Mexican free-tailed bats have been roosting in crevices beneath the West Sixth Street bridge, causing delays in construction repairs.

The construction is part of a larger restoration project by the Shoal Creek Conservancy (SCC) and the City of Austin. After discovering the bats, the two groups contacted Bat Conservation International (BCI) to devise a plan for how to proceed.

Construction crews are working to prevent the entombment of the bats during the construction, said Dianne Odegard, BCI public outreach manager.

“The worst case scenario would be sealing the bats into the bridge with the mortar, and that sort of thing happens more often than we know,” Odegard said. “We’re really glad that they got in contact with us to make sure that the bats wouldn’t be harmed.”

The bat exclusion, or removal, process involves the construction crews placing hollow caulk pipes beneath the crevices so the bats can exit safely when they emerge. Once the bats have left their crevices, they cannot re-enter because their claws cannot grip the smooth sides of the pipe.

Joanna Wolaver, executive director of SCC, said the discovery of the bats is only slowing the progress of the project because of the efforts to humanely remove them.

“We’re equally interested in restoring the historic integrity of the bridge as we are in really having healthy habitats for animals on Shoal Creek,” Wolaver said. “It was important for us to balance the historic restoration needs with the humane treatment of the animals living there.”

The goal of the restoration project is to highlight the historical significance of the bridge and transform it into a destination people want to visit. The first stage of the project is repairing the mortar loss, but SCC also hopes to resolve the graffiti problem and complete further placemaking and landscaping.

The exclusion process added about two weeks to the construction time and an additional $9,000 in costs to the city. Mathematics sophomore Emily Ballard said she supports the SCC and the city in their efforts to protect the bats.

“I think it’s so worth it that they’re taking the extra time and money to do this,” Ballard said. “I used to come here as a kid to see the bats with my parents, and I think the bats are one of the things that make Austin as unique as it is.”