MAMMALS
colored bat presence during winter and during the active season, and tricolored bat presence at “old” bridges more often than replaced bridges. This project will con- tinue until all historic bridges are surveyed, which should conclude in May 2025.
caves and underground mines are lacking in the Coastal Plain region, so it is assumed that this bat roosts pri- marily in trees, culverts, and bridges in the winter on the Coastal Plain. This project has reached the half- way point with surveys during two winter seasons and one active season completed, and one winter season and two active seasons remaining. Twen- ty-four percent of the bridges sur- veyed have yielded tricolored bat pres- ence (23% in winter, 27% in the active season). Tricolored bats are the spe- cies most often encountered during these bridge surveys, but bats other than tricoloreds have been found at 5% of bridges and include the state special concern Rafinesque’s big-eared bat (Corynorhinus rafinesquii), and common species like the big brown bat (Eptesicus fuscus), and evening bat (Nycticeius humeralis). Forty-two percent of bridges surveyed show roosting bats or evidence of bats in the form of guano. Bridges with presence of bats or guano are most often “old” bridges (70%), meaning the structure has not been replaced since the his- toric survey, and only 30% of bat or guano presence has occurred at replaced bridges. Of the bridges found with tricolored bat presence, 60% are “old” bridges and 40% are replaced bridges. Now that the project is halfway through, patterns in the results are beginning to emerge, particularly with tricolored bats. Current results show tricolored bat presence at about one-quarter of bridges surveyed, tri-
A tricolored bat roosting under a replaced bridge in January 2024 (Katherine Etchison)
Wildlife Diversity Biologist, Katherine Etchison, searches for roosting bats under an “old” bridge on the Coastal Plain (J. Weber)
49 2024 Wildlife Diversity Program Annual Report
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