Use of a bridge for day roosting by the Hoary Bat, Lasiurus cinereus

The Hoary Bat (Lasiums cinereus) is a migratory species with the widest distribution of all New World bats. It is a solitary species that roosts during the day and night primarily among tree foliage. During a survey of 130 highway structures (bridges and culverts) in south central Montana for evidence of use by bats, we discovered a female Hoary Bat with young in mid July 2003 using a wooden bridge as a day roost. This is the first report of Hoary Bats using a bridge as roosting habitat.