Irving College was home to some very small and endangered creatures recently. A spring migration study of the Indiana Bat took place at Hubbard’s Cave.
“This was our first year to be at the cave in Irving College,” said Chris Simpson, Tennessee Wildlife Resources Agency, Region 3 wildlife diversity coordinator. “We are tracking the Indiana Bat. We had good results. We weren’t sure if the bats would be reachable at the time when we went in but they were. We were able to get several out, apply transmitters and we were able to track them.”
Team members typically track the bats with airplanes, trucks and hand-held antennas. The effort caught the attention of local residents who made calls to the Southern Standard curious as to what is going on in their area.
Hubbard’s Cave is a 50-acre natural area located in the Irving College area of Warren County. It is owned by the Tennessee Chapter of The Nature Conservancy. Hubbard’s Cave is ecologically significant because it serves as a hibernaculum, a place for the creatures to seek refuge, for two federally endangered bat species, the gray bat (Myotis grisescens) and the Indiana bat (Myotis sodalis). The cave is known to be the largest gray bat hibernaculum in Tennessee with over 100,000 bats. Many other bat species use this cave as well.
While caves used as hibernaculum by bats are widely known by biologists, the trees female bats use for maternity colonies to raise their young is not. Simpson says tracking the bats is important for that reason.
“Indiana Bats are the most endangered mammals in Tennessee,” said Simpson. “Biologists know where a lot of their winter hibernaculum are but they don’t know a lot about where females raise their pups. They hibernate in caves in the winter and raise their pups in trees in the summer. The maternity tree, usually dead snags, are what we are using telemetry tracking to find.”
Indiana Bats are about the length of a business card and weigh about the same as a quarter. Despite their small size, the bats play a large role in the ecosystem and the control of night flying insects. Until tracking began, little was known about spring migratory habits.
The decline in the bat’s population was noticed in the 1960s and it was eventually placed on the endangered species list. Conservation measures were making an improvement until 2006 when some bats tested positive for White Nose Syndrome, a fungus that infects the epidermis layer of bats. The disease causes them to wake up during hibernation, depleting their fat reserves and they cannot make it through the winter. Basically, they starve to death.
Biologists hope to use the spring migration information gained through studies like the one done in Irving College to help understand how White Nose Syndrome is being transmitted and it’s move from cave to cave through bat-to-bat contact.
Access to Hubbard’s Cave was allowed during a few months of the year until a bat from Dunbar Cave State Natural Area tested positive for White Nose Syndrome. Hubbard’s Cave was closed indefinitely in an effort to take every necessary precaution to isolate the fungus as much as possible in order to protect bat populations.
A female bat affixed with a transmitter in Irving College is currently migrating west and is being followed by a tracking team, says Simpson.
“She has been held up in Marshal County for several days due to the rainy weather and low temperatures. The ground tracking crews are still waiting and hanging around there to see if we get good weather and if she will migrate any further west,” he said.
For more information about bats, visit www.tnbwg.org, which is the Tennessee Bat Working Group’s website.