Spatial and behavioural relations between migratory and resident wolves in a winter deer yard

John M. Pisapio, John B. Theberge, Faculty of Environmental Studies, University of Waterloo, Waterloo, ON N2G 1A2, Canada

Inter-pack spatial and behavioural relations between migratory and non-migratory wolves (Canis lupus lycaon) were studied in a large white-tailed deer (Odocoileus virginianus) yard located 13 km south of Algonquin Provincial Park, Onatrio (7,571 km2) in winters 1995-96 and 1996-97. Two resident packs, each consisting of a maximum of four members, maintained annual territories centered on the yard. A total of 29 migratory wolves from Algonquin Park, divided among six packs and three lone wolves, also utilized portions of the yard (100 km2). These migratory packs visited the yard an average of 3.6 times during each winter. Mean duration of each visit was 6.0 days, with the cumulative period in the yard averaging 26.4 days per pack. Mean straight-line distance of migratory excursions to the yard was 29 km.

Resident packs demonstrated territorial behavior by excluding migratory packs from the majority of their natal territories, thereby directing and limiting the distribution of migratory wolves in the yard. Despite representing only 15% of all wolves, the resident animals excluded migratory packs from a third of the total wolf distribution area throughout the duration of each winter, and by as much 47% during shorter periods. The resulting segregation of packs of resident and migratory status had the further effect of creating gradients of wolf density within the yard. By virtue of the fewer number of resident wolves and their exclusive occupation of territories, the density of wolves in these areas was frequently lower than in areas of the yard utilized by the more numerous migratory wolves. Migratory packs exhibited temporal avoidance and spatial overlap with other migratory packs by intermittently utilizing areas not occupied by resident wolves. The mean size of areas used by the migratory packs per visit in the yard was 5.2 km2, significantly smaller than the 9.1 km2 mean area used by the resident packs for equivalent time periods. Behaviroual plasticity in packs of resident and migratory status is discussed in relation to the spatial organization of wolves in the yard. Variable wolf density is discussed in relation to population level and anti-predation benefits to yarding deer.