Life-history notes on the Heather Vole, Phenacomys intermedius levis, in the Canadian Rocky Mountains

Heather Voles, Phenacomys intermedius , were live- and snap-trapped at two different elevations in the front range of the Canadian Rocky Mountains. Most animals were caught at 2240 m in a glacial cirque dominated by spruce (Picea spp.), sub-alpine Fir (Abies lasiocarpa ) and Larch (Larex lyalli ). The mean litter size was 4.2 and females produced a maximum of three litters per season. Young-of-the-year matured in the summer of their birth. Unlike other microtines, P. intermedius are characterized by low trappability, a sex ratio heavily skewed towards females in traps, and high live-trap mortality.