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Moose-wolf dynamics and the natural regulation of moose populations Messier, François 1984

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MOOSE-WOLF DYNAMICS AND THE NATURAL REGULATION OF MOOSE POPULATIONS By F r a n c o i s Mess i e r B . S c , U n i v e r s i t y L a v a l , 1976 M . S c , U n i v e r s i t y L a v a l , 1979 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Department of Animal Sc i ence ) we accept t h i s t h e s i s as conforming to the r e q u i r e d s tandard THE UNIVERSITY OF BRITISH COLUMBIA September 1984 © F. M e s s i e r , 1984 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e h e a d o f my d e p a r t m e n t o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . F r a n g o i s MESSIER D e p a r t m e n t o f An ima l S c i e n c e s  The U n i v e r s i t y o f B r i t i s h C o l u m b i a 1956 Main Mall V a n c o u v e r , Canada V6T 1Y3 D a t e 20 S e p t . 1984 )E-6 (3/81) ABSTRACT Long term data i n d i c a t e tha t n a t u r a l l y r e g u l a t e d moose p o p u l a t i o n s in southwestern Quebec s t a b i l i z e at a d e n s i t y of =0.40 a n i m a l - k m - 2 . To t e s t p o p u l a t i o n r e g u l a t i o n by forage c o m p e t i t i o n , moose body c o n d i t i o n was i n v e s t i g a t e d near t h i s e q u i l i b r i u m d e n s i t y (0.37=H) and at 2 lower d e n s i t i e s (=0.23=M, 0.17=L) . Measurements of head l e n g t h , c r a n i a l b r e a d t h , hear t we ight , and k idney weight were c o l l e c t e d from 443 moose k i l l e d du r i ng the autumn h a r v e s t i n g seasons of 1981 and 1982. There was no i n d i c a t i o n tha t body c o n d i t i o n was poorer at the h igh moose d e n s i t y , and hence no ev idence that c o m p e t i t i o n fo r forage e x p l a i n s the r e g u l a t o r y p r o c e s s . To t e s t p o p u l a t i o n r e g u l a t i o n by p r e d a t o r s , moose-wolf dynamics were s t u d i e d at the same 3 moose d e n s i t i e s ( p a r t i a l data i n a rea L ) . In a reas H and M, packs averaged 5.7 and 3.7 i n d i v i d u a l s , y ea r- long t e r r i t o r y s i z e s averaged 390 and 255 km 2 , and i n t e r s t i c e s between t e r r i t o r i e s r ep resen ted «*0% and 30% of the a v a i l a b l e a r e a , r e s p e c t i v e l y . The wolf p o p u l a t i o n in a rea M, as compared to a rea H, s u f f e r e d from a h ighe r m o r t a l i t y r a te due to m a l n u t r i t i o n and l e t h a l i n t r a s p e c i f i c combat, and from a lower success in p roduc ing pups . A n a l y s i s of summer s ca t s and w in te r f e ed ing o b s e r v a t i o n s i n d i c a t e d a g r e a t e r use of a l t e r n a t i v e food r e sou r ces at lower moose d e n s i t i e s . Each pack k i l l e d on average 5 .3 , 1.8, and 1.1 moose*100 days in a reas H, M, and L, r e s p e c t i v e l y . January wolf d e n s i t i e s were r e s p e c t i v e l y 1.38, 0 .82 , and 0.36 an ima ls*100 k m " 2 . Yea r- long p r e d a t i o n r a t es proved to be dens i t y-dependen t , i n c r e a s i n g w i th moose d e n s i t y from 6.1 to 19.3% of the p o s t n a t a l p o p u l a t i o n s . I conc lude tha t moose p o p u l a t i o n s in southwestern Quebec are r e g u l a t e d by p r e d a t o r s at a d e n s i t y where c o m p e t i t i o n fo r fo rage o f f e r s no d e t r i m e n t a l e f f e c t . P r e l i m i n a r y r e s u l t s of a wolf removal exper iment in area H support t h i s h y p o t h e s i s . A review of the n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s i s p r e s e n t e d . I support the concept that wolf p r e d a t i o n can have an important r e g u l a t o r y e f f e c t at low moose d e n s i t i e s (<0.5-1.0 a n i m a l ' k m " 2 ) but a l s o a depensatory ( i n v e r s e l y dens i t y-dependent ) e f f e c t at h ighe r d e n s i t i e s . Moose p o p u l a t i o n s that are r e g u l a t e d by p r eda to r s appear to be more s t a b l e than those r e g u l a t e d at h i gh d e n s i t i e s by fo rage c o m p e t i t i o n . i v RESUME Les donnees obtenues au cours d 'une etude de longue duree demontrent que l e s p o p u l a t i o n s d ' o r i g n a u x h a b i t a n t l e sud-ouest du Quebec a t t e i g n e n t un e q u i l i b r e l o r sque l e u r s d e n s i t e s approchent 0.40 an ima l•km" 2 . A f i n de v e r i f i e r s i l a c o m p e t i t i o n pour l a n o u r r i t u r e d i s p o n i b l e peut e x p l i q u e r ce phenomene, l a c o n d i t i o n phys ique des or ignaux a ete e tud i ee a des d e n s i t e s de 0.37 (H), =*0.23 (M) , et 0.17 a n i m a l ' k m " 2 (L) . Les mesures de longueur de t e t e , l a r g e u r du c r a n e , po ids du coeu r , et po ids des r e i n s , f u r e n t r e c u e i l l i e s sur 443 or ignaux aba t tus a l a chasse s p o r t i v e en 1981 et 1982. Les r e s u l t a t s n ' i n d i q u e n t pas une deg rada t i on de l a c o n d i t i o n phys ique des animaux a l a p l u s f o r t e d e n s i t e d ' o r i g n a u x . La compe t i t i on pour l a n o u r r i t u r e n ' e x p l i q u e r a i t done pas l e p rocessus de r e g u l a t i o n . A f i n de v e r i f i e r l a r e g u l a t i o n des p o p u l a t i o n s par l e s p r e d a t e u r s , l e s i n t e r a c t i o n s l oups-or ignaux ont e te e tud i ee s aux 3 memes d e n s i t e s d ' o r i g n a u x . Dans l e s a i r e s d ' e tudes H et M, l e s meutes ont regroupe 5.7 et 3.7 loups en moyenne. Les t e r r i t o i r e s annue ls ont couver t une s u p e r f i c i e moyenne de 390 et 255 km 2 , et l e s espaces en t r e l e s t e r r i t o i r e s ont r ep re sen t s respec t i vement =*0 et 30% de l ' a i r e d i s p o n i b l e . La p o p u l a t i o n de loups de l ' a i r e M a accuse un p l u s haut taux de m o r t a l i t e par m a l n u t r i t i o n et combats le thaux i n t r a -s p e c i f i q u e s , et un p l u s f a i b l e succes a p r o d u i r e des louveteaux que l a p o p u l a t i o n de l ' a i r e H. L ' a n a l y s e des excrements d ' e t e et des o b s e r v a t i o n s d ' a l i m e n t a t i o n des loups en h i v e r a ind ique une e x p l o i t a t i o n accrue des sources a l t e r n a t i v e s de n o u r r i t u r e a des d e n s i t e s moindres d ' o r i g n a u x . Chaque meute de loups a tue en moyenne 5 .3 , 1.8, et '1.1 o r i gnaux '100 jours dans l e s a i r e s H, M, et L, r e spec t i v emen t . En J a n v i e r , l e s d e n s i t e s de loups ont ete es t imees a 1.38, 0 .82 , et 0.36 an imaux« l00 k m " 2 , r e spec t i v emen t . Le taux de p r e d a t i o n annuel s ' e s t a c c r u avec l a d e n s i t e d ' o r i g n a u x , passant de 6.1 a 19.3% de l a p o p u l a t i o n est imee apres l a p a r t u r i t i o n . J ' e n conc l u s que l e s p o p u l a t i o n s d ' o r i g n a u x dans l e sud-ouest du Quebec sont maintenues a des f a i b l e s d e n s i t e s par l ' a c t i o n r e g u l a t r i c e des p r e d a t e u r s . Les r e s u l t a t s p r e l i m i n a i r e s d 'un c o n t r o l e expe r imenta l de l oups a l ' i n t e r i e u r de l ' a i r e H suppor tent c e t t e hypo these . Une revue des mecanismes de r e g u l a t i o n chez l ' o r i g n a l es t p r e s e n t e e . Je supporte l e concept que l a p r e d a t i o n par l e l oup peut a v o i r un e f f e t r e g u l a t e u r a des f a i b l e s d e n s i t e s d ' o r i g n a u x (<0.5-1.0 a n i m a l • k m " 2 ) , mais un e f f e t i n ve r se (non-r e g u l a t e u r ) a des d e n s i t e s p l u s e l e v e e s . Les p o p u l a t i o n s d ' o r i g n a u x e tant r e g u l a r i s e e s par l e s p r eda t eu r s appa r a i s s en t p l u s s t a b l e s que c e l l e s r e g u l a r i s e e s a des d e n s i t e s e l evees par l ' abondance de n o u r r i t u r e . TABLE OF CONTENTS Page A b s t r a c t i i Resume iv Tab le of Contents v i L i s t of T a b l e s ix L i s t of F i g u r e s x i Acknowledgements . . . x i i i Genera l i n t r o d u c t i o n 1 CHAPTER I - BODY CONDITION AND POPULATION REGULATION BY FOOD RESOURCES IN MOOSE I n t r o d u c t i o n 2 Study a rea 4 Methods 7 Resu l t s 9 Ev idence of p o p u l a t i o n r e g u l a t i o n 9 Body c o n d i t i o n vs moose d e n s i t y 13 D i s c u s s i o n 19 CHAPTER II - SOCIAL ORGANIZATION, SPATIAL DISTRIBUTION, AND POPULATION DENSITY OF WOLVES IN RELATION TO MOOSE DENSITY — I n t r o d u c t i o n 24 Study a rea and methods 25 v i i Page R e s u l t s 31 M o r t a l i t y and r e p r o d u c t i o n 31 S o c i a l o r g a n i z a t i o n 34 S p a t i a l d i s t r i b u t i o n 37 D i s c u s s i o n 47 CHAPTER III - MOOSE-WOLF DYNAMICS I n t r o d u c t i o n 55 Study a reas and methods 57 R e s u l t s 60 Feed ing eco logy 60 Age, sex , and c o n d i t i o n of dead moose 64 K i l l i n g r a t e s , food in take r a t e s , and h a n d l i n g time . . 68 Wolf d e n s i t i e s and moose:wolf r a t i o s 72 Year- long p r e d a t i o n r a t es and p o p u l a t i o n ba lances . . . . 72 D i s c u s s i o n 79 CHAPTER IV - MOOSE RESPONSE TO EXPERIMENTAL WOLF REMOVAL I n t r o d u c t i o n 85 Study a rea and methods 87 R e s u l t s 90 D i s c u s s i o n 95 Management i m p l i c a t i o n s 98 v i i i Page CHAPTER V - GENERAL DISCUSSION AND CONCLUSIONS 100 L i t e r a t u r e c i t e d 108 Appendix '. . 117 ix LIST OF TABLES Page 1. E s t ima te s of moose d e n s i t y and annual hun t ing r a te in in a reas H, M, and L, from 1976 to 1983 11 2. A g e - s p e c i f i c head l eng th (cm), c r a n i a l b read th (cm), hea r t weight (kg ) , and k idney weight (kg) f o r male moose, g i ven as mean va lues ± SE (n ) , in r e l a t i o n to 3 l e v e l s of moose d e n s i t y in southwestern Quebec . . . . 14 3. A g e - s p e c i f i c head l eng th (cm), c r a n i a l b read th (cm), hear t weight (kg ) , and k idney weight (kg) f o r female moose, g i ven as mean va lues ± SE (n ) , in r e l a t i o n to 3 l e v e l s of moose d e n s i t y in southwestern Quebec . . . . 15 4. A n a l y s i s of v a r i ance t r e a t i n g moose d e n s i t y and age e f f e c t s on head l e n g t h , c r a n i a l b r ead th , hea r t we ight , and k idney weight of h u n t e r - k i l l e d moose i n southwestern Quebec, data of 1981 and 1982 combined 16 5. Head l e n g t h (cm), c r a n i a l b read th (cm), hear t weight ( kg ) , and kidney weight (kg) f o r h u n t e r - k i l l e d moose, g i ven as the p r e d i c t e d mean v a l ues ± SE (n ) , in r e l a t i o n to 3 l e v e l s of moose d e n s i t y in southwestern Quebec 18 6. M o r t a l i t y o b s e r v a t i o n s from 54 wolves (>3 months of age) t r a c k e d du r i ng the s tudy 32 7. Summary of data r ega rd ing wolf t e r r i t o r i e s adequa te l y d e f i n e d , and the r e s p e c t i v e pack s i z e and moose d e n s i t y 38 8. E a r l y w in te r pack s i z e , wolf and moose d e n s i t i e s r e p o r t e d f o r d i f f e r e n t b o r e a l ecosystems in Nor th Amer ica 50 9. Comparat ive prey use by wolves d u r i n g summer in a reas M and H 61 10. Comparat ive prey use by wolves d u r i n g w in te r in a reas M and H 63 11. Age, sex , and m o r t a l i t y d i s t r i b u t i o n of 62 moose consumed by wolves in a reas M and H 65 X Page 12. Sex and age s t r u c t u r e s of moose i n h a b i t i n g areas H, M, and L, as ob ta ined from a e r i a l surveys and autumn h u n t e r - k i l l e d an ima ls 67 13. Summary of data used to es t imate moose k i l l i n g ra te by wo lves , and the t o t a l moose consumption r a t e (December to A p r i l ) in a reas H, M, and L •••• 69 14. I n d i c e s , r e l a t i v e i n d i c e s (RI ) , and best e s t ima tes of wolf d e n s i t y ( January) in a reas H, M, and L 73 15. D e r i v a t i o n of the d e n s i t y (No./km 2 ) of c a l f and adu l t (>1 y r ) moose in a reas H, M, and L, on 1 June ( i . e . , p o s t - n a t a l d e n s i t y ) 75 16. E s t i m a t i o n of the number of moose k i l l e d by wolves and the yea r- long p r e d a t i o n ra te in a 1000-km 2 area H, M, and L '76 17. Summarizat ion of the r ec ru i tmen t and m o r t a l i t y data in a reas H, M, and L, g i ven as the pe rcen tages of the p o s t - n a t a l p o p u l a t i o n s 77 18. I nd i ces of wolf p o p u l a t i o n s in the non-removal area (N-R) and the removal area (R) be fo re i n i t i a t i o n of the wolf r educ t i on programme (1980, 1981) and du r i ng the programme (1982, 1983) 91 19. Average (SE) number of moose observed per 60-km 2 p l o t (see methods) and es t ima tes (SE) of the moose d e n s i t y in the non-removal area and in the removal a rea 93 20. Ca l f-cow r a t i o s in the non-removal a rea and in the removal area be fo re i n i t i a t i o n of the wolf r e d u c t i o n programme (1981,1982) , and du r i ng the programme (1983, 1984) 94 x i LIST OF FIGURES Page 1. L o c a t i o n s of a reas H, M, and L, where the study was conducted 5 2. Percent success of hunt ing p a r t i e s (3 persons ) to k i l l 1 moose (the bag l i m i t ) in area H from 1967 to 1982 10 3. L o c a t i o n and d e s c r i p t i o n of the area where most of the r a d i o - t r a c k i n g of wolves was conducted . . . . . . . . 26 4. Group ing of wolves when they t r a v e l l e d in the LP or in the HP area 35 5. December to March changes in the p r o p o r t i o n of members forming the pack core ( i . e . , group cohes i veness ) when packs were observed in the LP or in the HP area 36 6. D e p i c t i o n of the a reas used annua l l y (May to A p r i l ) by i n d i v i d u a l packs d u r i n g the study p e r i o d 39 7. D e p i c t i o n of the t e r r i t o r y se t t l ement in the LP and HP areas from the poo led data between 1980 and 1984 41 8. Space-use pa t t e rn s of packs H6 and L4 du r i ng the summer p e r i o d (May to November), as compared to the w inter p e r i o d (December to A p r i l ) 43 .9. Space-use p a t t e r n s of 2 non-rep roduc t i ve packs (L5 and H8) du r i ng the summer p e r i o d , and the r e p r e s e n t a t i o n of the-seasona l t e r r i t o r y s h i f t demonstrated by the pack H2 44 10. Cumulat i ve r e l a t i v e f r e q u e n c i e s fo r the i n - t e r r i t o r y d a i l y d i s t a n c e s of r e p r o d u c t i v e and non-reproduc t i ve packs du r i ng the summer 46 11. Cumulat i ve r e l a t i v e f r e q u e n c i e s fo r the i n - t e r r i t o r y d a i l y d i s t a n c e s of packs d u r i n g the w inter p e r i o d . . . 48 12. Bone marrow fa t content by month fo r moose which d i e d of wolf p r e d a t i o n or m a l n u t r i t i o n 66 x i i Page 13. Time spent at a d u l t moose k i l l s ( hand l ing t ime) as a f u n c t i o n of the number of wolves present (pack s i z e ) 71 14. D e s c r i p t i o n of the study a rea fo r the wolf removal exper iment , and l o c a t i o n s of the wolves k i l l e d between November 1981 and March 1984 88 15. Percent s u r v i v a l of c a l v e s a s s o c i a t e d w i th r a d i o -c o l l a r e d female moose in the wolf removal and the non-removal area 96 16. The proposed concep tua l model of predator-moose-food supp ly i n t e r a c t i o n s 101 x i i i ACKNOWLEDGEMENTS D r s . D.M. Shack le ton and F . L . Bunne l l p r o v i d e d guidance and counse l throughout the s tudy . Other members of my s u p e r v i s o r y commit tee , D r s . B.D. Owen, R.G. P e t e r son , and C . J . W a l t e r s , p r o v i d e d v a l u a b l e input to the t h e s i s in the form of q u e s t i o n s , adv i ce and s u g g e s t i o n s . The e f f o r t s of s e v e r a l f i e l d a s s i s t a n t s , and p a r t i c u l a r l y those of L. G i g u e r e , C. Ca ron , R. Roy, J . Ca ron , A. Beaumont, D. S t - H i l a i r e , and M. Macquar t , are a p p r e c i a t e d . F i n a n c i a l and l o g i s t i c support fo r t h i s p r o j e c t was p r o v i d e d l a r g e l y by the M i n i s t e r e du L o i s i r , de l a Chasse , et de l a Peche, Quebec. A d d i t i o n a l support came from Canadian W i l d l i f e S e r v i c e , Canadian N a t i o n a l Spor tsmen 's Fund, and U n i v e r s i t y of B r i t i s h Co lumbia . I was suppor ted by Leonard S. K l i n k (UBC), S o c i e t e Zoo log ique de Quebec, and Fonds F . C . A . C . , s c h o l a r s h i p s . F . L . B u n n e l l , M. C r e t e , K .L . P a rke r , D. S e i p , D.M. S h a c k l e t o n , V. Van B a l l e n b e r g h e , and P. M i l l s (our a p p r e c i a t e d s e c r e t a r y ) , gave c r i t i c a l comments on the m a n u s c r i p t . 1 GENERAL INTRODUCTION It has been commonly c l a imed tha t p r e d a t o r s s t r o n g l y i n t e r a c t w i th ungu la te p o p u l a t i o n s ( e . g . , K e i t h 1974; Smuts 1978; Bergerud 1980; Bergerud et a l . 1983; Gasaway et a l . 1983; Pe te rson and Page 1983). Ye t , no study has demonstrated the r e g u l a t o r y e f f e c t of p r e d a t i o n upon u n g u l a t e s , i . e . , tha t p r e d a t i o n r a t e i n c r ea ses w i th ungu la te d e n s i t y . Here , I r epo r t on such a s tudy . The n a t u r a l r e g u l a t i o n of moose i s ana l y sed among 3 p o p u l a t i o n s , 1 near an e q u i l i b r i u m d e n s i t y and 2 o t h e r s d i s r u p t e d from t h i s e q u i l i b r i u m by i n t e n s i v e h a r v e s t i n g . I t was f e l t tha t on ly by " m a n i p u l a t i o n " would a c l e a r comprehension of the p o p u l a t i o n p rocess emerge. As an en t r y i n to the i n t r i c a t e i n t e r a c t i o n s between p r e d a t o r s , moose, and fo rage a v a i l a b i l i t y , I f i r s t address the q u e s t i o n of p o p u l a t i o n r e g u l a t i o n by food r e sou r ces v i a a study of moose body c o n d i t i o n (Chapter I ) . Subsequent ly (Chapter I I ) , I p resent i n f o r m a t i o n on the s o c i a l o r g a n i z a t i o n of wolves because of i t s p o t e n t i a l importance in de te rm in ing changes in wolf numbers. In Chapter I I I , I e l a b o r a t e on moose-wolf dynamics , d i s c u s s i n g the r e g u l a t o r y e f f e c t of wolf p r e d a t i o n . The p r e l i m i n a r y r e s u l t s of an on-going wolf removal exper iment are r e p o r t e d in Chapter IV. In the c o n c l u d i n g Chapter V, I rev iew the n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s , w i th summary s ta tements des igned to provoke thought and to i n s p i r e new l i n e s of r e s e a r c h . 2 Chapter 1 BODY CONDITION AND POPULATION REGULATION BY FOOD RESOURCES IN MOOSE INTRODUCTION Two f a c t o r s are commonly invoked to e x p l a i n p o p u l a t i o n r e g u l a t i o n in u n g u l a t e s : a v a i l a b i l i t y of food r esources ( e . g . , Caughley 1970,1976; S i n c l a i r 1977; S i n c l a i r and Norton-G r i f f i t h s 1982; Houston 1982), and p r e d a t i o n ( e . g . , P im lo t t 1967; K e i t h 1974; Bergerud 1980; Gasaway et a l . 1983). S tud i e s t e s t i n g these e x p l a n a t i o n s have been no tab l y s c a r c e , ma in ly because they are d i f f i c u l t to conduct in the f i e l d (but see Macnab 1983). When f a c i n g food l i m i t a t i o n , i n d i v i d u a l s in an ungu la te p o p u l a t i o n compete f o r p r e f e r r e d , h ighe r q u a l i t y forage ( K l e i n 1970; K ie et a l . 1980). As a r e s u l t , many important l i f e -h i s t o r y events are a d v e r s e l y a f f e c t e d : growth, f a t a c c u m u l a t i o n , and, u l t i m a t e l y , r e p r o d u c t i o n and s u r v i v a l ( rev iews in Hanks 1981; Huot 1982). Among the C e r v i d a e , there i s both c i r c u m s t a n t i a l and expe r imen ta l ev idence tha t i n t r a s p e c i f i c s i z e d i f f e r e n c e s e x i s t due to v a r i a t i o n s in food q u a l i t y , food q u a n t i t y , and p o p u l a t i o n d e n s i t y (Verme 1963; K l e i n 1964, 1968; K l e i n and S t randgaard 1972; Verme and Ozoga 3 1980a; S u t t i e 1980; Leader-Wi l l i ams and R i c k e t t s 1982; Reimers et a l . 1983; Skogland 1983). There i s s i m i l a r ev idence tha t f a t accumula t ions and t h e i r seasona l v a r i a t i o n s are l a r g e l y governed by the summer and the w inter f o r a g i n g c o n d i t i o n s (Dauphine 1976; M i t c h e l l et a l . 1976; Verme and Ozoga 1980b; Huot 1982). In s h o r t , the lower f e c u n d i t y r a t e , the r e t a r d a t i o n in p r e n a t a l and p o s t n a t a l deve lopment , the de l a y in the c a l v i n g time (which r e s u l t s in a s h o r t e r p e r i o d of growth be fo re the w i n t e r ) , and the i n c r ea se of p e r i n a t a l m o r t a l i t y , appear to be the most c r i t i c a l consequences of a poor n u t r i t i o n a l p lane (Verme 1963, 1969, 1979; Thorne et a l . 1976; Pe terson and Harper 1978; Robbins and Robbins 1979; B l a x t e r and Hami l ton 1980). I n i t i a l growth r e t a r d a t i o n has a permanent e f f e c t which can r e s u l t in a s i z e d i f f e r e n c e fo r a l l age c l a s s e s (Peterson 1977; S u t t i e 1980; Skogland 1983). T h i s permanent e f f e c t - i s an important premise in the present s t udy . Many of the authors l i s t e d above conc luded tha t the assessment of body c o n d i t i o n i s a more a p p r o p r i a t e approach wi th which to e va lua te h a b i t a t c o n d i t i o n than the d i r e c t e v a l u a t i o n of h a b i t a t , because body c o n d i t i o n r e p r e s e n t s an 'in v i v o ' e v a l u a t i o n of h a b i t a t q u a l i t y . T h i s study at tempted to t e s t whether or not moose (A l ces  a l c e s ) are r egu l a t ed by a v a i l a b l e food r e s o u r c e s . In southwestern Quebec, non-harvested moose p o p u l a t i o n s appear to s t a b i l i z e at a d e n s i t y of ^0.40 an ima l-km" 2 (Crete et a l . 1981; data h e r e i n ) . E lsewhere in North Amer i ca , where 4 p r e d a t i o n does not o c c u r , moose p o p u l a t i o n s can reach d e n s i t i e s of 2 to 4 an ima l s-km" 2 and s t i l l have a c a l f p r o d u c t i o n in e a r l y w in te r of 15 to 25% of the t o t a l p o p u l a t i o n (Bergerud and Manuel 1969; B lood 1973). The approach was to study moose body c o n d i t i o n near the expected e q u i l i b r i u m d e n s i t y (0.37 an ima l•kn r 2 ) and at 2 lower d e n s i t i e s (0.22 and 0.17 a n i m a l ' k m " 2 ) f o r compar i son . The 3 p o p u l a t i o n s d i f f e r e d i n d e n s i t y because they were man ipu la ted by d i f f e r e n t ha rves t i n t e n s i t y r a the r than by a r a d i c a l change in h a b i t a t q u a l i t y (Crete et a l . 1981). I p r e d i c t e d that moose in the h igh d e n s i t y area would e x i b i t body growth r e t a r d a t i o n and poorer body c o n d i t i o n , compared to moose in the 2 lower d e n s i t y a reas where food c o m p e t i t i o n shou ld be reduced and h a b i t a t q u a l i t y shou ld be h i g h e r . I f our p r e d i c t i o n proves to be c o r r e c t , p o p u l a t i o n r e g u l a t i o n by food r e sou r ces would be sugges ted . STUDY AREA The 3 study areas ( F i g . 1) are l o c a t e d w i t h i n the most p r o d u c t i v e moose h a b i t a t in Quebec ( B rassa rd et a l . 1974). Area H, the game rese r ve La Verendrye (13,615 km 2 ) , had a r e l a t i v e l y h igh moose d e n s i t y (0.37 a n i m a l • k m " 2 ) . Sport hunt ing was not a l lowed in the r ese r ve from i t s e s t ab l i shmen t in 1939 u n t i l 1964. S ince 1964 harves t has been r e s t r i c t e d by a - l i m i t e d en t r y system. Area M (2390 km 2) had a moderate 5 F i g . 1. L o c a t i o n s o f a r e a s H, M, and L, where t h e s t u d y was c o n d u c t e d . 6 moose d e n s i t y (0.22 an ima l•km" 2 ) , and encompasses the former game rese r ve Pont iac (1205 km 2) a b o l i s h e d in 1978. Hunt ing has been u n r e s t r i c t e d and h igh throughout area M s i n c e 1978. Area L (1185 km 2) had a r e l a t i v e l y low moose d e n s i t y (0.17 a n i m a l • k m " 2 ) . Dur ing the 15-year p e r i o d p reced ing the present s tudy , a rea L had been i n t e n s i v e l y ha r ves ted under an u n l i m i t e d en t r y system. The r e l i e f i s r o l l i n g h i l l s w i th e l e v a t i o n s rang ing from 200 to 600 m above sea l e v e l . Snow accumula t ion averages 75 cm in F eb rua r y , and i s comparable among the 3 study a reas (Soucy 1971; Mess ie r u n p u b l . ) . Lakes , ponds, and c reeks are common and we l l d i s t r i b u t e d . The f o r e s t c o n s i s t s of mixed c o n i f e r o u s and dec iduous s tands (Rowe 1972). The dominant t r ee spec i e s in the lower s i t e s are balsam f i r (Abies ba lsamea) , white spruce (P icea  g l a u c a ) , b l a ck spruce (P. mar i ana ) , t r emb l i ng aspen (Populus  t r e m u l o i d e s ) , and paper b i r c h (Be tu la p a p y r i f e r a ) . Shade-t o l e r a n t hardwoods, ma in ly sugar maple (Acer saccharum) and ye l low b i r c h (B. a l l e g h a n i e n s i s ) , cover tops and s i d e s of the h i l l s . Mountain maple (A. spicatum) and beaked haze lnu t (Co ry lus co rnuta ) compr ise most of the shrub s t r a t a . Cre te and Jordan (1982a, b) p rov i ded a d d i t i o n a l i n f o rma t i on on a v a i l a b i l i t y , q u a l i t y , and use of moose f o r a g e . Two l a r g e p reda to r s p e c i e s are p resen t in the study a r e a . Wolf (Can is lupus) d e n s i t i e s range from approx imate l y 0.4 to 1.4 an imals*100 k m " 2 , depending on the moose d e n s i t y (Messier 7 and Cre te in p r e s s ) . B lack bear (Ursus amer icanus) d e n s i t i e s are unknown, but t r a c k s and dropp ings are common in the 3 a r e a s ; area H appears to support the h i ghes t d e n s i t y (a minimum of 0.25 b e a r » k m ~ 2 ; L a c h a p e l l e et a l . 1984). METHODS Data were c o l l e c t e d du r i ng autumn 1981 and 1982 at compulsory h u n t e r - k i l l r e g i s t r a t i o n s t a t i o n s . Moose were k i l l e d from 18 September to 18 October in a rea H, and from 16 to 24 October i n a reas M and L. Age was determined by a comb ina t ion of t o o t h e r u p t i o n p a t t e r n s and counts of i n c i s o r cementum a n n u l i . Most moose d e n s i t i e s were es t ima ted from p a r t i a l a e r i a l surveys (minimum 500 km 2) i n i t i a t e d fo r o the r p r o j e c t s . Moose i n ven to r y t echn iques are d e s c r i b e d by C re te and S t - H i l a i r e (1979) and Cre te et a l . (1981) . Re su l t s were c o r r e c t e d fo r v i s i b i l i t y b i a s (Crete et a l . submi t t ed ) . When a e r i a l survey da ta were not a v a i l a b l e , moose d e n s i t i e s were c a l c u l a t e d from the p r e d i c t i v e r e l a t i o n s h i p between the number of hunt ing-days per k i l l ( h u n t i n g - e f f o r t ) and moose d e n s i t y (Crete a l . 1981). Con f idence i n t e r v a l s of d e n s i t y f i g u r e s are not a v a i l a b l e and can be as wide as 20-30% of the es t imate (Cre te et a l . s ubm i t t ed ) . I do not c o n s i d e r t h i s i m p r e c i s i o n to be a major weakness of the study because the a n a l y s i s r e l i e s on long term data in which y e a r - s p e c i f i c e r r o r s may compensate. Changes over a s i n g l e year p e r i o d exceed the accuracy of these 8 d a t a . To p rov ide a d d i t i o n a l past i n f o r m a t i o n f o r area H, the 1967-82 t r end of moose p o p u l a t i o n was es t ima ted by the hunt ing success ( i . e . , % of hun t ing p a r t i e s who k i l l e d 1 moose, the bag l i m i t ) . The number of hun t i ng p a r t i e s and the number of moose k i l l e d were known e x a c t l y . Harvest r e g u l a t i o n s remained comparable throughout t h i s p e r i o d . Between 1967 and 1978, p a r t i e s of two hunters and a gu ide were a l l owed to hunt 4 days (same fo r a l l years ) w i t h i n a p rede te rmined a r e a . From 1979 the guide was no longer r e q u i r e d and a t h i r d hunter c o u l d be i n c l u d e d in the p a r t y . Harves t r a t e s were computed by d i v i d i n g the ha rves t by the sum of the January moose p o p u l a t i o n and the h a r v e s t . Four body c o n d i t i o n i n d i c e s , e a s i l y measured at ha rves t r e g i s t r a t i o n s t a t i o n s , were chosen . Two s k e l e t a l measures, head l eng th (Haigh et a l . 1980) and c r a n i a l b readth (minimum i n t e r - o r b i t a l b readth w i th s k i n ) , were used as i n d i c a t o r s of the env i ronmenta l c o n d i t i o n s d u r i n g the body development phase ( i . e . , long-term e f f e c t s ) . Two o rgans , hear t weight (without f a t d e p o s i t , s u rp l u s b l o o d , and a t r i a ) , and k idney weight (w i thout f a t d e p o s i t ; average of the r i g h t and the l e f t ) were s e l e c t e d as proximate i n d i c a t o r s of body c o n d i t i o n ( i . e . , sho r t- te rm e f f e c t s ) at the end of the p l a n t growing season . These two organs appear s e n s i t i v e to e i t h e r energy or p r o t e i n i n t ake (Verme and Ozoga 1980a). I assumed that the 4 i n d i c e s , i n t e r p r e t e d t o g e t h e r , would be e f f e c t i v e to de t e c t poor body 9 c o n d i t i o n . Data were t r e a t e d by a n a l y s i s of v a r i a n c e (UBC GENLIN). ANOVA t a b l e s were i n t e r p r e t e d at 0.05 p r o b a b i l i t y l e v e l . The homogeneity of v a r i a n c e s was t e s t e d by the Layard ch i - squa re t echn ique wi th a p r o b a b i l i t y l e v e l of 0 . 01 . The p r e d i c t e d means of each index ( i . e . , a f t e r the age e f f e c t had been removed) were compared by the S che f f e method. Because t h i s method i s c o n s e r v a t i v e , (Neter and Wasserman 1974:479) , the p r o b a b i l i t y l e v e l was set at 0 .10 . S ix age c l a s s e s were used fo r males and 4 fo r f ema les . RESULTS Ev idence of p o p u l a t i o n r e g u l a t i o n From 1939 u n t i l 1964 (25 y e a r s ) , spor t h a r v e s t i n g was not a l l owed in area H and moose l i k e l y were at an e q u i l i b r i u m d e n s i t y . The i n i t i a t i o n of l i m i t e d h a r v e s t i n g in 1964 may have induced a s l i g h t d e c l i n e of the moose p o p u l a t i o n , but s i n c e 1967 the p o p u l a t i o n appears to be s t a b l e at 0.37 moose*km" 2 . Popu l a t i on s t a b i l i t y was i n d i c a t e d by the l a ck of t r end in the hunt ing success (r_2 = 0 .35 , P>0.10, n=l6 , F i g . 2) and in the d e n s i t y e s t ima tes ( r 2 = 0 . 3 6 , P>0.10, n=8, Tab le 1 ) . The c r i t i c a l po in t here i s that the data do not show any p o p u l a t i o n increment whatsoever . Assuming a d e n s i t y of 0 .37 , the annual ha rves t between 1964 and 1983 averaged 3.6% (186 ± (SD)25 moose) . T h i s r a te was s u s t a i n a b l e . 10 ~ 70 CO CO LU 8 50 CO 30 3 1970 1975 1980 F i g . 2 . P e r c e n t s u c c e s s o f h u n t i n g p a r t i e s (3 p e r s o n s ) t o k i l l 1 moose ( t h e bag l i m i t ) i n a r e a H f r om 1967 t o 1982. The l a c k o f t r e n d (p> 0 . 1 0 ) s u g g e s t s a s t a b l e p o p u l a t i o n . T a b l e 1. E s t i m a t e s o f moose d e n s i t y and annua l h u n t i n g r a t e i n t h e 3 s t u d y a r e a s f r om 1976 t o 1983 . Ma l e s r e p r e s e n t e d 66%, 47%, and 53% o f t h e h a r v e s t i n a r e a s H, M, and L, r e s p e c t i v e l y . No d a t a = n . d . A r e a H A r e a M A r e a L Moose H u n t i n g Moose H u n t i n g Moose H u n t i n g N / km 2 % N / km 2 % N / km 2 % 1976 0.41 c 3 0 . 3 0 a n . d . n . d . 1977 0 . 3 6 b 4 n . d . n . d . 1978 0 . 3 7 b 4 0 . 29 c 22 0 .15b 26 1979 0 . 3 9 c 3 0 . 2 6 c 25 0 . 2 2 c 20 1980 0 . 3 6 c 4 0 . 1 9 c 27 0 . 18 21 1981 0 .36 4 0 . 25 21 0 .16 23 1982 0 . 32 3 0 . 19 25 0 . 16 23 1983 0 . 37 4 0 . 22 c 22 0 .16 31 mean 0 .37 3 .6 d e c ! i n i n g 23 0 . 17 24 a C r e t e and S t - H i l a i r e , u n p u b l . b C r e t e e t a l . 1981 c e s t i m a t e d f r om t h e h u n t i n g - e f f o r t pe r k i l l ( C r e t e e t a l . 1 981 ) ; r e s u l t s f r o m T r emb l a y , u n p u b l . ) 12 Cre te et a l . (1981) e s t ima ted t h a t , w i thout h a r v e s t i n g , the moose p o p u l a t i o n in area H would s t a b i l i z e at a d e n s i t y of 0.40 a n i m a l • k m " 2 . O r i g i n a l v a lues g iven by C re t e et a l . (1981) were 0.28 and 0.30 but were d i v i d e d by 0.73 to c o r r e c t fo r the now-known v i s i b i l i t y b i a s in a e r i a l surveys (Crete et a l . s ubm i t t ed ) . From r e t r o - c a l c u l a t i o n , the e q u i l i b r i u m d e n s i t y i s e va lua t ed at a maximum of 0.41 an ima l-km" 2 ( i . e . , the 1967-82 d e n s i t y , 0 .37 , p l u s a maximum l o s s of 10% fo r the 1964-67 ha rves t or 3 to 4% a n n u a l l y ) . Both e v a l u a t i o n s suggested tha t the moose d e n s i t y in area H d u r i n g the present s tudy was not s u b s t a n t i a l l y lower than the e q u i l i b r i u m d e n s i t y (0.37 vs =0.40 a n i m a l • k m " 2 ) . In a rea M, the moose p o p u l a t i o n was at 0.30 an ima l-km" 2 i n 1976 and d e c l i n e d at an annual r a te of =5% u n t i l 1983 ( r 2 = 0 . 6 2 , s lope=-0 .0 l45 or 5%, P<0.05, Tab le 1 ) . T h i s p o p u l a t i o n r e c e i v e d an average annual ha rves t r a t e of 23% (Table 1) , so the s u s t a i n a b l e ha r ves t ra te was e va l ua t ed at =18% ( i . e . , the ha rves t r a t e , 23%, minus the p o p u l a t i o n decrement , 5%). In a rea L, the moose p o p u l a t i o n was a p p a r e n t l y s t a b l e and at a d e n s i t y of 0.17 an ima l-km" 2 (r_2 = 0 . l O , P>0.10, n = 6, Tab le 1 ) . T h i s p o p u l a t i o n s u s t a i n e d a ha rves t r a te of 24% (Table 1 ) . C o n s i d e r i n g the 3 study a r e a s , r e s u l t s i n d i c a t e that the p o p u l a t i o n growth r a t e , as e va lua t ed by the s u s t a i n a b l e ha r ves t (Caugh ley .1976 ) , d e c l i n e d from 24% to a maximum of 4% as moose d e n s i t y i n c r e a s e d from 0.17 to 0.37 a n i m a l * k m " 2 . 1 3 C l e a r l y , a dens i t y-dependent f a c t o r u n d e r l i e s these p o p u l a t i o n r e sponses . Moreover , these r e s u l t s imply tha t the 3 p o p u l a t i o n s were c e r t a i n l y at d i f f e r e n t l e v e l s below t h e i r r e s p e c t i v e e q u i l i b r i u m d e n s i t y . Note that I am not assuming tha t these 3 e q u i l i b r i u m d e n s i t i e s were n e c e s s a r i l y e q u a l , on l y tha t the 3 p o p u l a t i o n s were at d i f f e r e n t l e v e l s below t h e i r e q u i l i b r i u m d e n s i t y because of the d i f f e r e n c e s in p o p u l a t i o n growth r a te (Caughley 1976). Body c o n d i t i o n vs moose d e n s i t y A t o t a l of 443 moose were measured in the autumn 1981 and 1982; 232 in a rea H, 118 in a rea M, and 93 in a rea L. Obse r va t i ons in both years were combined because year had no s i g n i f i c a n t e f f e c t on e i t h e r head l e n g t h , hea r t we ight , or k idney we ight . The d i f f e r e n c e between years in c r a n i a l b read th was the r e s u l t of an unexp la ined d i f f e r e n c e in area L o n l y . Age i n t e r a c t e d s i g n i f i c a n t l y w i th sex in regard to head l e n g t h , c r a n i a l b r ead th , and hea r t we ight . These o b s e r v a t i o n s i n d i c a t e tha t males and females grow d i f f e r e n t l y which o b l i g e d me to t r e a t them s e p a r a t e l y . Body development con t i nued at l e a s t u n t i l 5 1/2 years of age in males and u n t i l 3 1/2 years in females (Tab les 2 and 3 ) . No i n t e r a c t i o n was p resen t between moose d e n s i t y and age fo r the 4 i n d i c e s (Table 4 ) . T h i s lack of response demonstra tes that the a g e - s p e c i f i c increments ( i . e . , growth Table 2. Age-specific head length (cm), cranial breadth (cm), heart weight (kg), and kidney weight (kg) for male moose, given as mean values ± SE(n), in relation to 3 levels of moose density in southwestern Quebec: area L, 0.17/km2; area M, 0.22 / km2; area H, 0.37/km2. Nodata=n.d. Calf Uyr. 1\ yr. 3jyr. 4J yr. > 5Jyr. Head length Area L 40.12±1.29 (8) 57.74±0.72(26) 60.89±1.29 (8) 63.82±1.63 (5) 64.14± 1.38 (7) 64.50 (1) Area M 43.77±1.22 (9) 58.01 ±0.94(15) 61.61 ±1.10(11) 64.83±2.11 (3) 63.63±2.11 (3) 65.25±1.82 (4) Area H 40.50±2.58 (2) 57.99±0.57(41) 62.73±0.62(35) 64.35±0.76(23) 64.54+0.86(18) 66.87±0.58(40) Cranial breadth Area L 15.62± 0.47 (8) 19.11±0.26(26) 19.14+0.47 (8) 20.10±0.59 (5) 22.22±0.54 (6) 21.00 (1) Area M 16.08±0.42(10) 19.14 + 0.33(16) 20.72 ±0.38(12) 22.50+0.76 (3) 21.40+0.76 (3) 21.87±0.66 (4) Area H 16.25+0.94 (2) 20.78+0.21(41 ) 22.06±0.22(36) 22.56+0.28(23) 22.75+0.31(18) 23.46+0.21(41) Heart weight Area L n.d. 1.49±0.07(10) 1.73±0.12 (3) 1.97 (1) 2.12 + 0.15 (2) n.d. Area M 0.98±0.12 (3) 1.37±0.08 (7) 1.75+0.07 (8) 2.0U0.12 (3) 2.03 (1) 1.97 + 0.12 (3) Area H 0.74±0.15 (2) 1.66±0.03(37) 1.94±0.04(33) 2.10±0.05(20) 2.30±0.06(14) 2.28±0.04(33) Kidney weight • Area L n.d. 0.46±0.03 (7) n.d. 0.51±0.06 (2) 0.59±0.06 (2) n.d. Area M 0.31 (1) 0.49±0.04 (5) 0.51+0.05 (4) n.d. n.d. n.d. Area H 0.30 (1) 0.52±0.01(38) 0.61 +0.02(29) 0.63±0.02(18) 0.78±0.03 (9) 0.84±0.02(28) T a b l e 3. A g e - s p e c i f i c head l e n g t h ( cm) , c r a n i a l b r e ad t h ( cm) , h e a r t w e i g h t ( k g ) , and k i d n e y w e i g h t (kg) f o r f ema l e moose, g i v e n as mean v a l u e s t S E ( n ) , i n r e l a t i o n t o 3 l e v e l s o f moose d e n s i t y i n s o u t hwe s t e r n Quebec: a r e a L, 0 . 1 7 / km^; a r ea M, 0 . 2 2 / k m ? ; a r e a H, 0 . 3 7 / k m 2 . No d a t a = n . d . C a l f 11 y r . 21 y r . > 3 | y r . Head l e n g t h A r e a L 42 .31 ±1.14 (8) 55 .24 ±0.81 (16) 6 0 . 9 3 ± 1 . 8 7 (3) 61 . 94 ±0 . 88 ( 13 ) A r e a M 44 . 65 ±1 .02 (10 ) 5 7 . 4 5 ± 0 . 6 6 ( 2 4 ) 6 2 . 7 3 ± 1 . 0 8 (9) 6 3 . 3 5 ± 0 . 7 1 ( 2 1 ) A r e a H n . d . 5 6 . 8 7 ± 0 . 6 2 ( 2 7 ) 63 .11 ±1 .08 (9) 6 2 . 8 9 ± 0 . 5 8 ( 3 1 ) C r a n i a l b r e a d t h A r e a L 1 4 . 9 4 ± 0 . 4 2 (8) 1 7 . 7 7 ± 0 . 3 1 ( 1 5 ) 2 0 . 3 3 ± 0 . 6 9 (3) 19 .17 ±0 . 33 (13 ) A r e a M 1 5 . 0 6 ± 0 . 3 5 ( 1 2 ) 1 7 . 5 2 ± 0 . 2 7 ( 2 8 ) 19 .50 ±0 .42 (8) 1 9 . 1 9 ± 0 . 2 6 ( 2 2 ) A r e a H n . d . 1 8 . 7 7 ± 0 . 2 3 ( 2 7 ) 20 . 33 ±0 .40 (9) 2 0 . 5 5 ± 0 . 2 0 ( 3 5 ) Hea r t w e i g h t A r e a L 0 .87 (1) 1 . 45±0 .09 (5) 1 . 8 6 + 0 . 1 4 (2) 1 . 8 3±0 . 09 (5) A r e a M 0 . 8 8 ± 0 . 0 8 (6) 1 . 59±0 . 05 ( 15 ) 1.68 ±0 .08 (6) 1 . 9 7 ± 0 . 0 6 ( 1 2 ) A r e a H n . d . 1 . 70±0 . 04 ( 26 ) 2 .06 ±0 .07 (8) 2 . 0 5 ± 0 . 0 4 ( 2 9 ) K i d n e y w e i g h t A r e a L 0 . 30 (1) 0 . 4 4 ± 0 . 0 3 (5) n . d . 0 . 6 7 ± 0 . 0 5 (2) A r e a M 0 .26 (1) 0 . 4 7 ± 0 . 0 2 (8) 0 .51 ± 0 . 03 (4) 0 . 5 4 ± 0 . 0 3 (6) A r e a H n . d . 0 . 5 3 ± 0 . 0 2 ( 1 9 ) 0 . 6 1 ± 0 . 0 3 (5) 0 . 6 8 ± 0 . 0 1 ( 3 0 ) T a b l e 4 . A n a l y s i s o f v a r i a n c e t r e a t i n g moose d e n s i t y and age e f f e c t s on head l e n g t h , c r a n i a l b r e a d t h , h e a r t w e i g h t , and k i d n e y we i gh t o f h u n t e r - k i l l e d moose i n s o u t h w e s t e r n Quebec , d a t a o f 1981 and 1982 comb ined . Moose d e n s i t y = 3 l e v e l s ( a r e a L, a r e a M, and a r e a H ) . Age = 6 l e v e l s f o r ma les ( c a l f , U y r . , Z\ y r . , 3h y r . , 4J y r . , \ 5£ y r . ) , and 4 l e v e l s f o r f e m a l e s ( c a l f , 1 | y r . , 2.1 y r . , £ 3 i y r . ) . Head l e n g t h C r a n i a l b r e a d t h Hea r t w e i g h t K i d n e y w e i g h t d f P* d f P d f P d f P Ma l e s Moose d e n s i t y 2 0 .296 2 0 .000 2 0 . 000 2 0 . 0 03 Age 5 0 .000 5 0 . 000 5 0 . 000 5 0 . 000 Moose d . X age j-10 0 .840 10 0 . 103 8 0 . 439 4 0 . 359 E r r o r 241 245 164 132 da les Moose d e n s i t y 2 0 .014 2 0 . 000 2 0 . 000 2 0 . 000 Age 3 0 .000 3 0 . 000 3 0 . 000 3 0 . 000 Moose d . X age 5 0.981 5 0 .732 5 0 . 230 4 0 . 230 E r r o r 160 169 104 71. * p r o b a b i l i t y o f F - r a t i o MS : MS e r r o r 17 ra te ) of head l e n g t h , c r a n i a l b r ead th , hear t we ight , and k idney weight were not a f f e c t e d by moose d e n s i t y . My i n t e r p r e t a t i o n here i m p l i e s that the p o s s i b l e e f f e c t of food c o m p e t i t i o n was un i fo rm du r i ng the 6 years or so p reced ing the s tudy . T h i s assumption i s most l i k e l y c o r r e c t in area L and H where moose p o p u l a t i o n s appeared to be s t a b l e . S i g n i f i c a n t e f f e c t s of moose d e n s i t y on the 4 i n d i c e s were found in both sexes , w i th the excep t i on of male head l eng th (Table 4 ) . These r e s u l t s i n d i c a t e t h a t , a l though i n d i v i d u a l growth r a t e s of the v a r i o u s m o r p h o l o g i c a l parameters f o l l owed the same p a t t e r n in the d i f f e r e n t p o p u l a t i o n s , the l e v e l s ach ieved w i t h i n age c l a s s e s d i f f e r e d between p o p u l a t i o n s ( i . e . , a c a r r y over e f f e c t ) . (The ana logy in r e g r e s s i o n a n a l y s i s would be tha t the s l opes of r e g r e s s i o n l i n e s were e q u a l , but t h e i r e l e v a t i o n s d i f f e r e d . ) Such d i f f e r e n c e s norma l l y are ana l ysed by the compar isons of the p r e d i c t e d means; i . e . , the means computed a f t e r the age e f f e c t has been removed from the measures (from the ANOVA, Tab le 4 ) . None of the 4 i n d i c e s had a s i g n i f i c a n t l y lower va lue in a rea H as p r e d i c t e d . C r a n i a l b readth in males and fema les , and hear t and kidney weight in females were s i g n i f i c a n t l y h ighe r in a rea H (Table 5 ) . T a b l e 5 . Head l e n g t h ( cm) , c r a n i a l b r e ad t h (cm) , h e a r t w e i g h t ( k g ) , and k i d n e y w e i g h t (kg) f o r h u n t e r - k i l l e d moose, g i v e n as t h e p r e d i c t e d mean v a l u e s t S E ( n ) , i n r e l a t i o n t o 3 l e v e l s o f moose d e n s i t y i n s ou t hwe s t e r n Quebec: a r e a L, 0 . 1 7 / k m 2 ; a r e a M, 0 . 2 2 / k m 2 ; a r e a H, 0 . 3 7 / k m 2 . P r e d i c t e d mean v a l u e s a r e t h e means o b t a i n e d a f t e r t h e age e f f e c t has been removed f r om t h e measures f o l l o w i n g t h e v a r i a n c e a n a l y s i s p r e s e n t e d i n T a b l e 4 . Means were compared by S c h e f f e t e s t , « = 0 . 1 0 . A r ea L A r ea M A r e a H Homogeneous D i f f e r i n g means means Ma l e s Head l e n g t h 59.91 ± 0 . 5 1 ( 5 5 ) 6 0 . 6 9 ± 0 . 5 6 ( 4 5 ) 6 0 . 8 5 ± 0 . 3 0 ( 1 5 9 ) L ,M,H none C r a n i a l b r e ad t h 19 .84 + 0 . 1 9 ( 54 ) 2 0 . 3 3 ± 0 . 2 0 ( 4 8 ) 2 1 . 6 6±0 . 11 (161) L,M H Hea r t we i g h t 1 . 7 8 + 0 . 0 5 ( 1 6 ) 1 . 7 5 + 0 . 0 4 ( 2 5 ) 1 . 9 5±0 . 02 ( 139 ) L,M ; L,H none K i d n e y we i gh t 0 . 5 4 ± 0 . 0 3 ( 1 1 ) 0 . 5 8 + 0 . 0 3 ( 1 0 ) 0 . 6 3 ± 0 . 0 1 ( 1 2 3 ) L ,M,H none Fema le s Head l e n g t h 5 7 . 0 9 ± 0 . 5 2 ( 4 0 ) 59 . 00±0 . 41 (64) 5 8 . 5 7 ± 0 . 4 1 (67) M,H L C r a n i a l b r e ad t h 1 8 . 2 5 ± 0 . 1 9 ( 3 9 ) 1 8 . 1 2±0 . 1 4 ( 70 ) 1 9 . 3 6 ± 0 . 1 5 (71) L,M H H e a r t w e i g h t 1 . 6 3 ± 0 . 0 5 ( 1 3 ) 1.61 ±0 .03 (39 ) 1 . 8 5 ± 0 . 0 3 (63) L,M H K i d n e y we i gh t 0 . 5 4 ± 0 . 0 2 (8) 0.51 ±0 .02 (19 ) 0.61 ±0.01 (54) L,M H 19 DISCUSSION The unders tand ing of p o p u l a t i o n r e g u l a t i o n i s r e l e v a n t to 3 important a spec t s of ungu la te management: c o n s e r v a t i o n , s u s t a i n e d y i e l d , and p o p u l a t i o n c o n t r o l . Caughley (1976) p resen ted a model of ungu la te p o p u l a t i o n dynamics w i th respec t to the ungu l a t e-vege t a t i on sys tem. In C a u g h l e y ' s model , an ungu la te p o p u l a t i o n w i th a growth r a te at or near ze ro ( i . e . , at e q u i l i b r i u m ) w i l l be food s t r e s s e d compared to a p o p u l a t i o n reduced much below the e q u i l i b r i u m d e n s i t y . The p resen t r e s u l t s on moose p o p u l a t i o n dynamics in southwestern Quebec are c o n t r a r y to C a u g h l e y ' s mode l , s p e c i f i c a l l y to the r e g u l a t o r y mechanism i m p l i e d r a the r than the gene r a l approach . In La Verendrye game r e s e r v e , a rea H, long-term data on p o p u l a t i o n d e n s i t y and ha rves t r a t e suggested t h a t : a) the p o p u l a t i o n was f a i r l y s t a b l e , b) i t s annual s u r p l u s was l e s s than 4%, and c) i t s d e n s i t y was not s u b s t a n t i a l l y lower than the e s t ima ted non-harvested p o p u l a t i o n d e n s i t y . T h i s study t e s t e d whether an imals in a rea H were n u t r i t i o n a l l y s t r e s s e d compared to the 2 o the r p o p u l a t i o n s at lower d e n s i t i e s wi th l e s s food c o m p e t i t i o n and a h ighe r p o p u l a t i o n growth r a t e . I d i d not de t e c t any d i f f e r e n c e s i n body development r a t e as a s sessed by the growth of head l e n g t h , c r a n i a l b r e a d t h , hear t we ight , and kidney we ight . D i f f e r e n c e s in the measurements were found w i th in age c l a s s e s , but c o n t r a r y to the p r e d i c t i o n s , none of them was lower in area H. In 4 cases the 20 va lues were s l i g h t l y but s i g n i f i c a n t l y h igher in a rea H ; a f a c t I cannot e x p l a i n r e a d i l y . One e x p l a n a t i o n i s that moose expe r i enced more f avourab l e f o r a g i n g c o n d i t i o n s in area H, but t h i s b e n e f i t was outweighed by another p o p u l a t i o n p rocess that p revented p o p u l a t i o n growth. There are two a l t e r n a t i v e e x p l a n a t i o n s fo r the l ack of ev idence of poorer body c o n d i t i o n as the p o p u l a t i o n growth r a te approaches zero ( i . e . , food resource r e g u l a t i o n ) . The f i r s t i s tha t I may have s e l e c t e d the wrong i n d i c e s . From food t r i a l expe r imen ts , Verme and Ozoga (1980a) demonstrated that c r a n i a l b readth and k idney weight of w h i t e - t a i l e d deer fawns (Oddco i l eus v i r g i n i a n u s ) are c o r r e l a t e d to p r o t e i n i n t a k e , whereas hear t weight i s a f f e c t e d by energy i n t a k e . Verme and Ozoga ' s f i n d i n g s were used fo r the j u s t i f i c a t i o n of these 3 body c o n d i t i o n i n d i c e s . In a d d i t i o n , head l eng th p rov ided a measure s p e c i f i c a l l y r e l a t e d to the s k e l e t a l growth, and moreover t h i s measure i s we l l r e l a t e d to c a r c a s s weight (Haigh et a l . 1980). Among the 3 a r e a s , the 2 s t r u c t u r a l and the 2 o r g a n - i n d i c e s l e ad to a common t r end (Table 5 ) . From t h i s c o n s i s t e n c y between i n d i c e s , I b e l i e v e tha t the combined i n f o rma t i on from the 4 i n d i c e s was s u f f i c i e n t to de tec t p o s s i b l e deg rada t i on of an imal body c o n d i t i o n . In a p a r a l l e l s tudy us i ng the same i n d i c e s , C re te (unpub l . ) found that the d u r a t i o n of the v e g e t a t i v e season s i g n i f i c a n t l y a f f e c t e d body growth of moose from d i f f e r e n t Quebec p o p u l a t i o n s . 21 Egress may have confounded the r e s u l t s . T h i s p o s s i b i l i t y i s u n l i k e l y f o r the f o l l o w i n g r easons . Moose in eas te rn Canada do not e x h i b i t seasona l d i r e c t i o n a l m i g r a t i o n s (Goddard 1970; Rousse l et a l . 1975; Add ison et a l . 1980; C re te u n p u b l . ) . Dur ing r a d i o - t r a c k i n g of over 60 moose w i t h i n the 3 study a r e a s , on ly 5 an imals (3 marked near a border ) moved between a reas (Crete u n p u b l . ) . From these o b s e r v a t i o n s , and c o n s i d e r i n g the l a rge s i z e of the study a r e a s , I assumed that the 3 moose p o p u l a t i o n s were d i s c r e t e . Even i f the d i s c r e t e n e s s i s su spec t , t h i s would not have v i t i a t e d r e s u l t s f o r c a l v e s and most y e a r l i n g s which are not yet at an age to d i s p e r s e (Gasaway et a l . 1980). The c o n c l u s i o n s would have been s i m i l a r r e l y i n g e x c l u s i v e l y on these data (see Tab le 2 and 3 ) . F e r t i l i t y of Ce rv idae has been r e l a t e d to the l e v e l of m a l n u t r i t i o n of females at the t ime of b r e e d i n g , and at the time they g i ve b i r t h ( B l ax t e r and Hami l ton 1980; Thomas 1982; Saether and Haagenrud 1983). In a rea H, the re was no ev idence of a low pregnancy ra te or low p o s t n a t a l c a l f p r o d u c t i o n . From 1964 to 1966 ( i . e . , f o l l o w i n g 25 years w i thout spor t h a r v e s t i n g ) , the number of c o r p o r a l u t e a p resen t was 35 per 100 y e a r l i n g cows (n=23), and 128 per 100 cows >2 1/2 y r . of age (n=132; Gau th i e r 1978). With the a i d of r a d i o - c o l l a r e d f ema les , C re te (unpubl . ) observed a minimum post-par tum p r o d u c t i v i t y of 96 c a l v e s per 100 cows >2 y r . of age ( i . e . , y e a r l i n g and o l de r cows at b reed ing time combined, n=26). 22 These i n d i c e s of p r o d u c t i v i t y are equa l or s u p e r i o r to the va lues r epo r t ed fo r o the r Nor th American moose p o p u l a t i o n s ( P im lo t t 1959; S ch l adwe i l e r and Stevens 1973; B lood 1973; S imkin 1974; Hauge and K e i t h 1981). C r e t e and Jordan (1982a) i n v e s t i g a t e d p r o d u c t i o n and q u a l i t y of both summer and winter moose forage in a reas H and L. They ma in ta ined tha t the p o p u l a t i o n growth of moose in area H was not l i m i t e d by h a b i t a t q u a l i t y . They a l s o showed tha t in a rea H the p r o p o r t i o n of i n-ya rd w inter forage removed by moose r a r e l y exceeded 10% (Crete and Jordan 1982b). Peek et a l . (1976) , and Peek and Eastman (1983) argued tha t an i n c r ease in moose p o p u l a t i o n i s the l i k e l y response to an a m e l i o r a t i o n of h a b i t a t q u a l i t y f o l l o w i n g d i s t u r b a n c e . Spruce budworm (Cho r i s t oneu ra fumiferama) had caused e x t e n s i v e m o r t a l i t y to c o n i f e r s in the study areas d u r i n g the e a r l y 1970 ' s . T h i s e p i s o d i c i n f e s t a t i o n en r i ched markedly the shrub s t r a t a in c o n i f e r o u s s tands (Crete and Jordan 1982a). Desp i t e t h a t , moose in area H d i d not respond by h ighe r r e c ru i tmen t and an i n c r ea se in d e n s i t y ( F i g . 2, Tab le 1 ) . T h i s o b s e r v a t i o n suppor ts the a s s e r t i o n tha t h a b i t a t q u a l i t y was not l i m i t i n g moose p o p u l a t i o n s . I conc lude t h a t , in southwestern Quebec, low moose p o p u l a t i o n growth r a te does not n e c e s s a r i l y r e f l e c t d e t e r i o r a t i o n of f o r a g i n g c o n d i t i o n s . A v a i l a b i l i t y of food r esources i s not s u f f i c i e n t to e x p l a i n n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s when d e n s i t y approaches 0.40 a n i m a l ' k n r 2 . 23 T h i s d e n s i t y appears to be the e q u i l i b r i u m d e n s i t y of moose in eas te rn Canada ( i . e . , bo r ea l f o r e s t ) where p r e d a t i o n occu r s (Crete et a l . 1981; Bergerud et a l . 1983; t h i s s t u d y ) . I showed tha t the p o p u l a t i o n growth r a te d i m i n i s h e d from 24% to 4% when d i f f e r e n t h a r v e s t i n g regimes a l l owed moose p o p u l a t i o n s to s t a b i l i z e at d e n s i t i e s rang ing from 0.17 to 0.37 a n i m a l ' k m - 2 . A long w i th t h i s d e c l i n e in the p o p u l a t i o n growth r a t e , there was no i n d i c a t i o n tha t moose body c o n d i t i o n d e t e r i o r a t e d . I would suggest t h a t , under these c o n d i t i o n s , management p o l i c y shou ld not be c en t e r ed on improv ing moose h a b i t a t when d e n s i t i e s are below 0.40 a n i m a l - k m " 2 . Because I c o u l d not f a l s i f y the n u l l h y p o t h e s i s , the study does not p rov ide a d e f i n i t i v e proof tha t a v a i l a b i l i t y of food r e sou r ces does not r egu l a t e moose in southwestern Quebec. The food r e g u l a t i o n hypo thes i s i s s t i l l v i a b l e , bu t , c o n s i d e r i n g a l l the e v i dence , t h i s h ypo thes i s c e r t a i n l y i s not very h e a l t h y . I con t i nue to f e e l the need fo r some c o n t r o l l e d s t u d i e s where the necessary c r i t e r i o n i s to r e l a t e a p o p u l a t i o n p rocess to the p o p u l a t i o n growth r a t e . As an a l t e r n a t i v e to food r e g u l a t i o n , I suggest tha t p r e d a t i o n by wolves and/or b lack bears may be d e n s i t y -dependent between 0.0 and 0.4 moose per km 2 , and thus has a r e g u l a t i n g c a p a b i l i t y . T h i s i s a t e s t a b l e h y p o t h e s i s , and a l r e ady proposed by C re te et a l . (1981) and Bergerud et a l . (1983) . 24 Chapter II SOCIAL ORGANIZATION, SPATIAL DISTRIBUTION, AND POPULATION DENSITY OF WOLVES IN RELATION TO MOOSE DENSITY INTRODUCTION The e f f e c t of wolf p r e d a t i o n on moose remains a q u e s t i o n of s u b s t a n t i a l t h e o r e t i c a l and a p p l i e d i n t e r e s t . Much of the p r e v i ous r e sea r ch has focussed p r i m a r i l y on a d e s c r i p t i v e approach : e . g . , e s t i m a t i o n of wolf numbers and t h e i r bas i c s o c i a l s t r u c t u r e , wolf food h a b i t s , prey s e l e c t i v i t y . , food in take r a t e , and a gene ra l e v a l u a t i o n of p r e d a t i o n ra te (Mech 1966; Haber 1977; Pe te rson 1977; F u l l e r and K e i t h 1980; Pe terson et a l . 1984b). R e l a t i v e l y l i t t l e work has been done toward unders tand ing c e r t a i n u n d e r l y i n g p rocesses and f u n c t i o n a l r e l a t i o n s h i p s by means of man ipu l a t i v e exper iments (Gasaway et a l . 1983; C re te and Mess i e r 1984; see a l s o Macnab 1983). In p a r t i c u l a r , s o l i d i n f o r m a t i o n i s l a c k i n g on the f u n c t i o n a l and numer i ca l responses of wolves to d i f f e r e n t moose d e n s i t i e s . Here , I p resent data on s o c i a l o r g a n i z a t i o n , s p a t i a l d i s t r i b u t i o n , and p o p u l a t i o n d e n s i t y of 2 wolf p o p u l a t i o n s r e l y i n g p r i m a r i l y on moose as p r e y . The study documents the wolf numer i ca l response and the important b e h a v i o u r a l 25 a t t r i b u t e s a s s o c i a t e d w i th t h i s p r o c e s s . One wolf p o p u l a t i o n expe r i enced r e l a t i v e l y h igh moose abundance due to low human e x p l o i t a t i o n , whereas the second i n h a b i t e d a con t i guous a rea where the moose p o p u l a t i o n had been reduced (manipulated) to about h a l f i t s n a t u r a l l y r e g u l a t e d d e n s i t y by h a r v e s t i n g . STUDY AREA AND METHODS The eco logy of wolves was i n v e s t i g a t e d in a 6400-km 2 a rea of southwestern Quebec, Canada ( 4 7 ° N , 77°W; F i g . 3) from June 1980 to February 1984. T h i s a rea was s e l e c t e d because i t covered a 3000-km 2 a rea of h i g h prey d e n s i t y (HP) in La Verendrye r e s e r v e , and a 3400-km 2 a rea of low prey d e n s i t y (LP) south of the rese rve ( F i g . 3 ) . The boundary of La Verendrye r ese r ve d e l i n e a t e d the HP a r e a . Moose, the predominant prey spec i e s of the wo l f , was at a s t a b l e d e n s i t y of 0.37 a n i m a l ' k m " 2 in HP, and d e c l i n e d d u r i n g the study from =0.25 a n i m a l " k m " 2 to =0.21 a n i m a l ' k m - 2 in LP (Mess ier and Cre te 1984). The n a t u r a l e q u i l i b r i u m d e n s i t y ( i . e . , non-harves ted ) was es t imated at 0.4 moose»km" 2 in HP (Mess ier and Cre te 1984). C re te et a l . (1981) p resen ted ev idence that moose d e n s i t y decreased a b r u p t l y (w i th in a few km) from the HP to the LP a r e a . Beaver (Castor canadens i s ) d e n s i t y was es t imated at 3.5 c o l o n i e s « 1 0 k m - 2 in HP, and at 1 co lony-10 km" 2 in LP (Crete and Samson u n p u b l . ; in 1981). Moose r ep resen ted approx imate l y 70% and beaver 15% of the annual 26 F i g . 3 . L o c a t i o n o f t h e a r e a where most o f t h e r a d i o t r a c k i n g o f wo l v e s was c o n d u c t e d . The number o f dee r h a r v e s t e d pe r 100 km 2 i n 1982 a r e p r e s e n t e d t o i l l u s t r a t e t h e dee r d i s t r i b u t i o n . 27 prey biomass i nges ted by wolves (Mess ier and Cre te in p r e s s ) . Deer , the on l y a l t e r n a t i v e ungu la te s p e c i e s , were p resen t southeas t of the study a rea ( F i g . 3 ) . Mess ie r and C re te (1984) have p resen ted i n f o r m a t i o n on other f e a t u r e s of the study a r e a . F i f t y - f o u r wolves from 14 con t iguous packs were r a d i o -t r a cked from an a i r p l a n e (methodology in Mech 1974). Some 4700 wolf l o c a t i o n s were accumulated d u r i n g 2000 h of f l y i n g t ime . Each year the f r e q u e n c i e s of t r a c k i n g f l i g h t s were 3-4 per week from 15 May to 1 November, a lmost d a i l y from 15 December to 1 A p r i l , and o c c a s i o n a l l y d u r i n g the remain ing p e r i o d s . Wolves were observed v i s u a l l y in 75% of the w inter l o c a t i o n s , but r a r e l y in o ther p e r i o d s . Each o b s e r v a t i o n i n c l u d e d group s i z e , whether or not a l l an ima ls were seen ( i . e . , in open h a b i t a t ) , and the i d e n t i t y of marked i n d i v i d u a l s . M o r t a l i t y ra te of wolves was c a l c u l a t e d from the cumu la t i ve r a d i o - t r a c k i n g t imes and the i n t e r i m d e a t h s . S u c c e s s f u l y e a r - s p e c i f i c r e p r o d u c t i o n was a s c e r t a i n e d when: 1) a pack i n c r e a s e d in s i z e from March to the f o l l o w i n g December p r o v i d i n g tha t f o c a l a c t i v i t y s i t e s (pup r e s t i n g a reas ) were observed in the i n t e r v e n i n g t ime , or 2) when at l e a s t one pup was cap tu red a f t e r Augus t . U n s u c c e s s f u l r e p r o d u c t i o n ( i . e . , no or f a i l e d r ep roduc t i on ) was a s c e r t a i n e d when: 1) a pack d i d not demonstrate f o c a l a c t i v i t y s i t e s in summer, or 2) when a p a i r remained as a p a i r from March to the f o l l o w i n g December. 28 I excepted 2 i n s t ances fo r which the a s s e r t i o n on r ep roduc t i on was u n c e r t a i n , 1 in HP and 1 in LP. Packs tha t had a t e r r i t o r y o v e r l a p p i n g HP and LP a r e a s , were a s s i gned to the a rea in which the pups had been r e a r e d . Wolf group ing was ana l y sed from 3 p e r s p e c t i v e s wi th s p e c i f i c meanings. In a l l c a s e s , I used those w in te r o b s e r v a t i o n s (December to A p r i l ) f o r which a l l wolves were counted r e l i a b l y . T h i s c o n d i t i o n o c c u r r e d f r e q u e n t l y in w in te r (=*70% of the v i s u a l o b s e r v a t i o n s ) because wolves tended to t r a v e l and r e s t in open areas such as l ake s h o r e s , s t reams, c l e a r c u t s t ands , and f o r e s t open ings . Moreover , about 40% of the f o r e s t stands in the a rea were dec iduous w i th good v i s i b i l i t y in w in t e r . T r a v e l l i n g group s i z e r ep resen ted the number of i n d i v i d u a l s w i t h i n a group when they moved about t h e i r t e r r i t o r y . T r a v e l l i n g group s i z e i s p a r t i c u l a r l y important in encounters wi th p rey . Pack s i z e r ep resen ted the number of s o c i a l l y i n t e r a c t i n g wolves w i t h i n a pack , and i n c l u d e d members t e m p o r a r i l y d i s s o c i a t e d from the pack . The assessment of pack s i z e r e l i e d on each p a c k ' s h i s t o r y ( i . e . , p ro longed o b s e r v a t i o n ) . Pack cohes i veness r e f e r s to the p r o p o r t i o n of pack members p resent in the pack core ( i . e . , the group i n c l u d i n g the r e p r o d u c t i v e p a i r ) at any g i ven t ime . For t h i s i ndex , a l l o b s e r v a t i o n s of a pack w i t h i n a 15-day p e r i o d were c o n s i d e r e d as one sample. T h i s r e s t r i c t i o n was imposed to a vo id b i a s among p e r i o d s . The yea r- long (1 May to 30 A p r i l ) t e r r i t o r i e s were 29 d e l i n e a t e d by the minimum-convex-polygon method us i ng 95% of the c l o s e s t l o c a t i o n s of ins t rumented pack member(s) . T e r r i t o r i e s were assumed to be d e f i n e d when the o b s e r v a t i o n -area-curve formed an asymptote (Mess ier and B a r r e t t e 1982; Bowen 1982; Bekoff and Mech 1984). Normal ly t h i s c o n d i t i o n was s a t i s f i e d a f t e r 40 to 80 d a i l y l o c a t i o n s , depending on the p a c k ' s r e p r o d u c t i v e s t a t u s and season . Radio f i x e s more than 5 km from the border of e s t a b l i s h e d t e r r i t o r y , were i n t e r p r e t e d as e x c u r s i o n s (Mess ier in p ress b) and were exc luded from the a n a l y s i s . I t was ev iden t tha t wolves engaged in e x c u r s i o n s of l e s s than 5 km, but I c o u l d not d i s c a r d these e x c u r s i o n s o b j e c t i v e l y because the c i r c u m s c r i p t i o n of a t e r r i t o r y was, to some e x t e n t , a r b i t r a r y ( i . e . , determined by the computa t iona l p r o c e d u r e ) . T h i s c o n s i d e r a t i o n j u s t i f i e d the use of the^95% convex-polygon method. On average , the areas of the 95% convex-polygons co r responded to 84% (±8% SD) of the 100% convex-po l ygons . Va lues of t e r r i t o r y s i z e were r eg ressed in r e l a t i o n to pack s i z e and moose d e n s i t y . Moose d e n s i t y e s t ima tes f o r the e n t i r e LP a r e a , HP a r e a , and fo r a t h i r d area east of HP (used f o r pack L8) have been p resen ted and d i s c u s s e d e lsewhere (Mess ier and Cre te 1984). Moose d e n s i t i e s were d e r i v e d from r e g r e s s i o n ana l y ses of y e a r l y e s t ima tes between 1976 and 1983 to min imize the y e a r - s p e c i f i c e r r o r . Moose d e n s i t y e s t ima tes of t e r r i t o r i e s encompassing 2 a reas were weighted by the area c o n t r i b u t e d and the r e s p e c t i v e d e n s i t y . I c o u l d not e va l ua t e 30 moose d e n s i t y w i t h i n each t e r r i t o r y d i r e c t l y . Thus , the a n a l y s i s c o n t a i n s an unde f ined v a r i ance l i n k e d wi th the h e t e r o g e n e i t y of moose d i s p e r s i o n . Wolf d e n s i t y in January was es t imated each year in the LP and the HP a r e a s . I used the t o t a l - a r ea-app roach because i t a l l ows i n c l u s i o n in the census area of i n t e r s t i c e s between t e r r i t o r i e s . The p o s s i b i l i t y of undetec ted p a i r s or packs in the census a rea was b e l i e v e d to be m in ima l . Dur ing the i n t ense ground p a t r o l l i n g and scann ing du r i ng f l i g h t s , s i g n s of known r e s i d e n t packs were f r e q u e n t l y n o t i c e d . I presume tha t the same would have been t rue fo r un t racked packs . For t e r r i t o r i e s p a r t i a l l y w i th i n a census a r e a , I m u l t i p l i e d the pack s i z e by the percentage of l o c a t i o n s in the census a rea ( i . e . , r e l a t i v e presence ) to a ssess the number of wolves to be used in the d e n s i t y e s t i m a t e s . Space-use p a t t e r n s were i l l u s t r a t e d by t y p i c a l s e t s of wolf l o c a t i o n s . For t h i s type of b e h a v i o r , i t was f e l t tha t a v i s u a l r e p r e s e n t a t i o n i s the s imp l e s t way to convey the i n f o r m a t i o n . More q u a n t i t a t i v e l y , d a i l y d i s t a n c e s ( i . e . , the d i s t a n c e between 2 c o n s e c u t i v e l o c a t i o n s sepa ra ted by 20 to 28 hours ) were t r e a t e d by cumu la t i ve f requency ana l y ses (Kolmogorov-Smirnov t e s t ) . I t was assumed that the d a i l y d i s t a n c e s r e f l e c t e d the a c t u a l d i s t a n c e s t r a v e l l e d by wolves . I d i v i d e d data i n t o 2 p e r i o d s : summer, 1 May to 30 November, and w i n t e r . In summer, because wolves were r a r e l y obse rved , I c o n s i d e r e d each pack member i ndependen t l y . I f 2 ins t rumented 31 an ima ls had t r a v e l l e d toge the r (same l o c a t i o n s ) on ly 1 movement was i n c l uded in the a n a l y s e s . In w i n t e r , d a i l y d i s t a n c e s of packs were q u a n t i f i e d e x c l u s i v e l y from the pack c o r e s . Nonparametr ic s t a t i s t i c a l t e s t s were used i f the assumpt ions of pa ramet r i c t e s t s were v i o l a t e d ( S i e g e l 1956; Soka l and Roh l f 1981). A l l t e s t s except F- tes t s were two-t a i l e d i f not o therwise s p e c i f i e d . Tes t s l e a d i n g to a p r o b a b i l i t y of r e j e c t i o n g rea t e r than 0.05 were judged to be not s i g n i f i c a n t . RESULTS M o r t a l i t y and reproduct ion Wolf s o c i a l o r g a n i z a t i o n r e l i e s on an extended f am i l y system. Thus , the in-group m o r t a l i t y and r e c ru i tmen t r ep resen t 2 important a t t r i b u t e s of the pack s i z e dynamics . O b s e r v a t i o n s of deaths (on ly an imals o l d e r than 3 months) i n d i c a t e tha t the annual m o r t a l i t y r a t e was h ighe r in LP (55%) than in HP (35%; Tab le 6 ) . These es t ima tes are l i k e l y h igh because more t r a c k i n g took p l a ce from October to February (54%) when wolves expe r i enced a h ighe r m o r t a l i t y r i s k , i . e . , the e x p l o i t a t i o n exe r t ed by man ( t r app ing and shoot ing ) was d i s t r i b u t e d e x c l u s i v e l y d u r i n g t h i s p e r i o d . Human-caused m o r t a l i t y was comparable in both study areas (30% in HP and 25% in LP a n n u a l l y , but was l i k e l y ove r-es t ima ted due to the T a b l e 6 . M o r t a l i t y o b s e r v a t i o n s f r om 54 wo l ve s (>3 months o f age) t r a c k e d d u r i n g t h e s t u d y . R a d i o - t r a c k i n g t ime when wo l v e s were i n s i d e t h e i r t e r r i t o r y i s r e f e r r e d t o as "home" , and when t h e y were o u t s i d e as " f o r a y " . A r e a T r a c k i n g t i m e ( i n w o l f - y e a r ) Home F o r a y N a t u r a l M o r t a l i t y Human-caused Ove r a l 1 M a l n u t r i t i o n S t r i f e Car T rap Gun Home Fo r a y HP LP T o t a l 2 0 . 2 19 .2 3 9 . 4 2 .2 2 .4 4 . 6 1 5 6 * 0 2 2 + 3 1 4 3 0 1 6 7 13 12 <t> 2 pups , 1 y e a r l i n g , 3 a d u l t s + 2 a d u l t s 33 y e a r l y d i s t r i b u t i o n of t r a c k i n g e f f o r t ) . Thus , the LP p o p u l a t i o n s u f f e r e d from a h ighe r m o r t a l i t y r a te because of the h ighe r occu r rence of n a t u r a l m o r t a l i t i e s such as m a l n u t r i t i o n and l e t h a l combat (Tab le 6 ) . Wolves had a h ighe r m o r t a l i t y ra te when t r a v e l l i n g over u n f a m i l i a r ground (Table 6 ) . Of 20 m o r t a l i t i e s , 7 o c cu r r ed d u r i n g e x t r a - t e r r i t o r i a l movements (3 from t r a p p i n g , 2 from m a l n u t r i t i o n , 1 c a r - k i l l e d , and 1 from i n t r a s p e c i f i c s t r i f e ) . C o n s i d e r i n g the r e s p e c t i v e t r a c k i n g t ime , the d i s t r i b u t i o n of m o r t a l i t i e s was not homogeneous (X 2 [ 1 ] = 12 .7 , P<0.01; Tab le 6 ) . D i r e c t counts of pups c o u l d not be conducted in t h i s s tudy due to the s e c r e t i v e nature of the wolves . In December, when most wolves were observed f o r the f i r s t t ime , pups c o u l d not be d i s t i n g u i s h e d from a d u l t s r e l i a b l y . None the l e s s , a d i f f e r e n c e in r e p r o d u c t i o n was apparent between HP and LP a r e a . In the HP a r e a , packs produced at l e a s t some pups in 14 of the 15 p o s s i b l e o c ca s i ons (93%). T h i s p r o p o r t i o n d i f f e r s s i g n i f i c a n t l y from the 62% observed in the LP a rea (n=21; one-t a i l e d Z-test = 2 . 1 , P=0.02) . Du r ing 3 u n s u c c e s s f u l o c c a s i o n s in LP , movements t y p i c a l of a den a t tendance were i n i t i a l l y obse r ved , but wolves subsequent l y resumed movements c h a r a c t e r i s t i c of non- rep roduc t i ve packs . 34 S o c i a l o r g a n i z a t i o n T r a v e l l i n g group s i z e in w inter averaged 2.7 i n d i v i d u a l s in HP and 2.3 in LP. Grouping of wolves d i f f e r e d s i g n i f i c a n t l y between the HP and the LP a reas (X 2 [3 ] = 3 7 . 5 , P<0.01; from o r i g i n a l f requency d i s t r i b u t i o n of wolf i n d i v i d u a l s ; F i g . 4 ) . S i n g l e wolves r ep resen ted as much as 46% of the groups encountered ( 1 8 % of the wo lves ; F i g . 4 ) , and were as f requent in the LP area as in the HP a r e a . More groups of 6 to 8 wolves were observed in the HP a r e a . In J anuary , pack s i z e averaged 5.7±0.5 (SE, n=12) i n d i v i d u a l s in the HP a r e a . T h i s es t imate was s i g n i f i c a n t l y l a r g e r than the average of 3.7±0.4 (n=20) observed in the LP a rea (t--test = 3 .9 , P<0.01) . From December to the end of March, average pack s i z e decreased by 6% in HP and 12% in LP. Prey abundance d i d not i n f l u e n c e s i g n i f i c a n t l y the decrement of pack s i z e through the winter ( o n e - t a i l e d Z-test = 1.2, P>0.10) . Pack c o h e s i v e n e s s , or the p r o p o r t i o n of the pack members in the pack c o r e , d e c l i n e d through the w in te r from about 0.90 to 0.75 ( F i g . 5 ) . The d e c l i n e appeared to be r e l a t e d to the h ighe r agg re s s i v enes s w i th in packs du r i ng the b reed ing season (Mess ier in p r e s s b; Pe te rson et a l . 1984b). No d i f f e r e n c e in pack cohes i v eness s was de tec t ed between LP and HP area (Mann-Whitney U- tes t [7 ,7 ] = 25, P > 0 . 2 0 ; . F i g . 5 ) . 35 5 0 r 40 n = 332 L P A R E A n=251 Vm H P A R E A 30 20 10 1111111' 10 20 30 40 2 - 3 4 - 5 6-8 T R A V E L L I N G G R O U P S I Z E F i g . 4. Grouping of wolves when they t r a v e l l e d in the LP or in the HP area. Sample sizes refer to the number of groups observed in winter. Fig. 5. December to March changes in the proportion of members forming the pack core ( i . e . , group cohesiveness) when packs were observed in the LP or in the HP area. 37 S p a t i a l d i s t r i b u t i o n T h i r t y yea r- long t e r r i t o r i e s were adequa te l y d e f i n e d in t h i s study ( i . e . , on l y t e r r i t o r i e s fo r which the o b s e r v a t i o n -area-curve asymptoted ; Tab le 7 ) . They ranged from 110 to 625 km 2 , and had a mean of 320±25 (SE) km 2 . T e r r i t o r y s i z e averaged 390±40 (SE) km2 in HP ( exc l ud ing pack H1 due to i t s s u b s t a n t i a l o v e r l a p between LP and HP), as compared to 255±20 (SE) km2 in LP . T h i s d i f f e r e n c e in t e r r i t o r y s i z e may have been caused by e i t h e r the d i f f e r e n c e in pack s i z e or moose d e n s i t y . The t e r r i t o r y - a r e a per wolf ( t e r r i t o r y s i z e pack s i z e ) was not c o r r e l a t e d to moose d e n s i t y (£=0 .14 , n=27, P>0.50; da ta in Tab le 7) and averaged 83 ± (SE)7 k m 2 « w o l f . In the o ther hand, pack s i z e was c o r r e l a t e d to moose d e n s i t y ( r=0.49 , n=27, P=0.01) . T h e r e f o r e , the l a r g e r t e r r i t o r i e s in the HP area was appa ren t l y r e l a t e d to the d i f f e r e n c e in pack s i z e . Each HP pack appeared to occupy the same gene ra l a rea throughout the s tudy . In the LP a r e a , 2 new p a i r s e s t a b l i s h e d t e r r i t o r i e s ( F i g . 6 ) , but the f a t e of 4 p a i r s was hazardous when I t e rm ina ted the study in January 1984. P robab l y , some of these p a i r s van i shed due to the death of 1 or both members. The t e r r i t o r y mosaic in the LP a rea was p robab l y more dynamic (h igher tu rnove r ) as a resulrt of low pack s i z e and marg ina l moose d e n s i t y . Maximum extent of i n t e r s t i c e s between t e r r i t o r i e s from 1981 to 1984 r ep resen ted 25%, 20%, 5%, and 5% of the HP area 38 r T a b l e 7 . Summary o f d a t a r e g a r d i n g w o l f t e r r i t o r i e s a d e q u a t e l y d e f i n e d , and t h e r e s p e c t i v e pack s i z e and moose d e n s i t y ( s ee m e t h o d s ) . Pack I . D . Yea r T e r r i t o r y ( km 2 ) Pack s i z e Moose ( N o . / k m 2 ) No. f i x e s HI 1980-81 305 2 0 . 29 53 HI 1981-82 340 6 0 . 27 222 HI 1982-83 575 5 0 . 2 8 245 HI 1983-84 475 6 0 . 27 117 H2 1980-81 425 7 0 . 37 163 H2 1981-82 500 6 0 . 34 340 H2 1982-83 625 7 0 . 34 409 H2 1983-84 350 3 0 . 37 112 H4 1981-82 215 4 0 . 37 87 H4 1982-83 210 ? 0 .37 68 H5 1983-84 285 ? 0 .37 109 H6 1982-83 430 8 0 . 34 166 H6 1983-84 380 7 0 . 34 120 H8 1982-83 440 ? 0 .37 37 LI 1981-82 275 3 0 . 24 74 L2 1980-81 300 4 0 . 25 45 L2 1981-82 225 4 0 . 24 81 L2 1982-83 295 3 0 . 23 96 L2 1983-84 250 2 0 .21 58 L3 1982-83 285 2 0 . 2 3 68 L4 1980-81 130 2 0 . 25 32 L4 1981-82 145 5 0 . 24 103 L4 1982-83 185 6 0 . 23 256 L4 1983-84 165 6 0 .21 98 L5 1982-83 400 6 0 . 2 3 114 L5 1983-84 330 3 0 .21 54 L6 1983-84 190 2 0.21 55 L7 1982 -83 245 4 0 . 23 45 L8 1981-82 365 3 0 . 22 84 L8 1982-83 300 2 0 . 22 60 39 F i g . 6. D e p i c t i o n o f t h e a r e a s used a n n u a l l y (May t o A p r i l ) by i n d i v i d u a l packs d u r i n g t h e s t u d y p e r i o d . E l l i p s e s r e p r e s e n t t h e a p p r o x i m a t e l o c a t i o n o f pack s known t o be p r e s e n t bu t no t r a d i o - t r a c k e d . The p e r c e n t a g e s a l o n g t h e b o r d e r o f a c ensus a r e a c o r r e s p o n d t o t h e p r o p o r t i o n o f pack l o c a t i o n s w i t h i n t h e c en su s a r e a . 40 (average = 15%), and 55%, 55%, 45%, and 30% of the LP area (average = 45%; F i g . 6 ) . These percentages are somewhat ove res t ima ted because not a l l t e r r i t o r i e s were d e f i n e d adequa te l y each y e a r . The mu l t i - yea r t e r r i t o r y mosaic ( F i g . 7) p r o v i d e s a b e t t e r i l l u s t r a t i o n of the a c t u a l t e r r i t o r y s e t t l e m e n t . Some t e r r i t o r y s e c t o r s were used i n f r e q u e n t l y which means t h a t , w i t h i n a 1-year p e r i o d , some of these s e c t o r s c o u l d have been missed by chance . O v e r a l l , the t e r r i t o r y mosaic appeared to be s a tu r a t ed in the HP a r e a , whereas i n t e r s t i c e s s t i l l accounted fo r =30% of the LP area ( F i g . 7 ) . Wolf d e n s i t y in the HP area was es t ima ted at 1.2, 1.3, 1.5, and 1.5 animals-100 km" 2 in January of 1981, ' 8 2 , ' 8 3 , ' 8 4 , r e s p e c t i v e l y (average = 1.4) . Co r respond ing va lues in LP a rea were 0 .6 , 1.0, 0 .8 , 0.9 wolf-100 km" 2 (average = 0 . 8 ) . I n e v i t a b l y , there was some s u b j e c t i v i t y on how to d e l i n e a t e the census areas (see F i g . 6 ) . The main c r i t e r i a were to enc lose on l y t e r r i t o r i e s of known pack s i z e , and to be c o n f i d e n t tha t the census a rea d i d not c o n t a i n r e s i d e n t and un t racked packs . C o n s i d e r i n g the l i m i t e d number of packs moni tored each yea r , on ly the average d e n s i t y v a l u e s ' a r e r e t a i n e d f o r d i s c u s s i o n . In summer, wolf d e n s i t y was es t ima ted at 2.1 animals-100 km" 2 in area HP, and at 1.2 animals-100 km" 2 in area LP. Summer d e n s i t i e s were de r i v ed from the observed January- Ju ly m o r t a l i t y (9% in area H, 17% in area M) and an assumed rec ru i tmen t of 4 pups fo r every packs 41 I L F i g . 7. D e p i c t i o n o f t h e t e r r i t o r y s e t t l e m e n t i n , t h e LP and t h e HP a r e a s f r om t h e p o o l e d d a t a between 1980 and 1984. The a pp r o x ima t e e l l i p s o i d a l t e r r i t o r y (H7) was h e l d by a n o n - r a d i o - c o l l a r e d pack ( l i m i t e d g round a c c e s s i b i l i t y ) f o r wh i c h t h e p r e s e n c e was c e r t i f i e d many t i m e s by a e r i a l o b s e r v a t i o n s . 42 which reproduced s u c c e s s f u l l y (93% of packs in area H, 62% in a rea M). Two wolves were c o n s t a n t l y observed a lone (Mess ier in p ress b) and they both t r a v e l l e d over the LP and HP a r e a s . The d e n s i t y e s t ima tes d i d not i n c l u d e lone wo lves . Space-use p a t t e r n s of pack members d i f f e r e d markedly wi th the p a c k ' s r e p r o d u c t i v e s t a t u s and the season . In summer, pups were g e n e r a l l y found e i t h e r at the n a t a l den or at a rendezvous s i t e . The s e d e n t a r i n e s s of pups f o r c ed a d u l t s to forage r a d i a l l y , and t h i s e f f e c t was q u i t e obv ious when m o n i t o r i n g r e p r o d u c t i v e packs ( F i g . 8a , c ) . In some packs , pups were moved o c c a s i o n a l l y d u r i n g summer. These changes produced a sudden and q u i t e n o t i c e a b l e s h i f t in movements of a d u l t wolves ( F i g . 9c_) . Y e a r l i n g s and young non-reproduc t i ve a d u l t s were l e s s a f f e c t e d by the presence of pups . They t r a v e l l e d e x t e n s i v e l y throughout the p a c k ' s t e r r i t o r y , and o c c a s i o n a l l y wi thout any apparent v i s i t s to the pups (Mess ier in p ress b ) . Non-reproduc t i ve packs p a t r o l l e d t h e i r t e r r i t o r y f r e e l y and used i t more homogeneously ( F i g . 9a , b ) . In w in t e r , p resence of moose c a r c a s s e s markedly i n f l u e n c e d pack movements ( F i g . 8b, c ) . When wolves used a moose c a r c a s s , r e s u l t i n g e i t h e r from p r e d a t i o n or other n a t u r a l m o r t a l i t y , they tended to s tay in i t s v i c i n i t y (o f ten s l e e p i n g bes ide i t ) f o r up to 3 weeks (Mess ier and Cre te 1984). The r e l a t i v e l y low pack s i z e in the study area p e r m i t t e d p ro longed consumption of a moose c a r c a s s . These t y p i c a l movements c r e a t e d a clumped d i s t r i b u t i o n of w inter 43 — WOLF PACK TERRITORIES * MOOSE C A R C A S S E S • WOLF LOCATIONS • CARRION OR GUT PILES X PUP RESTING AREAS F i g . 8 . S p a c e - u s e p a t t e r n s o f packs H6 and L4 d u r i n g t h e s u m m e r p e r i o d (May t o November ) , as compared t o t h e w i n t e r p e r i o d (December t o A p r i l ) . 44 WOLF PACK TERRITORIES APPROX. NORTHERN LIMIT OF DEER • WOLF LOCATIONS X PUP RESTING AREAS * MOOSE C A R C A S S E S * DEER C A R C A S S E S • CARRION OR GUT PILES 0 DUMP L5, SUMMER 1983 H8, SUMMER 1982 II F i g . 9 . S p a c e - u s e p a t t e r n s o f 2 n o n - r e p r o d u c t i v e packs (L5 and H8) d u r i n g t h e summer p e r i o d , and t h e r e p r e s e n t a t i o n o f t h e s e a s o n a l t e r r i t o r y s h i f t d emons t r a t e d by t h e pack H2. 45 l o c a t i o n s . Two packs , H1 and H2, repeated a t r a d i t i o n a l p a t t e r n of movements which can be d e s c r i b e d as a seasona l t e r r i t o r y ex t ens i on ( F i g . 9c, d ) . T y p i c a l l y , pack H2 moved southeast at the onset of winter and e x p l o i t e d an area where at l e a s t 3 sma l l c o n c e n t r a t i o n s of deer were s i t u a t e d . The t r i p norma l l y l a s t e d 1 or 2 weeks, and was repea ted a few t imes du r i ng the w i n t e r . A s i m i l a r sou theas t e rn t e r r i t o r y e x t e n s i o n was observed fo r pack H1, but in t h i s c a s e , farm and butchery o f f a l were used in a d d i t i o n to 1 deer w i n t e r i n g a r e a . In both packs , deer k i l l s were observed p e r i o d i c a l l y . Deer e x p l o i t a t i o n l i k e l y r ep resen ted the p r i n c i p a l m o t i v a t i o n fo r these t e r r i t o r y e x t e n s i o n s . Packs H1 and H2 always rea red t h e i r pups w i t h i n the p o r t i o n of t h e i r range i n h a b i t e d by very few, i f any, dee r . The a n a l y s i s of d a i l y d i s t a n c e s ( F i g . 10) r e vea l ed t h a t , d u r i n g the summer, r e p r o d u c t i v e packs t r a v e l l e d more e x t e n s i v e l y in the LP a rea than in the HP area (Kolmogorov-Smirnov (K-S) o n e - t a i l e d t e s t , D[421,202] = 0 .10 , P=0.05) . L i k e w i s e , non- rep roduc t i ve packs moved g rea t e r d i s t a n c e s in the LP a rea (K-S t e s t , D[26,89] = 0 .28 , P=0.04) . Summer appears to be the c r i t i c a l season to a cqu i r e an adequate q u a n t i t y of food (Peterson et a l . 1984b). Non-reproduc t i ve packs wandered more f r e e l y than r e p r o d u c t i v e packs (K-S t e s t , D[623,115] = 0 .18, P<0.01; combined data of LP and HP). In w i n t e r , the a n a l y s i s of d a i l y d i s t a n c e s r e vea l ed no 46 0 2 4 6 8 10 12 14 DAILY D ISTANCE (km) F i g . 10. C u m u l a t i v e r e l a t i v e f r e q u e n c i e s f o r t h e i n - t e r r i t o r y d a i l y d i s t a n c e s o f r e p r o d u c t i v e and n o n - r e p r o d u c t i v e packs d u r i n g t h e summer p e r i o d . In t h i s a n a l y s i s , t h e a r e a o f a f f i l i a t i o n o f each pack was t h e one i n wh i c h pups had been r e a r e d . 47 d i f f e r e n c e between LP and HP packs (K-S t e s t , D[451,296] = 0 .04 , P>0.20; F i g . 11) . D i s s o c i a t e d , s i n g l e pack members t r a v e l l e d s i m i l a r d i s t a n c e s i n s i d e or o u t s i d e the p a c k ' s t e r r i t o r y (K-S t e s t , D[120,130] = 0 .04 , P>0.20; combined data of LP and HP) . Packs and s i n g l e an ima ls ( i . e . , lone wolves and s o l i t a r y pack members) d i d not d i f f e r in t h e i r t r a v e l l i n g (K-S t e s t , D[747,566] = 0 .04 , P>0.20; combined data of LP and HP) . DISCUSSION R e c e n t l y , changes in wolf d e n s i t y have been l i n k e d to n u t r i t i o n a l s t a t u s (Packard and Mech 1980; K e i t h 1983). P resent r e s u l t s , where wolf eco logy has been i n v e s t i g a t e d at 2 l e v e l s of prey abundance, c o r r o b o r a t e t h i s v iew. Low moose d e n s i t y in the LP a rea r e s u l t e d in a wolf d e n s i t y app rox ima te l y 40% lower than in the HP a r e a . T h i s d e n s i t y d i f f e r e n c e r e s u l t e d from n a t u r a l p o p u l a t i o n p r o c e s s e s , i . e . , the LP wolves s u f f e r e d from a h ighe r m o r t a l i t y r a te due to deaths from m a l n u t r i t i o n and i n t r a s p e c i f i c combat. F u r t h e r , and p robab l y of g r ea t e r impor tance , LP packs had a much lower success in r e p r o d u c t i o n . Human-caused m o r t a l i t y was s i m i l a r in both study areas and cannot e x p l a i n the d i s p a r i t y in wolf d e n s i t i e s . E x t r a - t e r r i t o r i a l e x c u r s i o n s were commonly w i tnessed in t h i s s tudy , p a r t i c u l a r l y in the LP area (Mess ier in p ress b, 1.0 • • 1 1 1 • . . . . . • 0 2 4 6 8 10 12 14 DAILY DISTANCE (km) F i g . 11. C u m u l a t i v e r e l a t i v e f r e q u e n c i e s f o r t h e i n - t e r r i t o r y d a i l y d i s t a n c e s o f pack s d u r i n g t h e w i n t e r p e r i o d . A l s o p r e s e n t e d i s t h e d a i l y d i s t a n c e f r e q u e n c y o f s i n g l e wo l v e s ( l o n e a n i m a l s o r pack members d i s s o c i a t e d f r om t h e pack more t h an 5 d a y s ) d u r i n g t h e same p e r i o d . 49 or Append ix ) . Food s t r e s s upon packs e n t a i l e d hazardous e x t r a - t e r r i t o r i a l movements and may have caused some human-r e l a t e d deaths ( i . e . , concea l ed n a t u r a l m o r t a l i t y ) . P o s s i b l y , human-caused m o r t a l i t y a l t e r e d group dynamics of some packs , but not s u f f i c i e n t l y to i n v a l i d a t e the p r e ced ing d e s c r i p t i o n of pack s o c i a l o r g a n i s a t i o n . N a t u r a l m o r t a l i t y ( i n c l u d i n g the non-measured pup m o r t a l i t y ) and f a i l u r e in r e p r o d u c t i o n had a f a r - r e a c h i n g e f f e c t on pack dynamics . Pack s i z e , yea r- long t e r r i t o r y s i z e , and i n t e r s t i c e s between t e r r i t o r i e s p o t e n t i a l l y i n f l u e n c e wolf d e n s i t y . From a broad examinat ion of wolf p o p u l a t i o n s a c r o s s Nor th Amer i ca , pack s i z e appears to be i n t i m a t e l y r e l a t e d to moose d e n s i t y (Table 8 ) . The mechanism u n d e r l y i n g the r e g u l a t i o n of pack s i z e i s complex and i m p e r f e c t l y unders tood (Zimen 1976, 1982; Packard and Mech 1980). An i n c r ease in prey abundance seems to produce a d i r e c t increment in the in-group r ec ru i tmen t and s u r v i v a l r a t e s (Ke i th 1983). Moreover , pack s i z e may be r e l a t e d to the d i s p e r s a l s t r a t e g y of pack members. As prey abundance i n c r e a s e s , the t e r r i t o r y mosaic becomes p r o g r e s s i v e l y s a tu r a t ed ( lower t e r r i t o r y vacancy ; F i g . 7) which c o u l d provoke de l ayed d i s p e r s a l (Packard and Mech 1980; a l s o Mess i e r and B a r r e t t e 1982). Thus , g i ven the r a r i t y of vacant a r e a s , a matur ing wolf might b e n e f i t more by t r y i n g to o b t a i n r e p r o d u c t i v e s t a t u s w i t h i n i t s pack than by d i s p e r s i n g ; i . e . , a non-d i spe rse r c o u l d take advantage of the a b i l i t y of the e n t i r e pack to defend a space in which i t may e v e n t u a l l y 50 T a b l e 8 . E a r l y w i n t e r pack s i z e , w o l f and moose d e n s i t i e s r e p o r t e d f o r d i f f e r e n t b o r e a l e co s y s t ems i n N o r t h A m e r i c a . On l y s t u d i e s f o r wh i c h moose c o n s t i t u t e d t h e ma jo r p r ey s p e c i e s o f wo l v e s a r e i n c l u d e d . A r e a Wo l f / 1 00 km? Pack s i z e Moose /km 2 S ou r c e S.W. Quebec (LP a r e a ) 0 .8 3 .7 0 . 2 T h i s s t u d y N .E . A l b e r t a ( A t h aba s c a R i v e r ) 0 .8 4 . 4 # 0 . 3 F u l l e r and K e i t h 1980 N.W. O n t a r i o (Pukaskwa) 1 .5 4 . 0 # 0 . 4 B e r g e r ud e t a l . 1983 f r om T a b l e 1 S.W. Quebec (HP a r ea ) 1 .4 5.7 0 . 4 T h i s s t u d y S . A l a s k a (Kena i P e n i n s u l a ) 1 .1 - 2 . ,0 11 .2 0 . 8 P e t e r s o n e t a l . 1984 I s l e R o y a l e , MI (1971 - ' 8 4 ) 2, .0 - 9 . 5 8 . 6 1 . 0 - 2 . 2 P e t e r s o n e t a l . u n p u b l . I s l e R o y a l e , MI ( 1 9 5 9 - ' 7 0 ) 3, .1 - 5 . .1 11.1 1 . 5 - 2 . 6 P e t e r s o n 1977 # Minimum e s t i m a t e based on c u r s o r y o b s e r v a t i o n s o f n o n - r a d i o - c o l l a r e d p a c k s . 51 b r e e d . T h i s advantage c o u l d be c r u c i a l in a h i g h l y s a tu r a t ed c o n d i t i o n . T e r r i t o r y s i z e appears to be governed l a r g e l y by pack s i z e and prey abundance. Pe te rson et a l . (1984b) found a s i g n i f i c a n t e x p o n e n t i a l r e l a t i o n s h i p between pack s i z e (^3) and t e r r i t o r y s i z e . I showed tha t t e r r i t o r i e s were l a r g e r in the HP area because pack s i z e was g r e a t e r . Bowen (1982) found tha t t e r r i t o r y s i z e in coyotes (Canis l a t r a n s ) was p o s i t i v e l y r e l a t e d to f am i l y s i z e . Thus , m o d e l l i n g the adjustment of wolf t e r r i t o r y s i z e to changing moose d e n s i t y , w i thout c o n s i d e r i n g the concur ren t i n f l u e n c e of pack s i z e ( e . g . , Wa l te r s et a l . 1981), shou ld not be expected to r e f l e c t r e a l i t y . Wa l te rs et a l . (1981) suggested that t e r r i t o r y s i z e shou ld be i n v e r s e l y r e l a t e d to prey d e n s i t y so as to prevent d e p l e t i o n of prey w i th in each t e r r i t o r y . I would recommend use of the t e r r i t o r y - a r e a per wolf in such a r e l a t i o n , because of the confound ing e f f e c t of pack s i z e . Data here i n d i c a t e tha t between 0.2 and 0.4 moose«km" 2 , t e r r i t o r y - a r e a per wolf i s independent of moose abundance. When wolves are f a c i n g low moose d e n s i t i e s as he re , w i thout the presence of a l t e r n a t i v e ungu la te s p e c i e s , they seem to ma in ta in a cons t an t a rea per i n d i v i d u a l but they i n t e n s i f y the e x p l o i t a t i o n of t h e i r t e r r i t o r y i f moose d e n s i t y d e c r e a s e s . Wolves can ach ieve t h i s g o a l : 1) by p e r s e v e r i n g in each moose a t t a ck (many exceed ing 1 day and up to 5 d a y s ) , 2) by u s i ng each c a r c a s s t ho rough l y , 3) 52 by f eed ing on a l t e r n a t i v e and p o s s i b l y second cho i ce food r e sou r ces (Mess ier and Cre te in p ress fo r s tatements 1, 2, and 3 ) , and 4) by p a t r o l l i n g t h e i r t e r r i t o r y more i n t e n s e l y . In regard to the l a s t s ta tement , d a i l y d i s t a n c e s of LP packs were on average e i t h e r g r ea t e r (summer) or equa l (winter ) to d a i l y d i s t a n c e s of HP packs . However, t e r r i t o r y s i z e was approx ima te l y 35% sma l l e r in the LP area which suppor ts the f a c t that wolves were sea r ch ing each u n i t a rea at g r ea t e r i n t e n s i t y . Ac ross a l a rge range of moose d e n s i t i e s , t e r r i t o r y - a r e a per wolf appears to be i n v e r s e l y r e l a t e d to moose d e n s i t y . At 0 .2-0.4 moose-km" 2 , each wolf occup ied approx imate l y 85 km2 ( t h i s s t u d y ) . At 0.8 moose«km" 2 (Kenai P e n i n s u l a , A l a s k a ) , Pe te rson et a l . (1984) found an average f i g u r e of 55 k m 2 « w o l f . At 1.0-2.6 moose-km - 2 ( I s l e Roya le , M i c h i g a n ) , Pe te rson et a l . (1977 and unpub l . ) r e p o r t e d a range of 10-90 km 2 -wol f . Thus , the i nve r se r e l a t i o n s h i p proposed by Wa l te rs et a l . (1981) i s t enab le when the e f f e c t of pack s i z e i s c o n s i d e r e d . P resent r e s u l t s i n d i c a t e that a d e n s i t y of 0.2 moose«km~ 2 may rep resen t the d e n s i t y t h r e s h o l d below which a pack cannot s u b s i s t and/or reproduce s u c c e s s f u l l y . In the LP a rea (-0.23 moose•km" 2 ) , wolves o l d e r than 1 year of age tend t o : 1) p e r i s h from m a l n u t r i t i o n , 2) reproduce p o o r l y , 3) d i s s o c i a t e from t h e i r pack commonly (Mess ier in p ress b ) , and 4) engage in e x t r a - t e r r i t o r i a l e x c u r s i o n s f r e q u e n t l y (Mess ier in p ress b ) . A l l of which l e ad to an uns tab l e s o c i a l o r g a n i z a t i o n . In 53 w i n t e r , LP packs used an average of 3.2 moose per 100 days which i s f a r below the average found in the HP area (6.2) and tha t of 15 to 20 moose per 100 days observed in other s t u d i e s conducted at h igher moose d e n s i t i e s (Peterson 1977; F u l l e r and K e i t h 1980; Pe terson et a l . 1984b; moose d e n s i t y in Tab le 8 ) . As a gene ra l consequence of the marg ina l pack s i z e in the LP a rea ( 3 . 7 ) , the t e r r i t o r y mosaic appeared to be r e l a t i v e l y l e s s s t a b l e than in the HP a r e a , presumably w i th the o c c a s i o n a l fo rmat ion and d i sappearance of c e r t a i n packs . At a d e n s i t y of =0.23 moose*km~ 2 (LP a r e a ) , i n t e r s t i c e s between t e r r i t o r i e s were p resen t (=30% of the t o t a l a r e a ; F i g . 7 ) , and d i d not prevent the enlargement of t e r r i t o r i e s . The h a b i t a t w i th i n i n t e r s t i c e s was not n o t i c e a b l y d i f f e r e n t from that of su r round ing a r e a s . At a d e n s i t y of 0.37 moose*km" 2 (HP a r e a ) , the t e r r i t o r y mosaic appeared to be s a t u r a t e d ; i n t e r s t i c e s be ing f i l l e d from l a r g e r r a the r than a d d i t i o n a l t e r r i t o r i e s . The g rea te r abundance of the HP moose p o p u l a t i o n f a c i l i t a t e d the use of more e x t e n s i v e t e r r i t o r i e s by l a r g e r ( l e s s f ood-cons t r a i ned ) packs . HP wolf d e n s i t y accounted f o r 1.4 an imals*100 k m " 2 , a low dens i t y " compared to the p o s s i b l e d e n s i t y of 1 to 10 wolves-100 km" 2 r epo r t ed in many other wo l f-ungu la te s t u d i e s (Table 8; review in K e i t h 1983). The HP moose p o p u l a t i o n was s t a b l e and very c l o s e to the e s t ima ted n a t u r a l e q u i l i b r i u m d e n s i t y of 0.4 a n im a l * km" 2 (Mess ier and Cre te 1984; from a n a l y s i s of long-term d a t a ) ; a g a i n , a r e l a t i v e l y low d e n s i t y compared to the 2 54 to 4 moose«kir r 2 observed where p r e d a t i o n does not occur (Bergerud and Manuel 1969; B lood 1973). T h e r e f o r e , I concur w i th P i m l o t t (1967) who was one of the f i r s t to propose that wo l f -ungu la te systems, i f n a t u r a l l y r e g u l a t e d , may s t a b i l i z e at low prey and low p reda to r d e n s i t i e s ( a l so K e i t h 1974; Bergerud 1980; Bergerud et a l . 1983; Gasaway et a l . 1983). 55 Chapter III MOOSE-WOLF DYNAMICS INTRODUCTION P resent theory on the n a t u r a l r e g u l a t i o n of Nor th American moose p o p u l a t i o n s i s ambiguous. Peek and Eastman (1983) h y p o t h e s i z e d that moose p o p u l a t i o n s f l u c t u a t e wi th forage a v a i l a b i l i t y . They r e j e c t e d the no t i on that p r e d a t i o n may r ep resen t a b a s i c r e g u l a t i n g f a c t o r of moose numbers, a l t hough they r e c o g n i z e d that p r e d a t i o n d i m i n i s h e s moose p r o d u c t i v i t y and s u r v i v a l . Wa l te rs et a l . (1981) , and Gasaway et a l . (1983) suggested tha t p r e d a t i o n may become an i n c r e a s i n g l y important ( i . e . , depensatory ) m o r t a l i t y agent as a moose p o p u l a t i o n d e c r e a s e s . Both groups of au thors argued tha t t h i s i n v e r s e l y dens i ty-dependent e f f e c t may prevent a moose p o p u l a t i o n from i n c r e a s i n g i f , p r e v i o u s l y , an e x t r i n s i c m o r t a l i t y f a c t o r ( e . g . , e x t r a hunt ing ) caused t h i s p o p u l a t i o n to d e c l i n e ; o the rw i se , they p r e d i c t e d that food r e sou r ces would c o n s t i t u t e the u l t i m a t e r e g u l a t o r y agent . Pe te rson and Page (1983) r epo r t ed an example where a wolf p o p u l a t i o n a p p a r e n t l y induced i n s t a b i l i t y in a moose p o p u l a t i o n . They ma in ta ined tha t such a system would be c h a r a c t e r i z e d by long term p reda to r-p rey c y c l e s . C re t e et a l . (1981) , Bergerud et 56 a l . (1983) , and Mess i e r and C re te (1984) proposed that p r e d a t i o n by wolves may be dens i t y-dependent and r egu l a t e moose p o p u l a t i o n s we l l below the d e n s i t y which c o u l d be s u s t a i n e d by a v a i l a b l e food r e s o u r c e s . To r e s o l v e these compet ing hypo theses , the problem i s best approached by means of man ipu l a t i v e or n a t u r a l exper iments ( e . g . , Gasaway et a l . 1983; C re te and Mess ie r 1984; Mess ie r and Cre te 1984; see a l s o Macnab 1983). In p a r t i c u l a r , the concept of moose p o p u l a t i o n dynamics may l o se much of i t s p resent comp lex i t y and myst ique when the f u n c t i o n a l and numer i ca l responses of wolves to changing moose d e n s i t y w i l l be b e t t e r unde r s tood . T h i s study at tempted to t e s t whether or not moose were n a t u r a l l y r egu l a t ed by p r e d a t o r s . In southwestern Quebec, non-harves ted moose p o p u l a t i o n s s t a b i l i z e at a d e n s i t y of =0.40 a n i m a l ' k m - 2 (Mess ier and C re te 1984). Body c o n d i t i o n of moose was i n v e s t i g a t e d near t h i s e q u i l i b r i u m d e n s i t y (0.37 an ima l•km" 2 ) and at 2 lower d e n s i t i e s (0.22 and 0.17 a n i m a l ' k m " 2 ) c r e a t ed by more i n t e n s i v e h a r v e s t i n g . Based on the body c o n d i t i o n data and r e l a t e d e v i d e n c e , Mess i e r and C re t e (1984) conc luded tha t a v a i l a b i l i t y of food resources was not s u f f i c i e n t to e x p l a i n n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s when d e n s i t y approaches 0.40 a n i m a l « k m " 2 . Here , u s i ng the same 3 p o p u l a t i o n s , I ana l yse p r e d a t i o n by wolves . I show that t h i s m o r t a l i t y f a c t o r i s dens i t y-dependent and thus has a r e g u l a t o r y c a p a b i l i t y . I n fo rmat ion p resen ted 57 i n c l u d e s : wolf f eed ing e c o l o g y , prey s e l e c t i v i t y , k i l l i n g r a t e s , hand l i ng t imes , moose:wolf r a t i o s , and p r e d a t i o n r a t e s on moose. STUDY AREAS AND METHODS The 3 study areas are l o c a t e d w i t h i n the most p r o d u c t i v e moose h a b i t a t in Quebec (B rassard et a l . 1974; F i g . 1; 4 7 ° N , 7 7 ° W ) . Area H, the game rese rve La Verendrye (13,615 km 2 ) , had a s t a b l e d e n s i t y of 0.37 animal • k i r r 2 . Moose d e n s i t y in a rea M (2390 km 2) d e c l i n e d from =0.25 to =0.21 an imal-k i r r 2 d u r i n g the s tudy . Area L (1185 km 2) had a r e l a t i v e l y low and s t a b l e moose d e n s i t y of 0.17 an ima l *km" 2 (Mess ier and Cre te 1984). Moose d e n s i t i e s shou ld be reasonab ly accu ra te because they were c o r r e c t e d fo r v i s i b i l i t y b i a s (Crete et a l . s u b m i t t e d ; wi th a i d of r a d i o - c o l l a r e d moose) . However, the y e a r - s p e c i f i c i m p r e c i s i o n i s s t i l l unknown. Moose d e n s i t i e s were d e r i v e d by r e g r e s s i n g y ea r l y es t imates from 1976 to 1983 to reduce the annual v a r i a b i l i t y . Wolf eco logy was s t u d i e d from June 1980 to February 1984 in a 6400-km 2 s e c to r o v e r l a p p i n g the 3 study areas ( F i g . 1 and 3 ) . The s c a r c i t y of wolves in a rea L d i d not permit us to ob ta in complete i n fo rma t i on t h e r e . Food h a b i t s of wolves were determined from scat a n a l y s i s in summer (May to November) and d i r e c t obse r va t i ons in winter (December to A p r i l ) . Scat a n a l y s i s was not used in winter because s ca t s were u s u a l l y 58 found du r i ng a u t o p s i e s of k i l l s . In summer, scat sampl ing was independent of wolf a c t i v i t i e s . F r e sh s ca t s (<1 week o ld ) were c o l l e c t e d a long f o r e s t roads wh i le t r a p p i n g and du r i ng weekly scat su r veys . Prey remains in s ca t s were i d e n t i f i e d by macroscopic examina t ion , compar ison wi th a r e f e r ence c o l l e c t i o n of the major food i t ems , and h a i r - s c a l e impress ions (Adorjan and Kolenosky 1969). The p r o p o r t i o n of each food i tem w i t h i n a scat was v i s u a l l y es t imated to the neares t 0 .10 , and a va lue of 0.05 was a s s i gned to items o c c u r r i n g in t r a c e amounts. No e s t i m a t i o n was necessary in 71% of the samples , where on ly 1 food item was p r e s e n t . The e s t i m a t i o n took p l a ce a f t e r s c a t s were washed in a 1-mm mesh s c r e e n . Non-food e lements such as s t ones , c o n i f e r n e e d l e s , dry tw igs , and grass (4% of scat content ) were not i n c l u d e d in the a n a l y s i s . The sum of a l l p r o p o r t i o n s fo r a g iven item r e f e r s to the f requency of . occur rence expressed in whole sca t u n i t s . Such data p r e s e n t a t i o n i s r e q u i r e d to eva lua te the biomass o r i g i n a l l y i nges t ed us i ng the techn ique d e s c r i b e d by F l o y d et a l . (1978) . Winter f eed ing eco logy was s t u d i e d from d i r e c t o b s e r v a t i o n s du r i ng te l emet ry f l i g h t s . Each time a wolf was l o c a t e d , the observer c i r c l e d the a r e a , at tempted to count the an imals p resent ( s u c c e s s f u l in 70% of-~observat ions ) , and recorded the presence of food s o u r c e s . The ma jo r i t y (=90%) of f eed ing s i t e s (except obv ious i n s t ances of beaver k i l l s ) were g round- inves t i ga t ed w i t h i n a few days . The i n v e s t i g o r then 59 determined the nature of the food sou r ce , a s sessed prey c h a r a c t e r i s t i c s , the cause of d e a t h , and c o l l e c t e d m o r p h o l o g i c a l samples such as i n c i s o r s (age) and bone marrow (genera l p h y s i c a l c o n d i t i o n ; f o l l o w i n g N e i l a n d 1970). A feed ing-day was d e f i n e d as 1 wolf d a i l y - l o c a t i o n at a food source or w i t h i n 1 km i f i t was apparent tha t the an imal had f r equen ted the s i t e (from t r a ck i n t e r p r e t a t i o n ) . For example, I r e co rded 35 feed ing-days when a pack of 5 wolves was l o c a t e d at a moose c a r c a s s d u r i n g 7 days . E v a l u a t i o n of the number of wolves i n v o l v e d was q u i t e r e l i a b l e because wolves commonly used a food source f o r many c o n s e c u t i v e days and were e a s i l y obse r ved . Moose k i l l i n g r a t e was c a l c u l a t e d from the cumu la t i ve r a d i o - t r a c k i n g p e r i o d s and the i n t e r i m k i l l s . In t h i s a n a l y s i s , I c o n s i d e r e d on ly those w inter t r a c k i n g s e s s i o n s (23 ± 7 SD days) in which none of the pack r e l o c a t i o n s were sepa ra ted by more than 52 h (=2 d a y s ) . I a t tempted to f l y every day but weather c o n d i t i o n s o c c a s i o n a l l y i n t e r r u p t e d wolf t r a c k i n g . Pack e x c u r s i o n s o u t s i d e the study a reas were e x c l u d e d . Dead moose were c l a s s i f i e d a s : 1) wolf k i l l s i f there was p o s i t i v e ev idence of a t t a ck ( l a rge b loody a r e a , b lood-soaked h a i r on the i n s i d e t h i g h s or on the lower rear l e g s , and broken v e g e t a t i o n around the s i t e ) , or 2) as n a t u r a l death in absence of s t r u g g l i n g ( t y p i c a l l y w i th s i gns such as c a r c a s s on sternum wi th f o l d e d l e g s , rumen f rozen whole in the body, low 60 bone marrow f a t , and aged c a r c a s s on bare ground e m i t t i n g s t r ong s m e l l ) . Wolf d e n s i t i e s were a ssessed in both areas M and H from the number of wolves per pack, the s i z e of pack t e r r i t o r i e s , and the a rea between t e r r i t o r i e s (Mess ier in p ress a ) . To p rov i de a d d i t i o n a l i n f o rma t i on among areas H, M, and L, I p resen t 3 p o p u l a t i o n i n d i c e s : 1) weekly sca t counts a long a permanent c i r c u i t (48 km) of randomly s e l e c t e d road segments, 2) f r e q u e n c i e s of wolf o b s e r v a t i o n s by moose h u n t e r s , and 3) pe rcen tages of hunt ing-days fo r which hunters heard wolves how l i ng . The methodo log ies a s s o c i a t e d w i th these i n d i c e s w i l l be p r e sen t ed i n Chapter IV. RESULTS Feed ing eco logy Summer food h a b i t s were determined by a n a l y s i s of 628 s c a t s c o l l e c t e d in a reas H and M (Table 9 ) . Moose occu r rence in s c a t s ranged from 24 to 56%, and was c o n s i s t e n t l y h ighe r in a rea H (summer average = 52% in a rea H and 26% in a rea M) . In area M, wolves p a r t l y compensated fo r the lower use of moose by a g r e a t e r e x p l o i t a t i o n of secondary prey s p e c i e s such as beaver , woodchuck (Marmota monax), snowshoe hare (Lepus  ame r i c anus ) , and raccoon (Procyon l o t o r ) . For example, beaver d e n s i t y was es t ima ted at 3.5 c o l o n i e s * 1 0 k m - 2 in a rea H, and at 1.0 c o l o n y « 1 0 k m - 2 in a rea M (Crete and Samson u n p u b l . ) , Table 9. Comparative prey use by wolves during summer in areas M and H. Number of scats analysed are presented in parentheses (years combined). May & Jun Jul & Aug Sep to Nov Weighted X Species or M H M H M H M H food items (33) (109) (152) (228) (35) (71) (220) (408) Percent prey occurrence in scats Adult moose 7 17 10 17 10 21 9 19 Calf moose a 24 36 15 28 14 35 17 33 Beaver 31 28 41 26 62 33 47 30 Woodchuck 31 14 18 16 2 T e ' 15 9 Snowshoe hare 3 1 4 6 T 0 2 2 Fruits 0 T 8 5 6 8 5 5 Other items b 4 3 4 2 6 3 5 3 rcent biomass originally ingested 0 Adult moose 46 66 50 61 43 51 46 58 Calf moose 20 19 17 23 26 37 21 28 Beaver 18 9 18 8 23 7 21 8 Woodchuck 12 3 5 3 T T 5 2 Snowshoe hare 1 T 1 1 T 0 1 T Fruits 0 T 4 3 3 4 2 3 Other items 3 2 5 1 4 1 4 1 Relative number of prey ingested Adult moose 1.0 1.0 1.0 1.0 • 1. 0 1.0 1. 0 1.0 Calf moose 5.1 3.4 2.0 2.2 i , 6 2.0 ' 2. .7 2.5 Beaver 9.2 3.3 . 8.5 3.1 12. .5 3.1 10, .4 3.2 Woodchuck 29.7 4.9 12.0 5.0 1. .1 0.5 12, .4 3.0 Snowshoe hare 6.2 2.9 6.3 3.5 5. .0 0 5, .7 1.8 a By late August calves acquired a darker coat that resembled adult pelage. Thus, total moose in Sep to Nov was apportioned on the basis of the adult-calf ratio in Jul & Aug. b A l l scats totaled: 1.5% small rodent, 1.0% white-tailed deer, 0.5% raccoon, and 1.0% diverse items. 0 Estimation technique for mammals as described by Floyd et a l . 1978. Assumed whole prey weights (kg) were: adult moose (350), calf moose (30, 60, and 130, respectively), beaver (12.5), woodchuck (2.5), snowshoe hare (1.2), other mammals as Crete et a l . 1981a. Fruit percentages were halved after Andelt and Andelt 1984. d Consumable prey weight was estimated at 90% of whole weight for a l l prey except moose (75%) as in Peterson et a l . 1984. e Traces (< 1%). 62 y e t , beaver o c cu r r ence in s ca t s was 30% in area H and 47% in a rea M. R e l a t i v e d e n s i t y es t imates of other secondary prey spec i e s were not a v a i l a b l e . Moose r ep resen ted r e s p e c t i v e l y 84% and 65% of the biomass o r i g i n a l l y i nges ted in a reas H and M; co r r e spond ing v a l ues fo r a l t e r n a t i v e prey s p e c i e s were 10% and 27%. In terms of the r e l a t i v e number of prey i n g e s t e d , r a t i o s of c a l f : a d u l t moose were comparable in both a r e a s , but the r a t i o s of secondary p r e y r a d u l t moose d i f f e r e d markedly between areas (8.1:1 and 28.4:1 in a reas H and M, r e s p e c t i v e l y ) . In w in t e r , moose predominated as prey s p e c i e s , but more so in the a rea H than in the a rea M (85% of f eed ing-days in area H as compared to 60% in area M; Tab le 10) . Human-related foods ( b a i t s , o f f a l , and gut p i l e s ) were used more f r e q u e n t l y in area M (Table 10) . I suspect that wolves in a rea M d e l i b e r a t e l y searched fo r these types of food even though such a c t i o n s e n t a i l e d hazardous approaches to human h a b i t a t i o n s ( fa rms, l ogg ing and t r appe r camps) . L i m i t e d i n f o r m a t i o n d i d not permi t a d e s c r i p t i o n of the wolf food h a b i t s in a rea L. However, the few wolves i n h a b i t i n g t h i s area were p o s s i b l y more dependent on secondary food items than in the 2 o ther a r e a s . T a b l e 10 . C ompa r a t i v e p r e y use by wolves d u r i n g w i n t e r i n a r e a s M and H. Number o f f e e d i n g - d a y s ( see methods) a r e p r e s e n t e d i n p a r e n t h e s e s ( y e a r s c o m b i n e d ) . P e r c e n t f e e d i n g - d a y s S p e c i e s o r f o o d i t ems A r e a M (728) A r e a H (693) Moose ( c a l v e s & a d u l t s ) W h i t e - t a i l e d dee r Beave r T r a p p e r b a i t s a O f f a l b Gut p i l e s 60 4 3 21 4 1 25 85 6 2 0 11 3 14 a I n c l u d e d c a r c a s s e s o f f u r b e a r e r a n i m a l s ; t r a p p i n g was p e r m i t t e d i n bo th a r e a s . b I n c l u d e d dump, f a rm and b u t c h e r y o f f a l . 64 Age, sex , and c o n d i t i o n of dead moose'3 Ca r ca s se s of 62 moose were consumed by wolves d u r i n g w in te r p e r i o d s . Ground-examinat ion r e v e a l e d tha t 38 were v i c t i m s of wo lves , 16 d i e d from c h r o n i c m o r t a l i t y ( i . e . , senescence , m a l n u t r i t i o n , d i s e a s e , n a t u r a l i n j u r i e s ) , 3 succumbed from w o u n d s N i n f l i c t e d d u r i n g h u n t i n g , 1 was k i l l e d by a c a r , and 1 was poached but not r e t r i e v e d (Tab le 11) . The cause of m o r t a l i t y was u n c e r t a i n in 3 i n s t a n c e s . C h r o n i c m o r t a l i t y i n c l u d e d 7 pr ime-aged males ( i . e . , 1 to 9 yea r s of age ; i n c l u d e d 2 p a i r s w i th l o cked a n t l e r s ) and 9 s e n i l e (>12 yea rs ) f ema l e s . C a l v e s dead from m a l n u t r i t i o n were not observed in t h i s s t u d y . M a l n u t r i t i o n m o r t a l i t y o c c u r r e d from November to February ( F i g . 12) w i th no p e r i o d of c h r o n i c s t a r v a t i o n in l a t e w i n t e r . C a l v e s , pr ime-aged a d u l t s , and o l d e r a n i m a l s , compr i sed 16%, 50%, and 34% of w o l f - k i l l e d moose (Tab le 11) . The age s t r u c t u r e of k i l l s d i d not d i f f e r between a reas ( X 2 [ 2 ] = 0 .78 , P>0.20) , but d e v i a t e d s i g n i f i c a n t l y from the assumed age s t r u c t u r e of l i v i n g an ima l s ( r e s p e c t i v e l y , 21 , 70, and 9% of combined H and M d a t a ; Tab le 12; X 2 [ 2 ] = 2 2 . 7 , P<0.01 ) . Wolves s e l e c t e d o l d i n d i v i d u a l s , but s t i l l , the m a j o r i t y (66%) of the k i l l s were e i t h e r c a l v e s or p r ime-aged , r e p r o d u c t i v e moose. Bone marrow f a t r e s e r ve s were d e p l e t e d (<20% of marrow con ten t ) i n 27% of w o l f - k i l l e d moose (n=33; F i g . 12) . These cases i n c l u d e d 2 c a l v e s , 3 prime ma les , and 6 s e n i l e f ema les . T a b l e 11 . Age , s e x , and m o r t a l i t y d i s t r i b u t i o n o f 62 moose consumed by w o l v e s i n a r e a s M and H. O b s e r v a t i o n s were r e c o r d e d f r om 15 December t o 30 March o f each w i n t e r o f t h e s t u d y . A r e a M A r e a H C a l f 1-9 y r . 10+ y r . ? (>1 y r . ) . C a l f 1-9 y r . 1 0 + y r . ? (>1 y r . 9 c f ? 9 c f ? 9 c f ? 9 c f ? P r e d a t i o n 1 4 , 2 , 0 3 , 0 , 0 2 5 7 , 4 , 0 7 , 1 , 0 2 N a t u r a l m o r t a l i t y a 0 0 , 2 , 0 5 , 0 , 0 0 0 0 , 5 , 0 4 , 0 , 0 0 O the r c au s e s ^ 0 0 , 2 , 0 0 , 0 , 0 2 0 0 , 0 , 1 0 , 0 , 0 0 U n c e r t a i n 1 0 , 0 , 0 1 , 0 , 0 0 0 0 , 0 , 0 0 , 1 , 0 0 a A minimum o f 4 p r ime ma les p e r i s h e d f r om combat i n j u r i e s i n a r e a H. I n c l u d e d 4 dea th s r e l a t e d t o h u n t i n g , and 1 r o a d - k i l l i n a r e a H. 66 1 0 0 P R E D A T I O N • = ADULT o = C A L F x = M A L N UT R ITIO N < LL o or < 8 0 6 0 4 0 t LU Z o CO 2 0 •x __L_ i X NOV DEC JAN FEB D A T E O F D E A T H MAR F i g . 12. B o n e m a r r o w f a t c o n t e n t b y m o n t h f o r m o o s e w h i c h d i e d o f w o l f p r e d a t i o n o r m a l n u t r i t i o n . T a b l e 12 . Sex and age s t r u c t u r e s o f moose i n h a b i t i n g a r e a s H, M, and L, as o b t a i n e d f r om J a n u a r y a e r i a l s u r v e y s and autumn h u n t e r - k i l l e d a n i m a l s . P o o l e d d a t a were f r om 1981 t o 1984 f o r a e r i a l s u r v e y s , and f rom 1978 t o 1983 f o r h u n t i n g s amp l e s . From a e r i a l s u r v e y s From h u n t e r - k i l l e d a n i m a l s No. cows per No. c a l v e s per % c a l v e s % 1-9 y e a r s a % 1 0 + y e a r s 100 a d u l t s 100 cows (N=100%) (N) (N) A r e a H 63 37 19 (334) 71 (592) 10 (81) A r e a M 70 41 22 (224) 69 (163) 9 (22) A r e a L 63 65 29 (196) 65 (132) 6 (13) a C a l c u l a t e d as t h e % o f a l l h u n t e r - k i l l e d a d u l t s X ( 1 0 0 - % c a l v e s o b s e r v e d i n s u r v e y s ) = t h e assumed % i n l i v i n g p o p u l a t i o n s . 68 Animals tha t d i e d from o l d age or mainourishment c o n s i s t e n t l y had a bone marrow fa t l e v e l of < 20% ( F i g . 12) . Three p r ime , n a t u r a l l y dead males e x h i b i t e d f a t d e p l e t i o n (2 in January and 1 in F e b r u a r y ) . T h i s o c c a s i o n a l phenomenon may r e f l e c t a cos t a s s o c i a t e d w i th a h igh r e p r o d u c t i v e e f f o r t the p r ev i ous autumn (see C lu t ton-B rock et a l . 1982). K i l l i n g r a t e s , food in take r a t e s , and h a n d l i n g time K i l l i n g r a t e s were 5 .3 , 1.8, and 1.1 moose per 100 pack-days in a reas H, M, and L, r e s p e c t i v e l y (Table 13) . These r a t e s co r r espond r e s p e c t i v e l y to 1.1, 0 . 5 , and 0.4 moose per 100 wo l f -days . I am c o n f i d e n t tha t most, i f not a l l , moose k i l l e d d u r i n g t r a c k i n g s e s s i o n s were l o c a t e d because a pack l o c a t i o n was recorded every 28 hours on ave rage , and by the f a c t that wolves remained at t h e i r k i l l s from 8 to 23 days fo r adu l t moose and from 2 to 4 days fo r c a l v e s . Large packs (5-8 i n d i v i d u a l s ) in a reas H and M succeeded more f r e q u e n t l y in k i l l i n g moose than smal l packs (2-4 i n d i v i d u a l s ; Tab le 13) . Wolves in a reas M and L p a r t l y compensated f o r t h e i r lower k i l l i n g r a t e by scavenging moose c a r c a s s e s . The r a t i o of k i l l e d : s c a v e n g e d moose was 18 :3 , 12 :9 , and 1:1 in a reas H, M, and L, r e s p e c t i v e l y . O v e r a l l , app rox ima te l y 1.3, 0 .8 , and 0.7 moose were consumed per 100 wol f-days in the 3 a r e a s , r e s p e c t i v e l y (Table 13). These moose i n t akes represen t 2 .8 , 1.7, and 1.6 kg/wolf/day (assuming whole weight = 150 kg f o r a c a l f and 350 fo r an adu l t moose; consumable f r a c t i o n = 0.75 of T a b l e 13 . Summary o f d a t a used t o e s t i m a t e moose k i l l i n g r a t e by w o l v e s , and t h e t o t a l moose c on sump t i o n r a t e (December t o A p r i l ) i n a r ea s H, M, and L. The a n a l y s i s was based on d a t a c o l l e c t e d d u r i n g i n t e n s i v e t r a c k i n g s e s s i o n s (1 pack l o c a t i o n e v e r y 28 hours on a v e r a ge , f r om 14 p a c k s ) . T r a c k i n g - e f f o r t i s e x p r e s s e d i n w o l f - d a y s (w . - d ) and pa c k - day s ( p . - d ) . T r a c k i n g - e f f o r t No. moose consumed Moose k i l l i n g r a t e T o t a l moose consumed N w . - d N p . - d P r e d a t i o n O the r s N / 1 0 0 w . - d N / 1 0 0 p . - d N / 1 0 0 w . - d N / 1 0 0 p . - d A r e a H Pack s 2 - 4 a 577 193 6 1 1.04 3.11 1.21 3 .63 Packs 5-8 1033 146 12 2 1.16 8 . 22 1.36 9 .59 A l l 1610 339 18 3 1.12 5.31 1.30 6 . 19 A r e a M Packs 2-4 1283 413 5 5 0 . 39 1.21 0 . 7 8 2 .42 Packs 5-8 1293 242 7 4 0 . 54 2 .89 0 . 85 4 . 55 A l l 2576 655 12 9 0 . 47 1.83 0 . 82 3.21 A r e a L Packs 2-4 270 90 1 1 0 . 37 1.11 0 . 74 2 .22 Pack s i z e 70 whole we ight ; 20% of the sample c o n s i s t i n g of c a l v e s , Tab le 11) . I f i t i s accep ted that moose compr i sed 85%, 60%, and 60% of the prey biomass i nges ted (as i n d i c a t e d in Tab le 2 fo r a reas H and M; 60% fo r area L i s a c o n s e r v a t i v e e s t i m a t e ) , t o t a l i n t ake r a te i s best e va lua t ed at 3 .3 , 2 .8 , and 2.6 kg of food/wol f/day (or 0 .11 , 0 .09 , 0.08 kg/kg w o l f / d a y ) . T o t a l i n take r a t e s are l i k e l y underes t imated due to the p o s s i b i l i t y of m i s s i n g sma l l prey i t ems . The time spent at moose k i l l s ( hand l i ng t ime) decreased s i g n i f i c a n t l y w i th pack s i z e ( P<0.01, F i g . 13). The number of feed ing-days per c a r c a s s was not r e l a t e d to pack s i z e ( r=0.32, P>0.10) and averaged 48.7 ± (SE)3.5 wolf-days fo r a d u l t moose (n = 25 ) , and 12.5 ± (SE)2.4 fo r . ca l ves (n = 4 ) . These r e s u l t s suggest that a k i l l p r o v i d e s a f i x e d number of wo l f-mea l s , so sma l l e r the pack , l onger the time spent at a k i l l . Hand l ing time here d i d not i n c l u d e the time r e q u i r e d to sur round and k i l l a moose (as in Wa l te r s et a l . 1981). I n c l u d i n g t h i s t ime would have o b l i g e d us to c o n s i d e r the r e s p e c t i v e t ime a s s o c i a t e d wi th f a i l e d a t t a c k s (up to 90% of the t o t a l a t tempts in moose; Mech 1966; Haber 1977; Pe te rson et a l . 1984b) but such i n fo rma t i on was not a v a i l a b l e . Haber (1977) r epo r t ed that the time spent to pursue and k i l l a moose i s g e n e r a l l y l e s s than 2 h o u r s . Of the 38 f r e s h k i l l s obse r ved , 29 had been made in l e s s than 1 day (the minimum time i n t e r v a l ) , 5 between 1 and 2 days , 3 between 2 and 3 days , and 1 r e co rd of 5 days . Seven of the 9 pro longed 71 25, CO >- 20 • AREA H • AREA M 20.4 - 1.75X N = 25 r =-0.76 P < 0.01 LU 15 10 PACK SIZE F i g . 13 . Time spen t a t a d u l t moose k i l l s ( h a n d l i n g t i m e ) as a f u n c t i o n o f t h e number o f wo l v e s p r e s e n t (pack s i z e ) . 72 a t t a c k s were conducted by sma l l packs of 2 to 5 wo lves . These r e s u l t s c l e a r l y i n d i c a t e that wolves were p e r s e v e r i n g in many a t t a c k s . Wolf d e n s i t i e s and moose:wolf r a t i o s Wolf d e n s i t y in January averaged 1.38 an imals*100 km" 2 in area H and 0.82 in a rea M (Mess ier in p ress a , or Chapter I I ) . From 3 p o p u l a t i o n i n d i c e s , wolf d e n s i t y in a rea L was e x t r a p o l a t e d at 0.36 animal-100 km" 2 (Table 14) . Mooserwolf r a t i o s were a lmost equa l in the a reas H and M (27:1 and 28:1 r e s p e c t i v e l y ) but h igher in a rea L ( 4 7 : 1 ) . In summer, wolf d e n s i t y was e s t ima ted at 2.07 an imals*100 km" 2 in area H, and 1.16 in a rea M (Mess ier in p r e s s a ) . The r e l a t i v e p o p u l a t i o n i n d i c e s in a rea L suggest a summer d e n s i t y of 0.51 wol f*100 k m " 2 . Yea r- long p r e d a t i o n r a t es and p o p u l a t i o n ba lances To es t imate the yea r- long p r e d a t i o n r a t e , I c a l c u l a t e d the number of a d u l t moose (^i y r ) and c a l v e s a l i v e on 1 June, and the t o t a l number k i l l e d by wolves over the ensu ing b i o l o g i c a l y e a r . The bas i c r e f e r e n c e p o i n t f o r a l l m o r t a l i t y e s t ima tes are the p o s t n a t a l p o p u l a t i o n s , i . e . , a d u l t s p l u s the r e c ru i tmen t as e va lua t ed a f t e r the p e r i n a t a l m o r t a l i t y ( s t i l l b o r n , m a l f o r m a t i o n , n u t r i t i o n a l d e p r i v a t i o n , e t c . ) . P e r i n a t a l m o r t a l i t y i s b e l i e v e d to be r e s t r i c t e d l a r g e l y to T a b l e 14 . I n d i c e s , r e l a t i v e i n d i c e s ( R I ) , and b e s t e s t i m a t e s o f w o l f d e n s i t y ( J a n u a r y ) i n a r e a s H, M, and L. Week ly s c a t c o u n t s were conduc t ed i n J u l y and Augus t 1 9 8 0 - ' 8 1 - ' 8 2 - ' 8 3 , and d a t a used i n t h e 2 o t h e r i n d i c e s were c o l l e c t e d i n September and Oc tobe r 1 9 8 1 - ' 8 2 . No. s c a t s per 100 km • week X (No. km.week) RI No. wo l v e s seen pe r 100 h u n t i n g - d a y s X (No. h . - d ) RI No. days w i t h h o w l i n g pe r 100 h u n t i n g - d a y s X (No . h . - d ) RI Wo l f d e n s i t y X o f RI No. / 100 km 2 A r e a H 5 .6 (1440) 1.00 A r e a M 4 . 6 (1440) 0 . 82 A r e a L 1.4 (1392) 0 . 25 5.1 (1172) 1.00 2 .5 ( 483 ) 0 . 49 1.1 ( 631 ) 0 .22 11 .2 (1145) 1.00 4 . 9 ( 510 ) 0 . 4 4 3 .6 ( 631 ) 0 . 3 2 1.00 0 . 5 8 0 . 2 6 1.38 a 0 . 8 2 a 0.36b a A ve r age d e n s i t y i n J anua r y 1 9 8 0 - ' 8 1 - ' 8 2 - ' 8 3 e s t a b l i s h e d f r om an i n t e n s i v e t e l e m e t r y s t u d y o f pack s i z e , number p a c k s , and t e r r i t o r y s i z e ( M e s s i e r s u bm i t t e d a ) . ^ E s t i m a t e d f r om t h e ave rage RI i n a r e a L and t h e ob se r ved w o l f d e n s i t y i n a r e a H ( 0 . 2 6 X 1.38 = 0 . 3 6 ) . 74 the few days f o l l o w i n g p a r t u r i t i o n (Verme 1974) and , c o n s e q u e n t l y , i t s importance i s o f t e n d i f f i c u l t to q u a n t i f y . The computat ion of p r e d a t i o n r a t e s and the a s s o c i a t e d assumpt ions are summarized in Tab l e s 15 and 16. Regard ing the assumpt ions , I am c e r t a i n that o ther au thors may have chosen somewhat d i f f e r e n t v a l u e s , but I s t r e s s that the same assumpt ions were a p p l i e d fo r the 3 a r e a s , thus v a l i d a t i n g the compar i son . Year- long p r e d a t i o n r a t e s proved to be d e n s i t y dependent , i n c r e a s i n g from 6.1 to 19.3% as moose d e n s i t y d i f f e r e d from 0.17 to 0.37 a n i m a l . k m - 2 . Summer p r e d a t i o n , most ly o r i e n t e d toward c a l v e s , r ep resen ted 75 to 85% of the yea r- long p r e d a t i o n . I e s t imated tha t 10, 5, and 2% of a d u l t s p e r i s h e d a n n u a l l y from wolf p r e d a t i o n in a reas H, M, and L, r e s p e c t i v e l y . The co r r e spond ing v a l ues among c a l v e s were 38, 22, and 14%. -The f u l l i m p l i c a t i o n of a m o r t a l i t y f a c t o r i s r e v e a l e d on l y a f t e r be ing jux taposed to the o ther l i m i t i n g f a c t o r s on r e p r o d u c t i o n and s u r v i v a l . In Tab le 17, I p resent the n a t a l i t y - m o r t a l i t y ba lances fo r the 3 moose p o p u l a t i o n s . Recru i tment on 1 June accounted f o r 100 c a l v e s per 100 females aged ^2 years of' age and d i d not d i f f e r among areas (note d of Tab l e 15; C r e t e u n p u b l . ) . The importance of wolf p r e d a t i o n , h u n t i n g , and road k i l l s c o u l d be a s sessed wi th some c o n f i d e n c e . The importance of b l ack bear p r e d a t i o n and c h r o n i c m o r t a l i t y are not known r e l i a b l y and mer i t s p e c i f i c comments. 75 T a b l e 15 . D e r i v a t i o n o f t h e d e n s i t y ( N o . / k m 2 ) o f c a l f and a d u l t ( >1 y r ) moose i n a r e a s H, M, and L, on 1 June ( i . e . , p o s t - n a t a l d e n s i t y ) . A r e a H A r e a M A r e a L (A) O v e r a l l d e n s i t y on 15 Jan a 0. .37 0. ,23 0. ,17 (B) P r o p o r t i o n o f moose s u r v i v i n g u n t i l 1 J u n * 0. .91 0. ,94 0. ,97 (C) D e n s i t y o f a d u l t s on 1 J u n , (A) X (B) 0. ,337 0. ,216 0. ,165 (D) D e n s i t y o f f e m a l e s aged >2 y r c 0. ,172 0. ,118 0. ,074 (E) No. c a l v e s / f e m a l e >2 y r a f t e r p e r i n a t a l m o r t a l i t y ^ 1. ,00 1. ,00 1. ,00 (F ) D e n s i t y o f c a l v e s , (D) X (E) 0 . ,172 0. ,118 0. .074 (H) O v e r a l l d e n s i t y , (C) + ( F ) 0. .51 0 . 33 0 . ,24 From M e s s i e r and C r e t e i n p r e s s . b These f i g u r e s were d e r i v e d f r om t h e w o l f k i l l i n g r a t e s ( T a b l e 13 ) , w o l f d e n s i t i e s ( T a b l e 1 4 ) , and a b a s e l i n e m o r t a l i t y o f 4% pe r y r ( s ee t e x t ) . ° C a l c u l a t e d as (C) X ( l -% o f c a l v e s i n Jan ) X (% o f f e m a l e s among a d u l t s ) ; d a t a f r om T a b l e 12 . I i n f e r r e d t h a t t h e % o f c a l v e s i n Jan e q u a l l e d t h e % o f y e a r l i n g s on 1 J u n , i . e . , a p r o p o r t i o n a l m o r t a l i t y . ^ A c o m p o s i t e sample o f 45 r a d i o - t r a c k e d f e m a l e s were a s s o c i a t e d w i t h a minimum o f 46 c a l v e s on 1 Jun ( 5 - 1 0 days a f t e r p a r t u r i t i o n ) ; c a l f p r o d u c t i o n d i d no t d i f f e r among a r e a s U 2 [ 2 ] = 0 . 8 7 , P> 0 . 5 0 ) . 76 Table 16. Est imation of the number of moose k i l l e d by wolves and the year- long predat ion ra te in a lOOO-km? area H, M, and L. The c a l c u l a t i o n was made independently i n the summer (S=May to Nov) and winter period (W = Dec to Apr) . Area H Area M Area L S W S W S W (A) Wolf numbers a 20.7 13.8 11.6 8. .2 5.1 3. ,6 (B) Food intake (kg/wolf/day) b 2.6 . . . 2.2 -- 2.1 -(C) Moose consumed (kg) 0 Ca l f 3200 — 1180 - 500 -Adult 6700 — 2510 -• •- 1050 -(D) Number moose k i l l e d ^ Ca l f 57.0 8.2 23.4 2. .0 9.8 0. .7 Adult 17.9 15.2 6.7 3. .8 2.8 1. .3 CE) Year-long predation rate (%) ' e 19. .3 10. .7 6.1 a See t e x t . * Ca lcu lated as the observed winter food intake (3.3, 2.8, and 2.6 kg/wolf/day i n areas H, M, and L, r e spec t i ve l y ) f o r adu l t s , and ha l f these amounts f o r pups (=40% of wo lves ) ; "on ly the weighted food intakes are presented. c Ca lcu lated as (A) X (B) X (the proport ion of adult or c a l f moose i n the biomass o r i g i n a l l y ingested; Table 9 ) . P r o f i l e of wolf d i e t i n area L was assumed to be s i m i l a r to that i n area M. d In summer, we assume that 10% of the c a l f biomass ( a f te r cons iderat ion of Franzmann et a l . 1980, B a l l a r d et a l . 1981) and 30% of the adult biomass represented scavenging; see also notes c and d of Table 9 f o r the c a l c u l a t i o n . In w inter , the est imat ions were der ived d i r e c t l y from the observed k i l l i n g rate per 100 wolf-days (Table 11), assuming that ca lves count f o r 35% of k i l l s . e Ca lcu lated as (D)-j-[(H) i n Table |5 X 1000]. 77 Table 17. Summarization of the recruitment and mo r t a l i t y data i n areas H, M, and L, given as the percentages of the post -nata l populat ions. Values i n parentheses are not known r e l i a b l y (see t e x t ) . Area H Area M Area L Recruitment, ( F ) ^ (H) i n Table IS 33.8 35.3 31.0 M o r t a l i t y H u n t i n g a 3.1 22.2 23.7 Wolf predat ion, (E) i n Table Ik 19.3 10.7 6.1 Road k i l l s * 1.0 0.0 0.0 Black bear predation ° (5.0) (2.0) (1.5) Other natural m o r t a l i t i e s d (4.0) (4.0) (4.0) Net balance (+1.3) (-3.6) (-4.3) Populat ion t rend, 1976-1983 e Stable Dec l in ing at ~5%per y r Stable Comments Poss ib le egress Poss ib le ingress from area H Poss ib le from area Recruitment l i k e l y underestimated by 2-3% / a From 1980 to 1984, annual hunting averaged 15.9, 73.3, and 59.2 moose/1000 km2 i n areas H, M, and L, r e spec t i v e l y ; h u n t e r - k i l l e d r e g i s t r a t i o n was compulsory and poaching appeared n e g l i g i b l e . b Each year, 50-70 moose (4.4/1000 km2) were k i l l e d by accident along the 117 Highway t r ave r s i ng area H. c Assuming that 15%, 10%, and 5% of the calves were k i l l e d by black bears i n areas H, M, and L, r e s p e c t i v e l y . d Assuming a base l ine mo r t a l i t y of 4% f o r a l l areas (see t e x t ) . e From the ana ly s i s presented by Messier and Crete ( i n press ) . f We suspect an over - representat ion of males i n area L (Table 12); assuming that males comprised 30% of adults as i n area M ( s im i l a r ra te of harves t ing ) , the recruitment ra te i s 34.3%. 78 B lack bear p r e d a t i o n i s i n h e r e n t l y d i f f i c u l t to q u a n t i f y because moose consumption per i n d i v i d u a l bear i s presumably s m a l l . The p o s s i b l e importance of bear p r e d a t i o n o r i g i n a t e s from the h igh p o p u l a t i o n d e n s i t y of t h i s f a c u l t a t i v e c a r n i v o r e compared to a o b l i g a t o r y c a r n i v o r e such as the wo l f . A n a l y s i s of 375 b l ack bear s ca t s c o l l e c t e d in a rea H d u r i n g months of May, June, and J u l y , r e vea l ed tha t remains of c a l f moose (the on ly members presumably k i l l e d ) o c c u r r e d on l y in t r a c e amounts ( L achape l l e et a l . 1984). Bear p r e d a t i o n may be es t ima ted c r u d e l y from the premise tha t c a l f m o r t a l i t y between =10 days of age and the f o l l o w i n g w in te r i s most ly (=80%) a t t r i b u t a b l e to p r e d a t i o n (Franzmann et a l . 1980; B a l l a r d et a l . 1981; La rsen 1984). Beg inn ing wi th 100 c a l v e s : 1 0 0 females on 1 June and s u b s t r a c t i n g l o s s e s from wolf p r e d a t i o n u n t i l 1 J anuary , a r a t i o of 60-65 c a l v e s : 1 0 0 females would be expected in area H. The observed r a t i o was 37:100 (Table 12) which i n d i c a t e s an a d d i t i o n a l l o s s of 20-25% of the r e c r u i t m e n t . In a reas M and L, bear p r e d a t i o n was l i k e l y lower due to the apparent d i f f e r e n c e in bear d e n s i t y . Weekly sca t counts in J u l y and August 1980 to 1983 r e s u l t e d in 9 .6 , 3 .3 , and. 2.4 bear sca ts*100 week-km in a reas H, M, and L, r e s p e c t i v e l y (same methodology in a l l a r e a s ; e f f o r t s = 2880, 1440, and 1440 week-km, r e s p e c t i v e l y ) . From these c o n s i d e r a t i o n s , I e v a l ua t ed that 15%, 5%, and 5% of the c a l v e s were k i l l e d each summer by b lack bears in the 3 r e s p e c t i v e a reas (Table 17) . L i m i t e d data from r a d i o - c o l l a r e d female moose suggest a 79 c h r o n i c m o r t a l i l y of 2-3% (Crete u n p u b l . ; 2 cases du r i ng 84 moose-yr ) . I suspect that such m o r t a l i t y was r e l a t i v e l y uncommon because e i t h e r p r e d a t i o n (area H) or human e x p l o i t a t i o n (areas M and L) c u r t a i l e d the occu r rence of c h r o n i c m o r t a l i t y . C o n s i d e r i n g that males may be sub j ec t ed to h ighe r n a t u r a l m o r t a l i t y , I t e n t a t i v e l y e s t ima ted c h r o n i c m o r t a l i t y at 4% f o r a l l a r e a s . T h i s f i g u r e conforms wi th other va lues found at comparable moose d e n s i t i e s ( Ro l l e y and K e i t h 1980; Hauge and K e i t h 1981; Gasaway et a l . 1983). From the 1976-83 d e n s i t y e s t i m a t e s , moose p o p u l a t i o n s appeared s t a b l e in area H, s l i g h t l y d e c l i n i n g (=5% per year ) in a rea M, and s t a b l e in area L (Mess ier and Cre te 1984). The n a t a l i t y - m o r t a l i t y ba lances matched reasonab ly we l l w i th these p o p u l a t i o n t r ends (Table 17). These cor respondences s t r eng then the r e a l i s m of the u n d e r l y i n g e s t i m a t e s , a l though many p o s s i b l e sources of i m p r e c i s i o n remain . DISCUSSION In southwestern Quebec, the p l a s t i c i t y of prey s e l e c t i o n by wolves in response to moose d e n s i t y r ep resen ted an important aspec t of the moose-wolf dynamics . Both the a n a l y s i s of summer s ca t s and winter f eed ing o b s e r v a t i o n s i n d i c a t e d a g r ea t e r use of a l t e r n a t i v e , p robab l y l e s s p r o f i t a b l e , food r e sou r ces w i th a lower moose d e n s i t y . Prey s w i t c h i n g has been documented in o ther wolf s t u d i e s (Voigt et a l . 1976; Pe terson 80 1977; She l ton and Peterson 1983). K i l l i n g ra te r e f l e c t s the amount of t ime a p reda to r i s engaged in consuming prey (hand l ing t ime) and the amount of t ime s e a r c h i n g fo r prey ( H o l l i n g 1959). Wa l te rs et a l . (1981) r e p o r t e d tha t the time spent at a moose k i l l was nea r l y independent of pack s i z e . They argued tha t i t i s not the number of wolves that i s c r i t i c a l in de t e rm in ing p r e d a t i o n r a t e , r a t h e r , i t i s the number of packs . T h i s no t i on may prove to be dangerous ly decep t i v e fo r 2 r easons : 1) the p a u c i t y of the data p resen ted d i d not warrant such a c o n c l u s i o n , and 2) the v a r i a t i o n in the amount of t ime s e a r c h i n g between 2 k i l l s in r e l a t i o n to pack s i z e was not a d d r e s s e d . In the present s tudy , h a n d l i n g time (sensu t ime at k i l l ) was n e g a t i v e l y c o r r e l a t e d wi th pack s i z e . For an average pack s i z e of 5 .7 , 3 .7 , and 3.0 wolves in a reas H, M, and L (n=12, 20, and 2, r e s p e c t i v e l y ; Mess i e r in p r e s s a ) , I c a l c u l a t e d a hand l i ng time of 11, 13, and 15 days ( F i g . 13) . C o n s i d e r i n g the average time between k i l l s (19, 55, and 90 days r e s p e c t i v e l y ; from Tab le 13), the amount roi t ime between consuming 2 k i l l s was approx imate l y 8, 42, 75 days . T h e r e f o r e , a major determinant of the k i l l i n g r a t e s was the t ime s e a r c h i n g fo r p r ey . Wolves s u r v i v e d through these p r o t r a c t e d p e r i o d s without k i l l s by scaveng ing on a l r e a d y dead moose and by e x p l o i t i n g a l t e r n a t i v e food r e s o u r c e s . A p p a r e n t l y , l o c a t i n g these food-sources was enhanced by the f a c t that wolves were sea r ch ing each u n i t a rea at g r ea t e r 81 i n t e n s i t y where moose were l e s s numerous (Mess ier in p ress a ) . K i l l i n g r a t e s in winter ranged from 5.3 (area H) to 1.1 (area L) moose-100 pack-days . These r a t es are q u i t e low compared to the 15-20 moose*100 pack-days observed in o ther s t u d i e s (Mech 1966; Peterson 1977; F u l l e r and K e i t h 1980; Pe te rson et a l . 1984b). I t was apparent tha t wolves were not ab l e to k i l l at w i l l , even in a rea H. It was a l s o remarkable how complete every k i l l was u t i l i z e d ( d i s a r t i c u l a t e d s k e l e t o n , l eg bones sk inned down to the hooves ) . As a consequence, moose consumption in area H (0.09 kg/kg w o l f / d a y ) , and e s p e c i a l l y in a reas M and L, was low compared to the range determined fo r wolves p r e y i ng on moose in o the r s t u d i e s (0 .10-0.19 kg/kg wo l f /day ; Pe te rson 1977 and u n p u b l . ; F u l l e r and K e i t h 1980; Pe te rson et a l . 1984b). T h e r e f o r e , i t i s l i k e l y that wolves in t h i s study would have i n c r e a s e d t h e i r k i l l i n g r a te g i ven a moose d e n s i t y h ighe r than 0.4 a n i m a l ' k n r 2 . The r e l a t i v e l y low body weight of wolves (=26 kg f o r a d u l t females and 30 kg f o r a d u l t males) and the sma l l s i z e of packs ( i . e . , l onger r e f r a c t o r y p e r i o d a f t e r a k i l l ) were 2 o ther f a c t o r s i n v o l v e d in the markedly lower k i l l i n g r a t e s i n t h i s s tudy . Wolf d e n s i t i e s in a reas H and M were determined r e l i a b l y w i th the a i d of r a d i o - c o l l a r e d a n i m a l s . The d e n s i t y in a rea L was e x t r a p o l a t e d from 3 i n d i c e s to i nc rease p r e c i s i o n . Thus , the p o s s i b l e e r r o r a s s o c i a t e d w i th the wolf d e n s i t y e s t ima tes i s b e l i e v e d to be m in ima l . Wolf d e n s i t i e s in a reas H and M p a r a l l e l e d the change in moose d e n s i t y . T h e r e f o r e , the n e a r l y 82 2- fo l d d i f f e r e n c e in the p r e d a t i o n r a t es (19.3 and 10.7%) was a t t r i b u t a b l e to changes in prey s e l e c t i o n and k i l l i n g r a t e s ( f u n c t i o n a l response) r a the r than a r e l a t i v e d i f f e r e n c e in wolf d e n s i t y . I suggest that moose-wolf r a t i o s may r e f l e c t p r e d a t i o n r a t e a c ross a l a r g e range of moose d e n s i t i e s , but so i m p e r f e c t l y tha t t h e i r u t i l i t y in a management p e r s p e c t i v e remain q u e s t i o n a b l e (see Gasaway et a l . 1983 f o r a d i f f e r e n t advocacy ) . In area L, wolf d e n s i t y was much lower , r e s u l t i n g in a h i ghe r mooserwolf r a t i o . Mess i e r ( in p r e s s a) suggested tha t a d e n s i t y of 0.2 moose-km" 2 approximated the d e n s i t y t h r e s h o l d below which a pack cannot s u b s i s t and/or reproduce s u c c e s s f u l l y in the absence of o ther ungulate s p e c i e s . In a rea L (0 .17 moose«km~ 2 ) , a food in take of =0.08 kg meat/kg wol f/day was obse rved , which i s f a r below the food requi rement of 0.13 kg meat/kg wol f/day to reproduce s u c c e s s f u l l y , as proposed by Mech (1977). Dur ing 4 summers that the area L was i n t e n s i v e l y p a t r o l l e d , I found ev idence of on l y 1 pack tha t produced a l i t t e r of pups , and a p o r t i o n (25%) of i t s t e r r i t o r y was in area H. E s t ima ted p r e d a t i o n r a t e s i n c r ea sed from 6.1% at 0.'17 moose 'k i r r 2 to 19.3% at 0.37 m o o s e ' k n r 2 . Con f idence i n t e r v a l s of p r e d a t i o n r a t e s cannot be computed due to the comp lex i t y of the a n a l y s i s , and the presence of a s s u m p t i o n s ^ The e r r o r a s s o c i a t e d wi th p r e d a t i o n r a t e s may e a s i l y be in the range of 15-30% of the e s t i m a t e s . Even w i th such an e r r o r , the study p r o v i d e s s o l i d ev idence that wolf p r eda t i on was d e n s i t y -83 dependent . E m p i r i c a l j u s t i f i c a t i o n s fo r t h i s a s s e r t i o n a r e : 1) the sharp d e c l i n e in k i l l i n g r a te w i th d e c r e a s i n g moose d e n s i t y , 2) the tendency to consume a l t e r n a t i v e food resources at lower moose d e n s i t y , and 3) the d i s r u p t i o n of the wolf p o p u l a t i o n at moose d e n s i t i e s below =0.2 a n i m a l • k m - 2 . In southwestern Quebec, non-harvested moose p o p u l a t i o n s p l a t e a u at a d e n s i t y of =0.4 a n i m a l ' k i r r 2 (Mess ier and Cre te 1984). Wolf p r e d a t i o n appears to r ep resen t the dominant dens i t y-dependent mechanism but the e n t i r e r e g u l a t o r y p rocess may i n v o l v e o ther d e p r e s s i v e f a c t o r s . For example, wolf p r e d a t i o n a lone cannot e x p l a i n the low r a t i o of 37 c a l v e s : 1 0 0 females observed in area H du r i ng January s u r v e y s . B lack bears were found to prey on c a l v e s in A l a s k a (Franzmann et a l . 1980) and probab ly they i n f l i c t e d a f u r t h e r r e d u c t i o n of c a l v e s in our s i t u a t i o n . Whether or not bear p r e d a t i o n i s a l s o dens i t y-dependent remains unknown. If i t i s , bear p r e d a t i o n w i l l r e i n f o r c e the r e g u l a t o r y e f f e c t of p r e d a t i o n on moose p o p u l a t i o n s . In regards to food resource l i m i t a t i o n , there i s no i n d i c a t i o n that f o r a g i n g c o n d i t i o n s d e t e r i o r a t e when a moose p o p u l a t i o n reaches the e q u i l i b r i u m d e n s i t y of 0.40 a n i m a l ' k i r r 2 (Mess ier and Cre te 1984; C re te et a l . 1981; C re te and Jordan 1982a, b) . O v e r a l l , wolf p r e d a t i o n , in combina t ion wi th the o ther l i m i t i n g f a c t o r s on rec ru i tment and m o r t a l i t y , appears capab le of r e g u l a t i n g a moose p o p u l a t i o n we l l below the d e n s i t y s u s t a i n a b l e by a v a i l a b l e food r e s o u r c e s . I conc lude 84 tha t n a t u r a l l y r e g u l a t e d moose p o p u l a t i o n s in southwestern Quebec are h e a v i l y c o n s t r a i n e d by p r e d a t o r s , but at the same time wolves are n u t r i t i o n a l l y s t r e s s e d due to t h e i r own a c t i o n on the abundance of moose. 85 Chapter IV MOOSE RESPONSE TO EXPERIMENTAL WOLF REMOVAL INTRODUCTION In southwestern Quebec, as in some other p l a c e s in b o r e a l ecosys tems, non-harvested moose p o p u l a t i o n s appear to s t a b i l i z e at a d e n s i t y of =0.4 a n i m a l « k n r 2 (Crete et a l . 1981; Bergerud et a l . 1983; Mess i e r and Cre te 1984; C re te s u b m i t t e d ) . Hab i t a t p r o d u c t i o n and i t s use by moose have been i n v e s t i g a t e d near t h i s n a t u r a l e q u i l i b r i u m and at lower moose d e n s i t i e s fo r compar ison ( i . e . , p o p u l a t i o n s reduced by h a r v e s t i n g ; C re t e and Jordan 1982a, b ) . Body c o n d i t i o n of moose was a l s o s t u d i e d in an e f f o r t to a ssess h a b i t a t q u a l i t y from an animal p e r s p e c t i v e (Crete et a l . 1982; Mess i e r and C re te 1984). The gene ra l c o n c l u s i o n was tha t a v a i l a b i l i t y of food r esources was not s u f f i c i e n t to e x p l a i n the observed n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s . T h i s ongoing study a t tempts to t e s t whether or not wolf p r e d a t i o n , combined wi th other l i m i t i n g f a c t o r s on r e p r o d u c t i o n and s u r v i v a l , can h o l d a moose p o p u l a t i o n we l l below the d e n s i t y that can be s u s t a i n e d by a v a i l a b l e food r e s o u r c e s . I p o s t u l a t e d that wolf p r e d a t i o n i s d e n s i t y -dependent between 0.0 and 0.4 moose-km - 2 (Crete et a l . 1981; 86 Mess ie r and Cre te 1984, in p r e s s ) . T h i s m o r t a l i t y may depress r ec ru i tmen t and i n c r ease a d u l t m o r t a l i t y to a p o i n t where p o p u l a t i o n growth i s reduced to zero be fo re food compe t i t i on s u b s t a n t i a l l y impa i r s moose p r o d u c t i v i t y ( i . e . , presence of a low d e n s i t y e q u i l i b r i u m ) . However, I r e c o g n i z e the p o s s i b i l i t y that at h ighe r moose d e n s i t i e s ( i . e . , >0.5 m o o s e ' k n r 2 ) wolf p r e d a t i o n may decrease and ac t as a depensatory m o r t a l i t y f a c t o r (Walters et a l . 1981; Gasaway et a l . 1 9 8 3 ) . The re fo r e I am a l s o a t t empt ing to v e r i f y i f the wolf-moose system i s c h a r a c t e r i z e d by a lower and an upper s t a b l e e q u i l i b r i u m (C la rk 1976:236; Van Ba l l enbe rghe 1980). The exper imenta l des ign was to reduce wolves in an a rea where the moose p o p u l a t i o n was n a t u r a l l y r e g u l a t e d and near a s t a b l e e q u i l i b r i u m . An i n c r ea se in the moose p o p u l a t i o n (h igher r e c r u i t m e n t , h ighe r p o p u l a t i o n growth r a te ) would support the hypo thes i s tha t moose are ma in ta ined at low d e n s i t i e s by wolf p r e d a t i o n . In order to t e s t the m u l t i p l e e q u i l i b r i a h y p o t h e s i s , wolf removal w i l l be s topped when the moose d e n s i t y has at l e a s t doubled ( i . e . , =1.0 a n i m a l • k m " 2 ) . I f in subsequent yea rs the moose p o p u l a t i o n d e c l i n e s to i t s former l e v e l , a s i n g l e low d e n s i t y e q u i l i b r i u m w i l l be sugges t ed . A l t e r n a t i v e l y , i f the moose p o p u l a t i o n con t i nues to i n c r e a s e , a second h ighe r d e n s i t y e q u i l i b r i u m c r e a t e d by food c o m p e t i t i o n w i l l be i n d i c a t e d . O b v i o u s l y , these responses w i l l be q u a n t i f i a b l e on ly in a long-term study (>10 y e a r s ) . In t h i s paper , the p r e l i m i n a r y r e s u l t s accumulated 87 d u r i n g the f i r s t four years of the ongoing wolf r e d u c t i o n programme i s p r e s e n t e d . STUDY AREA AND METHODS The study was conducted in La Verendrye game r e s e r v e , southwestern Quebec ( F i g . 14) , from June 1980 to March 1984. The moose p o p u l a t i o n has been l i g h t l y ha r ves ted fo r the past 15 yea rs (3-4% annua l l y ) but i t s s t a b l e d e n s i t y was b a s i c a l l y de te rmined by n a t u r a l r e g u l a t i o n (Crete et a l . 1981a; Mess ie r and C re te 1984). Two study areas were s e l e c t e d : a wolf removal a rea of 700 km2 bounded by a 10-km b u f f e r zone , and a non-removal area of 900 km2 ( F i g . 14). Wolf p o p u l a t i o n s t a tus was determined by sca t counts and hunter i n t e r v i e w s . Weekly sca t counts on f o r e s t roads began on 1 J u l y and l a s t e d 10, 8, 8, and 6 weeks r e s p e c t i v e l y from 1980 to 1983. W i th in each a r e a , I r ecorded a l l f o r e s t roads fo r which human use was s u f f i c i e n t l y low to i n s u r e tha t s ca t s remained n o t i c e a b l e fo r a 1-week p e r i o d . S u i t a b l e road segments had an average l eng th of 6.9 ± (SD)3.0 km. They were randomly s e l e c t e d to form a permanent 48-km c i r c u i t in each study s i t e . Counts were made by two observe rs on m o t o r c y c l e s p a t r o l l i n g at a maximum speed of 20 km«h. A l l s c a t s were c o l l e c t e d d u r i n g each p a t r o l . Moose hunters were i n t e r v i ewed at the compulsory r e g i s t r a t i o n o f f i c e of the r ese rve from 15 September to 20 88 76°45 W 76° 00 W T LAVERENDRYE \ . RESERVE!—-) x . 1 WOLVES KILLED: o Nov.'81- Feb. '82 * Nov. '82- Feb. '83 a Nov.'83-Feb. '84 r V 10-km BUFFER ZONE o 47 15 N L WOLF-REMOVAL AREA 47 45' N 47 15' N 76° 45' W 76° 00' W F i g . 14 . D e s c r i p t i o n o f t h e s t u d y a r e a f o r t h e w o l f remova l e x p e r i m e n t , and l o c a t i o n s o f t h e wo l v e s k i l l e d between November 1981 and March 1984. 89 O c t o b e r . One person of each pa r t y was asked how many wolves he observed du r i ng h i s 1-4 days of h u n t i n g , and how many days he heard wolves how l i ng . The l o c a t i o n of the a rea hunted and the number of hunt ing-days were a l s o no ted . Moose p o p u l a t i o n s t a tus was determined by a e r i a l surveys conducted du r i ng the f i r s t three weeks of January each y e a r ( C r e t e and S t - H i l a i r e 1979). Four p l o t s of 60 km2 (6X10 km) were randomly s e l e c t e d in each study a rea . W i th in each p l o t twelve 10-km t r a n s e c t s at 500 m i n t e r v a l s were p a t r o l l e d in f i xed-w ing a i r c r a f t (speed =165 km«h; a l t i t u d e above ground =120 m). Two o b s e r v e r s , one on each s ide of the a i r c r a f t , r e p o r t e d the number of moose seen to a n a v i g a t o r . Number of moose seen per p l o t was used as an index of moose d e n s i t y . In a d d i t i o n , moose d e n s i t y e s t ima tes w i t h i n p l o t s were d e r i v e d from the s imple r e g r e s s i o n p resen ted by C re te et a l . ( submit ted) wherein the number of moose seen per 100 km flown was c o r r e l a t e d to the d e n s i t y found by h e l i c o p t e r from t o t a l coverage censuses and c o r r e c t e d f o r v i s i b i l i t y b i a s . Rec ru i tment , in terms of c a l f r c o w r a t i o s , was es t ima ted d u r i n g January a e r i a l su r veys . From h e l i c o p t e r , sex of a d u l t s was a s c e r t a i n e d from vu l va-pa tch and a n t l e r c r i t e r i a , and c a l v e s were i d e n t i f i e d by r e l a t i v e s i z e (Rousse l 1975). A d d i t i o n a l i n f o rma t i on on c a l f s u r v i v a l was ga ined from r a d i o -c o l l a r e d cows in both study a r e a s . Females were moni tored i n t e n s i v e l y du r i ng the p a r t u r i t i o n p e r i o d to a s se s s the number of c a l v e s bo rn . A f te rwards cows were l o c a t e d approx imate l y at 90 1 month i n t e r v a l s to determine c a l f l o s s e s . Wolf removal began d u r i n g the t h i r d year of the exper iment . From November to March, wolves were e i t h e r cap tu red by l o c a l t r a p p e r s or k i l l e d from h e l i c o p t e r . Dur ing a e r i a l shoo t i ng s e s s i o n s the aim was to remove e n t i r e packs . A l s o , wolves were k i l l e d when they were t r a cked from the removal a rea to the 10-km b u f f e r zone . RESULTS From November 1981 to February 1984, a minimum of 31 wolves were k i l l e d in the 700-km 2 removal a rea and the 10-km b u f f e r zone . The annual removals were: 14 in 1981-82, 7 in 1982-83, and 10 in 1983-84. For most wolves k i l l e d in the b u f f e r zone, (n=20), there was ev idence from t r a ck o b s e r v a t i o n s that they were us i ng pa r t of the removal a r e a . An average of 6.7 h of h e l i c o p t e r time was necessa ry per wolf k i l l e d (n= l8 ) . The t r a p p i n g e f f o r t f o r the remain ing 13 wolves c ap tu r ed by l o c a l peop le i s unknown. Pups were cap tu red each year (n=17; 12 ma les , 4 f ema les , 1 unknown). Thus , r e p r o d u c t i v e a d u l t s were never t o t a l l y e l i m i n a t e d a l t hough at l e a s t 8 males and 5 females were k i l l e d . — Weekly scat counts (Tab le 18) i n d i c a t e d tha t the wolf p o p u l a t i o n in the removal a rea was s u c c e s s f u l l y reduced (Mann-Whitney U- tes t [20 ,14 ] = 237 .5 , P<0.01) but remained s t a b l e in the non-removal area (U- tes t [20 ,14 ] = 153.5 , P>0.10) . Hunter 91 T a b l e 18 . I n d i c e s o f w o l f p o p u l a t i o n s i n t h e non - r emova l a r e a (N-R) and i n t h e remova l a r e a (R) b e f o r e i n i t i a t i o n o f t h e w o l f r e d u c t i o n programme (1980 , 1981) and d u r i n g t h e programme (1982 , 1 983 ) . No. s c a t s pe r No. wo l v e s seen pe r No. days w i t h h o w l i n g 100 km • week 100 h u n t i n g - d a y s pe r 100 h u n t i n g - d a y s (No. o f s i g h t i n g s ) (No. days h o w l i n g ) N-R R N-R • R N-R R P r e - r e m o v a l 1980 5 .6 3.1 1981 4 . 8 13.1 3 . 4 ( 3 ) 8 . 3 ( 2 ) 7 . 0 ( 6 ) 2 0 . 8 ( 5 ) P o s t - r e m o v a l 1982 6 . 0 2.1 2 . 9 ( 3 ) 2 . 1 ( 2 ) 1 2 . 4 ( 1 3 ) 1 0 . 3 ( 1 0 ) 1983 8 . 0 0 . 4 5 . 0 ( 7 ) 1 . 0 (1 ) 3 . 6 ( 5 ) 8 . 1 ( 8 ) 92 i n t e r v i ews gave i n c o n s i s t e n t r e s u l t s ; a wolf r e d u c t i o n was i n d i c a t e d by the f requency of wolf s i g h t i n g s , but not from the percentage of days that hunters heard wolves (Table 18). Smal l sample s i z e s and the p o s s i b l e l a ck of independence between o b s e r v a t i o n s obscure any s t a t i s t i c a l a n a l y s i s of these r e s u l t s . The l i m i t a t i o n of hunter i n t e r v i ews when used on a sma l l s c a l e shou ld be r e c o g n i z e d . Be fore the wolf r e d u c t i o n programme (1981 +'82 ) , moose d e n s i t i e s were es t imated at 0.28 an ima l «km~ 2 in the removal a r e a , and at 0.34 in the non-removal area (Tab le 19) . A f t e r the f i r s t year of wolf r e d u c t i o n , the moose d e n s i t y s i g n i f i c a n t l y i n c r eased to an e s t ima ted 0.73 an ima l-km" 2 in the removal area ( t - t e s t [ l 0 ] = 2 .38 , P<0.05; data of 1981+'82 vs 1983) but remained s t a b l e in the non-removal a rea (t-t e s t f l O ] = 0 .38 , P>0.10) . Unusual deep snow c o n d i t i o n s in 1984 p reven ted assessment of moose d e n s i t y f o r the second year of the programme. Be fore wolf r educ t i on ( l 9 8 l + ' 8 2 ) , c a l f : c o w r a t i o s were approx ima te l y 40:100 in both study areas (Table 20 ) . A f t e r one year of t rea tment , c a l f : c o w r a t i o i n c r e a s e d to 68:100 in the removal area but d e c l i n e d to 39:100 the subsequent yea r . Summing the f i r s t two years of the programme, 52 c a l v e s : 1 0 0 cows were counted in the removal a rea and 36:100 in the non-removal a rea ( s i g n i f i c a n t l y lower at P=0.07, Tab le 20 ) . A h ighe r c a l f s u r v i v a l in the removal a rea was a l s o i n d i c a t e d by the improved s u r v i v a l of c a l v e s a s s o c i a t e d wi th 93 T a b l e 19 . Ave rage (SE) number o f moose o b s e r v e d pe r 60-km p l o t ( see methods) and e s t i m a t e s (SE) o f t h e moose d e n s i t y i n t h e non - r emova l and i n t h e remova l a r e a . R e s u l t s i n 1983 were d u r i n g t h e w o l f r e d u c t i o n programme. No. moose o b s e r v e d 2 pe r 60-km p l o t Non- remova l Removal a r e a a r e a Moose d e n s i t y N o . / k m 2 Non- remova l a r e a Removal a r e a P r e - r e m o v a l 1981 1982 P o s t - r e m o v a l 1983 4 . 7 ( 0 . 8 ) 4 . 3 ( 0 . 6 ) 5 .0 ( 1 . 5 ) 2 . 8 ( 2 . 7 ) 4 . 3 ( 2 . 3 ) 10 .7 ( 2 . 7 ) 0 . 36 ( 0 . 1 2 ) 0 . 32 ( 0 . 1 1 ) 0 .37 ( 0 . 1 4 ) 0 . 2 3 ( 0 . 2 1 ) 0 . 32 ( 0 . 1 8 ) 0 . 7 3 ( 0 . 2 2 ) 94 T a b l e 2 0 . C a l f - c o w r a t i o s i n t h e non - r emova l a r e a and i n t h e remova l a r e a b e f o r e i n i t i a t i o n o f t h e w o l f r e d u c t i o n programme ( 1 981 , 1 9 8 2 ) , and d u r i n g t h e programme (1983 , 1 9 8 4 ) . The r a t i o s were compared w i t h a t w o - t a i l e d Z - t e s t , = = 0 . 1 0 . No . c a l v e s : 100 cows ±90% CL (n) Non- remova l a r e a Removal a r e a Z - t e s t P r e - r e m o v a l 1981 1982 P o s t - r e m o v a l 1983 1984 65 ± 30 (43) 2 4 ± 1 1 (56) 45 ±17 (61) 30 ±11 (74) 30 ±18 (35) 52 ±25 (38) 68 ±29 (47) 39 ±18 (50) n . s . n . s . n . s . n . s . 1981 +82 39 ±11 (116) 40 ± 15 (73) n . s . 1983 +84 36 ± 8 (154) 52 ± 16 (97) P = 0 . 0 7 95 r a d i o - c o l l a r e d f ema les . In the removal a r e a , c a l v e s had a s u r v i v a l r a te of =65% compared to =50% in the non-removal area ( F i g . 15) . DISCUSSION A l though the r e s u l t s are p r e l i m i n a r y and t h e i r p r e c i s i o n can be improved, they are c o n s i s t e n t w i th the h y p o t h e s i s tha t p r e d a t i o n ma in ta ins moose p o p u l a t i o n s at d e n s i t i e s w e l l below the food c a r r y i n g c a p a c i t y . The wolf p o p u l a t i o n in the removal a rea was l i k e l y reduced by at l e a s t 40% in 1981-82, and subsequen t l y h e l d at t h i s l e v e l . In the removal area and i t s b u f f e r zone ( i . e . , 2150 km 2 ) , wolf removal r ep resen ted 0 .7 , 0 . 3 , and 0.5 an imal per 100 km2 in 1981-82, 1982-83, and 1983-84. As an es t imate of the wolf d e n s i t y be fore wolf remova l , wolf d e n s i t y in the non-removal area averaged 1.4 an imals*100 km" 2 from 1980-81 to 1983-84 (from i n t e n s i v e r a d i o - t r a c k i n g ; Mess i e r i n p r e s s a ) . K e i t h (1983) and Peterson et a l . (1984b) argued tha t a removal r a t e exceed ing 30% causes a wolf p o p u l a t i o n to d e c l i n e . Scat counts and the number of wolves seen per 100 hunt ing-days suggested a r e d u c t i o n in the wolf p o p u l a t i o n . Moose d e n s i t y i n c r eased d u r i n g the f i r s t year of the wolf r e d u c t i o n programme. However, I have some r e s e r v a t i o n s about the d e n s i t y increment (0.28 to 0.73 moose«km~ 2 ) , but none the l ess a t r end i s i n d i c a t e d . A e r i a l survey p r e c i s i o n 100 r 80 -w CD > 60 CO O "CO 40 > CO 20 a) © R E M O V A L (—•—) ® © © 0 0 L I L 53 E] EH Ea N O N - R E M O V A L (—o—) J I 1 M J J A S O N O J F M A M O N T H F i g . 15 . P e r c e n t s u r v i v a l o f c a l v e s a s s o c i a t e d w i t h r a d i o - c o l l a r e d f e m a l e moose i n t h e w o l f remova l and t h e non - r emova l a r e a . T o t a l numbers o f c a l v e s f o l l o w e d t h r o u g h t h e subsequen t month a r e i n c i r c l and s q u a r e s . 97 must be improved to q u a n t i f y more p r o p e r l y p o p u l a t i o n inc rement . Moose i nven to r y techn ique w i l l be r e v i s e d in 1985 to meet t h i s goa l (Crete et a l . submi t t ed ) . H igher r e c r u i t m e n t , as expressed by the 6-month c a l f r cow r a t i o , r ep resen t s the most important i n d i c a t o r of a moose p o p u l a t i o n r e l i e v e d from i n t e n s i v e p r e d a t i o n (Gasaway et a l . 1983). In t h i s s tudy , r e c ru i tmen t i n c r e a s e d from 40 c a l v e s : 1 0 0 cows to 68:100 in the f i r s t year of wolf removal and d e c l i n e d to 39:100 fo r the second yea r . P robab ly the second year r e d u c t i o n was c r e a t e d by a l a r g e r non-reproduc t i ve y e a r l i n g cohor t e n t e r i n g the cow p o p u l a t i o n ( i . e . , cows ^1.5 yr o l d in our c o u n t s ) . As a r e s u l t of the h ighe r r e c ru i tmen t in 1983, y e a r l i n g males ( sp i ked a n t l e r ) r ep re sen t ed 53% (n=17) of a l l males in the removal a rea but on ly 23% (n=31) in the non-removal area ( two- ta i l ed Z-test = 2 .13 , P<0.05) . If I assume s i m i l a r pe rcentages fo r y e a r l i n g f ema les , the number of c a l v e s : 1 0 0 cows ^2.5 yr o l d was 82 in the removal area and 39 in the non-removal a r e a . Thus there was an i n d i c a t i o n tha t the r e c ru i tmen t was much improved in both yea rs of wolf r e d u c t i o n . T h i s c o n c l u s i o n w i l l be supplemented in the f u tu r e by more p r e c i s e r e c ru i tmen t e s t ima tes where sample s i z e s shou ld be approx imate l y d o u b l e d . The e v a l u a t i o n of s u r v i v a l r a te of c a l v e s a s s o c i a t e d wi th r a d i o - c o l l a r e d females gave a l e s s pronounced response . The sma l l number of cows t r a cked to date n e c e s s i t a t e s a c a u t i o u s i n t e r p r e t a t i o n of these p r e l i m i n a r y r e s u l t s . 98 B lack bears are common in both study s i t e s at a minimum d e n s i t y of 0.25 a n i m a l ' k n r 2 ( L a chape l l e et a l . 1984). They are p o t e n t i a l c a l f p r eda to r s (Franzmann et a l . 1980), and p robab l y impose a l i m i t to the i n c r ease in c a l f s u r v i v a l even i f the wolf p o p u l a t i o n was reduced more s e v e r e l y . A bear removal exper iment was i n i t i a t e d in 1983 w i t h i n a t h i r d study s i t e in the r e s e r v e . T h i s p r o j e c t shou ld p rov ide some i n s i g h t s on the importance of bears as c a l f p r e d a t o r s . Management i m p l i c a t i o n s P reda to r c o n t r o l r ep re sen t s one of the many p o s s i b l e o p t i o n s to s t i m u l a t e p o p u l a t i o n growth of ungu la tes (Conno l l y 1978; Gasaway et a l . 1983). The immediate purpose of the p resen t wolf removal i s to e x p e r i m e n t a l l y determine i f moose p o p u l a t i o n s are r e g u l a t e d at low d e n s i t i e s by p r e d a t i o n . I f t h i s h y p o t h e s i s i s t r u e , moose managers face a di lemma. They may accep t tha t the ' n a t u r a l h a r v e s t a b l e s u r p l u s ' i s l i m i t e d . For example, the d e n s i t y o f f e r i n g a maximum s u s t a i n e d y i e l d wi thout i n t e r f e r e n c e in Quebec was es t imated at on l y 0 .2-0.3 moose«km" 2 (Crete at a l . 1981). With t h i s a l t e r n a t i v e , hun t ing success would remain low ( e . g . , the 1983 p r o v i n c e wide hun t ing success was-8%), and a v a i l a b l e food r e sou r ces c o u l d not be used to support h igher moose p o p u l a t i o n s . A l t e r n a t i v e l y , they may advocate that the p r i s t i n e na ture of the p reda to r-moose-vege ta t ion system are pe r tu rbed by man. In t h i s p e r s p e c t i v e , and c o n s i d e r i n g the l a r g e demand fo r moose 99 hunt ing in some a r e a s , an i n t e g r a t e d ungu la te management p o l i c y may i n c l u d e o p t i o n s to s i m u l t a n e o u s l y manage p reda to r p o p u l a t i o n s by means of t r a p p i n g and h u n t i n g . 100 Chapter V GENERAL DISCUSSION AND CONCLUSIONS P reda tor-moose-vegeta t ion dynamics can be summarized by a g r a p h i c a l r e p r e s e n t a t i o n ( F i g . 16) . In a p r e d a t o r - f r e e a r e a , a moose p o p u l a t i o n i s expected to d i s p l a y l o g i s t i c growth, r e s u l t i n g in a s i n g l e , upper d e n s i t y e q u i l i b r i u m ( D „ ) , as suggested f o r o ther ungu la te s p e c i e s (Caughley 1976; S i n c l a i r 1977; McCu l lough 1979). In t h i s s i t u a t i o n , c o m p e t i t i o n fo r n u t r i t i o u s fo rage wi th i n c r e a s i n g p o p u l a t i o n d e n s i t y r e s t r a i n s f e c u n d i t y and accen tua tes c h r o n i c m o r t a l i t y u n t i l p o p u l a t i o n growth i s no longer p o s s i b l e . In the presence of p r e d a t o r s , systems may have q u a l i t a t i v e l y 3 v a r i a n t s , but a cont inuum of p o s s i b l e outcomes e x i s t s . In the f i r s t v a r i a n t , p r e d a t i o n reduces the increment of a moose p o p u l a t i o n , but never s u f f i c i e n t l y to c r e a t e an e q u i l i b r i u m d e n s i t y wi thout c o m p e t i t i o n fo r forage hav ing a d e p r e s s i v e e f f e c t ( i . e . , food- induced e q u i l i b r i u m , D 3 ) . The second v a r i a n t i s a system c h a r a c t e r i z e d by a lower (p redator-induced) and an upper ( food- induced) e q u i l i b r i u m d e n s i t y . T h i s type of system i m p l i e s that p r e d a t o r s can s top p o p u l a t i o n growth at a d e n s i t y where forage c o m p e t i t i o n has no d e t r i m e n t a l e f f e c t (D , ) , but at h ighe r moose d e n s i t i e s , a l e s s e n i n g of p r e d a t i o n ra te permi ts p o p u l a t i o n growth u n t i l 101 F i g . 16 . The p r opo sed c o n c e p t u a l model o f p r e d a t o r - m o o s e - f o o d s u p p l y d y n a m i c s . In p r e d a t o r - f r e e a r e a s , moose p o p u l a t i o n s a r e h y p o t h e s i z e d t o s t a b i l i z e a t h i g h d e n s i t y (D^ e q u i l i b r i u m ) . Where p r e d a t i o n o c c u r s , 3 v a r i a n t s o f s y s t em b e h a v i o r a r e p o s s i b l e : 1) a s i n g l e , upper e q u i l i b r i u m (Dg ) , 2) a l o w e r , p r e d a t o r - i n d u c e d e q u i l i b r i u m ( D n ) and an u p p e r , f o o d -i n d u c e d e q u i l i b r i u m and 3) a s i n g l e , l owe r e q u i l i b r i u m (D-|). In t h i s m o d e l , p r e d a t i o n i s e n v i s i o n e d as h a v i n g a d e n s i t y - d e p e n d e n t phase f o l l o w e d by an i n v e r s e d e n s i t y - d e p e n d e n t phase ( i n s e t ) . 102 c o m p e t i t i o n fo r forage has a r e g u l a t o r y e f f e c t ( D 2 ) . The t h i r d v a r i a n t c o n s i s t s of a system s t a b i l i z i n g at a low d e n s i t y (D,) due to heavy p r e d a t i o n . In t h i s c a s e , the p e r s i s t e n t e f f e c t of a h igh p r e d a t i o n ra te p r e c l u d e s p o p u l a t i o n growth at h igher d e n s i t i e s (negat i ve inc rement , F i g . 16) . The c r u c i a l element in de t e rm in ing the s y s t em ' s behav io r i s the r e l a t i o n s h i p between p r e d a t i o n ra te and moose d e n s i t y . Wa l te rs et a l . (1981), and Gasaway et a l . (1983) argued that the impact of wolf p r e d a t i o n i n c r e a s e s d u r i n g a moose p o p u l a t i o n d e c l i n e . T h i s s o - c a l l e d depensatory impact may f o r c e a moose p o p u l a t i o n to e x t i n c t i o n , but such an event was never r e p o r t e d in the l i t e r a t u r e . Consequen t l y , some feedback mechanisms must be i n v o l v e d . In t h i s s tudy , I have demonstra ted the dens i ty-dependent i n f l u e n c e of wolf p r e d a t i o n at the lower range of moose d e n s i t i e s . O v e r a l l , the p r e d a t i o n r a te by wolves appears to be c h a r a c t e r i z e d by a d e n s i t y -dependent phase fo l l owed by an i n ve r se dens i t y-dependent phase ( i n s e t of F i g . 16). H o l l i n g (1959) in h i s p i o n e e r i n g work w i th mammalian p r eda to r s found a s i m i l a r r e l a t i o n s h i p (see a l s o H a s s e l l 1978 fo r examples in a r th ropod p reda to r-p rey s y s t ems ) . At very low moose d e n s i t i e s (<0.2 moose•knr 2 ) , p r e d a t i o n by wolves appears n e g l i g i b l e because wolves are n u t r i t i o n a l l y s t r e s s e d and t h e r e f o r e ra re or absen t , and a l s o because they tend to consume a l t e r n a t i v e food r e s o u r c e s . When moose d e n s i t y i n c r eases above the d e n s i t y t h r e s h o l d of =0.2 103 moose-km - 2 , wolves can c o l o n i z e the system, but in t h e i r i n i t i a l s t r u g g l e to s u b s i s t they must e x p l o i t t h e i r t e r r i t o r i e s i n t e n s i v e l y (Mess ier in p ress a ) . Dur ing t h i s c o l o n i z a t i o n phase ( approx imate l y between 0.2 and 0.5 moose«km" 2 ) p r e d a t i o n r a te appears to i n c r e a s e d r a m a t i c a l l y , p r o v i d i n g a s t rong feedback mechanism. At d e n s i t i e s h ighe r than 0 .5-1.0 moose-km" 2 , the impact of wolf p r e d a t i o n l i k e l y dec reases f o r 2 r easons : 1) s o c i a l behav io r ( t e r r i t o r i a l i t y , d e f e r r e d r ep roduc t i on ) would r e s t r a i n wolf p o p u l a t i o n growth (Packard and Mech 1980; Packard et a l . 1983), and 2) subs tandard moose i n d i v i d u a l s are more a v a i l a b l e and would compose a g r ea t e r f r a c t i o n of w o l f ' s k i l l s (Peterson et a l . 1984b). The r e a l i z a t i o n that p r e d a t i o n r a te peaks somewhere between low and moderate moose d e n s i t i e s has important i m p l i c a t i o n s on moose p o p u l a t i o n dynamics . For example, the annual increment curve may not have a b e l l shape as suggested by Caughley (1976) . Ra ther , the gene ra l form of the annual increment curve in the presence of p r e d a t i o n may be b imoda l , w i th a range of d e n s i t i e s at which the h a r v e s t a b l e su rp l u s i s l i m i t e d or n i l ( F i g . 16). T h i s phenomenon poses a problem fo r w i l d l i f e managers because such a " p r eda to r p i t " i n c r eases the r i s k of an unexpected d e c l i n e when human-exp lo i t a t i on i s l i b e r a l i z e d at h igh moose d e n s i t i e s . Moreover , the consequences of an i n i t i a l d e c l i n e can be aggrava ted by the t y p i c a l l ag response of wolf numbers to d e c r e a s i n g ungulate 1 04 d e n s i t i e s (Mech and Karns 1977; Gasaway et a l . 1983; Pe terson and Page 1983). Because 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 , the form of the p reda to r p i t i s h y p o t h e t i c a l , but some p r e d i c t i o n s may be proposed at t h i s t ime . In a reas where moose cohab i t w i th o ther ungu la te s p e c i e s ( e . g . , Carbyn 1983), the p reda to r p i t shou ld be l e s s pronounced because pa r t of the impact of p r e d a t i o n i s l i k e l y to be absorbed by the o ther ungula te s p e c i e s . T h i s e f f e c t dec reases the p o s s i b i l i t y that moose s t a b i l i z e at low d e n s i t y due to wolf p r e d a t i o n . A l t e r n a t i v e l y , i f a second s p e c i e s of p r e d a t o r s i s p resent ( e . g . , b l ack b e a r ) , I expect the p reda to r p i t to be r e l a t i v e l y deep because the r e c ru i tmen t w i l l be reduced by t h i s second p r e d a t o r . In such s i t u a t i o n s (as in southwestern Quebec ) , moose p o p u l a t i o n s are more l i k e l y to s t a b i l i z e at low d e n s i t i e s , and may never i n c r ease n a t u r a l l y to h igher d e n s i t i e s . Gasaway et a l . (1983) argued tha t a " p ruden t " p reda to r ( S lobodk in 1974) i s r e q u i r e d to e x p l a i n a s t a b l e moose-wolf sys tem. Ev idence e x i s t s tha t some n a t u r a l l y r egu l a t ed moose p o p u l a t i o n s are in f a c t remarkably s t a b l e . In Dena l i N a t i o n a l Park , A l a s k a , Haber (1977) r epo r t ed no major i r r u p t i o n s fo r at l e a s t 30-40 years or any obv ious c rashes f o l l o w i n g severe w in te r s ( dens i t y = 0 .3-0 .4 moose•knr 2 ) . In area H, Mess i e r and C re te (1984) c o u l d not de t e c t any changes in moose d e n s i t y between 1967 to 1983. Among the 3 study a r e a s , p r e d a t i o n ra te 105 i n c r e a s e d sha rp l y from 6.1% (Area L) to 19.3% (area H ) , and moreover , p r e d a t i o n ra te d i d not appear to be at i t s maximum, j udg ing by the low k i l l i n g r a t e and food i n t a k e . Wolves were a b l e to prevent an i n c r ease in the moose p o p u l a t i o n p r e c i s e l y because they were very e f f i c i e n t , r a the r than prudent p r e d a t o r s . The sharp change in p r e d a t i o n r a t e w i t h i n a narrow range of moose d e n s i t i e s c o n s t i t u t e s an e f f e c t i v e feedback mechanism. In t h i s sense , p reda to r-moose-vege ta t ion systems are not always dynamic as p o s t u l a t e d by Peek (1981), but may be f a i r l y s t a b l e where p r e d a t i o n r e p r e s e n t s the r e g u l a t o r y mechanism. Ev idence a l s o e x i s t s that n a t u r a l l y r e g u l a t e d moose p o p u l a t i o n s may undergo major f l u c t u a t i o n s , the best example be ing the I s l e Royale p o p u l a t i o n (Peterson and Page 1983). From the concep tua l model , I p r e d i c t r a the r c h a o t i c changes in moose numbers around the upper e q u i l i b r i a D 2 and D 3 . At the h i g h range of d e n s i t i e s (1 to =4 moose-km - 2 ) , fo rage c o m p e t i t i o n induces a dens i t y-dependent e f f e c t on r ec ru i tmen t (B lood 1973; Saether and Haagenrud 1983) and presumably on c h r o n i c m o r t a l i t y . However, the impact of p r e d a t i o n l i k e l y dec reases at the same time (above ) . Because these 2 p o p u l a t i o n p rocesses are a n t a g o n i s t i c , i t i s reasonab le to b e l i e v e tha t the net r e s u l t would be a weak r e g u l a t o r y feedback mechanism at h igh moose d e n s i t i e s ; tha t i s , p o p u l a t i o n growth r a te does not change r a p i d l y wi th p o p u l a t i o n d e n s i t y . O c c a s i o n a l severe w in te r s may cause important 1 06 f l u c t u a t i o n s of moose numbers at h i g h d e n s i t i e s (Peterson 1977). I t may we l l be tha t the phenomenon observed on I s l e Royale over the past 15 years (Pe terson and Page 1983) was in essence one of these s t o c h a s t i c ( in c o n t r a s t to c y c l i c ) d i s t u r b a n c e s exaggera ted by the m u l t i p l i e r e f f e c t of p r e d a t i o n ; the lack of an e f f e c t i v e feedback mechanism at h igh d e n s i t y be ing the fundamental r e a son . A l though t h i s view r e p r e s e n t s my i n t e r p r e t a t i o n , the b a s i c phenomenon remains un tes t ed and other e x p l a n a t i o n s are p l a u s i b l e (Bergerud et a l . 1983; Pe te rson et a l . 1984a). Caughley (1977) and McCul lough (1979) proposed that p r e d a t i o n d i v e r t s an ungu la te p o p u l a t i o n to a new and lower e q u i l i b r i u m than in a p r e d a t o r - f r e e s i t u a t i o n . But , how much lower w i l l t h i s new e q u i l i b r i u m be? Both au thors argued that p r e d a t o r s cannot prevent an ungu la te p o p u l a t i o n from i n c r e a s i n g to a l e v e l where fo rage c o m p e t i t i o n has a d e p r e s s i v e e f f e c t . T h e r e f o r e , they are r e f e r r i n g to the decrease from D„ to D 3 ( F i g . 16) . Two p r e d i c t i o n s can be fo rmu la ted r ega rd ing D 3 or D „ : 1) moose i n d i v i d u a l s must be n u t r i t i o n a l l y s t r e s s e d , and 2) enr ichment of forage w i l l c r e a t e an upsurge of moose d e n s i t y (Peek 1980). There i s no i n d i c a t i o n that these two p r e d i c t i o n s are t rue in southwestern Quebec (Mess ier and C re t e 1984). A l t e r n a t i v e l y , one p r e d i c t i o n can be fo rmu la ted r e g a r d i n g D , : p r e d a t i o n must be dens i t y-dependent up to t h i s d e n s i t y . Because t h i s p r e d i c t i o n appears t r u e , I conc lude that moose p o p u l a t i o n s are e i t h e r 107 p r e d a t o r - r e g u l a t e d , or s t a b i l i z e d at low d e n s i t y below a p r eda to r p i t ( i . e . , m u l t i p l e e q u i l i b r i a sys tem) . C re t e and Mess i e r (1984) are c u r r e n t l y a t tempt ing to d i s c r i m i n a t e between these 2 a l t e r n a t i v e s by means of a wolf removal expe r iment . At t h i s t ime, i t i s u n c e r t a i n tha t a moose p o p u l a t i o n c o u l d s t a b i l i z e at h igh d e n s i t i e s a f t e r a temporary wolf r e d u c t i o n programme; moose may r e tu rn to t h e i r former low d e n s i t y due to heavy p r e d a t i o n a f t e r recovery of the wolf p o p u l a t i o n . Fu r the rmore , the s t a b i l i t y of a h igh d e n s i t y e q u i l i b r i u m remains to be demonst ra ted , h a b i t a t over-u t i l i z a t i o n and n a t u r a l c r a shes s t i l l r ep resen t p o s s i b l e outcomes. 108 LITERATURE CITED Addison RB, W i l l i amson JC , Saunders BP, F r a se r D (1980) Radio-t r a c k i n g of moose in the bo r ea l f o r e s t of nor thwestern O n t a r i o . Can. F i e l d - N a t . 94: 269-276. Ador jan AS, Kolenosky GB (1969) A manual f o r the i d e n t i f i c a t i o n of h a i r s of s e l e c t e d O n t a r i o mammals. Ont . Dept . Lands F o r . , Res. Rep. W i l d l . No. 90. 47 pp . Ande l t WF, Ande l t SH (1984) D ie t b i a s in sca t d e p o s i t i o n - r a t e surveys of coyote d e n s i t y . W i l d l . Soc . B u l l . 12: 74-77. B a l l a r d WB, Spraker TH, T a y l o r KP (1981) Causes of neona ta l moose c a l f m o r t a l i t y in south c e n t r a l A l a s k a . J . W i l d l . Manage. 45: 335-342. Bekoff M, Mech LD (1984) S i m u l a t i o n a n a l y s e s of space use : home range e s t i m a t e s , v a r i a b i l i t y , and sample s i z e . Behav ior Res. Meth. I n s t r . Comp. 16: 32-37. Bergerud AT, (1980) Review of the p o p u l a t i o n dynamics of c a r i b o u in North Amer i c a . I n : Reimers E, Gaare E, Skjenneberg S (eds) P roc . 2nd I n t . R e i n d e e r / c a r i b o u Symp. R0ros , Norway, 1979 D i r e k t o r a t e t for ' v i l t og f e r s k v a n n s f i s k , Trondheim, pp . 556-581. Bergerud AT, Manuel F (1969) A e r i a l census of moose in c e n t r a l Newfoundland. J . W i l d l . Manage. 33: 910-916. Bergerud AT, Wyett W, Sn ider B (1983) The r o l e of wolf p r e d a t i o n in l i m i t i n g a moose p o p u l a t i o n . J . W i l d l . Manage. 47: 977-988. B l a x t e r KL, Hami l ton WJ (1980) Rep roduc t i on in farmed red deer 2. C a l f growth and m o r t a l i t y . J . A g r i c . S c i . , Camb. 95: 275-284. B lood DA (1973) V a r i a t i o n in r e p r o d u c t i o n and p r o d u c t i v i t y of an enc l o sed herd of moose (A l ces a l c e s ) . P roc . I n t . Congr . Game B i o l . 11: 59-66. Bowen WD (1982) Home range and s p a t i a l o r g a n i z a t i o n of coyo tes in J asper N a t i o n a l Park , A l b e r t a . J . W i l d l . Manage. 46: 201-216. B rassa rd JM, Audy E, C re te M, G r en i e r P (1974) D i s t r i b u t i o n and winter h a b i t a t of moose in Quebec. N a t u r a l i s t e Can. 101: 67-80. 109 Carbyn LN (1983) Wolf p r e d a t i o n on e l k in R i d i n g Mountain N a t i o n a l Park , Man i toba . J . W i l d l . Manage. 47: 963-976. Caughley G (1970) E r u p t i o n of ungu la te p o p u l a t i o n s , w i th emphasis on Himalayan thar in New Zea l and . Eco logy 51: 53-71. Caughley G (1976) W i l d l i f e management and the dynamics of ungu la te p o p u l a t i o n s . In : Coaker TH (ed) A p p l i e d b i o l o g y , V o l . 1. Academic P r e s s , London, pp. 183-246. Caughley G (1977) A n a l y s i s of v e r t e b r a t e p o p u l a t i o n s . John Wi ley and Sons, New York . C l a r k CW (1976) Mathemat i ca l b i oeconomics : the op t ima l management of renewable r e s o u r c e s . John Wi ley and Sons, New York . C lu t t on-B rock TH, Guinness FE , A lbon SD (1982) Red d e e r : b e h a v i o r , and eco logy of two sexes . Un i v . Ch icago P r e s s , C h i c a g o . C o n n o l l y GE (1978) P r eda to r s and p reda to r c o n t r o l . In : Schmidt J L , G i l b e r t DL (eds . ) B ig game of North Amer i ca . S t a ckpo le C o . , H a r r i s b u r g , pp . 369-394. C re t e M (Submitted) The impact of spor t hunt ing on North American moose. Swedish W i l d l . Res. C re t e M, Be langer M, Tremblay J (1981a) Regime a l i m e n t a i r e du loup dans l e sud-ouest du Quebec ent re l e s mois de Mai et d ' O c t o b r e . N a t u r a l i s t e Can. 108: 167-173. C re t e M, Jordan PA (1982a) P roduc t i on and q u a l i t y of forage a v a i l a b l e to moose in southwestern Quebec. Can. J . Res. F o r . 12: 151-159. C re t e M, Jordan PA (1982b) P o p u l a t i o n consequences of winter fo rage r esources f o r moose, A l c e s a l c e s , in southwestern Quebec. Can . F i e l d - N a t . 96: 467-475. C r e t e M, Mess ie r F (1984) Reponse de l ' o r i g n a l a un pre levement de loups dans l e sud-ouest du Quebec. A l c e s 20: ( in p r e s s , e n g l i s h v e r s i o n a v a i l a b l e ) . C re t e M, R i ve t LP, J o l i c o e u r H, B r a s sa rd JM, Mess i e r F (Submitted) C o r r e c t i n g v i s i b i l i t y b i a s fo r moose a e r i a l census over mixed f o r e s t s of Quebec. J . W i l d l . Manage. C re te M, S t - H i l a i r e D (1979) L ' h e l i c o p t e r e et l ' a v i o n pour denombrer l e s or ignaux dans l e sud-ouest du Quebec. N a t u r a l i s t e Can. 106: 487-495. 1 10 C re te M, T a y l o r RJ, Jordan PA (1981) O p t i m i z a t i o n of moose ha r ves t in southwestern Quebec. J . W i l d l . Manage. 45: 598-611 . C re t e M, Tremblay A, Jordan PA (1982) Hunter c o l l e c t e d b lood samples fo r comparing the p h y s i c a l c o n d i t i o n of two Quebec moose p o p u l a t i o n s . A l c e s 18:25-44. Dauphine TC (1976) B i o l ogy of the Kaminur iak p o p u l a t i o n of bar ren-ground c a r i b o u . Par t 4, growth, r e p r o d u c t i o n and energy r e s e r v e s . Can. W i l d l . S e r v . , Rep. Se r . No. 38. 71 pp . F e r l a n d MG, Gagnon RM (1967) C l ima t du Quebec m e r i d i o n a l . Q u e . , Min R i chesses N a t u r e l l e s , MP-13, 97 pp . F l o y d T J , Mech LD, Jordan PA (1978) R e l a t i n g wolf scat content to prey consumed. J . W i l d l . Manage. 42: 528-532. Franzmann AW, Schwartz CC, Pe te rson RO (1980) Moose c a l f m o r t a l i t y in summer on the Kenai P e n i n s u l a , A l a s k a . J . W i l d l . Manage. 44:764-768. F u l l e r TK, K e i t h LB (1980) Wolf p o p u l a t i o n dynamics and prey r e l a t i o n s h i p s in no r theas t e rn A l b e r t a . J . W i l d l . Manage. 44: 583-602. Gasaway WC, DuBois SD, B r ink KL (1980) D i s p e r s a l of subadu l t moose from a low d e n s i t y p o p u l a t i o n in i n t e r i o r A l a s k a . P r o c . North Am. Moose Con f . 16: 314-337. Gasaway WC, Stephenson RO, Dav i s JL , Shepherd PEK, B u r r i s OE (1983) I n t e r r e l a t i o n s h i p s of wolves , p r e y , and man in i n t e r i o r A l a s k a . W i l d . Monogr. No. 84, 50 pp . Gau th i e r C (1978) Taux d ' o v u l a t i o n et p r o d u c t i v i t y des p o p u l a t i o n s d ' o r i gnaux de t r o i s pares et r e se r ves du Quebec. Que . , M in . L o i s i r Chasse et Peches , RRF No. 28; 36 pp . Goddard J (1970) Movements of moose in a h e a v i l y hunted area of O n t a r i o . J . W i l d l . Manage. 34: 439-445. Haber GC (1977) S o c i o - e c o l o g i c a l dynamics of wolves and prey in a s u b a r c t i c ecosys tem. Ph. D. t h e s i s , Un i v . B r i t i s h Co lumb ia , Vancouver . Haigh JC , Steward RR, Mytton W (1980) R e l a t i o n s among l i n e a r measurements and weights fo r moose (A l ces a l c e s ) . P roc . Nor th Am. Moose Conf . 16: 1-11. 111 Hanks J (1981) C h a r a c t e r i z a t i o n of p o p u l a t i o n c o n d i t i o n . In : Fowler CW, Smith TD (eds) Dynamics of l a r g e mammal p o p u l a t i o n s . John Wi ley and Sons, New York , pp. 47-73. H a s s e l l MP (1978) The dynamics of a r t h ropod p reda to r-p rey systems. Monogr. Pop. B i o l . No. 13, P r i n c e t o n Un i v . P r e s s , P r i n c e t o n . Hauge TM, K e i t h LB (1981) Dynamics of moose p o p u l a t i o n s in no r theas the rn A l b e r t a . J . W i l d . Manage. 45: 573-597. H o l l i n g CS (1959) The components of p r e d a t i o n as r e v e a l e d by a study of sma l l mammal p r e d a t i o n of the European p ine s aw f l y . Can. En tomol . 91: 293-320. Houston DB (1982) The no r the rn Ye l lowstone e l k . Macmi l l an P u b l i s h i n g C o . , New York Huot J (1982) Body c o n d i t i o n and food r e sou r ces of whi te-t a i l e d deer on A n t i c o s t i I s l a n d , Quebec. Ph .D. t h e s i s , Un i v . of A l a s k a , F a i r b a n k s . K e i t h LB (1974) Some f e a t u r e s of p o p u l a t i o n dynamics in mammals. P roc . I n t . Congr . Game B i o l . 11: 17-58. K e i t h LB (1983) P o p u l a t i o n dynamics of wo lves . In : Carbyn LN (ed) Wolves in Canada and A l a s k a : t h e i r s t a t u s , b i o l o g y , and management. E n v i r . C a n . , Can. W i l d l . S e r v . , Rep. Se r . No. 45. pp. 66-77. K ie JG, Drawe DL, Sco t t G (1980) Changes in d i e t and n u t r i t i o n wi th i n c r eased herd s i z e in Texas w h i t e - t a i l e d d e e r . J . Range Manage. 33: 28-34. K l e i n DR (1964) Range-re la ted d i f f e r e n c e s in growth of deer r e f l e c t e d in s k e l e t a l r a t i o s . J . Mamm. 45: 226-235. K l e i n DR (1968) The i n t r o d u c t i o n , i n c r e a s e , and c r a sh of r e i ndee r on S t . Matthew I s l a n d . J . W i l d l . Manage. 32: 350-367. K l e i n DR (1970) Food s e l e c t i o n by North American deer and t h e i r response to o v e r u t i l i z a t i o n of p r e f e r r e d p l a n t s p e c i e s . In : Watson A (ed) Animal p o p u l a t i o n s in r e l a t i o n to t h e i r food r e s o u r c e s . B l a ckwe l l S c i e n t . P u b l . , O x f o r d , pp. 25-44. K l e i n DR, S t randgaard H (1972) F a c t o r s a f f e c t i n g growth and body s i z e of roe dee r . J . W i l d l . Manage. 36: 64-79. L a c h a p e l l e A, Mess ie r F, C re te M (1984) E f f e t de l a p r e d a t i o n de l ' o u r s n o i r sur l e s p o p u l a t i o n s d ' o r i g n a u x du sud-1 1 2 ouest du Quebec.' A l c e s 20: La r sen DG (1984) The r a te and causes of moose c a l f and adu l t female m o r t a l i t y in southern Yukon. A l c e s 20: Leade r-W i l l i ams N, R i c k e t t s C (1982) Growth and c o n d i t i o n of th ree i n t roduced r e i n d e e r herds on South G e o r g i a : the e f f e c t s of d i e t and d e n s i t y . H o l a r t i c Eco logy 5: 381-388. Macnab J (1983) W i l d l i f e management as s c i e n t i f i c e x p e r i m e n t a t i o n . W i l d l . Soc . B u l l . 11: 397-401. McCu l lough DR (1979) The George Reserve deer h e r d . Un i v . M i ch igan P r e s s , Ann A r b o r . Mech LD (1966) The wolves of I s l e Roya l e . U.S. N a t l . Park S e r v . , Fauna S e r i e s No. 7, 210 pp. Mech LD (1974) Cur ren t t e chn iques in the study of e l u s i v e w i l d e rnes s c a r n i v o r e s . P roc . I n t . Congr . Game B i o l . 11: 315-322. Mech LD (1977) P o p u l a t i o n t r end and winter deer consumption in . a Minnesota wolf pack . In : P h i l l i p s RL, J onke l C (eds) P r o c . 1975 P reda tor Symp. Montana For . . Conse rv . Exp. S t n . , M i s s o u l a , pp . 55-83. Mech LD, Karns PD (1977) Role of the wolf in a deer d e c l i n e in the Super io r N a t i o n a l F o r e s t . U.S. Dep. A g r i c . F o r . S e r v . , Res. Pap. NC-148, 23 pp . Mess i e r F (In p ress a) S o c i a l o r g a n i z a t i o n , s p a t i a l d i s t r i b u t i o n , and p o p u l a t i o n d e n s i t y of wolves in r e l a t i o n to moose d e n s i t y . Can . J . Z o o l . Mess i e r F (In p ress b) S o l i t a r y l i v i n g and e x t r a - t e r r i t o r i a l movements of wolves in r e l a t i o n to s o c i a l s t a t u s and prey abundance. Can. J . Z o o l . Mess i e r F, B a r r e t t e C (1982) The s o c i a l system of coyote (Can is l a t r a n s ) in a f o r e s t e d h a b i t a t . Can. J . Z o o l . 60: 1743-1753. Mess i e r F, Cre te M (In p ress ) Moose-wolf dynamics and the n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s . O e c o l o g i a ( B e r l i n ) . Mess i e r F, Crete M (1984) Body c o n d i t i o n and p o p u l a t i o n r e g u l a t i o n by food r esources in moose. O e c o l o g i a ( B e r l i n ) . 1 1 3 M i t c h e l l B, McCowan D, N i cho l son IA (1976) Annual c y c l e s of body weight and c o n d i t i o n in S c o t t i s h red dee r , Cervus  e l a p h u s . J . Z o o l . Lond. 180: 107-127. N e i l a n d KA (1970) Weight of d r i e d marrow as i n d i c a t o r of f a t in c a r i b o u femurs. J . W i l d l . Manage. 34: 904-907. Neter J , Wasserman W (1974) A p p l i e d l i n e a r s t a t i s t i c a l mode ls . R i cha rd D. I rw in , Homewood. Packard JM, Mech LD (1980) P o p u l a t i o n r e g u l a t i o n in wo lves . In : Cohen MN, Malpass RS, K l e i n GH (eds) B i o s o c i a l mechanisms of p o p u l a t i o n r e g u l a t i o n . Ya l e U n i v e r s i t y P r e s s , New Haven, pp. 135-150. Packard JM, Mech LD, Sea l US (1983) S o c i a l i n f l u e n c e s on r e p r o d u c t i o n in wo lves . In : Carbyn LN (ed) Wolves in Canada and A l a s k a : t h e i r s t a t u s , b i o l o g y , and management. Can. W i l d l . S e r . , Rep. Se r . No. 45, pp . 78-85. Peek JM (1980) Na tu r a l r e g u l a t i o n of ungu la tes (what c o n s t i t u t e s a r e a l w i l d e r n e s s ? ) . W i l d l . Soc . B u l l . 8: 217-227. Peek JM (1981) Comments on C a u g h l e y ' s comment. W i l d l . Soc . B u l l . 9: 234-237. Peek JM, U r i c h DL, Mackie RJ (1976) Moose h a b i t a t s e l e c t i o n and r e l a t i o n s h i p s to f o r e s t management in n o r t h e a s t e r n M inneso ta . W i l d l . Monogr. 48: 1-65. Peek JM, Eastman DS (1983) F a c t o r s which n a t u r a l l y c o n t r o l moose p o p u l a t i o n s . In : Bunne l l FL , Eastman DS, Peek JM (eds) Symposium on n a t u r a l r e g u l a t i o n of w i l d l i f e p o p u l a t i o n s . P roc . No. 14, W i l d l . Soc . Northwest S e c t . , pp . 175-193. Pe te rson JC , Harper KT (1978) F a c to r i n f l u e n c i n g p r o d u c t i v i t y of two mule deer herds in U tah . J . Range Manage. 31 : 105-110. Pe te rson RO (1977) Wolf eco logy and prey r e l a t i o n s h i p s on I s l e Roya l e . US Dep I n t e r , N a t l Park Se rv , S c i e n t . Monogr. S e r i e s , No. 11, 210 pp . Pe te rson RO, Page RE (1983) Wolf-moose f l u c t u a t i o n s at I s l e Royale N a t i o n a l Park , M i c h i g a n , USA. Ac t a Z o o l . F enn i ca 174: 251-253. Pe te rson RO, Page RE, Dodge KM (1984a) Wolves , moose, and the a l l o m e t r y of p o p u l a t i o n c y c l e s . S c i ence 224: 1350-1352. 1 1 4 Pe te rson RO, Wool ington JD, B a i l e y TN (1984b) Wolves of the Kenai P e n i n s u l a , A l a s k a . W i l d l . Monogr. No. 88, 52 pp. P im lo t t DH (1959) Reproduc t ion and p r o d u c t i v i t y of Newfoundland moose. J . W i l d l . Manage. 23: 381-401. P i m l o t t DH (1967) Wolf p r e d a t i o n and ungu la te p o p u l a t i o n s . Am. Z o o l . 7: 267-278. Reimers E, K l e i n DR, Sorumgard R (1983) C a l v i n g t ime , growth r a t e , and body s i z e of Norwegian r e i ndee r on d i f f e r e n t r anges . A r c t i c and A l p i n e Res. 15: 107-118. Robbins CT, Robbins BL (1979) F e t a l and neona ta l growth p a t t e r n s and materna l r e p r o d u c t i v e e f f o r t in ungu la tes and subungu la t es . Am. Nat . 114: 101-116. R o l l e y RE, K e i t h LB (1980) Moose p o p u l a t i o n dynamics and winter h a b i t a t use at Roches te r , A b e r t a , 1965-1979. Can. F i e l d - N a t . 94: 9-18. Rousse l YE (1975) A e r i a l sex ing of a n t l e r l e s s moose by white vu l va p a t c h . J . W i l d l . Manage. 39:450-451. Rousse l YE, Audy E, Po t v i n F (1975) P r e l i m i n a r y study of seasona l moose movements in L au r en t i de s P r o v i n c i a l Park , Quebec. Can. F i e l d - N a t . 89: 47-52. Rowe JS (1972) Fo res t r eg ions of Canada. Can . M i n i s t . Env i ronment , F o r . Se rv . P u b l . No. 1300, 172 pp . Saether BE, Haagenrud H (1983) L i f e h i s t o r y of the moose (A l ces a l c e s ) : f e c u n d i t y r a t e s in r e l a t i o n to age and c a r c a s s we ight . J . Mamm. 64: 226-232. S ch l adwe i l e r P, Stevens DR (1973) Reproduc t ion of S h i r a s moose in Montana. J . W i l d l . Manage. 37: 535-544. She l ton PC, Peterson RO (1983) Beaver , wolf and moose i n t e r a c t i o n s in I s l e Royale N a t i o n a l Park , USA. Ac ta Z o o l . Fenn i ca 174: 265-266. S i e g e l S (1956) Nonparametr ic s t a t i s t i c s fo r the b e h a v i o r a l s c i e n c e s . McGraw-Hi l l , New York . S imkin DW (1974) Reproduc t ion and p r o d u c t i v i t y of moose. N a t u r a l i s t e Can. 101: 517-526. S i n c l a i r ARE (1977) The A f r i c a n b u f f a l o . Un i v . Ch icago P r e s s , Ch i c ago . 1 1 5 S i n c l a i r ARE, N o r t o n - G r i f f i t h s M (1982) Does c o m p e t i t i o n or f a c i l i t a t i o n r e g u l a t e migrant ungula te p o p u l a t i o n s in the Se r enge t i ? A t e s t of hypotheses . O e c o l o g i a 53: 364-369. Skogland R (1983) The e f f e c t s of d e n s i t y dependent resource l i m i t a t i o n on s i z e of w i l d r e i n d e e r . O e c o l o g i a 60: 156— 1 68. S l obodk in LB (1974) Prudent p r e d a t i o n does not r e q u i r e group s e l e c t i o n . Am. Nat . 108: 665-678. Soka l RR, Rohl f FJ (1981) B iomet ry . W.H. Freeman and Company, San F r a n c i s c o . Soucy G (1971) Moyennes et v a r i a b i l i t y des v a l e u r s n i vomet r iques du Quebec. M in . R i chesses N a t u r e l l e s du Quebec. S e r v i c e M e t e o r o l o g i q u e . Smuts GL (1978) I n t e r r e l a t i o n s between p r e d a t o r s , p r e y , and t h e i r env i ronment . B io-Sc ience 28: 316-320. S u t t i e JM (1980) I n f l uence of n u t r i t i o n on growth and sexua l ma tu ra t i on of c a p t i v e red deer s t a g s . In : Reimers E, Gaare E, Skjenneberg S (eds) P roc . 2nd. I n t . Re i ndee r /Ca r i bou Symp., R0ros , Norway, 1979. D i r e k t o r a t e t f o r v i l t og f e r s k v a n n s f i s k , Trondheim, pp. 341-349. Thomas DC (1982) The r e l a t i o n s h i p between f e r t i l i t y and f a t r e s e r v e s of Peary c a r i b o u . Can. J . Z o o l . 60: 597-602. Thorne ET, Dean RE, Hepworth WG (1976) N u t r i t i o n du r i ng g e s t a t i o n in r e l a t i o n to s u c c e s s f u l r e p r o d u c t i o n in e l k . J . W i l d . Manage. 40: 330-335. Van Ba l l enbe rghe V (1980) U t i l i t y of m u l t i p l e e q u i l i b r i u m concep ts a p p l i e d to p o p u l a t i o n dynamics of moose. P roc . N. Am. Moose Conf . 16:571-586. Verme LJ (1963) E f f e c t of n u t r i t i o n on growth of w h i t e - t a i l e d deer fawns. T r a n s . Nor th Am. W i l d l . Nat . Res . Conf . 28: 431-443. Verme LJ (1969) Reproduc t ion p a t t e r n s of w h i t e - t a i l e d deer r e l a t e d to n u t r i t i o n a l p l a n e . J . W i l d l . Manage. 33: 881 -887. Verme LJ (1974) Problems in a p p r a i s i n g r e p r o d u c t i o n in C e r v i d a e . P roc . N. Am. Moose Conf . 10: 22-36. Verme LJ (1979) I n f l uence of n u t r i t i o n on f e t a l organ development in dee r . J . W i l d l . Manage. 43: 791-796. 1 16 Verme L J , Ozoga J J (1980a) I n f l uence of p ro t e i n-ene rgy in take on deer fawns in autumn. J . W i l d l . Manage. 44: 305-314. Verme L J , Ozoga JJ (1980b) E f f e c t of d i e t on growth and l i p o g e n e s i s in deer fawns. J . W i l d l . Manage. 44: 315-324. V o i g t DR, Kolenosky GB, P im lo t t DH (1976) Changes in summer foods of wolves in c e n t r a l O n t a r i o . J . W i l d l . Manage. 40: 663-668. Wa l te rs C J , S tocker M, Haber GC (1981) S i m u l a t i o n and o p t i m i z a t i o n models fo r a wo l f-ungu la te sys tem. In : Fowler CW, Smith TD (eds) Dynamics of l a r g e mammal p o p u l a t i o n s . John Wi ley and Sons, New York . pp . 317-337. Zimen E (1976) On the r e g u l a t i o n of pack s i z e in wo lves . Z. T i e r p s y c h o l . 40: 300-341. Zimen E (1982) A wolf pack soc iog ram. In : H a r r i n g t o n FH, Paquet PC (eds) Wolves of the wo r l d : p e r s p e c t i v e s of b e h a v i o r , e c o l o g y , and c o n s e r v a t i o n . Noyes, Park Ridge (New J e r s e y ) , pp. 282-322. 1 17 Appendix SOLITARY LIVING AND EXTRA-TERRITORIAL MOVEMENTS OF WOLVES IN RELATION TO SOCIAL STATUS AND PREY ABUNDANCE INTRODUCTION In s o c i a l b i r d s and mammals, the d i s p e r s a l of group members may p l ay a c e n t r a l r o l e in group dynamics and p o p u l a t i o n r e g u l a t i o n (Brown 1983; Macdonald 1983). The b e h a v i o u r a l and e c o l o g i c a l an tecedents of d i s p e r s a l , or of n a t a l p h i l o p a t r y , have a t t r a c t e d b i o l o g i s t s ' i n t e r e s t in the l a s t decade . The unde rs t and ing of such an tecedents shou ld h e l p to comprehend s o c i a l i t y (Barash 1974; Armitage 1977; Bekof f 1977; Emlen 1982; Brown 1983; Waser and Jones 1983). In C a r n i v o r a , group l i v i n g opera tes w i t h i n a framework of c o s t - b e n e f i t c o n s t r a i n t s determined l a r g e l y by : 1) the d i s p e r s i o n and abundance of food r e s o u r c e s , 2) the c o m p e t i t i o n fo r space ( hab i t a t s a t u r a t i o n ) , 3) the c o m p e t i t i o n w i th other p r e d a t o r s over c a r c a s s e s , and 4) the a s s i s t a n c e needed to rea r young o p t i m a l l y ( rev iews in Lamprecht 1981; Macdonald and Moehlman 1982; Mess ie r and B a r r e t t e 1982; Macdonald 1983; Bekoff et a l . in p r e s s ) . I propose t h a t , in wolves (Cards l u p u s ) , f a c t o r s 1 and 2 govern the tendency of an i n d i v i d u a l to l i v e t e m p o r a r i l y apar t from i t s pack ( s o l i t a r y l i v i n g ) , and 1 18 to engage i n s o l o e x t r a - t e r r i t o r i a l movements. As an ex tens ion of t h i s p r o p o s a l , I suggest that food r e sou r ces in c o n j u n c t i o n w i th t e r r i t o r y vacancy u l t i m a t e l y set the r u l e s fo r the d i s p e r s a l s t r a t e g y of pack members (see a l s o Zimen 1976; Packard and Mech 1980; Macdonald 1983). Here I r epo r t on s o l i t a r y l i v i n g and e x t r a - t e r r i t o r i a l movements of 54 wolves s t u d i e d du r i ng a 4-year r e sea r ch programme. Data are i n t e r p r e t e d in r e l a t i o n to prey abundance, age of the a n i m a l s , t h e i r sex , and the s p a t i a l d i s t r i b u t i o n of packs . Obse r va t i ons of pack e x c u r s i o n s are i n c l u d e d fo r compar i son . Mech (1977), F r i t t s and Mech (1981) , Stephenson and James (1982) , Van Ba l l enberghe (1983), and Pe te rson et a l . (1984) p u b l i s h e d r e l a t e d f i e l d o b s e r v a t i o n s which are d i s c u s s e d . STUDY AREA .AND METHODS Wolf s p a t i a l d i s t r i b u t i o n was i n v e s t i g a t e d in a 6400-km 2 a rea of southwestern Quebec, Canada ( 4 7 ° N , 77°W) from June 1980 to February 1984. T h i s area was d e l i b e r a t e l y s e l e c t e d because i t covered a 3000-km 2 h igh prey a rea (HP) in La Verendrye r e s e r v e , and a 3400-km 2 low prey area (LP) south of the rese rve ( i . e . , same study area than Chapter I I ) . F i f t y - f o u r wolves from 14 con t iguous packs were r ad i o-t r a cked by a i r p l a n e s . Some 4700 wolf l o c a t i o n s were accumulated du r i ng the 2000 h of f l y i n g t ime . Wolves were 119 v i s u a l l y observed in 75% of the l o c a t i o n s d u r i n g w i n t e r , but r a r e l y in o ther p e r i o d s . Each wolf obse r v a t i on i n c l u d e d the group s i z e , whether or not a l l the an imals were seen ( i . e . , in open h a b i t a t ) , and the i d e n t i t y of marked i n d i v i d u a l s . Captured wolves were c l a s s i f i e d as e i t h e r pup (<12 months, s t a r t i n g 1 May) , y e a r l i n g (12-24 months) , or adu l t (>24 months ) . Pups were aged a c c u r a t e l y from too th e r u p t i o n p a t t e r n s . Y e a r l i n g s were e i t h e r of known age ( t rapped as pups or aged a f t e r dea th , n=5), or of assumed age (n=3) from t h e i r can ine l e n g t h s , too th wear, and r e p r o d u c t i v e s t a t u s . The p o s s i b i t y tha t y e a r l i n g s were mistaken as a d u l t s i s b e l i e v e d to be m i n i m a l ; i f so , they would have been young, non-r e p r o d u c t i v e a d u l t s . S o l i t a r y l i v i n g c o u l d be s t u d i e d r e l i a b l y on l y from 1 December to 30 A p r i l each year (winter pe r i od ) when wolves c o u l d be observed d i r e c t l y from a i r p l a n e s . In t h i s paper , I used on l y o b s e r v a t i o n s fo r which I was c e r t a i n whether or not a wolf seen from the a i r was accompanied by o ther pack members. Frequency ana l y ses on the f u l l set of r e l i a b l e o b s e r v a t i o n s (n=1l92) were based on con t ingency t a b l e s and G-t e s t s (Sokal and Rohl f 1981: 747-764). F r equenc i e s at which wolves were observed apar t from the packs ( i . e . , d i s t a n t more than 500 m) were r e l a t e d to the age of a n i m a l s , t h e i r sex , and the abundance of prey (HP or LP ) . I used s i m i l a r ana l y ses to r e l a t e the p o r t i o n of these o b s e r v a t i o n s o u t s i d e the p a c k ' s t e r r i t o r y . Data from known lone wolves , i n c l u d i n g an imals 1 20 d u r i n g t h e i r a c t u a l or assumed d e f i n i t i v e d i s p e r s a l , were e l i m i n a t e d from these ana l y ses and were t r e a t e d s e p a r a t e l y because they r ep resen t a d i f f e r e n t phenomenon. I d e f i n e d e x t r a - t e r r i t o r i a l e x c u r s i o n s as be ing any t r a v e l 5 km beyond the boundary of the yea r- long t e r r i t o r y of the pack . Such areas were d e l i n e a t e d by the convex-polygon c o n t a i n i n g 95% of the c l o s e s t l o c a t i o n s of ins t rumented pack member(s) ob t a ined d u r i n g the c u r r e n t 1-year p e r i o d (1 May to 30 A p r i l ) . In the 3 cases where the annual t e r r i t o r y c o u l d not be p r o p e r l y d e f i n e d because of i n s u f f i c i e n t d a t a , I took the boundary of the p r e v i o u s or subsequent y e a r . The minimum s t r a i g h t l i n e d i s t a n c e of an e x c u r s i o n was measured from the most d i s t a n t wolf l o c a t i o n to the c l o s e s t po in t of the home t e r r i t o r y . The approximate d u r a t i o n of each e x c u r s i o n was c a l c u l a t e d from the mid-date between the l a s t l o c a t i o n i n s i d e the t e r r i t o r y and the f i r s t l o c a t i o n of the e x c u r s i o n , to the mid-date between the l a s t l o c a t i o n of the e x c u r s i o n and the f i r s t l o c a t i o n on r e tu rn to the t e r r i t o r y . E l apsed time was not computed i f the e x c u r s i o n was not bounded by a pre- and a p o s t - e x c u r s i o n l o c a t i o n w i t h i n 5 days , or i f an a c t u a l or assumed d i s p e r s a l o c c u r r e d . Radio f i x e s d u r i n g an e x c u r s i o n were assumed to be independent because most l o c a t i o n s were w i t h i n 1 or 2 t r a v e l l i n g days (30-40 km) from the p a c k ' s t e r r i t o r y . T h e r e f o r e , wolves had, in most days , the o p p o r t u n i t y e i t h e r to con t i nue f o r a y i n g or to be in t h e i r home t e r r i t o r y by the next 121 day . On ave rage , I recorded an o b s e r v a t i o n of s o l i t a r y an imals tha t met my c o n s t r a i n t s each 4 days . Radio f i x e s of an imals separa ted from t h e i r pack, but w i t h i n the t e r r i t o r y , a l s o were assumed to be independent . Radio f i x e s of s o l i t a r y wolves were ana l y sed in r e l a t i o n to the c o n f i g u r a t i o n of pack t e r r i t o r i e s . In the cases of pack members, I used on ly l o c a t i o n s d u r i n g e x t r a - t e r r i t o r i a l movements. Because such o b s e r v a t i o n s were a v a i l a b l e from 1980 to 1984, pack t e r r i t o r i e s were d e l i n e a t e d from the 1980-84 data set in t h i s a n a l y s i s ; most yea r- long t e r r i t o r i e s were f a i r l y s t a b l e and the 2 new t e r r i t o r i e s formed d u r i n g the study covered few l o c a t i o n s of s o l i t a r y wo lves . Radio f i x e s were c a t e g o r i z e d w i th in t e r r i t o r y c o r e s , b u f f e r zones , or i n t e r s t i c e s . P l an imet ry of these areas was conducted as f o l l o w s : t e r r i t o r y co res = t e r r i t o r y areas minus the 2-km wide b u f f e r zones bo rde r i ng i n t e r n a l l y each t e r r i t o r y ; i n t e r s t i c e s = areas between t e r r i t o r i e s p l u s a 2-km s t r i p b o r d e r i n g e x t e r n a l l y the whole t e r r i t o r y mosa i c . The t o t a l a rea e q u a l l e d i n t e r s t i c e s , p l u s b u f f e r a r e a s , p l u s t e r r i t o r y c o r e s . L o c a t i o n s o u t s i d e the t o t a l a rea were e x c l u d e d . Nonparametr ic s t a t i s t i c a l t e s t s ( S i ege l 1956; Soka l and Roh l f 1981) were used i f the assumpt ions of pa ramet r i c t e s t s were v i o l a t e d . A l l - t e s t s except F-test were t w o - t a i l e d , and p r o b a b i l i t i e s g rea te r than 0.05 were judged to be not s i g n i f i c a n t . 122 RESULTS S o l i t a r y l i v i n g Wolves which were c o n s t a n t l y observed a lone were uncommon in the study a r e a . Out of 54 wolves t r a c k e d , 2 an ima ls (both females) c o u l d not be a s s o c i a t e d w i th e s t a b l i s h e d packs , and 3 o the r s d i s p e r s e d s h o r t l y a f t e r t h e i r cap tu re which c a s t s doubt on t h e i r pack o r i g i n . One lone an ima l cove red 2310 km2 a c ross 7 pack t e r r i t o r i e s du r i ng a p e r i o d of 13 months p o s t c a p t u r e . The second covered 710 km2 a c ro s s 3 pack t e r r i t o r i e s d u r i n g the 9 months p o s t c a p t u r e . The l a t t e r an imal was l o c a t e d most ly w i t h i n one pack t e r r i t o r y (85% of l o c a t i o n s , n=93), which s u g g e s t s ' a p r e v i ous a rea f a m i l i a r i t y and group a s s o c i a t i o n (perhaps the n a t a l p a ck ) . Movements of these 2 lone wolves can be d e s c r i b e d as " i t i n e r a n t " but not w i th a random o r i e n t a t i o n because they r e g u l a r l y r e tu rned to f a m i l i a r a r e a s . In c o n t r a s t to pack members, the area each lone an imal covered i n c r e a s e d wi th the number of l o c a t i o n s . T h i s o b s e r v a t i o n i m p l i e s tha t o c c a s i o n a l l y new areas were be ing v i s i t e d . The most f r e q u e n t l y observed s o l i t a r y wolves were pack members t e m p o r a r i l y d i s s o c i a t e d from t h e i r s o c i a l groups du r i ng p e r i o d s ex tend ing from a few days to a few months. From the con t ingency t a b l e a n a l y s i s on the f u l l set of w in te r d a t a , I r e j e c t e d the n u l l h ypo thes i s of independency between prey abundance and age (G[2 ]=18 .48, P<0 . 0 1 ) . A low prey base caused y e a r l i n g s to break t i e s more f r e q u e n t l y w i th t h e i r pack (45% 123 of l o c a t i o n s in HP vs 80% in LP, n=122 and 61) , as compared to pups (26% vs 36%, n=242 and 53) or a d u l t s (17% vs 26%, n=390 and 324) . Because of t h i s i n t e r a c t i o n , I proceeded from a 3-way a n a l y s i s to a 2-way a n a l y s i s ( i . e . , prey base and sex) w i t h i n separa te age c l a s s e s . Pups were observed a lone in 28% of the o b s e r v a t i o n s ( F i g . 1 ) . The n o n - s i g n i f i c a n t G-tes ts (Table 1) i n d i c a t e that s o l i t a r y l i v i n g among pups was independent of both prey abundance (P>0.15) , and sex of the an ima ls (P>0.20) . In terms of pack d i s s o c i a t i o n , pups showed a q u a l i t a t i v e s i m i l a r i t y to ( F i g . 1) , but a q u a n t i t a t i v e d i f f e r e n c e from a d u l t wolves (G[1]=5.82, P=0.02) . Y e a r l i n g s r ep resen ted the most l o o s e l y a s s o c i a t e d pack members. I observed y e a r l i n g s a lone in 57% of w in te r o b s e r v a t i o n s ( F i g . 1) , a much g rea t e r f requency than a d u l t s (21%; G[1]=84.72, P<0.01) , or pups (28%; G [1 ] , P<0.01) . Both abundance of prey and sex s t r o n g l y i n f l u e n c e d the tendency of y e a r l i n g s to l eave t h e i r pack t e m p o r a r i l y (Table 1 ) . Male and female y e a r l i n g s e x h i b i t e d a lower pack a f f i l i a t i o n in the low prey a r e a . In a d d i t i o n , y e a r l i n g females l i v e d more s o l i t a r i l y than y e a r l i n g males ( F i g . 1 ) . The n o n - s i g n i f i c a n t i n t e r a c t i o n between prey abundance and sex i n d i c a t e s an a d d i t i v i t y of t h e i r e f f e c t s (Table 1 ) . A d u l t s ma in ta ined the c l o s e s t con t a c t w i th t h e i r s o c i a l groups ( F i g . 1 ) . None the l e s s , abundance of prey and sex s i g n i f i c a n t l y i n f l u e n c e d s o l i t a r y l i v i n g of a d u l t s (Table 1) . 8 0 70 60 50 40 30 20 10 (3) 61 (5) 53 (9) 242 (5) 122 (17) 324 (7) (7) 157 138 (12) 390 (5) 85 (3) 98 (8) 183 (14) 288 (15) 426 (14) 295 (29) 714 LP HP LP HP LP HP Cf 9 PUP YRLG ADULT PUP c? 9 d" 9 p Y A YRLG ADULT OVERALL Fig. 1. Percentage of sightings when wolves were observed alone and separated from their packs in relation to prey abundance (LP or HP), age of the animals, and their sex. Number of sightings is given above the columns, and the figure in parentheses denotes the number of animals involved. The portion of sightings during extra-territorial movements is stippled. 125 T a b l e 1. Summary o f t h e c o n t i n g e n c y t a b l e a n a l y s e s , w i t h i n age c l a s s e s , where t h e e f f e c t s o f p r e y base (HP o r LP) and sex were r e l a t e d t o t h e f r e q u e n c y t h a t a w o l f l e f t t e m p o r a l l y i t s pack ( A ) , and t h e p o r t i o n o f t h e s e o d s e r v a t i o n s o u t s i d e t h e p a c k ' s t e r r i t o r y ( B ) . The G - t e s t v a l u e s ( d . f . =1 f o r a l l ) a r e p r e s e n t e d , as w e l l as t h e i r p r o b a b i l i t y l e v e l s ( ) . O b s e r v a t i o n s were c o l l e c t e d f r om 1 December t o 30 A p r i l .  H y p o t h e s i s t e s t e d Pup Y e a r l i n g A d u l t P r e y base Sex I n t e r a c t i o n P r e y base Sex I n t e r a c t i o n 1.82 (>0.15) 0 . 52 (>0.20) 1.76 (>0.15) 0 .04 (>0.20) 0 .02 (>0.20) 1.80 (>0.15) 21 . 86 (<0 .01) 4 4 . 54 (<0.01) 1.67 (>0.15) 8 . 3 0 (<0.01) 58 .22 (<0.0T) 2 .52 (>0.10) 9 . 72 (<0.01) 22 . 42 (<0.01) 1.50 (>0 .20) 2 .80 (=0.09) 0 . 22 (>0.20) 0 . 02 (>0.20) 1 26 As w i th y e a r l i n g s , a d u l t females t r a v e l l e d a lone more f r e q u e n t l y than ma les . A low prey base s i g n i f i c a n t l y i n c r e a s e d the f requency at which a d u l t s of both sexes t e m p o r a r i l y l e f t t h e i r pack . Once a g a i n , the lack of i n t e r a c t i o n between prey base and sex suggests tha t t h e i r e f f e c t s were a d d i t i v e (Table D . As w in te r p r o g r e s s e d , the f requency of pack d i s s o c i a t i o n i n c r e a s e d in pups (G[3]=9.47, P=0.03) , y e a r l i n g s (G[3]=16.7, P<0.01) , and a d u l t s (G[3]=104.06, P<0.01; F i g . 2 ) . From e a r l y May to the end of November (summer p e r i o d ) , i t was u s u a l l y imposs ib l e to a ssess w i th c e r t a i n t y whether or not a wolf was w i th other pack members. From m o n i t o r i n g movements c l o s e l y , y e a r l i n g s appeared to be more independent of pack a c t i v i t i e s . In summer, a d u l t movements converged to p r e d i c t a b l e s i t e s such as n a t a l dens and pup r e s t i n g a r e a s . A l though some y e a r l i n g s demonstrated t h i s p a t t e r n , they d e f i n i t e l y tended to wander more e x t e n s i v e l y than a d u l t s throughout the t e r r i t o r y d u r i n g p ro longed p e r i o d s , p r e s u m a b l y d i s s o c i a t e d from the pack , and w i th no apparent at tempt to v i s i t the f o c a l a c t i v i t y s i t e s of the pack . I n d i v i d u a l e x t r a - t e r r i t o r i a l movements I r eco rded 56 i n s t a n c e s of wolves that i n d i v i d u a l l y engaged in e x t r a - t e r r i t o r i a l movements ( F i g . 3 ) . In 9 c a s e s , the an imals d i d not renew t i e s w i th t h e i r packs . They r e p r e s e n t e d : 4 s u c c e s s f u l d i s p e r s a l s where 2 an ima ls a c q u i r e d 127 UJ z < Q UJ I-< < Q_ UJ Z CO < CO * o o z < i= °-X UJ 0 X co »" o ° DC 8 0 r 70 6 0 50 4 0 30 20 10 (10) 77 (13) 98 (6) 89 (8) 31 D J F M PUP (5) 69 (8) 58 (6) 12 (5) 44 D J F M YEARLING (20) 165 (17) 257 C22) 212 80 D J F M ADULT F i g . 2 . December t o March changes i n t h e p e r c e n t a g e o f s i g h t i n g s when pup , y e a r l i n g , and a d u l t wo l v e s were o b s e r v e d a l o n e and s e p a r a t e d f r om t h e i r p a c k s . Number o f s i g h t i n g s i s g i v e n above t h e c o l umns , and t h e f i g u r e i n p a r e n t h e s e s deno t e s t h e number o f a n i m a l s i n v o l v e d . The p o r t i o n o f s i g h t i n g s d u r i n g e x t r a - t e r r i t o r i a l movements i s s t i p p l e d . 128 BOUNDARY OF LA VERENDRYE RESERVE APPROX. NORTHERN LIMIT OF DEER WOLF PACK TERRITORIES EXTRATERRITORIAL EXCURSIONS, SINGLE ANIMALS ? PACK ORIGIN UNCERTAIN * DISPERSAL F i g . 3 . The 56 e x t r a - t e r r i t o r i a l e x c u r s i o n s made by s i n g l e wo l v e s d u r i n g t h e s t u d y . The e x c u r s i o n s a r e p r e s e n t e d as t h e minimum s t r a i g h t l i n e d i s t a n c e s . 1 29 a new a s s o c i a t e and formed a pack n u c l e u s , and 2 were accep ted by an ad jacen t pack ; 3 probab le d i s p e r s a l s d u r i n g which we l o s t a l l r a d i o - c o n t a c t a f t e r e x t e n s i v e j o u r n e y i n g ; and 2 m o r t a l i t i e s . D i s p e r s a l s i n v o l v e d 4 males and 3 females and oc cu r r ed e x c l u s i v e l y from m i d - A p r i l to August ( F i g . 4 ) . Each wolf that d i s p e r s e d d e f i n i t i v e l y , i n i t i a t e d a minimum of 2.1 p r e - d i s p e r s a l t r i p s , on ave rage . Wolves accep ted by ad jacen t packs were both young adu l t males (1 in March and 1 in May) . In 1 case (March) , the presumed dominant male of a t r i o - p a c k was k i l l e d ( p o s s i b l y by the incomer) when the change o c c u r r e d . E x c u r s i o n f requency of pups (9 ) , y e a r l i n g s (21) , and a d u l t s (26 ) , d i f f e r e d s i g n i f i c a n t l y from the expected f r e q u e n c i e s c a l c u l a t e d from the r a d i o - t r a c k i n g times. (101, 86, and 317 months r e s p e c t i v e l y ; G [2 ]=13.2 , P<0.01) . Pups and a d u l t s i n i t i a t e d fewer so l o e x c u r s i o n s than expected ( 1.1 and 1.0 per year r e s p e c t i v e l y ) , whereas y e a r l i n g s were much more prone to fo ray o u t s i d e the p a c k ' s t e r r i t o r y (3.0 e x c u r s i o n s per y e a r ) . T h i r t y - e i g h t of the 56 e x c u r s i o n s o c c u r r e d du r i ng the w inter p e r i o d , but the seasona l p a t t e r n s d i f f e r e d between age c l a s s e s ( F i g . 4 ) . Pups d i d not ven ture o u t s i d e the p a c k ' s t e r r i t o r y a lone be fo re mid-February . Y e a r l i n g excu r s i ons were r e s t r i c t e d p r i m a r i l y to the w in te r p e r i o d , whereas adu l t f o rays showed no obv ious seasona l p a t t e r n . At l e a s t 8 of the 15 adu l t e x c u r s i o n s du r ing the summer p e r i o d i n vo l v ed young non-reproduc t i ve a d u l t s (24 to 30 months, from known-age 130 PA: v TR? T$X7Vp iFvfi? MONTH F i g . 4. C h r o n o l o g i c a l d i s t r i b u t i o n s o f t h e i n i t i a t i o n o f e x t r a -t e r r i t o r i a l e x c u r s i o n s made by s i n g l e p u p s ( P ) , s i n g l e y e a r l i n g s ( Y ) , s i n g l e a d u l t s ( A ) , a n d p a c k s ( P A ) . T h e c l o s e s y m b o l s d e n o t e t h e e x c u r s i o n s w h i c h r e s u l t e d i n an a c t u a l o r a s s u m e d d e f i n i t i v e d i s p e r s a l . A m e a s u r e o f r a d i o - t r a c k i n g t i m e ( n u m b e r o f a n i m a l - m o n t h s w i t h o p e r a t i n g t r a n s m i t t e r s ) i s p r e s e n t e d t o f a c i l i t a t e i n t e r p r e t a t i o n . 131 a n i m a l s ) . In summer, I d i d not observe known or presumed r e p r o d u c t i v e a d u l t s i n i t i a t e e x t r a - t e r r i t o r i a l movements. A l s o , I never had ev idence that a pack engaged in e x t r a -t e r r i t o r i a l movements in summer ( i . e . , when more than 1 wolf were marked) . T h e r e f o r e , I assumed that a l l movements o u t s i d e the t e r r i t o r y i m p l i c a t e d s i n g l e wo l f . The d u r a t i o n of e x c u r s i o n s averaged 9.1 ± (SE)2.6 days f o r pups , 13.3 ± 3.2 fo r y e a r l i n g s , and 10.3 ± 2.1 fo r a d u l t s . No d i f f e r e n c e among age c l a s s e s c o u l d be de t e c t ed (one-way ANOVA, F [2 ,40 ]=0 .54 , P>0.20) . L i k e w i s e , the minimum s t r a i g h t l i n e d i s t a n c e of e x c u r s i o n s d i d not d i f f e r among age c l a s s e s (one-way ANOVA, F [2 ,53 ]=0 .30 , P>0.20) , and averaged 22.2 ± (SE)5.3 km fo r pups , 21.7 ± 2.6 fo r y e a r l i n g s , and 25.5 ± 4.2 f o r a d u l t s . These data i n d i c a t e that the h ighe r tendency of y e a r l i n g s to be ou t s i de the p a c k ' s t e r r i t o r y ( F i g . 1) was caused main ly by the h ighe r ra te at which they i n i t i a t e d e x c u r s i o n s as opposed to the d u r a t i o n or l eng th of these e x c u r s i o n s . To examine the p o s s i b l e e f f e c t s of prey abundance and sex upon e x t r a - t e r r i t o r i a l movements, I conducted con t ingency t a b l e ana l y ses on the a g e - s p e c i f i c w inter o b s e r v a t i o n s (Table 1 ) . N e i t h e r prey abundance nor sex i n f l u e n c e d e x t r a -t e r r i t o r i a l movements of pups (P>0.20) . Both f a c t o r s a f f e c t e d the tendency of y e a r l i n g s to leave the p a c k ' s t e r r i t o r y (P<0.01) ; these e f f e c t s were not i n t e r a c t i v e (P>0.10) . In a d u l t s , on ly prey abundance was p o t e n t i a l l y e f f e c t i v e 1 32 (P=0.09) . Among age c l a s s e s , the d i f f e r e n c e was h i g h l y s i g n i f i c a n t (G[2]=45.8, P<0.01) ; pups and a d u l t s had comparable f o r a y i n g t e n d e n c i e s , but y e a r l i n g s were more i n c l i n e d to t r a v e l o u t s i d e the p a c k ' s t e r r i t o r y ( F i g . 1) . L o c a t i o n s of lone wolves and pack members d u r i n g e x t r a -t e r r i t o r i a l movements (n=359) were ana l y sed in r e l a t i o n to pack t e r r i t o r i e s ( dep i c t ed in F i g . 3; the h ypo thes i s be ing tha t s o l i t a r y wolves would tend to a v o i d t e r r i t o r y co r e s and to use p r e f e r e n t i a l l y the edges of the t e r r i t o r i e s . I observed s o l o f o r a y i n g pack members l e s s f r e q u e n t l y than expec ted ( i . e . , assuming homogeneous d i s t r i b u t i o n ) w i t h i n t e r r i t o r y co res of ne ighbour ing packs , and more f r e q u e n t l y w i t h i n the 2-km wide b u f f e r zones b o r d e r i n g these t e r r i t o r i e s (Table 2 ) . However, they used the i n t e r s t i c e s between t e r r i t o r i e s l e s s f r e q u e n t l y (Table 2 ) , even though these areas presumably r ep re sen t ed the s a f e s t p l a c e s in which to a vo id pack i n t e r a c t i o n s . Known lone wolves showed a d i f f e r e n t p a t t e r n ; they used t e r r i t o r y co res i n t e n s i v e l y , and i n t e r s t i c e s l e s s than expec ted (Table 2 ) . A l t o g e t h e r , the a n a l y s i s does not r e v e a l a p r o g r e s s i v e i n c r ea se of use from t e r r i t o r y co res to b u f f e r zones , and to i n t e r s t i c e s . Pack e x t r a - t e r r i t o r i a l movements I observed 23 i n s t a n c e s of packs engaged in e x t r a -t e r r i t o r i a l movements ( F i g . 5 ) . These excu r s i ons were observed e x c l u s i v e l y from 1 December to 30 March, and many of them (13) T a b l e 2 . L o c a t i o n f r e q u e n c i e s o f pack members d u r i n g s o l o e x t r a - t e r r i t o r i a l e x c u r s i o n s and o f l o n e w o l v e s , a r e r e p o r t e d f o r t h e t e r r i t o r y c o r e s , t h e 2-km w i de b u f f e r z o n e s , and t h e 2 i n t e r s t i c e s (see me t hod s ) . A l s o p r e s e n t e d a r e t h e - t e s t s o f homogene i t y , and t h e i r p r o b a b i l i t y l e v e l { d . f . = 2 f o r a l l ) . T e r r i t o r y c o r e s B u f f e r zones I n t e r s t i c e s A2 P % a r ea %f i xes %area %f i xe s %area %f i x e s Pack members 56 33(57) 24 48 (84) 20 19(33) 59 . 4 <0.01 Lone Wolves 56 80(148) 24 16(29) 20 4( 8 ) 4 7 . 0 <0.01 T o t a l 56 57(205) 24 32(113) 20 11(41) 2 1 . 6 <0.01 ( ) = sample s i z e 134 F i g . 5 . The 23 e x t r a - t e r r i t o r i a l e x c u r s i o n s made by w o l f packs d u r i n g t h e s t u d y . E x c u r s i o n s a r e p r e s e n t e d as t h e minimum s t r a i g h t l i n e d i s t a n c e s . 1 35 were d e s t i n e d to deer w i n t e r i n g a r e a s . A minimum of 8 deer were k i l l e d by wolves d u r i n g these e x c u r s i o n s but l i k e l y more were v i c t i m s . G iven the d i f f i c u l t y of d e t e c t i n g deer c a r c a s s e s from a e r i a l t r a c k i n g , the exact number c o u l d not be a s c e r t a i n e d . As d e p i c t e d by F i g . 5, packs c l o s e to deer d i s t r i b u t i o n were more i n c l i n e d to make e x c u r s i o n s from t h e i r t e r r i t o r i e s and to e x p l o i t d e e r . E x c u r s i o n f requency was h ighe r fo r packs a s s o c i a t e d w i th a low prey abundance (n=l8, 60 t rack ing-months of packs d u r i n g w i n t e r ) , as compared to packs in the h igh prey base area (n=5, 46 t r a ck ing-months ; X 2 [ 1 ] = 4 . 3 9 , P=0.04) . The minimum s t r a i g h t l i n e d i s t a n c e of e x c u r s i o n s was a l s o g r ea t e r in LP (average=26.1 km, range=5.0 to 75.7) than in HP (average= 12.0 km, range=5.5 to 3 0 . 7 ; Mann-Whitney U-tes t [18 ,5 ]=72, P=0.03) . The d u r a t i o n of e x c u r s i o n s showed the same t r end between areas (LP average=16.5 days , range=2 to 84; HP average=7.0 days , range=2 to 25 ) , but the d i f f e r e n c e was not s t r o n g l y expressed (Mann-Whitney U-tes t [13 ,5 ]=47, P=0.10) . DISCUSSION S o l i t a r y l i v i n g , e x t r a - t e r r i t o r i a l movements, and d i s p e r s a l To many peop le " d i s p e r s a l " connotes a "movement of an i n d i v i d u a l from i t s n a t a l s i t e and out of the home range of i t s pa r en t ( s ) to another s i t e at which i t b reeds , or at l e a s t a t tempts to p a i r w i th a c o n s p e c i f i c of the oppos i t e sex fo r 1 36 purpose of b r e e d i n g " (Bekoff 1977:715) . The f i r s t c o n c l u s i o n to be drawn from the present wolf study i s tha t d i s p e r s a l i s not an unique "one d e c i s i o n - one t r i p " even t . D i s p e r s a l appeared to be a dynamic and g radua l p r o c e s s , w i th a wolf b r eak ing t i e s wi th i t s pack over a p r o t r a c t e d p e r i o d of a few months to a few years beg inn ing as e a r l y as 10 months of age . Recen t l y in c e n t r a l A l a s k a , Van Ba l l enberghe (1983) r e p o r t e d tha t d i s p e r s i n g wolves showed a common p a t t e r n of one or more p r e l i m i n a r y e x t r a - t e r r i t o r i a l t r i p s . In t h i s s tudy , I observed tha t y e a r l i n g wolves i n i t i a t e d on average 3 e x t r a - t e r r i t o r i a l f o r a y s per y e a r , a l though most d i s p e r s e d permanent ly at an a d u l t age (6 out of 7 d i s p e r s a l s ) . Even among a d u l t s , of which on l y a f r a c t i o n were non-breeders and t h e r e f o r e prone to d i s p e r s e , an average f requency of 1 s o l o e x c u r s i o n per year was r e c o r d e d . From these o b s e r v a t i o n s , ^ addressed the q u e s t i o n of what had c o n s t i t u t e d the i n c e n t i v e fo r such e x t r a -t e r r i t o r i a l f o r a y s . A g e ' o f the an imals was i d e n t i f i e d as a predominant f a c t o r i n f l u e n c i n g s o l i t a r y l i v i n g and e x t e r r i t o r i a l movements. Y e a r l i n g s are an imals r each ing pube r t y , and were c l e a r l y the an ima ls most l i k e l y to t r a v e l s o l i t a r i l y and to spend p ro longed p e r i o d s out of t h e i r n a t a l t e r r i t o r i e s . Many y e a r l i n g s and young non-reproduc t i ve a d u l t s ac ted as l o o s e l y -a s s o c i a t e d pack members, appa r en t l y w i th a minimal r o l e in the pack . It has been suggested that the a s s i s t a n c e of y e a r l i n g s and other a u x i l i a r i e s in p r o v i d i n g food fo r wolf pups does not 1 37 i n f l u e n c e t h e i r s u r v i v a l (Ha r r ing ton and Mech 1982; Ha r r i ng ton et a l . 1983; F i g . 13 in Peterson et a l . 1984). Thus , many y e a r l i n g s and young non- rep roduc t i v e a d u l t s c o u l d be t y p i f i e d b i o l o g i c a l l y as " f l o a t e r a n i m a l s " , but wi th the p e c u l i a r i t y tha t they keep a min imal a s s o c i a t i o n w i th t h e i r packs ; p o s s i b l y , they use o ther packmates s e l f i s h l y as an a i d in s u r v i v i n g and u l t i m a t e l y in a c h i e v i n g breeder s t a t u s . I t i s in the p a r e n t s ' i n t e r e s t to f a c i l i t a t e the s u r v i v a l and b reed ing p r o b a b i l i t y of these h i g h l y - v a l u e d o f f s p r i n g . Concomitant w i th the e f f e c t of age , low prey abundance i n c r e a s e d pack d i s s o c i a t i o n and e x t r a - t e r r i t o r i a l movements. Without access to s u f f i c i e n t prey d u r i n g an extended p e r i o d , a subord ina te wolf may e i t h e r be a c t i v e l y e v i c t e d from the pack , or i t may v o l u n t a r i l y forage a lone (Zimen 1976, 1982). Both y e a r l i n g s and a d u l t s had a g r ea t e r tendency to l i v e s o l i t a r i l y and to make e x c u r s i o n s in the low prey area (Table 1) . Dur ing w i n t e r , wolf packs used an average of 6.2 moose per 100 days in HP but on ly 3.2 i n LP (Mess ier and Cre te in p r e s s ) . In the low prey a r e a , packs were e x p e r i e n c i n g p e r i o d s of food s c a r c i t y which undoubted ly encouraged pack d i s s o c i a t i o n . Under these c i r c u m s t a n c e s , f o r ays cannot be a s c r i b e d to a s p e c i f i c d i s p e r s a l s t r a t e g y , but ra the r as an immediate n e c e s s i t y to s u r v i v e through a temporary r esource f a i l u r e . However, the i n f o rma t i on a c q u i r e d d u r i n g these e x c u r s i o n s may be advantageous subsequent l y ( e . g . , t e r r i t o r y vacancy , prey d i s t r i b u t i o n i n c l u d i n g the l o c a t i o n s of deer w i n t e r i n g a r e a s ) . 138 The g r ea t e r tendency of y e a r l i n g females and a d u l t females to d i s s o c i a t e from the pack , and to fo ray o u t s i d e the t e r r i t o r y ( y e a r l i n g s o n l y ) , appears l a r g e l y a t t r i b u t a b l e to the r e l a t i v e l y low a v a i l a b i l i t y of moose c a r c a s s e s to the packs . Under n u t r i t i o n a l s t r e s s , females are more o f t en subord ina te and ha rassed by o ther pack members than are males (Zimen 1976, 1982). These a g g r e s s i v e i n t e r a c t i o n s may r e s u l t in weak pack bonds or even in a temporary pack e v i c t i o n . Not enough i s known about wolf d i s p e r s a l s t r a t e g y to suggest tha t females are more i n c l i n e d than males to depar t v o l u n t a r i l y from the pack . However, a s e x - s p e c i f i c d i f f e r e n c e in d i s p e r s a l s t r a t e g y i s not exc luded (Zimen 1982). E x t r a - t e r r i t o r i a l movements can o f t en be i n t e r p r e t e d as p r e - d i s p e r s a l f o r a y s du r i ng which t e r r i t o r y vacancy can be a s s e s s e d . The tendency of wolves to r e tu rn to t h e i r t e r r i t o r y and to r e j o i n t h e i r pack r e f l e c t s t h e i r f a i l u r e to f i n d q u i c k l y a r e c e p t i v e , a l i e n wolf and/or a s u i t a b l e vacant a rea (Van Ba l l enberghe 1983). C o n c e i v a b l y , a wolf c o u l d use i t s n a t a l s o c i a l u n i t (and area) as a base from which to f i n d a r e c e p t i v e pack or to form a nuc leus of a new pack d u r i n g i t s e x p l o r a t o r y e x c u r s i o n s (see Mess i e r and B a r r e t t e 1982). If h a b i t a t s a t u r a t i o n i s h i g h , d i s p e r s i n g wolves may have to t r a v e l g rea t d i s t a n c e s be fo re they can s e t t l e . T h i s p rocess may n e c e s s i t a t e many p r e - d i s p e r s a l t r i p s . The r e s u l t s of t h i s study appear to be in c o n f l i c t w i th t h i s v iew. More e x t r a -t e r r i t o r i a l e x c u r s i o n s were observed in LP than in HP area 1 39 even though vacant areas were more a v a i l a b l e in LP (Messier in p r e s s ) . However, the low prey abundance in LP most l i k e l y prompted subord ina te an imals to i n i t i a t e e x c u r s i o n s more f r e q u e n t l y . T h i s poor prey base would a l s o tend to make any vacant a reas un favourab le fo r r e p r o d u c t i o n . These two f a c t o r s have l i k e l y confounded the r e s u l t s . Of i n t e r e s t i s the f a c t tha t F r i t t s and Mech (1981) r a r e l y observed p r e - d i s p e r s a l f o r a y s when they s t u d i e d a newly-protec ted wolf p o p u l a t i o n in M inneso ta . The Minnesota p o p u l a t i o n was, however, not s a t u r a t e d and wolves there were e x p e r i e n c i n g an ample prey base . The h ighe r s o c i a l s t r e s s w i t h i n packs p r i o r to and du r i ng the b reed ing season (approxmat i ve l y from 1 February to 15 March) l i k e l y e x p l a i n s the i n c r e a s i n g tendency of some i n d i v i d u a l s to leave t h e i r pack du r i ng t h i s p e r i o d . S tud i e s in c a p t i v i t y showed that r e p r o d u c t i v e wolves exe r t a g rea te r dominance over other pack members du r i ng t h i s p e r i o d (Rabb et a l . 1967; Zimen 1982). R e c e n t l y , Pe terson et a l . (1984) r e p o r t e d tha t e x t r a - t e r r i t o r i a l movements were undertaken more commonly by subord ina te wolves du r i ng the b reed ing season . An a l t e r n a t i v e e x p l a n a t i o n based on a h igher food s t r e s s at the end of the w inter i s l e s s p r o b a b l e . I have an i n d i c a t i o n of a s t a b l e , but low food a v a i l a b i l i t y throughout the w in t e r . Pack e x c u r s i o n s , which u s u a l l y s i g n i f y a shor tage of food (Mech 1977; t h i s s t u d y ) , were even ly d i s t r i b u t e d from December to March ( F i g . 4 ) . 1 40 S o l i t a r y an ima ls and pack spat i a l d i s t r i b u t i o n O f t e n , i t has been p o s t u l a t e d that l o c a t i o n s of lone wolves were p r i m a r i l y in a reas l e s s u t i l i z e d by packs (see F r i t t s and Mech 1981: 44 ) . However, p u b l i s h e d ev idence suppor ted by q u a n t i t a t i v e data i s not yet a v a i l a b l e to my knowledge. The o b s e r v a t i o n s r e p o r t e d he re , based on 25 d i f f e r e n t an ima l s , d i d not r e v e a l tha t i n t e r s t i c e s between t e r r i t o r i e s were more f r e q u e n t l y used by s o l i t a r y an ima l s . The h a b i t a t w i t h i n i n t e r s t i c e s was not n o t i c e a b l y d i f f e r e n t from that of su r round ing a r e a s . D i s s o c i a t e d pack members appeared to u t i l i z e the pe r i phe r y of ne ighbou r i ng t e r r i t o r i e s more f r e q u e n t l y . However, t h i s t r end was induced l a r g e l y by a s i n g l e an imal which undertook 4 p ro longed e x c u r s i o n s to a p a r t i c u l a r b u f f e r zone (38 o b s e r v a t i o n s ) where butcher o f f a l was a v a i l a b l e (a minimum of 9 beef gut p i l e s ; see the 4 p a r a l l e l arrows in the eas t s i d e of F i g . 4 ) . If t h i s an imal i s excep ted , the a n a l y s i s r e v e a l s no t r e n d . The 2 known lone wolves used t e r r i t o r y co res more f r e q u e n t l y . I conc lude that wolves d i d not a vo id t e r r i t o r y c o r e s . I do not sugges t , however, tha t s o l i t a r y wolves d i d not a v o i d con t a c t w i th a l i e n packs , but i t appears tha t t h i s tempora l s eg rega t i on d i d not produce a s p a t i a l s e g r e g a t i o n . Pack e x t r a - t e r r i t o r i a l movements Four packs undertook e x t e n s i v e winter movements appa ren t l y to e x p l o i t d e e r . In one case (the southermost 141 p a c k ) , the wolves had been r e p e a t i n g each year what appears to be a t r a d i t i o n a l p a t t e r n of movements at the onset of w i n t e r . The low moose d e n s i t y in the study a r e a , and the r e l a t i v e ease of c a p t u r i n g deer in t h e i r w i n t e r i n g a r e a s , p robab l y encouraged such pack e x c u r s i o n s . Other pack e x c u r s i o n s were s h o r t e r w i th no apparent p remed i ta ted d e s t i n a t i o n . Mech (1977) argued that m a l n u t r i t i o n i n c i t e s packs to t r e s p a s s a c ross ne ighbour ing t e r r i t o r i e s . My data conform to Mech 's (1977) i n t e r p r e t a t i o n . Packs a s s o c i a t e d wi th a low prey abundance i n i t i a t e d more e x c u r s i o n s than packs in HP. Moreover , the e x c u r s i o n s of LP packs were s u b s t a n t i a l l y l o n g e r . These o b s e r v a t i o n s a l s o suggest that wolves in low prey a reas have a weaker t e r r i t o r i a l h a b i t in w inter than wolves w i th ample p r e y . Such p a t t e r n of space use resembles the t e r r i t o r i a l i n s t a b i l i t y of wolves r e l y i n g on a s p a t i a l l y changeable prey base (Kuyt 1972; Stephenson and James 1982). LITERATURE CITED Armi tage KB (1977) S o c i a l v a r i e t y in the y e l l o w - b e l l i e d marmot: a p o p u l a t i o n - b e h a v i o r a l sys tem. Anim. Behav. 25: 585-593. Barash DP (1974) The e v o l u t i o n of marmot s o c i e t i e s : a genera l t h e o r y . Sc i ence 185: 415-420. Bekof f M (1977) Mammalian d i rspersa l and the ontogeny of i n d i v i d u a l b e h a v i o r a l phenotypes . Am. Nat . 111: 715-732. Bekof f M, D a n i e l s TA, G i t t l eman JL (In p ress ) L i f e h i s t o r y p a t t e r n s and the comparat ive s o c i a l eco logy of c a r n i v o r e s . Ann. Rev. E c o l . S y s t . 142 Brown JL (1983) Coope ra t i on - a b i o l o g i s t ' s di lemma. In : Rosenb l a t t JS, Hinde RA, Beer C, Busnel M-C (eds) Advances in the study of b e h a v i o r , v o l . 13. Academic P r e s s , New York . pp . 1-37. Emlen ST (1982) The e v o l u t i o n of h e l p i n g . I. An e c o l o g i c a l c o n s t r a i n t model . I I . The r o l e of b e h a v i o r a l c o n f l i c t . Am. Nat . 119: 29-39 and 40-53. F r i t t s ST, Mech LD (1981) Dynamics, movements, and f eed ing eco logy of a new ly-pro tec ted wolf p o p u l a t i o n in nor thwestern M inneso t a . W i l d l . Monogr. No. 80, 79 pp . H a r r i n g t o n FH, Mech LD (1982) Pa t t e rns of homesi te a t tendance in two Minnesota wolf pa cks . In : H a r r i n g t o n FH, Paquet PC (eds) Wolves of the w o r l d : p e r s p e c t i v e s of b e h a v i o r , e c o l o g y , and c o n s e r v a t i o n . Noyes, Park Ridge (New J e r s e y ) , pp . 81-109. H a r r i n g t o n FH, Mech LD, F r i t t s SH (1983) Pack s i z e and. wolf pup s u r v i v a l : t h e i r r e l a t i o n s h i p under v a r y i n g e c o l o g i c a l c o n d i t i o n s . Behav. E c o l . S o c i o b i o l . 13: 19-26. Kuyt E (1972) Food h a b i t s and eco logy of wolves on ba r ren-ground c a r i b o u range in the Northwest T e r r i t o r i e s . E n v i r o n . C a n . , Can. W i l d l . S e r v . , Rep. Se r . No. 21, 36 pp . Lamprecht J (1981) The f u n c t i o n of s o c i a l hun t ing in l a r g e r t e r r e s t r i a l c a r n i v o r e s . Mamm. Rev. 11: 169-179. Macdonald DW (1983) The eco logy of c a r n i v o r e s o c i a l behav iou r . Nature 301 : 379,-384. Macdonald DW, Moehlman PD (1982) C o o p e r a t i o n , a l t r u i s m , and r e s t r a i n t in the r e p r o d u c t i o n of c a r n i v o r e s . I n : Bateson PPG, K l o p f e r PH (eds) P e r s p e c t i v e s in e t h o l o g y , v o l . 5. Plenum P r e s s , New York . pp . 433-467. Mech LD (1977) P r o d u c t i v i t y , m o r t a l i t y , and p o p u l a t i o n t rends of wolves in n o r t h e a s t e r n M inneso ta . J . Mamm. 58: 559-574. Mess i e r F (In p ress ) S o c i a l o r g a n i z a t i o n , s p a t i a l d i s t r i b u t i o n , and p o p u l a t i o n d e n s i t y of wolves in r e l a t i o n to moose d e n s i t y . Can. J . Z o o l . Mess i e r F, B a r r e t t e C (1982) The s o c i a l system of coyote (Canis l a t r a n s ) in a f o r e s t e d h a b i t a t . Can. J . Z o o l . 60: 1743-1753. 143 Mess ie r F, C re te M (In p ress ) Moose-wolf dynamics and the n a t u r a l r e g u l a t i o n of moose p o p u l a t i o n s . O e c o l o g i a . Packard JM, Mech LD (1980) P o p u l a t i o n r e g u l a t i o n in wolves . In : Cohen MN, Malpass RS, K l e i n GH (eds) B i o s o c i a l mechanisms of p o p u l a t i o n r e g u l a t i o n . Ya le U n i v e r s i t y P r e s s , New Haven, pp . 135-150. Pe terson RO, Wool ington JD, B a i l e y TN (1984) Wolves of the Kenai p e n i n s u l a , A l a s k a . W i l d l . Monogr. No. 88, 52 pp . Rabb GB, Woolpy JH, G insburg BE (1967) S o c i a l r e l a t i o n s h i p s in a group of c a p t i v e wo lves . Amer. Z o o l . 7: 305-311. S i e g e l S (1956) Nonparametr ic s t a t i s t i c s fo r the b e h a v i o r a l s c i e n c e s . McGraw-H i l l , New York . Soka l RR, Rohl f FJ (1981) B iomet ry . W.H. Freeman and Company, San F r a n c i s c o . Stephenson RO, James D (1982) Wolf movements and food h a b i t s in northwest A l a s k a . In : H a r r i n g t o n FH, Paquet PC (eds) Wolves of the w o r l d : p e r p e c t i v e s of b e h a v i o r , e c o l o g y , and c o n s e r v a t i o n . Noyes, Park Ridge (New J e r s e y ) , pp . 26-42. Van Ba l l enberghe V (1983) E x t r a t e r r i t o r i a l movements and d i s p e r s a l of wolves in s o u t h c e n t r a l A l a s k a . J . Mamm. 64: 1 68-171. Waser PM, Jones WT (1983) Na t a l p h i l o p a t r y among s o l i t a r y mammals. Qua r t . Rev. B i o l . 58: 355-390. Zimen E (1976) On the r e g u l a t i o n of pack s i z e in wo lves . Z. T i e r p s y c h o l . 40: 300-341. Zimen E (1982) A wolf pack soc iog ram. In : H a r r i n g t o n FH, Paquet PC (eds) Wolves of the w o r l d : p e r s p e c t i v e s of b e h a v i o r , e co l ogy , and c o n s e r v a t i o n . Noyes, Park Ridge (New J e r s e y ) , pp . 282-322. 

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