Researchers are gauging the health of Blue Ridge bats in winter.
Photo Above: University of Georgia doctoral student Santiago Perea deploys an acoustic bat detector in a forest research area. Courtesy of Santiago Perea
For decades, studies have been conducted on the health of Southeastern bats in summer. But one University of Georgia researcher wanted to know: How are they doing in cold-weather months?
“There has been very little work done in the winter, mostly because people perceive that bats aren’t active,” says Dr. Steven Castleberry, UGA wildlife ecology and management professor. “In the Southeast, they are actually active a good bit during the winter. … No bats are going to be active when it’s really cold, but in the Blue Ridge area, you get a warm day in the winter and you’ll see bats flying around.”
So when the National Council for Air and Stream Improvement, a private timber company advisory group, contacted Castleberry about assessing the health of bats on its members’ wooded properties in colder months, when some species struggle to survive, he jumped at the chance to find out. “If you’re not looking,” he says, “you could be missing something really big.”
The study, which spanned 400 nights in three consecutive winter seasons starting in January 2020, took place on timber company lands at six sites throughout the Southeast. Wildlife recorders documented bat echolocation calls — their frequency is too high for human ears to hear — which the animals emit when they’re looking for food. Then the researchers used a special type of software to identify the different species, along with how many bats were found in various locations and under what conditions they were most active. “And then we tried to figure out the basic question: Why is this bat foraging there? What about the habitat makes it suitable for it to feed there?” Castleberry explains. “Then we can try to create those conditions on the landscape.”
Bats have long been considered a valuable form of natural insect control; one estimate places the economic value of bats at $22 billion for their positive impact on the agricultural industry. While the UGA winter study once again confirmed the insect link, the widespread belief that bats target mosquitoes in particular is a myth, says Castleberry. But “our data suggests that they eat more flies, which does include mosquitoes, in the winter than in the summer.” One reason, he adds, could be that mosquitoes are simply more plentiful in cold weather than the bats’ favorites, moths and beetles.
It’s nearly impossible to glean an accurate count of bat numbers because they’re nocturnal, and they fly, making them hard to see. And, says Castleberry, the populations have likely been declining for some time due to habitat loss and modification, turbines and wind energy facilities and, in the case of cave-dwelling bats, white nose syndrome.
Fortunately, the UGA researchers found that Southeastern bats, overall, are doing well in winter in privately-owned woodlands, as well as in state and national forests. But that management has to be done right. For bats, that means keeping the forest canopy open by thinning out trees so they can spread their wings. “Bats are not going to live in a Walmart parking lot,” Castleberry notes. “You need forests, so the ultimate goal is to create forest conditions that are suitable for bats.”
The story above first appeared in our January / February 2026 issue.
