DORSET, Vt. - The entrance to the Aeolus cave in Dorset is littered with the bones of thousands of bats that have died since white nose syndrome first appeared in Vermont. Biologists are hoping research gathered from data collected over the winter there will help determine if more bats are surviving the disease.
Last fall, biologists glued radio tags to the backs of more than 400 bats and lined the cave with electronic equipment that monitors how many of the bats emerged in the winter - a sign of white nose infection and near-certain death - or how many waited until spring to wake up.
Vermont Fish and Wildlife bat biologist Alyssa Bennett and Antioch University New England graduate student Morgan Ingalls crawled into the cave Thursday to retrieve the data from the electronic equipment that has been recording the passage of the tagged bats through a constricted area near the cave's opening on the eastern slope of Mount Aeolus.
"In Vermont and New York and some of the places where white nose has been for a long time, this many years into it, we're not seeing as many visible signs of the fungus, the characteristic white nose, white powdery substance, which is the reproductive stage of the fungus," Bennett said.
There's no question the decline of what was once Vermont's most common bat species - the little brown bat - has slowed, but it's too soon to say the species is recovering, Bennett said. Even though there are bat maternal colonies in New York where the reproduction rate of little brown bats appears to be about the same as before white nose, it's not clear if the young bats are surviving at the same rate, she said.
"It's hopeful. I am hesitant to communicate to the public that bats are recovering because what I get back from the public is 'Oh, I read that bats are doing OK now,'" Bennett said. "I don't know if you can call it recovery if you don't know for sure that (the population) is going to go back up."
White nose, which has killed up to 99 percent of some species, is caused by a fungus that prompts bats to wake from their winter hibernation and die when they fly into the frigid, insect-less winter landscape. It was detected in New York's Adirondack Mountains in 2006 and has spread across North America, killing at least a million bats.
Ingalls said researchers also downloaded data in January and April and will have to analyze the numbers collected Thursday before drawing any conclusions.
"The number of lines of data, there's more today than the other two times combined," Ingalls said. "Between the beginning of April and now, it's warmed up and they've mostly emerged."