Bringing Back the Bats

TVA scientists have now installed 50 artificial bat roost habitats around the Tennessee Valley, and they’re seeing evidence that bats are moving in and setting up house.

Bats get a bad rap. After all, they’re often portrayed as spooky, freaky or downright nasty, when in truth they’re our helpful neighbors. Unless seriously disturbed or harmed, bats are peaceful and quiet, and bats in our area eat bugs, not blood—feasting on moths, flies, beetles and mosquitoes. In fact, the more you understand about bats, the more you want them around.

Several species of bats in the Tennessee Valley are already on the endangered and threatened species lists, including the Indiana bat and the northern long-eared bat. Other species, including the tricolored and the little brown bat, are being evaluated for listing. It’s clear the bats need our help—and this is where the experts at TVA come in.

Going Batty

“White-nose syndrome [see sidebar] is taking a toll on these bats,” explains Heather Hart, senior specialist in Natural Resource Conservation at TVA, who is managing a project to install artificial roosting habitat to improve bat populations throughout the Valley. “At the same time, because they roost under exfoliated bark on dead or dying trees, they’re losing summer habitat to storms and to human development.” These are, by their nature, the very trees most likely to fall or to be cleared out in the name of progress.

Hart explains that these dwindling bat populations are a cause worth championing.

“Not only do the bats help control insect populations, their guano (droppings) provides key nutrients to the soil,” she says. “There are also other species—insects and other little critters—that use their guano for fuel. They are a link in the food chain in the Tennessee Valley. We can’t afford to have them wiped out.”

There is no easy solution; nor is there a quick fix. Female bats typically bear only one young in May or June each year; and the human need for adding roads and houses means that it’s not always possible to leave all bats in peace. TVA itself has encountered trees that are suitable for roosting by bats in the installation of its transmission lines, which sometimes require tree removal.

What to Do?

Hart has identified an alternative: the installation of artificial bat roost structures designed for safe and secure long-term habitation by one of the most at-risk species, the Indiana bat. Far from the more familiar—and largely ineffective—bat houses, these structures include untreated utility poles covered with a layer of tough synthetic bark, called Brandenbark, installed over a grid-like surface designed to help bats cling with their feet and “hang in there.”

Hart explains that these dwindling bat populations are a cause worth championing.

“Not only do the bats help control insect populations, their guano (droppings) provides key nutrients to the soil,” she says. “There are also other species—insects and other little critters—that use their guano for fuel. They are a link in the food chain in the Tennessee Valley. We can’t afford to have them wiped out.”

There is no easy solution; nor is there a quick fix. Female bats typically bear only one young in May or June each year; and the human need for adding roads and houses means that it’s not always possible to leave all bats in peace. TVA itself has encountered trees that are suitable for roosting by bats in the installation of its transmission lines, which sometimes require tree removal.

Starter Homes

Since 2016, Hart has worked with Liz Hamrick, terrestrial zoologist in TVA Biological Permitting and Compliance, and with Copperhead Consulting Services, to oversee the installation of roosts on TVA sites throughout the Valley. They chose four locations to put 25 roosts: a transmission right-of-way at Big Sandy on Kentucky Reservoir in Benton County, Tenn.; the Cave Mountain Small Wild Area on Guntersville Reservoir in Marshall County, Ala.; Loyston Point on Norris Reservoir in Union County, Tenn.; and Marbut Bend Trail on Wheeler Reservoir in Limestone County, Ala..

In April 2019, 25 additional roosts were installed at five locations: Rankin Bottoms Wildlife Management Area on Douglas Reservoir; Chatuge Dam Day Use Area on Chatuge Reservoir; Nottely Dam Recreation Area on Nottely Reservoir; Bayou Creek Small Wild Area near Shawnee Fossil Plant; and Tupelo Creek Small Wild Area on Kentucky Reservoir.

“Each of these roosts can host anywhere from 70 to 100 bats,” Hart explains. “Some of them are right beside trails, and hikers can see them. We’ve been monitoring the roosts all summer long, and we’re seeing evidence that bats are beginning to use them. No matter the species of bat, we hope they will continue to come back to the area and inhabit these, giving the bats an opportunity to be sustained and continue to exist.”

Surveys in 2020 found a small number of big brown bats using the poles at Loyston Point, which marks the first time bats have been observed at that location.  At Big Sandy, a colony of evening bats was observed using the roosts installed in 2016.

TVA’s scientists will continue to monitor the roosts, and TVA will also share findings with other government agencies and private groups in the interest of saving the bats.