Intersexual roost site selection by the little brown Myotis in Cypress Hills, Saskatchewan

Abstract

Roost structures provide habitats for bats to engage in critical life processes. Identifying, characterizing, and conserving these structures is crucial for individual fitness and survival to mitigate population loss, especially for species such as the little brown Myotis facing threats such as pathogen spread from White-Nose Syndrome. During summer, little brown Myotis rely on roosts to maintain populations through successful reproduction and winter preparation, including rapid development of young and fat accumulation for the winter for all individuals. Summer daytime roosts are particularly critical for these processes to occur effectively. My research aimed to characterize the natural roost selection of nonreproductive female and male little brown Myotis during the summer in Cypress Hills, Saskatchewan (SK). I determined if roost choice differed from random available roosts and explored intersexual variation in roost use between nonreproductive females and males. Using radio-telemetry, I tracked nonreproductive female and male bats to their daytime roosts in Cypress Hills, Saskatchewan, over the summers of 2022 and 2023. Identifying occupied roost structures for males and females, and comparing them against data for random available roosts may provide valuable insight to roost characteristics such as tree structure and temperature, which are essential for forest-dwelling bats. I found individuals of both sexes roosting in anthropogenic structures, though nonreproductive females were observed roosting in a known maternity colony consisting of several anthropogenic structures more than males. In terms of natural roosts, my results suggest that little brown Myotis are roosting mostly in white spruce in Cypress Hills, SK though the characteristics of these trees may differ between male and nonreproductive females. Assessing the roost selection of little brown Myotis and how intersexual variation affects such selection can guide future conservation efforts by protecting and promoting these sites for future populations.