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UBC Theses and Dissertations

Ecology of the short-tailed weasel (mustela erminea) in the mixedwood boreal forest of Alberta Lisgo, Kimberly Ann


I examined diet, home range size, habitat use, and rest sites of short-tailed weasels (Mustela erminea) in the mixedwood boreal forest of Alberta. Of the 8 food groups identified in 585 scats, Arvicolidae, mainly red-backed voles (Clethrionomys gapperi), were the primary prey of weasels. In summer, weasels supplemented their diet with birds and eggs. Male weasels are 2- 3 times larger than females and included red squirrels (Tamiasciurus hudsonicus) in their summer and fall diets. Despite relatively high abundance of deer mice in my study area, this species was not exploited substantially by weasels. I radio-collared 7 female and 10 male short-tailed weasels. Female (n=4) and male (n=4) weasels had home range sizes of 65.5-94.8 ha and 122.6-204.6 ha, respectively. Male and female weasels showed similar trends in their use of birch, shrub, aspen, and jack pine habitats but differed in their use of other habitats. Male weasels preferred habitats associated with high abundance of red squirrels (black spruce and larch) and under-utilized habitats associated with low abundance of red squirrels (3-year-old regenerating aspen cutblocks). Female weasels showed the opposite trend. They preferred habitats associated with high abundance of voles (3- year-old regenerating aspen cutblocks) and under-utilized black spruce and larch habitats. Weasels used a variety of rest sites and most of these sites were associated with their prey. Squirrel middens and the bases of trees or snags were the most common rest sites used by male weasels. Most rest sites used by female weasels were in residual logging material. In cutblocks, female weasels preferentially used areas with slash. Abundant small mammals, in particular C. gapperi, appeared to be a factor promoting the use of slash by females. To ensure suitable habitat is provided for male weasels, forest managers should retain patches of coniferous trees that are old enough to produce cones. These patches support red squirrels that are prey to male weasels and whose middens are their preferred resting sites. Forest managers should retain forest stands (undisturbed by timber harvesting) adjacent to 3-year-old regenerating aspen cutblocks to ensure occupation of by females. The retention of logging slash in these cutblocks had high densities of red-backed voles and also provided rest sites for females.

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