Bat night roost at an abandoned mine in western Maryland

Abstract

Few published records of night roosts used by bats in eastern North America exist. We describe seasonal use and species composition at an abandoned mine used as a night roost by bats in western Maryland. A total of 81 bats from five species were captured from July to September 1999 and March to September 2000. Big Brown Bats (Eptesicus fuscus) used the mine regularly and were the most abundant species captured. Capture success (number of bats/trap hour) was positively correlated with nightly ambient temperature, but not correlated with relative humidity.