enlarge Courtesy New York Department of Environmental Conservation

Two little brown bats, a species common to Maine, show symptoms of white-nose syndrome – rings of white fungus around the noses of hibernating bats.

Something is killing bats as they hibernate in parts of the Northeast, and biologists in Maine and other states are worried about what it could mean for natural systems that rely on the nocturnal predators.

Tens of thousands of bats have died in New York, Vermont and Massachusetts, apparently because of some mystery disease or change in the environment that has left them starving and dehydrated.

In some cases, bats have flown out of caves in the daylight before falling onto the snow and dying.

The phenomenon has been called white-nose syndrome because afflicted bats have rings of fungus around their noses.

"It's something new to science, and it seems to be spreading at an alarming rate," said Eric Hynes, staff naturalist for Maine Audubon. "It's pretty devastating (and) it's pretty scary."

The die-off has not yet shown up in Maine, although finding the evidence would be more difficult here than in other states.

While bats do hibernate in Maine, the state has no expansive bat caves, called hibernacula, where thousands of the flying mammals gather for the winter slumber, said Walter Jakubas, the top mammal scientist for the Maine Department of Inland Fisheries and Wildlife. Hibernating bats in Maine are more spread out, often sleeping in small caves or the crevices of rocks and trees.

"We're very concerned about it," Jakubas said.

"The disease is going to have a much better chance, we think, of spreading among the animals that are packed closely together."

But, Jakubas said, "we still don't have a good idea of what we're dealing with."

It's unknown whether the culprit is a disease that spreads from one animal to another or an environmental factor that is simply being discovered in more places as scientists look for it.

The Department of Inland Fisheries and Wildlife does not have a bat specialist because of budget cuts, but it will look for signs of the syndrome during wildlife habitat surveys this summer, Jakubas said.

David Yates, a research biologist and bat specialist with the BioDiversity Research Institute in Gorham, visited one of two known bat hibernacula in the Rumford area last month.

He found 110 bats in an old mine on the side of White Cap mountain, and all appeared healthy, Yates said.

But Yates, who studies bats throughout the Northeast, is worried by the rapid spread. "The biggest reason for concern right now is, we don't really know anything about it," he said.

Many of Maine's bats migrate out of the state for the winter and return in the spring, when there are insects to eat.

The syndrome is affecting several species of bats, including little brown and northern long-eared bats, two common varieties in Maine.

The big brown bat, another Maine resident, does not appear to be affected.

Federal, state and university biologists are studying dead bats in laboratories around the region but have no answers yet, said Diana Weaver, a spokeswoman for the U.S. Fish & Wildlife Service based in Boston.

Weaver said scientists who visit caves are finding thousands of dead bats, and other bats that are behaving abnormally and dying.

"We're still seeing bats flying around when they shouldn't be flying – in the daylight and in the cold weather," Weaver said.

A video posted on a U.S. Fish & Wildlife Service Web page shows afflicted bats flying in daylight around a Massachusetts neighborhood and falling on the snow.

Once a cause is found, figuring out what to do about the die-off may be a more difficult challenge, experts said.

The syndrome first showed up last winter in New York, but appears much more widespread this year.

"Last year, 9,000 to 10,000 died, and I think it's going to be in the hundreds of thousands this year," said John Whitaker, professor and director of the Center for North American Bat Research and Conservation...