Rafinesque’s big-eared bats (Corynorhinus rafinesquii; RBEB) and southeastern myotis (Myotis austroriparius; SEM) are listed on IUCN Red List of Threatened Species. Limited information on roost sites exists. I conducted roost surveys for RBEB and SEM on public forest lands in central Mississippi during winter and spring 2010. During winter, RBEB and SEM roosted in cavity trees with greater trunk diameters. In spring, roost trees used by SEM were located in forested areas of lower elevation, less slope, and greater distances from roads. Because imperfect detection can affect occupancy estimates, I estimated detection probabilities under different survey methods. Detection probability ranged from 95 – 100% and 92 – 99% when one to 2 observers used repeated surveys and removal method, respectfully. When estimating for abundance, presence of ≤20 bats led to count errors of <4%. When >20 bats were present, count errors were 38.1%. Observers correctly identified species 91% of the time.

Rafinesque’s big-eared bat (Corynorhinus rafinesquii) and southeastern myotis (Myotis austroriparius) are listed as species of concern in Mississippi. They use bottomland hardwood forests for roosting habitat; however, much of these forests in Mississippi have been lost or degraded. I seek to characterize availability and evaluate use of diurnal tree roosts for these presumably rare bats. Approximately 1,250 ha of bottomland hardwood forest on Noxubee National Wildlife Refuge were surveyed. I measured characteristics of 622 cavity trees. Analyses revealed that these bats most often used cavities of large diameter trees (≥70 cm DBH). Rafinesque’s big-eared bat and southeastern myotis roosted commonly in baldcypress (Taxodium distichum), black tupelo (Nyssa sylvatica), and American sycamore (Platanus occidentalis). This research will be used to provide guidance for management plans to conserve these bats and their habitat.