Northern long-eared bat

Endangered Bat Makes Reappearance During TVA Cave Survey

A return to pandemic-paused field work led a group of TVA terrestrial zoologists to an unexpected discovery. While doing a cave survey near Norris Reservoir, the scientists observed a friend they hadn’t seen in years – a northern long-eared bat.

The northern long-eared bat is listed as a threatened species under the Endangered Species Act. Like many other bats native to the Tennessee Valley, the spread of white-nose syndrome has impacted northern long-eared bat populations. Since the fungus was discovered on the noses, ears and wings of bats in the Northeast in 2006, WNS has killed millions of bats in North America. The northern long-eared bat is one of the hardest hit species affected by WNS.

TVA monitors several bat populations across the Valley and noted the northern long-eared bat in three different TVA-managed caves in 2014.

“These bats are notoriously hard to find in caves. They’re tiny – they fit in the palm of your hand and hibernate in small crevices or cracks,” said TVA Terrestrial Zoologist Liz Hamrick.

According to statewide data collected by several contributing partners including TVA, the Tennessee Wildlife Resources Agency reports that populations of northern long-eared bats in Tennessee have dropped more than 98 percent since 2010.

TVA continues to monitor bat populations and collect swab samples for local and continental-wide researchers. A treatment for WNS has not been discovered, and TVA Terrestrial Zoologist Jesse Troxler has a caution for other cave explorers.

“Disturbing hibernating bats contributes to the decline of this species,” Troxler said. “Avoid trespassing in caves and, if you are authorized to explore a cave, take care to not disturb resting bats and disinfect your clothing and gear after each trip.”

As Hamrick and Troxler’s teams continue their cave surveys through the winter, they have reason to hope.

“Our data collection supports studies across North America, and we remain hopeful that enough bats are able to survive with white-nose syndrome in their environment that we will start to see increases in populations in the near future,” Hamrick said.