Department of Fish and Wildlife
Kentucky Afield Outdoors:Winter cave surveys track bat population, health
Winter surveys to assess bat populations and monitor the spread of white-nose syndrome are underway in Kentucky and will continue for the next several weeks.
“This is a busy time of the year,” said Brooke Hines, bat ecologist with the Kentucky Department of Fish and Wildlife Resources. “Our goal is to get close to 100 caves done. If it’s as cold as it’s been, we will be able to do some counts into April.”
There are thousands of caves in Kentucky and roughly half of the 15 species of bats found in the state find them hospitable for hibernating.
The hibernation period ranges from late November through March, when bats are most susceptible to becoming infected with the fungus that causes white-nose syndrome.
“If we have a cave that we know has maybe 50 or more total bats in it we try to do a count to determine the status of the species and to also determine if it’s white-nose positive,” Hines said. “The only way we can do it right now is just to see it actively growing. Researchers believe that when you start to see visible infection it’s probably been in the cave at least the winter before or was introduced to that cave at the beginning of that winter.”
Named for the white fungus that develops on the muzzles, ears, wings and tails of affected bats, white-nose syndrome has been linked to the deaths of millions of bats of varying species. The fungus has spread to 23 states and five Canadian provinces since it was first discovered in New York in 2007, according to the U.S. Fish and Wildlife Service.
Kentucky joined the list in 2011 after a little brown bat from a cave in Trigg County tested positive. To date, white-nose syndrome has been detected at more than 30 sites in 16 counties across the state, Hines said. New sites have been found this year in counties already documented to have white-nose syndrome, she said.
“We have disease issues in other species groups,” said Sunni Carr, Wildlife Diversity Branch manager with Kentucky Fish and Wildlife. “But in my career this is biologically the most devastating and significant thing that we’re going to work on. No doubt about it.”
Kentucky was the first state to develop a response plan for white-nose syndrome, and did so before its arrival.
Kentucky Fish and Wildlife works closely with U.S. Fish and Wildlife and other agencies on local surveillance and monitoring. Local caving clubs assist by notifying the agencies of potentially infected sites and providing their expertise.
“As soon as we found out it was significant, we have been on board on both a regional and national level,” Carr said. “We are supporting research within the state. A lot of the folks that have the capacity to do the high-tech research don’t have the field resource. They’ll call us and say, ‘We’re interested in being able to swab this cave or get these samples or take these hair samples or blood samples from these animals. Can you help us get the materials so that we can do the work?’ That’s where we come in. We can help them facilitate their projects.”
The fungus takes hold during hibernation and can linger on cave walls and sediment.
A bat suppresses its immune system while in winter torpor, and the fungus thrives until the extreme irritation rouses it to groom. Affected bats may then move closer to the cave entrance in an attempt to cool their body temperatures and induce torpor again, Hines said.
“When they start rousing more, they start burning through more fat reserves,” she said. “Then, they start arousing in January or February instead of March and April. They come out into the landscape and they’re either dying of exposure or starvation.”
White-nose syndrome presents no threat to people, pets or livestock but a bat die-off could have a significant and noticeable impact.
Bats play a unique role ecologically. They can eat their weight of insects in a single night and also pollinate plants. Their loss would be felt by farmers and consumers alike, Hines said.
Three federally-endangered bat species call Kentucky home: the Indiana, gray and Virginia big-eared. The little brown, northern long-ear and tri-colored bats could be listed in the next few years, Hines said.
Virginia big-eared and gray bats have shown resistance to white-nose syndrome in studies, Hines said.
“They’re starting to look at what makes those bats so much different,” she said. “Is it just because those bats are bigger or is there something on their skin that doesn’t allow this fungus to become as irritable to them as others?”
Bat movement is considered the leading cause of the spread of white-nose syndrome, but there is evidence to suggest people may be contributing by accidentally spreading the fungal spores. U.S. Fish and Wildlife advises avoiding contact with potentially affected sites, equipment or bats and cleaning and disinfecting caving gear. More information about decontamination protocols and white-nose syndrome can be found online at www.whitenosesyndrome.org.
“Once something blips off the radar, this is not Jurassic Park, you can’t get it back,” Carr said. “When you’re in biology, we’re the last group to give up hope. We’ve got to figure something out.”