Hoff, S., C.J. Pendergast, L. Johnson, E. Olson, D. O'Dell, Z. Dowling, K.M. Gorman, C. Herzog and W.C. Turner. 2024. Seasonal roost characterization and fall behavior of coastal northern myotis (Myotis septentrionalis) populations, Journal of Mammalogy, 105:(2): 277-288. DOI: 10.1093/jmammal/gyad102
Abstract
Temperate bats exhibit seasonal and sex differences in resource selection and activity patterns that are associated with ambient conditions. During fall, individuals face energetic tradeoffs as they make choices relating to migration, mating and hibernation that may diverge for populations throughout their range. However, research efforts in North America have largely focused on the summer maternity and winter hibernation seasons, whereas the pre-hibernation period remains understudied. Northern myotis (Myotis septentrionalis) have experienced precipitous population declines from white-nose syndrome (WNS), leading to their protected status in the United States and Canada. Therefore, understanding their behavioral patterns is paramount to inform conservation efforts. Our study compared seasonal roosts and documented fall behaviors between study sites and sexes on three islands: Long Island, New York, and Martha’s Vineyard and Nantucket Island, Massachusetts. Between 2017 – 2020, we radio-tracked 54 individuals to analyze activity patterns and characterize fall roosts to compare with summer roosts documented in previous studies on each island. Summer tree roosts were of smaller diameter, later stages of decay, and lower canopy closure, while bats of both sexes selected trees of similar diameter and decay stage during fall. Anthropogenic roost use was documented in both seasons but use of anthropogenic structures was greater during fall and increased as the season progressed. Bats made short inter-roost movements with males traveling greater distances than females on average. Activity on the landscape occurred until late November, with males exhibiting a longer active period than females. Current timing of restrictions on forest management activities may be mismatched based on the pre-hibernation bat activity observed in these coastal populations. A portion of tagged bats were tracked to local hibernacula in subterranean anthropogenic structures and the farthest distance traveled from capture location to hibernaculum was 6 km. Use of anthropogenic structures for roosts and hibernacula may facilitate survival of this species in coastal regions despite the presence of WNS infections.