Bat hibemacula on Lake Superior's north shore, Minnesota

Abstract

In January 1990, 308 individual bats of four species (Myotis lucifugus, M. sptentrionalis, Eptesicus fuscus, Pipistrellus subflavus) were found hibernating in two caves along Lake Superior's North Shore in Minnesota. These are the first known natural hibernacula in northern Minnesota, and this is a northerly range extension for P. subflavus. Local rock structure suggests the possibility of a significantly larger overwintering population than observed to date.