Big Brown Bat (Eptesicus fuscus) is a Threatened species in Wisconsin. It has a dark brown dorsal fur coat and may have light-brown ventral fur. During the summer months, big brown bats are found in various habitats including mixed landscapes of deciduous woodlands, farmlands, edges near water, and urban areas. Females may form large colonies in bat houses and buildings over the summer. During the winter months, they are found in natural and manmade structures such as caves, mines, human dwellings, and other suitable hibernacula. The big brown bat is insectivorous and feeds primarily on small beetles found among tree foliage. Mating occurs in the fall at cave and mine entrances and females store sperm until the spring. One or two pups are born in early-June and mature after six weeks. See the species guidance document for avoidance measures and management guidance from the Natural Heritage Conservation Program.
