Bat Disease Spreads Into Wisconsin

A bat disease that has raced across the eastern U.S. and Canada, killing upwards of seven million bats, is following the same pattern in Wisconsin, winter hibernacula surveys show. Twenty-four of 28 counties (including Door County) with known bat hibernacula are now confirmed to have bats infected with white-nose syndrome or the fungus that causes it, and sites in their second and third year of infection are seeing population decreases of 30 to 100 percent.

“The disease has progressed in Wisconsin as it did out east,” says Owen Boyle, species management section chief for the Department of Natural Resources Natural Heritage Conservation program. “That doesn’t make the numbers any easier to see. The effect of white-nose syndrome on our cave bats in Wisconsin, as nationally, is catastrophic.”

Bat populations are important to agriculture and ecosystems. A single bat can consume thousands of insects each night, and researchers have estimated that bats save Wisconsin farmers alone $600 million to $1.5 billion on pesticides every year. Studies are underway at the University of Wisconsin-Madison and elsewhere to understand such impacts. People can help surviving bats by building and installing bat houses; avoiding disturbing bat roosts between June 1 and Aug. 15 when bats raise their young; and helping to monitor bat populations. Most importantly, people can report the buildings where bats are present in the summer as well as sites where bats are no longer showing up. Bats continuing to return to summer roosts are likely survivors of WNS. Email location information to [email protected].