CSI: What's Killing the Bats?

Appropriately timed after last night's nightwalk at the Audubon Center at Francis Beidler Forest, today's Post and Courier carried an article by the AP's Michael Hill regarding the mysterious die-off of several bat species in the northeastern United States from what is being called White Nose Syndrome. The U. S. Fish and Wildlife Service has extensive information here.

Although our bat detector picked up the ultrasonic sounds of at least one bat hunting prey over Goodson Lake during our nightwalk, many bats hibernate in large groups during the winter. This congregating behavior aids in the transmission of whatever is killing the bats. Scientists are not sure if the fungus causing the white tufts around the bats' noses is the cause of their deaths or merely a symptom of a bacterial or viral infection that may be preventing the bats from properly grooming themselves or possibly a reaction to some environmental toxin. Until scientists can determine the cause of the illness, the problem is likely to get worse, since the bats hibernating together will disperse over hundreds of miles, possibly taking the cause of the illness with them, once the weather warms.

Why care about the fate of these flying mammals that sometimes carry rabies and give many folks the "creeps" simply thinking about them? Like the die-off of bees that pollinate many of the crops that we eat, the die-off of bats is a concern because bats eat many of the insect pests that attack the crops that we eat. A bat can eat half of its body weight (a nursing female 100% of her body weight) in insects per night! Multiply that by the many thousands of bats flying around in your area and a tremendous mass of insects disappear from your area of the planet each night.

The images by Paul Koehler of the Silver Bluff Audubon Center show Eastern Big-earred Bats roosting in an abandoned house on the property. These bats are endangered due to a loss of habitat as they prefer to roost in hollow trees. Few forests, unlike the old-growth forest at the Francis Beidler Forest, are allowed to age to the point where trees become hollow, so these bats have settled for the next best option.