Day-roost selection by rafinesque's big-eared bats (Corynorhinus rafinesquii) in Louisiana forests

Availability of bridge roosts is a poorly understood but possibly important component underlying abundance and distribution of the potentially threate ned bat Corynorhinus rafinesquii. We analyzed structural characteristics an d surrounding habitat of 81 bridges in west-central Louisiana forests to de termine which attributes of bridges influenced the selection of roosts by C . rafinesquii. Type of support structure under bridges, material with which bridges were built, proportion of surrounding habitat composed of mature d eciduous forest, and road surface of bridges were significantly associated with selection of roost sites. On average, bats tagged with radiotransmitte rs roosted under bridges 50% of the time and in black gum trees (Nyssa sylv atica) 50% of the time. Preservation of bridges with beam supports and cons ervation of mature deciduous forest are likely to be important for maintain ing populations of C. rafinesquii.