Why are thousands of bats dying in New York?

Nor are there any known links between what is wiping out the bees and what is killing the bats. The cause of the bee deaths is still a mystery, though scientists are looking at pesticides, parasites and a virus not previously seen in the U.S.

Researchers said there is no evidence the mysterious killer is any threat to humans. Scientists venturing into the caves wear hazardous-materials suits and breathing masks primarily to protect the bats, not themselves.

Hicks said it is possible that a cave explorer introduced the problem in the Albany-area caves and that it spread from there. "It could have been some caver in Tanzania with a little mud on his boot and a week later he's in a cave in New York," he said.

New York officials are asking people to stay out of bat caves in case humans are unwittingly spreading the problem. The U.S. Fish and Wildlife Service is asking people not to enter caves with gear or clothing used in any New York and Vermont cave within the past two years.

The first inkling of trouble came in January 2007, when a cave explorer spotted an unusual number of bat carcasses around the mouth of a cave in the hills west of Albany. Within a month, people in the area were calling in with reports of bats flying outside in the middle of the day.

"We didn't know anything other than bats were coming out and they were just dying on the landscape," Hicks said. "They were crashing into snow banks, crawling into wood piles and dying."

By winter's end, 8,000 to 11,000 bats were presumed dead in the four caves. The mystery affliction has spread much farther this winter.

Death counts are not in yet for this winter since afflicted bats die slowly. But Hicks said there are 200,000 or more bats hibernating in caves where white nose has been detected.

Hicks recently led a team of scientists into an abandoned mine in this Hudson Valley town about 80 miles north of New York City. He directed his headlamp on a cluster of seven brown bats, smaller than mice, hanging high on the limestone wall. Four had the telltale white flecks on their muzzles.

He tapped one of the afflicted bats with a long stick, and it fell, already dead. Another groggily spread its papery wings on Hicks' gloved hand. The sickly bat was put into a cardboard takeout-soup container to be put to death and studied, since it was doomed anyway.

A group of Indiana bats, a federally protected endangered species, was spotted hanging lower down in the mine for cooler air, a common strategy for sick bats.

Hicks whispered grimly: "These guys are toast."

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