Cryan, Paul M. 1997. Distribution and Roosting Habits of Bats in the Southern Black Hills, South Dakota. M.S. Thesis. The University of Mew Mexico. 98 p.

Abstract

The objectives of this project were to learn more about the summer distributional patterns and the summer roosting habits of bats in the southern Black Hills. During the summers of 1995 and 1996 I captured bats throughout the region and followed the movements of individuals instrumented with radiotransmitters. Capture records from 1995 and 1996 were incorporated with those gathered by previous researchers, representing a total of 3276 records of bats belonging to 10 species. Eithgy-five percent of captured bats wre male. Analysis of capture data revealed that elevation is a significant factor affecting the distribution of reproductive female bats. Reproductive females were captured primarily at low elevation sites, while males and non-reproductive females were captured in a wider range of elevations.

I successfully radiotracked 24 bats of three different species. All roosts used by the northern myotis, Myotis septentrionalis, were found in tree snags, while all roosts used by the fringed myotis, Myotis thysanodes, were found in rock crevices. Roosts of the long-legged myotis, Myotis volans, were found in both snags and rock crevices. There were several trends in roosting habits observed across all species. Males and non-reproductive females roosted alone, while reproductive females formed colonies. Solitary bats roosted in structures that were less thermally stable and less permanent than those used by maternity groups. All bats changed roots frequently, yet remained within relatively small geographic areas. There were differences in the mean capture elevations and roost elevations of reproductive females, suggesting possible habitat partitioning.