Status, Habitat Preference, and Management of Southwest Wisconsin Bats

Abstract

This project was an investigation of the status of the Indiana bat (Myotis sodalis) in Wisconsin. The Indiana bat is a federally endangered species that has been collected only once in the state. The objectives of the project were: to determine 1) the status of the Indiana bat and other bat species in southwest Wisconsin; 2) habitat preferences of southwest Wisconsin bat species; and 3) the amount and types of human use of select caves. The Indiana bat was not captured during spring and late summer bat trapping at cave entrances, summer mist netting in a variety of habitats, or during monthly surveys of 11 caves and mines in southwest Wisconsin in 1981. The little brown bat(M. lucifugus) was most common, followed by Keen's myotis (M. keenii), red bat (Lasiurus borealis), big brown bat (Eptesicus fuscus), eastern pipistrelle (Pipistrellus subflavus), and hoary bat (b. cinereus), respectively, in summer. Winter hibernating populations of little brown bats were most abundant, followed by big brown bats, eastern pipistrelles, and Keen's myotis, respectively. Summer habitats having greatest bat relative abundance were dry-mesic northern forests, mesic northern forests, xeric southern forests, dry-mesic southern forests, and mesic southern forests, respectively. The 2 habitats showing greatest bat species diversity were dry-mesic northern forest, and mesic southern forest respectively. Little brown bats showed the highest foraging diversity index, followed by Keen's myotis, red bats and big brown bats, respectively. Bear Creek cave, Atkinson's Diggings, Pop's Cave and Roger's Cave had the most stable microclimates for overwintering bats and relatively large hibernating bat populations. Other caves, with similar microclimates, harbored few or no bats. Caves were used by humans during the period of bat hibernation (October-April). Five of 8 caves had evidence of use as party sites.