The number of occurrences or subpopulations with good or excellent estimated viability may be fewer than 30 (more than 50 percent of these are in Florida). Recent surveys (e.g., Hofmann et al. 1999, Mirowsky et al. 2004) suggest that the number of small maternity colonies may be quite large, but these are of uncertain viability. Only two large (more than 100 bats) winter colonies have been reported in recent years, but there are several small colonies throughout the species range. In Florida, large numbers form maternity colonies in caves; the species has been reported a few times in buildings. Maternity colonies also have been found in a small number of caves in Georgia and Alabama. In the rest of the deep south, these bats generally use buildings and other structures, mines, and hollow trees (e.g., water tupelo, black gum, water hickory, bald cypress) for spring and summer roosts. In Louisiana, a hollow water tupelo (Nyssa aquatica) studied in late summer and early fall contained about 50 individuals (Gooding and Langford 2004). By winter in this region they roost in small groups in outdoor sites, often over water, such as bridges, culverts, storm sewers, and boat houses, as well as in hollow trees (Barbour and Davis 1969). In Florida (and perhaps elsewhere) these bats also roost in caves in winter; apparently they may use different caves for summer and winter roosts (Gore and Havis 1992). In the north, the pattern of cave use is different. Kentucky populations winter in caves (often with Myotis sodalis) but are rare in most caves in the summer, when most roost in large hollow trees. The few old records from Indiana also were mostly from caves in winter. Summer roost sites are poorly known from this part of their range. At least one cave in Indiana had bats every month except May, June, and July (Mumford and Whitaker 1982). Only a few maternity colonies have been reported in this region: one was in the Kentucky cave already mentioned; additional maternity colonies exist in southern Illinois, where one was in a hollow-based water tupelo (Nyssa aquatica) (Hofmann et al. 1999). The key characteristics for maternity sites are high humidity and constant warm temperatures. Foraging habitat is riparian floodplain forests or wooded wetlands with permanent open water nearby (Gardner et al. 1992). These bats may forage primarily over lakes, ponds, or slow-moving streams.

The geographic range of this species includes the southeastern United States, west to southeastern Oklahoma and eastern Texas (Mirowsky et al. 2004, Schmidly 2004), north in the Mississippi River drainage through Arkansas, Mississippi, western Tennessee, southeastern Missouri, and western Kentucky to southern Illinois (Hofmann et al. 1999) and southern Indiana, and east to southeastern Virginia (Hobson 1998), southern North Carolina, South Carolina (Menzel et al. 2003), Georgia, and Florida (Jones and Mamming 1989). Summer and winter ranges are the same. Although widespread in southeast, the vast majority of the known population is concentrated in northern Florida, and the species is rare and local outside the Gulf coastal plain.

There are several protected occurrences in Florida; also Bat Cave in Kentucky. Several caves in Jackson County, Florida, are protected due to use by endangered M. grisescens. The species is afforded nominal protection via Florida's Cave Protection Act. Bat Conservation International, TNC, and the state of Florida were instrumental in protecting Judge's Cave; a few other maternity caves on private land in Florida have various levels of protection (Gore and Hovis 1992). South Carolina has used posting and controlled access to roost sites to protect this species (Bunch pers. comm.). One occurrence in Indiana is in a state park and is protected. In Texas, two maternity roosts are in state parks and one is in a national wildlife refuge, and populations are known to exist in other state parks and wildlife management areas, national forests, Big Thicket National Preserve, and Nature Conservancy lands. Determine status and trend in South Carolina, Georgia, Louisiana, Texas, Arkansas, and Tennessee. Protect roosting sites of all large (> 100) colonies, both breeding and wintering. Protect frequently used foraging habitat in their natural forested state. Obtain more information about summer and winter roosting requirements. Determine viability and importance of small maternity colonies. Develop techniques for monitoring with minimum disturbance. Determine effects of disturbance on survival and reproductive success. Determine dispersal distances and roosting sites for bats when away from the large cave colony sites. Determine importance of hollow trees and other non-cave sites as maternity roosts.