Reproduction and Den Site Selection by Wolves in a Disturbed Landscape

Abstract

We studied litter sizes, den characteristics, and den site selection by wolves (Canis lupus ligoni) on Prince of Wales and adjacent islands in Southeast Alaska, USA. The study area was extensively logged and roaded enabling us to examine effects of those factors on den site selection. We counted pups in dens during May using an infrared video camera with a flexible-shaft. We recorded habitat features at dens and used logistic regression to compare den site characteristics within 100-m and 1000-m circular buffers around dens with randomly matched unused locations. Litter size averaged 4.1 (SD = 1.7) pups, however, average litter sizes of six first-time breeding females were smaller ( = 3.0, SD = 2.5). Dens were located in root wads of large living or dead trees within old-growth forest stands <150m from freshwater. Within 100-m and 1000-m buffers, wolves selected coarse-canopy old-growth forest stands and muskegs adjacent to lakes, ponds or streams, on gentle slopes, that were farther from logged stands and roads than unused locations. Landscape features such as elevation and slope, and proximity of fresh water had the greatest effects on den site selection. Covariates tabulated within 100-m buffers had much greater influence on den site selection than variables tabulated within 1000-m buffers indicating that wolves mostly responded to features within the immediate vicinity of dens. Wolves generally avoided clearcuts and roads but they tolerated intense disturbances of short duration during our den visits. We suggest wolves prefer locations away from roads and clearcuts but will select them if suitable alternative locations do not exist. Once established at den sites, wolves will tolerate some human disturbance at least of short duration.