View beneath bridge where chain link fencing was installed to protect roosting bats from potential harassment or vandalism - Photo courtesy of Tom Cervone, Bernardin, Lochmueller & Associates)

Vulnerable bats are seen here roosting beneath bridge near grafitti. - Photo courtesy of Tom Cervone, Bernardin, Lochmueller & Associates

In 2004, the Service's Bloomington Ecological Services Field Office, Indiana, requested that the Indiana Department of Transportation conduct mist net surveys for Federally endangered Indiana bats along the proposed, 142-mile long, Interstate 69 extension project through southwestern Indiana. 

In conjunction with the mist net surveys, the office also requested that all bridges in the project area be inspected for the presence of day- or night-roosting bats.  Indiana DOT agreed to the requests, which lead to the discovery of Indiana bats roosting beneath one of 259 bridges that were inspected. 

The Indiana bats were found roosting within the cave-like abutments of a large bridge that spans a river in the I-69 project area.  The bridge is not being specifically named for sensitivity reasons. 

Periodic inspections in 2004 and again in 2005 revealed that small numbers of Indiana bats roosted beneath this bridge from spring migration throughout the summer and during the fall migration period and were joined by hundreds of other bats of different species including, big brown bats, little brown bats, and eastern pipistrelles.  For example, on August 13, 2005 a total of 501 bats of several species including 9 Indiana bats was found day-roosting beneath the bridge.

Unfortunately, bats weren’t the only mammals spending time beneath the bridge.  Both the north and south ends of the bridge showed obvious signs of human activity and vandalism, such as garbage and spray-painted graffiti.  Most of the bats’ roost sites were within easy reach making them particularly vulnerable to human disturbance or vandalism. 

To prevent harm or harassment to the bats roosting beneath the bridge, Indiana DOT consulted with the Bloomington Office staff and proposed to install fencing at both ends of the bridge as a Conservation Measure for the proposed I-69 project. The staff agreed and approved the fence designs, and Indiana DOT’s contractors installed the fencing in March 2006. 

After the first summer of monthly monitoring visits, it appears that the new fencing has been very successful at protecting the bridge-roosting bats.  Ultimately, this simple conservation measure should help ensure the long-term conservation of migratory and resident bat populations in this part of southwestern Indiana.