Roosting behaviour of little brown bats (Myotis lucifugus) in the Canadian Rocky Mountains
Date
2022-05-08
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Abstract
Little brown bats (Myotis lucifugus) are highly adaptable bats that occur throughout most of North America. The presence of reproductive individuals in northern and mountainous environments is surprising, however, as small, volant, insectivorous mammals should face many challenges to surviving and reproducing in regions with short, cool summers. The objective of my research was to examine the roosting ecology of female little brown bats in Banff and Yoho National Parks, with a focus on the relative importance of building and natural roosts, to help understand how populations persist in the Canadian Rocky Mountains. Better understanding little brown bat ecology is also important given the endangered listing of this species in Canada and by the IUCN.Over two summers, I captured little brown bats at varying distances from buildings, and tracked 49 females to their day roosts. Buildings were the dominant roost type used throughout the reproductive period, and the only structures in which bats formed maternity colonies. Building roosts were particularly relied on by bats in May and June, and by lactating bats. Bats monitored in building roosts were often warmer than those in natural roosts, suggesting that the benefits of building roosts are their warm microclimates. Buildings also appeared to shape the distribution of female little brown bats; reproductive females remained near building clusters, and all females remained near municipalities. Despite the apparent importance of building roosts, building colonies were unusually small, and bats had relatively low fidelity to building roosts, suggesting that building roosts may not consistently meet bats’ needs. Some non-reproductive and pregnant females also frequently used natural roosts, particularly after colder nights. This, combined with bats’ lower skin temperature in natural roosts, points to an importance of natural roosts in facilitating torpor. My results suggest that little brown bats may successfully reproduce in cold environments by relying on warm building roosts. However, natural roosts are likely important in allowing pregnant bats and non-reproductive bats to save energy. Because bats are long-lived with low reproductive output and low juvenile survival, the survival of both reproductive and non-reproductive individuals is important for population stability.
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Keywords
little brown myotis, roost, myotis lucifugus
Citation
Micalizzi, E. (2022). Roosting behaviour of little brown bats (Myotis lucifugus) in the Canadian Rocky Mountains (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.