RESPONSE BY WOLVES TO PREY VARIATION IN CENTRAL ONTARIO

The influence of variation in prey availability in a wolf-moose-deer-b eaver predator-prey community was studied from 1987 to 1992 in Algonqu in Park, Ontario, Canada. Density, food habits, and movements of 57 ra dio-collared gray wolves (Canis lupus) were compared among three regio ns of varying moose (Alces alces) and white-tailed deer (Odocoileus vi rginianus) spatial and temporal abundance. Relative moose and deer ava ilability was determined annually from 16 track surveys (5 km each), 1 50 pellet surveys (300 x 2 m), stratified aerial surveys (2 or 3 each winter), and prey carcass data. One region contained high moose abunda nce and virtually no deer year-round. The second region had high moose levels with moderate levels of deer, and a third region varied in dee r winter abundance annually. Wolf use of deer was high, based on the p roportion of deer in winter seats (9.3-32.1% frequency of occurrence; 4.3-22.5% total biomass) and the number of deer predation cases (50 ca rcasses) that occurred in all three regions, even in areas where deer were considered to be very rare. Wolf use of deer was positively corre lated with increases in winter deer abundance (r(2) = 0.66). Wolf dens ity correlated with deer numbers (r(2) = 0.74). In winter, deer in the third region migrated to a deer yard 15 km from Algonquin Park. A rem aining overwintering deer density of less than 0.02/km(2) appears to h ave prompted a movement of wolves to the deer yard. Of the 41 moose co nsumed by wolves in winter, most (71%) were scavenged animals that had died with infestations of winter tick (Dermacentor albipictus). Beave r (Castor canadensis) apparently acted as important buffer prey specie s when deer numbers were low. The Algonquin wolf's reliance on smaller prey items appears to be a function of the fluctuating prey base, whi ch promotes alternative hunting strategies, and the small size of the Algonquin wolf, which makes it an inefficient predator of moose. Even though moose were relatively constant in availability, and a major foo d item, the wolf population was responding primarily to the availabili ty of deer.