Texas wins award for protecting bats - Public Information and Information Exchange - Brief Article

Public Roads, March-April, 2003

When the Texas Department of Transportation (TxDOT7) learned that migrating bats were joining motorists as frequent bridge users, the agency started a habitat protection project that earned the department and bridge engineer Mark Bloschock an award of excellence from Bats Conservation International (BCI).

The bat habitat project started in 1994 when a large colony of Mexican Free-Tailed bats settled under the Congress Avenue bridge in Austin. Bloschock and BCI began a study to determine why the bats settled there. Also, they were concerned about the damage bats might do to the bridge and potential effects on human health.

The study determined that slot-shaped crevices under the bridge were similar in size to spaces found in bat caves. Under ideal roosting conditions, bats need a crevice that is 1.9-2.5 centimeters (0.75-1.0 inch) wide and 30.5 centimeters (12 inches) deep. Bats also may consider crevices as wide as 3.8 centimeters (1.5 inches) and 10.2-20.3 centimeters (4-8 inches) deep. Any slot larger or smaller and the bats will not use the roost. Bats also are comfortable with culverts and will even settle under wooden bridges.

The study showed that the bats do not threaten the highway structures or community health. Biologists estimate that the bats eat 10 to 15 tons of insects on their nightly flights.

Based on the success of the bat habitat in Austin, Bloschock established the Bats and Bridges program, which has spread to 24 States and 17 countries. Overall, TxDOT has 218 structures currently used as roosts- almost three times more bat habitats than any other State taking part in the program.

For more information on the bat habitat project, visit www.batcon.org or contact Mark Bloschock at 512-416-2178.