Something is killing whole populations of bats in the eastern U.S. as they hibernate in caves and mines. Bats are losing their fat reserves (which are needed to survive hibernation) long before the winter is over and dying of starvation.
The cause is unknown, but the affliction has been given the name “White Nose Syndrome” (WNS) because of the telltale white fungus growing on the noses of infected bats. This previously undescribed fungus, Pseudogymnoascus destructans, may also appear on a bat’s wings, ears, and tail. However, bats affected with WNS do not always have the fungus growing on their bodies, and may instead display abnormal behavior.
Scientists do not know if the fungus is the sole cause of the bat deaths, or if it is merely an opportunistic pathogen, taking advantage of immune systems weakened by another biological or chemical agent. The earliest evidence of WNS is in a 2006 photograph taken in Howe Caverns, New York, but the condition was not recognized until a year later. Since then, hundreds of thousands of bats have died.
Mortality rates of 70-100% have been documented in the first year in many hibernacula found to have WNS. In caves where fewer than 100% of the bats died the first year, populations continued to decline in successive years. Damage to wings and bodies persists in bats that survive a winter in WNS-affected populations.
Report unusual bat behavior or bats that appear diseased to your state wildlife agency. Unusual behaviors may include daytime flight, especially during very cold weather. Report dead or dying bats you find on the ground, trees, or buildings.
Text and photos courtesy of the NSS. White Nose Brochure
The Fish and Wildlife service has issued a list of decontamination procedures for cavers to follow. Find them here.