There’s a Bridge in Kentucky Specifically Designed To Protect Endangered Bats
In 2018, the Bridging Kentucky team assessed the bridge for any signs of potential impact of threatened endangered species. What they found was a lot of staining on the underside of the bridge, a clear sign that there were bats using the bridge.
“Bats in the United States are threatened because of habitat loss and conversion,” said Andrew Logsdon, ecology and permitting branch manager for the Kentucky Transportation Cabinet (KYTC). “There are lots of conservation measures in place by both resource agencies and state departments of wildlife that are trying to replace habitat, and this is a unique opportunity that we were able to try to do some of ourselves.”
Project leaders and state officials have been working with stakeholders such as the KYTC’s Division of Environmental Analysis, district engineers, the U.S. Fish and Wildlife Service and ecologists to design a bat-friendly structure for the bridge, now deemed the “bat bridge.”
“Traditionally, with parallel box beam bridges, they have tension rods within them that kind of pull the boxes together,” said Drew Powell, bat bridge team member and ecologist with consulting firm ICF Jones and Stokes in Louisville. “Over time, you’ll get weather — rain and freeze-and-thaw — and those boxes will expand and the concrete will start to spall a little bit. That’s where the bats usually take to.”
The bats were nestling into the nooks and crannies—a habitat that wound up kept them safe from wind, rain and other natural causes.
“We wanted to recreate those exact gaps, but do it from the very first day that the bridge was built and not have to wait for 30 years of deterioration,” Powell said.
For inspiration, they looked at a similar structure in Texas. In March 2021, construction completed and officials waited to see if the bats will return—which they did. As of June 2021, there were around 400 bats at the bridge, and in August, there were more than 1,100 bats using the bridge.
This is the very first bridge in Kentucky to be used in this way, and officials are just hoping that all the effort could perhaps encourage other similar ones to be built in the future.
What do you think of this “bat bridge”? Have you ever seen a bat before?