MS Thesis Defense | Johnny Baakliny

Artificial roosts supplement natural roosting habitat for tree-roosting bats, although questions remain about their use and suitability throughout the maternity season. I used long-term monitoring and radio-telemetry data to examine artificial-roost use, group size, and roost switching in a maternity colony of federally endangered Indiana bats (Myotis sodalis) near Indianapolis International Airport, Indiana. Large artificial roosts had the highest predicted probability of use, while counts within large roosts were higher in clusters with less total roosting surface area. Roost use and group size varied through the maternity season, and reproductive females were more likely to switch from tree roosts than from artificial boxes. I also compared the thermal performance and use of standard rocket boxes and two modified designs incorporating insulation and water storage. Both modified designs reduced temperature fluctuations within buffered chambers, with the externally insulated water-jacketed design moderating temperatures throughout the box. Occupancy probability did not differ significantly among designs, although emergence counts were lower in internally insulated water-jacketed boxes than in the other two designs. These results provide guidance for managing artificial-roost networks and improving box designs, while identifying the need to evaluate whether modified thermal conditions improve reproductive success and survival.