Cory Holliday’s job title is Cave and Karst Program Manager for the Tennessee chapter of the Nature Conservancy but many simply refer to him as “Batman.”
This is a guy who likely knows as much about those beady-eyed, razor-sharp fanged, winged creatures known as bats (aka flittermice and flying foxes) as anyone in the state.
Holliday, whose role for the Conservancy combines research and conservation, says he and his cohorts remain much in the dark when it comes to knowing the lifestyles of these critters that do a world of good for mankind, mainly due to their voracious appetite for insects.
“There are so many unknowns. Bats are pretty challenging to understand because they are small, fly at night and hard to detect on the landscape. Millions of them are out there. Hundreds of thousands every night are flying around eating bugs. We can’t see them. We don’t really know that much about what is really important to them,” said the bat man. “We’re trying to understand foraging areas, roosting habitats, what is critical to their lives and where the threats are.”
These mostly carnivorous mammals make their homes in caves, barns, trees, buildings and under bridges. The ones that live in the wild have an average lifespan of 30 years. There are 1,300 species of bats around the globe and 16 species that hang in Tennessee. Their wingspans range from five inches to six feet wide, while they may weigh between .07 ounces up to 3.3 pounds.
The bat wizard shares that little was known about Indiana bats in Tennessee until about 10 years ago. It turns out that, within the state, Wilson County is the summer mecca for the members of this endangered species.
“We have tracked bats to Wilson County from all around the state. The combination of tree-covered hilltops and agricultural bottomland is something they really seem to like, and they are doing great here,” he said.
He estimates that he spends about 80 percent of his time scrutinizing bats. That’s largely due to the devastating effects that white-nose syndrome has had on them.
“It is a disease that effects cave-hibernating bats and is caused by an introduced fungus,” explained Holliday. “It’s just like the coronavirus in humans. These small microorganisms were brought to North America from around the world. The fungus grows well in the cool, dark, dank cave environment. Bats come into hibernate and have to shut their lives down to go months without food.
“Their metabolism slows down. They do not have much immune response so the fungus grows on them while they’re hibernating and causes tissue damage, and they use up their fat reserve, and bats don’t make it through the winter.”
Giving a helping hand to bats
The Nature Conservancy of Tennessee along with the Tennessee Wildlife Resources Agency and the U.S. Fish and Wildlife Service have joined forces to conserve prime roosting areas for gray bats, but, according to Holliday, the health of the general bat population in the southeastern U.S. is “fairly poor.”
“There have been some ups and some downs, but overall, in Tennessee bats have not been doing very well,” he said. “Indiana bats continue to decline. And now we have really big losses of little brown bats, Northern long-eared bats and tri-colored bats from this disease.
“The tri-colored have been seriously declining and the Northern long-eared are almost extirpated in Tennessee (that occurs when a species is not extinct but has disappeared from one geographic region). They are likely to be gone from Tennessee in a short number of years.”
The Nature Conservancy of Tennessee owns 10 to 12 caves including Hubbard’s Cave in Warren County, which is home to half a million gray bats in winter. Three other caves within the state each provide shelter for hundreds of thousands of bats: Bellamy Cave in Montgomery County, Rattling Cave in Cocke County and Pearson Cave in Hawkins County.
The Conservancy also has erected 34 cave gates around the state, which offer access and exit to bats but keep out humans. The benefit of protecting bat roosts comes from these mammals’ love of chowing down on insects.
“Bugs are the only things they eat: moths, beetles, flies, and bats certainly do eat mosquitoes, but if a bat’s flying around a moth and a mosquito, the moth is a big juicy steak and the mosquito is a piece of popcorn,” said Holliday.
“The University of Tennessee did a paper in 2011, trying to understand the benefits of bats, and calculated a value just for agriculture in Tennessee at over $30 million a year. Bats save farmers from using pesticides. That study was only limited to agriculture.”
Shifting to the coronavirus pandemic, when asked if scientists know for sure if it originated in bats in China, the bat scholar answered, “They do not know for sure. It’s certainly similar to a coronavirus carried by bats in that part of the world, but they haven’t really narrowed it down yet. It is not uncommon for viruses to move from bats to an intermediate host and then to humans.”
So, have bats been given a bad rap on the virus?
“I would say it is not the fault of bats, but more often comes from people killing and eating wildlife in an unclean way. When you get a lot of dead animals in an open market, you have a lot of ways for spreading virus and bacteria around,” said Holliday.
As for whether humans pass the virus on to bats, known as Covid-19 reverse zoonosis, he said, “We do not know. That research is pending.”
He added, “Earlier in the year we did have to shut down some of our research. We are very concerned about potentially giving the virus to North American bats. Now we have some guidance on being exposed to bats and handling bats that is pretty similar to protocol with humans. We’re wearing face masks and gloves trying to protect our bats.”
Developing bat respect
Holliday, 43, who has been involved in cave work for the Conservancy for the past 16 years, was born in north-central Pennsylvania and moved to Todd County, Ky., when he was 13. He majored in natural resource management and minored in biology at Murray State University.
As for what passion came first for him, he said, “Caves came first and bats were a quick second. I started with cave invertebrates, doing inventories and trying to understand what was alive in our caves in Tennessee. The majority of the biological diversity was invertebrates, spiders and insects. I got pretty enthusiastic about bats.”
He and his family make their home near Gainesboro in Jackson County. They chose the area for two reasons — It is centrally located to Tennessee’s cave region and the population is dwindling.
“I found that appealing,” he said. “The development is a little bit limited here due to the topography.”
Returning to the topic of humans helping bats, Holliday said that the Tennessee Nature Conservancy is part of a global network attempting to lessen the impact of white-nose syndrome. While they do not have a lot of tools, he noted that “people can let bats rest in the wintertime. The less disturbed they are, the better.”
Among other projects the Conservancy has teamed with Bat Conservation International in Operation: Fat Bats, which involves placing specialized lights near more significant bat caves.
“The lights are to attract insects so bats will have a buffet and eat more insects using less energy to enable them to put on more fat on the early end of hibernation, which equips them to get through the winter without this disease,” he said.
Closer to home, he is hoping to gain more knowledge about the migration of gray bats.
“What’s unique about them is that they spend 75 percent of their lives in caves and almost never go out. In summertime they come out at night to feed and forage, and they fly long distances, up to 300 miles between summer and winter cave sites, and we don’t know much about that.”
To that end, Holliday has been placing antennas at high-elevation sites across Middle Tennessee in recent months including one in Wilson County.
“We put one on the Jennings Knob fire tower six to eight weeks ago. It consists of four antennas and a 12-inch-square UHF radio receiver that gets signals from anything with a frequency. We’ll be putting transmitters on bats and trying to build a network of receiver stations all the way from South America to Canada and hopefully get a much better idea of where these flying animals are moving around and when,” he said.
While the future of bats in the Volunteer State may look a bit dismal at the moment, “Batman” Holliday remains optimistic, saying, “I have been delighted that gray bats have not been largely impacted by white-nose syndrome. We have over around a million-and-a-half of these bats in Tennessee that we can see and count, and the thought of losing that many animals in a short period of time in our landscape would really be devastating.
“I’m really glad they are not impacted and seem to be doing really well. On top of that, technology is coming a long way, so scientists and researchers can better understand these small animals.”
NATURE CONSERVANCY IN TENNESSEE
Since 1978, the Nature Conservancy has helped to create or expand 30 state natural areas, 13 wildlife management areas and three national wildlife refuges in Tennessee in addition to establishing its own system of nature preserves. The Conservancy’s four priorities are protecting land and water, tackling climate change, providing food and water sustainably and building healthy cities. For information, go to: facebook.com/natureconservancytennessee/