Bats Perish, and No One Knows Why
It was broad daylight in the middle of winter, and bats flew out of the mine about one a minute. Some had fallen to the ground where they flailed around on the snow like tiny wind-broken umbrellas, using the thumbs at the top joint of their wings to gain their balance.
All would be dead by nightfall. Mr. Hicks, a mammal specialist with the state’s Environmental Conservation Department, said: “Bats don’t fly in the daytime, and bats don’t fly in the winter. Every bat you see out here is a ‘dead bat flying,’ so to speak.”
In what is one of the worst calamities to hit bat populations in the United States, on average 90 percent of the hibernating bats in four caves and mines in New York have died since last winter.
Wildlife biologists fear a significant die-off in about 15 caves and mines in New York, as well as at sites in Massachusetts and Vermont. Whatever is killing the bats leaves them unusually thin and, in some cases, dotted with a white fungus. Bat experts fear that what they call White Nose Syndrome may spell doom for several species that keep insect pests under control.
Researchers have yet to determine whether the bats are being killed by a virus, bacteria, toxin, environmental hazard, metabolic disorder or fungus. Some have been found with pneumonia, but that and the fungus are believed to be secondary symptoms.Merlin Tuttle, the president of Bat Conservation International, an education and research group in Austin, Tex., said: “So far as we can tell at this point, this may be the most serious threat to North American bats we’ve experienced in recorded history. “
This month, Mr. Hicks took a team from the Environmental Conservation Department into the hibernaculum that has sheltered 200,000 bats in past years, mostly little brown bats (Myotis lucifugus) and federally endangered Indiana bats (Myotis sodalis), with the world’s second largest concentration of small-footed bats (Myotis leibii).
In a dank galley of the mine, Mr. Hicks asked everyone to count how many out of 100 bats had white noses. About half the bats in one galley did. They would be dead by April, he said.
In January 2007, a cave explorer reported an unusual number of bats flying near the entrance of a cavern near Albany. In March and April, thousands of dead bats were found in three other mines and caves. In one case, half the dead or living bats had the fungus.
One cave had 15,584 bats in 2005, 6,735 in 2007 and an estimated 1,500 this winter. Another went from 1,329 bats in 2006 to 38 this winter. Some biologists fear that 250,000 bats could die this year.
Since September, when hibernation began, dead or dying bats have been found at 15 sites in New York. Most of them had been visited by people who had been at the original four sites last winter, leading researchers to suspect that humans could transmit the problem.
In Vermont, Scott Darling, a wildlife biologist with the Fish and Wildlife Department, said: “The last tally that I have is approximately 20 sites in New York, 4 in Vermont and 2 in Massachusetts. We only have estimates of the numbers of bats in the affected sites — more or less 500,000. It is impossible for us to count the dead bats, as many have flown away from the caves and died — we have over 90 reports from citizens across Vermont — as well as many are still dying.”
People are not believed to be susceptible to the affliction. But New Jersey, New York and Vermont have advised everyone to stay out of all caverns that might have bats. Visitors to affected caves and mines are asked to decontaminate all clothing, boots, ropes and other gear, as well as the car trunks that transport them.
It’s very scary and a little overwhelming from a biologist’s perspective,” Ms. von Oettingen said. “If we can’t contain it, we’re going to see extinctions of listed species, and some of species that are not even listed.”
Biologists are concerned that if the bats are being killed by something contagious either in the caves or elsewhere, it could spread rapidly, because bats can migrate hundreds of miles in any direction to their summer homes, known as maternity roosts. At those sites, females usually give birth to one pup a year, an added challenge for dropping populations.
Nursing females can eat up to half their weight in insects a day, Mr. Hicks said.
Other researchers want to know whether recently introduced pesticides, including those released to stop West Nile virus, may be contributing to the problem, either through a toxin or by greatly reducing the bat’s food source.
The die-offs are big enough that they may have economic effects. A study of Brazilian free-tailed bats in southwestern Texas found that their presence saved cotton farmers a sixth to an eighth of the cash value of their crops by consuming insect pests.source
My comment:Weird, huh? Reminds you of the movie "The happening"? I know it's not on air yet, but the story goes in similar lines. Anyway, I think that any massive die-off of living things should be investigated thoroughly. We simply have to know what's going on. Because we could be the next.