Biology professor, bat expert quoted in USA Today story on epidemic affecting bats...
Jul 7, 2008
Northeast bat population is in its own hell
By DAN VERGANO
July 7, 2008
The deaths started in a few caves, with hibernating bats dying in place and falling in charnel heaps to the floor. Others, emaciated and starving, fled their roosts to freeze in the chill of winter.Deepening the mystery: The dead and dying bats had a white fungus on their faces, giving the name "white-nose syndrome" to a plague killing thousands of bats in five Northeastern states.
"Our guys went in and reported thousands of dead bats," says Alan Hicks of the New York State Department of Environmental Conservation. "Immediately it was clear this was very bad."
Perhaps 11,000 bats eventually died in four nearby caves in 2007; tens of thousands died this past winter in five states, and the deaths continue.
The true death toll could be even higher, says biologist Susi von Oettingen of the U.S. Fish & Wildlife Service office in Concord N.H., because more bats may have died in uncharted cave roosts.
The die-off triggered a nationwide call last year to find an answer to what was killing the bats. But so far the syndrome remains a riddle. The only clue to its origin Hicks and his colleagues possess is a photo taken by a curious cave explorer of a single afflicted bat inside a cave west of Albany in 2006.
Conservation officials have asked cave explorers to report signs of afflicted bats, but have also asked them not to travel from affected caves to cleared ones, to prevent the transmission of disease.
All six species of cave-hibernating bats in the Northeast — Eastern pipistrelle, little brown, northern long-eared, small-footed, Indiana and big brown bats — have been killed by the syndrome. All are nocturnal insect-eating mammals that hibernate during winter months in caves and mines, burning body fat slowly to stay just barely warmer than cave temperatures and waking only occasionally.
Yet, says Scott Darling of the Vermont Department of Fish & Wildlife, "during the daytime in March and April, residents would see them flopping around on the ground."
During hibernation, the bats have a lowered immune response, perhaps making them more vulnerable to some new, cold-tolerant germs, says biologist Jacques Veilleux of Franklin Pierce University in Rindge, N.H. The species that cluster most tightly together, little brown bats and endangered Indiana bats, are the ones most heavily affected, with 90% dying in some caves.
But necropsies of dead bats have not narrowed the fungus down to any one species, or signs of any particular disease common to them all, Veilleux says.
At a white-nose syndrome meeting in Albany last month, government, academic and non-profit researchers discussed potential causes, including a fungus-related disease, a new parasite or environmental disturbances from farming or development.
Fungal growth is usually retarded at the temperature inside winter caves, about 40 degrees, says biologist David Blehert of the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis., but the white fungus afflicting the bats may be able to thrive at the low temperature and prey on the hibernating bats when they are vulnerable.
On the other hand, the fungus simply may be an opportunistic infection that strikes bats weakened by some other cause. Parasites — fleas, mites and lice — have been found on affected bats, but not any more than usual.
|"The questions we are trying to answer are the same ones we'd face in a human epidemic," Veilleux says. "We are right smack in the beginning of the investigation."
One question is whether migrating tree bats, which come north during the summer, are affected. Researchers are collecting bats killed by wind turbines to look for white fungus, Hicks says.
The public feel sympathy
For creatures with as bad an image as bats, the public response to their disappearance has been heartening, Darling says. "I've gotten a lot of calls from residents worried about their bats."
|Girl Scout groups have even sewn up collecting bags for some bat researchers, Veilleux says.
Some surveys of summer bat colonies are underway, but the big effort will come this fall, Hicks says, when researchers will try to determine whether bats are arriving in caves already emaciated, or if something is rousting them during the time they should be hibernating, causing the burn-off of fat stores.
"The trend is just really bad," he says. "You go to a cave where you saw thousands of bats, now you see hundreds. If you see only a handful next year, then you are looking at their disappearance."