The behaviour, diet and morphology of the little brown bat (Myotis lucifugus) near the northern extent of its range in Yukon Canada.

Abstract

I investigated how nocturnal mammals, specifically little brown bats (Myotis lucifugus), adjust their foraging behaviour and diet in northern areas where there is a short reproductive season, low temperatures and short nights. In Watson Lake, Yukon (60°06' N, 128°46' W), M. lucifugus remained nocturnal throughout the summer, despite considerable variation in temperature and night length. Individuals did not use open-field habitat except when emerging from or returning to the maternity roost. Myotis lucifugus used habitats not commonly used in more southern latitudes, specifically the forest interior. Unlike more southern populations, M. lucifugus in Watson Lake foraged extensively on non-volant prey, specifically spiders, particularly when temperatures and flying insect abundance were low. Myotis lucifugus in the north was more adapted to foraging in cluttered environments and possibly gleaning insects from vegetation than those in a southern location (Calgary, Alberta, Canada; 51°05’N, 114°05’W) because they were significantly smaller and had smaller wings.