f o o d t y p e s a r e s i m i l a r ( i e . A r t e m e s i a f r i q i d a . C a r e x s p . , and Penstemmon g o r m a n i i ) b u t s e v e r a l s p e c i e s , h i q h i y u t i l i z e d by s q u i r r e l s were o n l y a v a i l a b l e on CCC ( i e . D r y a s s p . , S a l i x s p . and A r c t o s t a p h v l o s r u b r a ) . Food r e s o u r c e s on CCC a p p e a r t o be much more a b u n d a n t t h a n on.SRC.and I. b e l i e v e . t h e . . a v a i l a b i l i t y o f b u r r o w s i s a more i m p o r t a n t , p r o x i m a t e l i m i t i n q f a c t o r * . 176 The r e l a t i o n s h i p between t h e a v a i l a b i l i t y o f b u r r o w s and s u f f i c i e n t f o o d r e s o u r c e s may be i m p o r t a n t i n t h e d e t e r m i n a t i o n o f maximum p o p u l a t i o n s i z e . When f o o d i s abundant t h e number o f e x i s t i n g and p o t e n t i a l burrow s i t e s would l i m i t t h e p o p u l a t i o n s i z e . I b e l i e v e t h i s i s t h e c a s e on CCC. As a r e s u l t , t h e r e c r u i t m e n t o f j u v e n i l e s would depend on t h e number o f v a c a n t b u r r o w s c r e a t e d by t h e l o s s o f mature a n i m a l s . E x c e s s young would be f o r c e d t o d i s p e r s e . When t h e q u a l i t y o r g u a n t i t y o f f o o d d e c r e a s e s however, s o c i a l mechanisms, s u c h a s i n c r e a s e d t e r r i t o r y s i z e , would l e a d t o a d e c r e a s e i n p o p u l a t i o n s i z e t h u s l e a v i n g some s i t e s v a c a n t . I b e l i e v e t h i s h a s o c c u r r e d on SBC. D e s p i t e t h e e x c e s s b u r r o w s , young a r e f o r c e d t o d i s p e r s e and o n l y when o c c u p i e d s i t e s become v a c a n t , do young r e c r u i t t o t h e b r e e d i n g p o p u l a t i o n . T h e r e i s t h e p o s s i b i l i t y however t h a t young which a r e a b l e t o s u c c e s s f u l l y c h a l l e n g e t e r r i t o r i a l a n i m a l s , do r e c r u i t t o t h e b r e e d i n g p o p u l a t i o n . I n b o t h c a s e s , d i s p e r s a l as a r e s u l t o f s o c i a l s t r e s s i s t h e l i k e l y u l t i m a t e r e g u l a t i n g mechanism. D i s p e r s a l i s common i n many s p e c i e s o f g r o u n d s g u i r r e l s , marmots, and o t h e r s m a l l mammals, s u g g e s t i n g t h a t d i s p e r s a l may i n d e e d be o f some a d a p t i v e s i g n i f i c a n c e . Howard (1960) s u g g e s t e d t h a t g e n e t i c p o l y m o r p h i s m s f o r d i s p e r s a l t e n d e n c i e s may e x i s t w i t h i n s m a l l mammal p o p u l a t i o n s . He t e rmed a n i m a l s l i k e l y t o e m i g r a t e f r o m a p o p u l a t i o n due t o g e n o t y p i c e f f e c t s , i n n a t e d i s p e r s e r s . A n i m a l s e m i g r a t i n g i n r e s p o n s e t o i n c r e a s e d d e n s i t i e s ( i e . c o m p e t i t i o n f o r mates, t e r r i t o r i a l i t y , l a c k o f h o m e s i t e s , s o c i a l i n t e r a c t i o n s e t c . ) were t e r m e d e n v i r o n m e n t a l d i s p e r s e r s . I n n a t e d i s p e r s a l i s i n d e p e n d e n t o f d e n s i t y whereas 177 e n v i r o n m e n t a l d i s p e r s a l i s d e n s i t y d e p e n d e n t . Murray (1967) f e l t t h a t t h e o b s e r v e d non-random d i s t r i b u t i o n o f d i s p e r s a l d i s t a n c e s was d e t e r m i n e d by t h e d i s t r i b u t i o n o f b r e e d i n g s i t e s u n o c c u p i e d by dominant a n i m a l s . Dominant a n i m a l s were a b l e t o r e p r o d u c e on o r n e a r t h e c o l o n y whereas s u b o r d i n a t e a n i m a l s c o u l d maximize t h e i r c h a n c e s o f r e p r o d u c i n g by moving away from t h e i r b i r t h s i t e . D i s p e r s a l p o l y m o r p h i s m s were t h e r e s u l t t h e n , o f b e h a v i o u r a l d i f f e r e n c e s . I t i s n o t known, however, i f b e h a v i o u r a l d i f f e r e n c e s a r e g e n e t i c a l l y c o n t r o l l e d . B e k o f f (1977) a g r e e d t h a t d i s p e r s i n g a n i m a l s may m a ximize t h e i r c h a n c e s o f r e p r o d u c t i v e s u c c e s s t h r o u g h d i s p e r s a l b u t t h o u g h t t h a t d i s p e r s i n g a n i m a l s were n o t a l w a y s s u b o r d i n a t e . I n s t e a d , he s u g g e s t e d t h a t a n i m a l s f a i l i n g t o d e v e l o p s o c i a l t i e s were more l i k e l y t o d i s p e r s e . Group s e l e c t i o n has been s u g g e s t e d as a means o f e x p l a i n i n g i n d i v i d u a l d i s p e r s a l t e n d e n c i e s (Wynne-Edwards 1962, Howard 19 6 0 ) . L i d i c k e r (1962) however, s u g g e s t e d t h a t t h e r e were s e v e r a l a d v a n t a g e s t o t h e i n d i v i d u a l t h a t d i s p e r s e d . D i s p e r s i n g a n i m a l s m i g h t come i n t o c o n t a c t w i t h more c o n s p e c i f i c s and so b r e e d more o f t e n . F u r t h e r , d i s p e r s a l would l e a d t o t h e t r a n s f e r o f g e n e t i c m a t e r i a l and so i n c r e a s e t h e c h a n c e s o f p r o d u c i n g new, a d v a n t a g e o u s r e c o m b i n a t i o n s ( o f f s p r i n g may be more h e t e r o z y g o u s a n d s o may be more f i t ) . D i s p e r s i n g a n i m a l s t o o may be a b l e t o a v o i d p o p u l a t i o n d e c l i n e s or l o c a l e x t i n c t i o n s . , The w i d e s p r e a d d i s p e r s a l o f j u v e n i l e males and t h e l i m i t e d d i s p e r s a l o f j u v e n i l e f e m a l e s i n A r c t i c g r o u n d s g u i r r e l s o f f e r some s u p p o r t t o s e v e r a l o f t h e s e t h e o r i e s . T h r o u g h o u t most o f i t s r a n g e , A r c t i c g r o u n d s q u i r r e l s f a c e a r e l a t i v e l y s h o r t 1 7 8 a c t i v e s e a s o n i n w h i c h t h e y must r e p r o d u c e b u t s t i l l a c q u i r e s u f f i c i e n t f a t s t o r e s t o s u r v i v e t h r o u g h t h e w i n t e r . Male r e p r o d u c t i v e c o s t s a r e l o w e r t h a n t h a t o f t h e f e m a l e y e t males have a l o n g e r p e r i o d t o r e p l e n i s h t h e i r f a t s t o r e s . D i s p e r s a l i s presumed t o be e n e r g e t i c a l l y e x p e n s i v e . M a l e s would be more a b l e t o " a f f o r d " t o d i s p e r s e and s t i l l be a b l e t o r e p r o d u c e t h e f o l l o w i n g s p r i n g . F u r t h e r , i n a polygamous m a t i n g s y s t e m , d a u g h t e r s would more l i k e l y be a b l e t o s u c c e s s f u l l y r e p r o d u c e . S ons would have t o compete w i t h t h e i r f a t h e r o r o t h e r males and s o would maximize t h e i r c h a n c e s o f r e p r o d u c t i o n by d i s p e r s a l . The c h a n c e s o f s u c c e s s f u l d i s p e r s a l may be low b u t s u c c e s s f u l male d i s p e r s e r s ( i e . t h o s e o b t a i n i n g a t e r r i t o r y e l s e w h e r e ) would have a h i g h p r o b a l i t y o f f a t h e r i n g many young and s o would be g e n e t i c a l l y more f i t ( C a r l 197 1 ) . L i t t l e i s known o f t h e i m p o r t a n c e o f d i s p e r s a l i n t h e t r a n s f e r o f g e n e t i c m a t e r i a l between p o p u l a t i o n s o f s m a l l mammals. Myers (1974) s t u d i e d p o p u l a t i o n s o f f e r a l Mus m n s c u l u s and c o n c l u d e d t h a t on t h e b a s i s o f s e v e r a l p o l y m o r p h i c b l o o d p r o t e i n s , t h a t d i s p e r s a l d i d l e a d t o t h e t r a n s f e r o f g e n e t i c m a t e r i a l between s u b p o p u l a t i o n s . M i c h e n e r and M i c h e n e r (1977) compared t h e f r e g u e n c y o f t h r e e t r a n s f e r r i n a l l e l e s i n j u v e n i l e and a d u l t s g u i r r e l s , males and f e m a l e s and i n r e s i d e n t v e r s u s i m m i g r a t i n g (unmarked) i n d i v i d u a l s . No s i g n i f i c a n t d i f f e r e n c e s were f o u n d . B o t h e x t r i n s i c and i n t r i n s i c f a c t o r s a p p e a r t o be i m p o r t a n t t o t h e p o p u l a t i o n r e g u l a t i o n o f A r c t i c g r o u n d s g u i r r e l s ( C a r l 1971, t h i s s t u d y ) . I would l i k e t o p r o p o s e a g r a p h i c a l model o f p o p u l a t i o n r e g u l a t i o n b a s e d on t h e r e l a t i o n s h i p between 179 d e m o g r a p h i c c h a n g e s and s o c i a l b e h a v i o u r o b s e r v e d i n t h i s and o t h e r g r o u n d s g u i r r e l s t u d i e s . A Model Of P o p u l a t i o n R e g u l a t i o n I n A r c t i c Ground S g u i r r e l s I n t h e e a r l y s p r i n g , j u s t a f t e r e m e r g e n c e , t h e mature a n i m a l p o p u l a t i o n s i z e i s d e t e r m i n e d by t h e number o f mature and j u v e n i l e a n i m a l s s u r v i v i n g o v e r - w i n t e r { F i g . 3 0 ) . The number o f j u v e n i l e s s u c c e s s f u l l y r e c r u i t i n g t o t h e mature r e s i d e n t a n i m a l p o p u l a t i o n i s s i m i l a r l y d e t e r m i n e d by t h e number o f v a c a n t t e r r i t o r i e s as a r e s u l t o f o v e r - w i n t e r mature a n i m a l m o r t a l i t y . M ales compete f o r b r e e d i n g t e r r i t o r i e s i n t h e e a r l y s p r i n g w i t h t h e l a r g e r and l o n g e r - r e s i d e n c y a n i m a l s more l i k e l y t o win t e r r i t o r i a l e n c o u n t e r s (Watton and K e e n l e y s i d e 1974). Y e a r l i n g m ales t h u s h a v e a l o w e r p r o b a b i l i t y o f r e c r u i t i n g t o t h e r e s i d e n t b r e e d i n g p o p u l a t i o n . The e s t a b l i s h m e n t o f f e m a l e t e r r i t o r i e s i n v o l v e s l e s s p h y s i c a l a g g r e s s i o n t h a n males and d a u g h t e r s a r e o f t e n a l l o w e d t o r e m a i n i n t h e v i c i n i t y o f t h e m o t h e r ' s b u r r o w . The number a l l o w e d t o r e m a i n on t h e c o l o n y would depend on t h e number o f a v a i l a b l e b r e e d i n g s i t e s . As A r c t i c g round s g u i r r e l s a r e poly g a m o u s , a l l f e m a l e s o b t a i n i n g b r e e d i n g t e r r i t o r i e s a r e b r e d . Male and f e m a l e t e r r i t o r y s i z e may be d e t e r m i n e d by t h e f o o d r e s o u r c e s and burrow a v a i l a b i l i t y . Whereas t h e q u a l i t y o f male t e r r i t o r i e s i s l i k e l y b a s e d on t h e number o f b r e e d i n g f e m a l e s , t h e q u a l i t y o f a f e m a l e b r e e d i n g s i t e i s l i k e l y b a s e d on t h e q u a l i t y o f t h e burrow and f o o d r e s o u r c e s . D u r i n q t h e d e v e l o p m e n t and weaning o f t h e young, b r e e d i n g 180 F i g u r e 30: G r a p h i c a l n o d e l o f p o p u l a t i o n r e g u l a t i o n i n A r c t i c g r o u n d s g u i r r e l s . The model i s d e s c r i b e d i n t h e t e x t . R e c r u i t m e n t t o t h e p o p u l a t i o n due t o b i r t h o r i m m i g r a t i o n i s i n d i c a t e d w i t h d o t t e d l i n e s . l o s s f r o m t h e p o p u l a t i o n due t o e m i g r a t i o n o r o t h e r m o r t a l i t y f a c t o r s i s i n d i c a t e d w i t h a dashed l i n e . , Waved l i n e s i n d i c a t e t h e p e r i o d s where e x t r i n s i c f a c t o r s may be i m p o r t a n t t o p o p u l a t i o n l i m i t a t i o n . The ' f o l l o w i n g e x t r i n s i c f a c t o r s a r e l i k e l y i m p o r t a n t a t : 1. The number o f v a c a n t b r e e d i n g t e r r i t o r i e s . , 2. The number o f h i b e r n a c u l a . 3 . , H i b e r n a c u l u m q u a l i t y , f a t s t o r e s a n d e x p o s u r e . 181 Spring # MATURE ANIMALS AT EMERGENCE •EMIGRATION IMMIGRATION # BREEDING RESIDENT ANIMALS BIRTH OF YOUNG EMIGRATION MATURE FEMALES SUMMER POPULATION IMMIGRATION OF JUVENILES (•<*•> 9 ) IN LATE SUMMER # IN FALL WITH HIBERNACULA LOSS OF YOUNG TO PREDATION Summer DISPERSAL OF . JUVENILES (o*> 9) Fall 182 f e m a l e s become i n c r e a s i n g l y more a g g r e s s i v e , p r e s u m a b l y t o m i n i m i z e d i s t u r b a n c e o f t h e young. F e m a l e s which f o r some r e a s o n f a i l t o r e p r o d u c e , d i s p e r s e . When t h e young emerge, a m i c a b l e s o c i a l c o n t a c t between mother and young and between s i b l i n g young i s h i g h and f a m i l y u n i t s a r e m a i n t a i n e d . Some l o s s o f young due t o p r e d a t i o n o c c u r s s h o r t l y a f t e r emergence when young a r e most s u s c e p t i b l e t o p r e d a t i o n . I n A u g u s t , f a l l t e r r i t o r i e s and h i b e r n a c u l u m " r i g h t s " a r e e s t a b l i s h e d . R e s i d e n t a d u l t a n i m a l s a p p e a r t o r e c o g n i z e t e r r i t o r i e s w hereas j u v e n i l e s do n o t . As a r e s u l t , most i n t e r a c t i o n s d u r i n g t h i s p e r i o d i n v o l v e j u v e n i l e s and a d u l t s . L a r g e r j u v e n i l e s , p a r t i c u l a r l y j u v e n i l e m a l e s a p p r o a c h a d u l t " s i z e " s o o n e r and so r e c e i v e more a g o n i s t i c b e h a v i o u r i n i t i a t e d by a d u l t s . As a r e s u l t t h e y a r e more l i k e l y t o d i s p e r s e . Whereas j u v e n i l e males compete w i t h t e r r i t o r i a l m a l e s , j u v e n i l e f e m a l e s b e n e f i t a male by i n c r e a s i n g h i s d e g r e e o f polygamy {Downhower and A r m i t a g e 1971) and so r e c e i v e l e s s a g o n i s t i c b e h a v i o u r f r o m t h e t e r r i t o r i a l male t h a n j u v e n i l e males. J u v e n i l e f e m a l e s may s i m i l a r l y compete w i t h r e s i d e n t mature f e m a l e s b u t i f a l l o w e d t o r e m a i n on t h e c o l o n y , e n s u r e m oderate r e p r o d u c t i v e s u c c e s s f o r h e r mother. Some j u v e n i l e f e m a l e s a r e as a r e s u l t , a l l o w e d t o r e m a i n n e a r t h e i r b i r t h s i t e , whereas a l m o s t a l l j u v e n i l e males a r e f o r c e d t o move. J u v e n i l e a n i m a l s f o r c e d away f r o m t h e n a t a l b u r r o w and n o t a b l e t o o b t a i n and h o l d a n o t h e r h i b e r n a c u l a on t h e c o l o n y may move i n t o p e r i p h e r a l a r e a s o r i n t e r - t e r r i t o r i a l s i t e s . H i b e r n a c u l a may be l i m i t i n g and hence j u v e n i l e : j u v e n i l e i n t e r a c t i o n s i n c r e a s e . J u v e n i l e s f a i l i n g t o o b t a i n a h i b e r n a c u l u m d i s p e r s e . O v e r - w i n t e r s u r v i v a l i s t h e n d e t e r m i n e d 183 by e n v i r o n m e n t a l c o n d i t i o n s , h i b e r n a c u l a s u i t a b i l i t y and amount o f f a t s t o r e s . , A d j u s t m e n t s t o i n c r e a s e d d e n s i t y o r d e c r e a s e d d e n s i t y a r e p o s s i b l e t h r o u g h s o c i a l b e h a v i o u r s as s u g g e s t e d by B a r a s h {1974). I f o v e r ^ w i n t e r s u r v i v a l i s h i g h , few v a c a n t t e r r i t o r i e s on t h e c o l o n y a r e a v a i l a b l e and d i s p e r s a l d u r i n g t h e s p r i n g p e r i o d i s h i g h . C o n v e r s e l y , i f o v e r - w i n t e r s u r v i v a l i s low, many v a c a n t p o s i t i o n s a r e a v a i l a b l e and d i s p e r s a l w i l l be low. The a d u l t r e s i d e n t p o p u l a t i o n i s t h u s k e p t a t r e l a t i v e l y c c n s t a n t numbers. In c a s e s where o v e r - w i n t e r s u r v i v a l i s low and y e a r l i n g r e c r u i t m e n t i s i n s u f f i c i e n t t o occupy a l l t e r r i t o r i e s , i m m i g r a t i o n f r o m o t h e r c o l o n i e s may moderate t h e l o s s . a l t h o u g h I have shown t h a t d e f i n i t e s e a s o n a l p eaks o f d i s p e r s a l o c c u r i n e a c h age and s e x c l a s s o f a r c t i c g r o u n d s g u i r r e l s i n t h e K l u a n e r e g i o n , I c o u l d o n l y e s t i m a t e t h e r e l a t i v e m a g n i t u d e s o f l o s s e s due t o d i s p e r s a l , p r e d a t i o n and o t h e r f o r m s o f m o r t a l i t y . He need t o know more o f t h e m a g n i t u d e and i m p o r t a n c e o f l o s s e s due t o p r e d a t i o n and o v e r - w i n t e r m o r t a l i t y t o p o p u l a t i o n c h a n g e . S i m i l a r l y , I was n o t a b l e t o show t h a t d e f i n i t e m o r p h o l o g i c a l o r b e h a v i o u r a l d i f f e r e n c e s o c c u r r e d between r e s i d e n t and d i s p e r s i n g a n i m a l s . Some i n t e r e s t i n g and s u g g e s t i v e t r e n d s were a p p a r e n t b u t f u r t h e r e v i d e n c e i s needed t o d e t e r m i n e i f t h e s e t r e n d s a r e r e a l . P a r t i c u l a r l y , t h e r e l a t i o n s h i p s between body s i z e , b r e e d i n g c o n d i t i o n , s o c i a l b e h a v i o u r s , and d i s p e r s a l t e n d e n c i e s must be c l a r i f i e d . The c o l l e c t i o n o f a d e q u a t e d e m o g r a p h i c i n f o r m a t i o n i s r e l a t i v e l y e a s y whereas t h e c o l l e c t i o n o f a d e q u a t e b e h a v i o u r a l 181 i n f o r m a t i o n i s n o t . The c o l l e c t i o n o f i n f o r m a t i o n p e r t a i n i n g t o t h e s o c i a l i n t e r a c t i o n s o f e v e n a s m a l l g r o u p o f a n i m a l s i s t i m e - c o n s u m i n g . New methods o f b e h a v i o u r a l d a t a c o l l e c t i o n a r e now b e c o m i n g a v a i l a b l e ( i e . b e h a v i o u r a l c o d i n g d i g i t i z e r s (Gass 1976)) p e r m i t t i n g a l m o s t c o n t i n u o u s o b s e r v a t i o n s . W i t h s u c h a i d s a s t h e s e a n d / o r ample manpower, s u f f i c i e n t b e h a v i o r 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 , p a r t i c u l a r l y t h e s o c i a l i n t e r a c t i o n s b u d g e t s , c o u l d be o b t a i n e d . We need t o c l a r i f y t h e r e l a t i o n s h i p o f a m i c a b l e and a g o n i s t i c b e h a v i o u r as w e l l as t h e i n t e n s i t y o f t h e s e b e h a v i o u r s , t o d i s p e r s a l . Age, s e x , and p e r h a p s most i m p o r t a n t , g e n e t i c r e l a t e d n e s s must be c o n s i d e r e d i n any s t u d y o f t h e r e l a t i o n s h i p s between s o c i a l b e h a v i o u r and p o p u l a t i o n r e g u l a t i o n . Ground s g u i r r e l s , p a r t i c u l a r l y A r c t i c g r o u n d s g u i r r e l s a r e e a s y t o t r a p * a r e r e a d i l y o b s e r v a b l e , and a r e s u f f i c i e n t l y a b undant t o o b t a i n a d e q u a t e i n f o r m a t i o n o f t h i s s o r t . C o n t i n u e d s t u d y w i l l h o p e f u l l y p r o v i d e t h e i n f o r m a t i o n needed t o d e t e r m i n e i f i n d e e d s o c i a l b e h a v i o u r i s a c r i t i c a l f a c t o r t o t h e i n i t i a t i o n o f d i s p e r s a l and t h e r e g u l a t i o n o f p o p u l a t i o n s i z e i n s m a l l mammals. 185 CONCLUSIONS S o c i a l b e h a v i o u r s , p a r t i c u l a r l y a g g r e s s i v e b e h a v i o u r s , a r e p o t e n t i a l l y t h e major c a u s e o f d i s p e r s a l i n a r c t i c g r o u n d s g u i r r e l s . a d u l t : j u v e n i l e a g o n i s t i c i n t e r a c t i o n s f o r c e young t o move t o p e r i p h e r a l a r e a s o r i n t e r - t e r r i t o r i a l a r e a s c f t h e c o l o n y . T h e r e , j u v e n i l e : j u v e n i l e a g o n i s t i c i n t e r a c t i o n s a r e l i k e l y an i m p o r t a n t c a u s e o f more w i d e s p r e a d j u v e n i l e d i s p e r s a l . Body s i z e and r e p r o d u c t i v e s u c c e s s were r e l a t e d t o d i s p e r s a l o f j u v e n i l e m ales and mature f e m a l e s r e s p e c t i v e l y . No c o n c l u s i v e t r e n d s were a p p a r e n t i n mature males o r j u v e n i l e f e m a l e s . I t i s s u g g e s t e d t h a t t h e a t t a i n m e n t o f an " a d u l t " body s i z e l e a d s t o a s h a r p i n c r e a s e i n a d u l t : j u v e n i l e a g g r e s s i o n . The " a d u l t " body s i z e may, as B a r a s h (1974) has s u g g e s t e d , be r e l a t e d t o an o p t i m a l s i z e f o r s u c c e s s f u l d i s p e r s a l and r e p r o d u c t i o n . The r e l a t i o n s h i p between mature f e m a l e d i s p e r s a l and r e p r o d u c t i v e s u c c e s s i s u n c l e a r and f u r t h e r s t u d y i s needed. B e h a v i o u r a l p a r a m e t e r s i n d i c a t e d t h a t d i s p e r s i n g a n i m a l s r e c e i v e more and i n i t i a t e l e s s a g g r e s s i v e b e h a v i o u r t h a n r e s i d e n t a n i m a l s . T h i s s u g g e s t s t h a t d i s p e r s i n g a n i m a l s a r e s u b o r d i n a t e t o r e s i d e n t a n i m a l s . S o c i a l i n t e r a c t i o n b u d g e t s f o r e a c h c l a s s i n d i c a t e t h a t age, s e x and g e n e t i c - r e l a t e d n e s s a r e i m p o r t a n t f a c t o r s i n s o c i a l i n t e r a c t i o n s and hence d i s p e r s a l . They must be c o n s i d e r e d t h e n i n any s t u d y o f t h e mechanisms o f p o p u l a t i o n r e g u l a t i o n i n A r c t i c g r o u n d s g u i r r e l s . C o h o r t s u r v i v a l and t h e o r i g i n s o f r e s i d e n t a d u l t a n i m a l s i n d i c a t e d t h a t i n A r c t i c g r o u n d s g u i r r e l s , males a r e more l i k e l y t o move between c o l o n i e s whereas mature f e m a l e s a r e more 186 l i k e l y t o r e m a i n n e a r t h e i r s i t e o f b i r t h . As a r e s u l t , r e s i d e n t a d u l t males a r e o f t e n n o t r e l a t e d t o r e s i d e n t a d u l t f e m a l e s , whereas r e s i d e n t f e m a l e s a r e o f t e n c l o s e l y r e l a t e d t o o t h e r f e m a l e s i n h a b i t i n g b u r r o w s n e a r b y . R e l a t e d f e m a l e s o c i a l c o m p l e x e s were common i n b o t h o f t h e p o p u l a t i o n s I s t u d i e d . The o v e r a l l s u g g e s t i o n , i s . , t h a t a g r e a t e r p r o p o r t i o n o f t h e i n t e r - c o l o n y movement o f g e n e t i c m a t e r i a l i s due t o male d i s p e r s a l b u t f u r t h e r s t u d y i s r e g u i r e d . S o c i a l b e h a v i o u r s a r e s t r o n g l y i m p l i c a t e d a s t h e c a u s e o f d i s p e r s a l and t h e s u b s e q u e n t r e g u l a t i o n o f p o p u l a t i o n c h a n g e s , we need more i n f o r m a t i o n however, c o n c e r n i n g : 1. The r e l a t i o n s h i p o f r a t e s and i n t e n s i t i e s o f a g o n i s t i c and a m i c a b l e b e h a v i o u r to d i s p e r s a l and p o p u l a t i o n r e g u l a t i o n . 2. The r e l a t i o n s h i p between g e n e t i c r e l a t e d n e s s and d i s p e r s a l . 3. The r e l a t i o n s h i p o f a d u l t f e m a l e r e p r o d u c t i v e s u c c e s s t o d i s p e r s a l o f mature f e m a l e s . 4. The r e l a t i o n s h i p between f o o d r e s o u r c e s and burrow ( h i b e r n a c u l a ) a v a i l a b i l i t y and i t s i m p o r t a n c e t o p o p u l a t i o n l i m i t a t i o n . 5. The i m p o r t a n c e o f o v e r - w i n t e r s u r v i v a l t o p o p u l a t i o n c h a n g e . 6. The i m p o r t a n c e o f i n t e r s p e c i f i c p r e d a t i o n t o p o p u l a t i o n c h a n g e s , p a r t i c u l a r l y t h e e f f e c t on d i s p e r s i n g a n i m a l s . I n c l u d e f m t . s t a r t 187 LITERATURE CITED Adams,G.D..1961. Ec o l o g y o f t h e Columbian ground s g u i r r e l i n the Sheep R i v e r r e g i o n . MSc. T h e s i s . Univ. o f A l b e r t a . Altmann, J . 1974. O b s e r v a t i o n a l s t u d y o f b e h a v i o u r : s a m p l i n g methods. B e h a v i o u r 49:227-267. Armitage K.B. 1962. S o c i a l b e h a v i o u r o f a c o l o n y o f y e l l o w - b e l l i e d marmot (Marmota f l a v i v e n t r i s ) . Anim. Behav. 10:319-331. 1973. P o p u l a t i o n changes and s o c i a l b e h a v i o u r f o l l o w i n g c o l o n i z a t i o n by t h e y e l l o w - b e l l i e d marmot. J . Mammal 54:842-854. 1974. Male b e h a v i o u r and t e r r i t o r i a l i t y i n t h e y e l l o w b e l l i e d marmot. J . Z o o l . Lond. 172x233-265. 1975. S o c i a l b e h a v i o u r and p o p u l a t i o n dynamics o f marmots. Oikos 26:341-354. and J.F. Downhower 1974. Demography o f y e l l o w b e l l i e d marmot (Marmota f l a v i v e n t r i s ) . E c o l . 55:1233-1245. J.F. Downhower and G.E. Svendson 1975.. S e a s o n a l changes i n t h e w e i g h t s o f y e l l o w b e l l i e d marmots. Am. M i d i . Nat. Balph,D.M. And D.F. B a l p h 1966. Sound communication o f U i n t a ground s g u i r r e l s . J . Mammal. 47:440-450. and A.w. Stokes 1963. On t h e e t h o l o g y o f a p o p u l a t i o n o f U i n t a ground s g u i r r e l s . Am. M i d i . Nat. 69:106-126. B a r a s h , .0.P.. .1974: the e v o l u t i o n of marmot s o c i e t i e s : a g e n e r a l t h e o r y . S c i e n c e 185:415-420. 1975. E c o l o g y o f p a t e r n a l b e h a v i o u r i n t h e Hoary Marmot (Mamota c a l i g a t a ) : a e v o l u t i o n a r y i n t e r p r e t a t i o n . J . Mammal. 56:613-618. B e k o f f , M. 1977a. S o c i a l development , s o c i a l bonding and d i s p e r s a l i n c a n i d s : t h e s i g n i f i c a n c e o f s p e c i e s and i n d i v i d u a l d i f f e r e n c e s i n b e h a v i o u r a l ontogeny. IV I n t e r n a t i o n a l Conference on t h e World C a t s and S o c i o b i o l o g y of C a r n i v o r e s . S e a t t l e , Washington. 1977b. Mammalian d i s p e r s a l and t h e ontogeny of i n d i v i d u a l b e h a v i o u r a l phenotypes. Am. Nat. 111: ( i n pr e s s ) 188 B o s t o c k 1952. G e o l o g y o f t h e n o r t h w e s t Shakwak V a l l e y , Yukon T e r r i t o r y . G e o l o g i c a l S u r v e y o f Canada, Mem. 267p. B r o n s o n F.H. 1964: A g o n i s t i c b e h a v i o u r i n woodchucks. Anim. Behav. 12: 470-478. C a r l , E . A . 1971. P o p u l a t i o n c o n t r o l i n A r c t i c g r o u n d s g u i r r e l s . E c o l . 52:395-413. C h i t t y , D. 1967: The n a t u r a l s e l e c t i o n o f s e l f r e g u l a t o r y b e h a v i o u r i n a n i m a l p o p u l a t i o n s . P r o c . E c o l . , . S o c . A u s t r a l i a . 2:51-78. C l a r k , T.S. 1973. B i c h a r d s o n ' s g r o u n d s g u i r r e l ( S p e r m o p h l i u s r i c h a r d s o n i i ) i n t h e L a r a m i e B a s i n , Wyoming. G r e a t B a s i n Nat. 30:55-73. C r a i g h e a d , J . J . And F.C. C r a i g h e a d 1956. Hawks, o w l s and w i l d l i f e . S t a c k p o l e , H a r r i s b u r g and W i l d l i f e Mgmt. I n s t . W a s h i n g t o n . 443p. D a v i s , D . E . , 1 9 7 6 . . H i b e r n a t i o n i n g r o u n d s g u i r r e l s . Q u a r t . Bev. B i o l . : DeVos, A. And D.I. G i l l e s p i e 1960. A s t u d y o f woodchucks on an O n t a r i o f a r m . Can. F i e l d N a t . 74:130-145. D o n a l d s o n , J . 1977. HSc. T h e s i s . U n i v . Of B.C. ( i n p r e p a r a t i o n ) . D o r r a n c e , M.J. 1974. The a n n u a l c y c l e and p o p u l a t i o n d y n a m i c s o f R i c h a r d s o n ' s g r o u n d s g u i r r e l s . PhD. T h e s i s . U n i v e r s i t y o f W i s c o n s i n , M a d i s o n . 150p. Downhower,J.F. And K.B. A r m i t a g e 1971. The y e l l o w b e l l i e d marmot and t h e e v o l u t i o n o f polygamy. , Am. Nat. 105:353-370. D o u g l a s , G. 1974. Montane z o n e v e g e t a t i o n o f t h e A l s e k R i v e r r e g i o n , s o u t h w e s t e r n Yukon. C a n . J . B o t . 52:2505-2532. D r e s c h e r 1967; E n v i r o n m e n t a l i n f l u e n c e s i n t h e i n i t i a t i o n and m a i n t e n a n c e o f h i b e r n a t i o n i n t h e A r c t i c g r o u n d s g u i r r e l , C i t e l l u s u n d u l a t u s . E c o l . . 4 8 : 9 6 2 - 9 6 8 . E l i o t , J . M . 1971. Some methods f o r t h e s t a t i s t i c a l a n a l y s i s o f s a m p l e s o f b e n t h i c i n v e r t e b r a t e s . F r e s h w a t e r B i o l . A s s . S c . Pub. 25: 144p F i t c h , H.S. 1948. E c o l . Of t h e C a l i f o r n i a n G r ound S g u i r r e l on g r a z i n g l a n d s . Am. M i d i . Nat. 39:513-596. 189 G a s s , C. L. 1976. A d i g i t a l e n c o d e r f o r f i e l d r e c o r d i n g o f b e h a v i o u r a l , t e m p o r a l , and s p a t i a l i n f o r m a t i o n i n d i r e c t l y c o mputer a c c e s s i b l e f o r m . Behav. Res. Meth. And I n s t r u m e n t . 9:5-11. H o e f s , M.E.G. 1976. 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E c o l . Res. 8:267-399. I. W i n g a t e , J . LeDuc, J . a . B e d f i e l d , M. T a i t t and R. H i l b o r n . 1974. M i c r o t i n e p o p u l a t i o n b i o l o g y : d i s p e r s a l i n f l u c t u a t i n g p o p u l a t i o n s o f M i c r o t u s t o w n s e n d i . Can. J . Z o o l . 54:79-95. L e i c h l e i t n e r , R . B . , L. Kartman, M.I. G o l d e n b e r t , and B.W. Hudson 1968. An e p i z o o t i c o f p l a g u e i n G u n n i s c n * s p r a i r i e dogs fCynomys g u n n i s o n i ) i n s o u t h c e n t r a l C o l o r a d o . E c o l . 49:734-743. l i d i c k e r , W.Z. J r . 1962. E m i g r a t i o n as a p o s s i b l e mechanism p e r m i t t i n g t h e r e g u l a t i o n o f a p o p u l a t i o n d e n i s t y below c a r r y i n g c a p a c i t y . Amer. Nat. 69:29-33. L i n c o l n B . J . 1972. B e h a v i o u r a l s t u d y o f A r c t i c g r o u n d s g u i r r e l s . IBBP S c i . B e s u l t s 3:245-253. 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An e x p e r i m e n t a l c o m p a r i s o n o f S c r e e c h Owl p r e d a t i o n on r e s i d e n t and t r a n s i e n t w h i t e - f o o t e d mice (Peromyscus l e u c o p u s ) . J . Mammal. 48:387-391. M i c h e n e r , D.B. 1972. P o p u l a t i o n d y n a m i c s o f B i c h a r d s o n ' s g r o u n d s g u i r r e l s . PhD. T h e s i s . U n i v . S a s k . B e g i n a Campus. 116p. 1974. A n n u a l c y c l e o f a c t i v i t y and w e i g h t c h a n g e s i n B i c h a r d s o n ' s g r o u n d s g u i r r e l s , S p e r m o p h l i u s r i c h a r d s o n i . Can. F i e l d N a t . 88:409-413. and G.B. M i c h e n e r 1971., Sex r a t i o and i n t e r - y e a r r e s i d e n c e i n a p o p u l t i o n o f S p e r m o p h l i u s r i c h a r d s o n i . J . Mammal. 5 2:853. M i c h e n e r . G . B . 1972. 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