After receiving reports in February from Vermont and New York about large numbers of bats dying in caves, biologists from MassWildlife and the U.S. Fish and Wildlife Service investigated caves and mines in western Massachusetts where colonies of bats are known to spend the winter. Biologists observed bats flying around outside of the state's larges mine when they should have all been inside hibernating, and found dead bats near the entrance of the hibernacula (winter quarters) which were collected for further study. Biologists confirmed that these bats, like the ones in Vermont and New York, were affected with white nose syndrome (WNS), a term used to describe some of the bats found at these sites that look like their faces were dipped in powdered sugar. This white material is a fungus that is growing on the faces of up to 10% of the bats at the affected sites. Up to 97% of the bats at some affected sites in New York have died.