SELECTION OF SUMMER ROOSTING SITES BY INDIANA BATS (MYOTIS-SODALIS) IN MISSOURI

Slimmer roosting sites were studied at four maternity colonies of Indi ana bats (Myotis sodalis) in northern Missouri. Colonies of Indiana ba ts used two types of roosts, primary and alternate, that differed in i ntensity of use, number, and probable function. Primary roosts were de fined as roosts where use by >30 bats on more than one occasion was ob served. The number of primary roosts per colony ranged from one to thr ee. All primary roosts were in standing dead trees situated in trees e xposed to direct sunlight. Alternate roosts were used by smaller numbe rs of bats. These roosts included both living and dead trees that typi cally were located within the shaded forest interior. Differences in p atterns of use between types of roosts seemed to be influenced by weat her conditions in that use of alternate roost trees increased during p eriods of elevated temperature and precipitation. Indiana bats have sp ecific requirements for roost sites, but also must be able to relocate when loss of bark, tree fall, or other events render their current ro ost sites unusable. Practices of forest management within the summer r ange of Indiana bats should favor retention of large-diameter, mature, and senescent trees.