ALBANY COUNTY — Bats, which usually hibernate in the cold, or migrate South, have been spotted flying around the region this winter.

They have been seen dead on front lawns and huddled on window sills. This week they were found dead on the floor of Haile’s Cave in Thacher Park, where many of them hibernate for the winter.

The Department of Environmental Conservation is beginning to study why. In March, the DEC conducted a survey of the bats in Haile’s Cave, which it does every two years. Nancy Heaslip, a senior wildlife biologist at the DEC, was there for the survey on March 14 and again on Tuesday to count the bats in the back compartment of the cave, which had not been accessible in March.

Haile’s Cave once housed almost 27,000 bats over the winter, said Heaslip. Roughly 7,000 were counted this year. She couldn’t speculate about why the numbers were low, but she said that there had been a flood in the mid-1990’s that wiped out a large part of the bat population.

Alan Hicks, a wildlife biologist with the DEC, said that he had expected about 15,000 bats to be counted in this year’s survey. Both Heaslip and Hicks said that it is unusual to find dead bats in the cave.
"Something odd is going on," said Hicks. "The dead bats in the cave are only a fraction of the bats that died."

The most striking discovery made during this year’s survey, said Heaslip, was that her group found no Indiana bats, which are an endangered species that is usually found in the cave. Most of the bats found were little brown bats, she said.

Many of the bats that hibernate from October to April left their cave during the warm weather early this winter, said Hicks. Their fat supply was likely used too early and they were in search of food, Hicks said. He added that the strange temperatures this year might have confused them.

State wildlife pathologist, Ward Stone, said that he had examined a number of dead bats this winter. He, too, said that the likely causes for the bat deaths this year were the weather and depletion of the bats’ fat supplies. It’s not just in Albany County, either, he said.
Stone has heard similar reports of deaths in Saratoga County, Columbia County, and Rensselaer County. "I believe it’s related to the very unusual weather we’ve had," he said. "Global warming may well be part of the problem."
"Somehow, they ran out of gas," Stone said of the bats running out of energy. When the bats used up their energy stores, they came out looking for food and got caught in the cold.

That’s just a theory, Stone said; this is a problem that needs a lot more research. Hicks is looking for any information on bat behavior that people might have noticed this year; he can be reached at 402-8854.
"What we’re trying to do is just document what happened here," Hicks said. "We’re just trying to piece it together."