Habitat associations of short-tailed weasels in winter

We sampled short-tailed weasel (Mustela erminea) presence in three study areas in the Selkirk and Purcell mountains of southeast British Columbia using hair removal traps and snow tracking. We extracted measures of forest cover and ecosystem type from digital resource databases to investigate habitat associations of weasels. We summarized use at the sample location (site scale) and in 500 m radius windows (home range scale) to investigate the effect of scale on our findings. Short-tailed weasels were detected in all forests surveyed. These covered the range from open dry Douglas-fir (Pseudotsuga menziesii) forests to dense wet western redcedar (Thuja plicata)-western hemlock (Tsuga heterophylla) forests, and varied in structure from very recent clear-cuts to mature stands >300 yr in age. At the site scale, weasels were detected more often in younger stands with incomplete crown closure. At the larger scale, weasels used home ranges that had less mean crown closure, but no trend was observed across stand age. We conclude that weasels in montane forests prefer open habitats and that stand age is not functionally related to habitat preference. The greater use of younger stands at the site scale can be explained by the correlation between crown closure and age. Weasels occurred in all the ecosystems sampled, including sub-alpine parkland, but appeared to be more abundant in wetter ecosystems, perhaps due to the greater primary productivity of these ecosystems.