Published: July 19, 2008 09:55 am            

Researchers urgently probe mystery of dying bats

WEST SAND LAKE, N.Y. — As the sun drops, bats that survived a catastrophic winter begin to flutter by the treetops to feed. Al Hicks gets into a car to count them.

He drives a jury-rigged batmobile, a state-issue SUV with a high-frequency microphone stuck on top. Hicks, a state wildlife biologist, uses it to tally a species in danger of decimation from a mysterious affliction called white-nose syndrome. The setup detects and records bats' sonar signals as they swoop over rural roads near Albany in search of insects. Hicks interprets the sounds from his laptop's speaker as he navigates the darkened curves.

"Did you hear that? 'Zzzzzzzzzzzzz!' That's the feeding buzz. He's closing in on prey," Hicks says. Then the mike picks up another bat. "That's a searching phase, 'Dit, it, dit dit.' He's looking for dinner."

Northeast bat populations were ravaged this year as they hibernated, and Hicks is part of an alliance of scientists urgently trying to get a grip on the disaster before next winter. Researchers are watching the skies, counting bat breaths and cultivating fungus as they try to understand why so many seem to starve as they sleep for the winter.

"We need to figure out what it is. Then we can figure out what to do," said Cal Butchkoski, a wildlife biologist with the Pennsylvania Game Commission.

White nose is named for the sugary smudge of fungus around the nose of some of the emaciated bats. It was noticed two winters ago in a cluster of caves west of Albany. By last year, it spread to dozens of caves within a roughly 150-mile radius that stretched into Vermont, Massachusetts and Connecticut. Mortality rates differ among the half-dozen affected species, though some caves were all but wiped out. Death tolls cannot be pinpointed, but Bat Conservation International said it could run in the hundreds of thousands.

Some residents around the cluster of caves west of Albany where white nose was first noticed say the summer skies there seem practically bat-free.

White nose seemed to spread out in a circle from cave to carcass-littered cave like a pathogen. The fungus could be the cause, but it also might be an "opportunistic" fungus that shows up when bats are already weakened. Bats might be heading into hibernation with not enough fat, which could be related to fewer moths and other insects around for bats to gorge on in the fall. That means insecticides or climate change could be playing an indirect role.

"There's a cascade effect that might be operating here, though we don't really have a good handle on it," said Thomas Kunz, director of the Center for Ecology and Conservation at Boston University. "This caught us all by surprise."

Bat researchers met for a white-nose summit in Albany this summer to come up with unified plan. One thing they want to know is if the dead bats were underweight when they start to hibernate. So bats will be caught this fall and their fat stores will be analyzed. Researchers have already caught bats in New York this summer and placed them in airtight chambers as a way of testing their metabolism. Microbiologist David Blehert of the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis., said progress is being made on identifying the fungus, a crucial step to fighting white nose.

In upstate New York, Hicks and two other New York Department of Environmental Conservation researchers spend some nights driving loops around rural roads. It's a clever way to count an airborne species that comes out in the dark.

A rough-carpentered wood box holds the mike upright as Hicks drives at 17 to 20 miles per hour — or just slightly faster than a bat can fly. As cars constantly pass him by, Hicks picks up the sonic signatures of dozens of bats over several hours. Bat screeches are represented on the laptop screen as little blue streaks on a graph. Hicks can tell which species is overhead by looking at the graph. Quiet stretches are punctuated by quite a few big brown bats and an occasional surprise.

"Holy cow!" Hicks says, glancing at the screen. "We might have had a silver-haired bat!"

By driving predetermined routes at the same time of night, Hicks and his colleagues are building baseline population estimates. Find an average of six big brown bats over a particular stretch of road this year and two the next year, it could indicate a population drop.

As they collect data, Hicks and the other researchers around the country are constantly in touch. In Wisconsin, Blehert said white-nose researchers have been making "good progress." But even if researchers key in on a culprit this summer, signs point to another rough winter. Identifying the cause of the problem does not mean they can stop it.

Butchkoski in Pennsylvania said he expects white nose to spread to his state this winter. Hicks does too. On a recent night patrol, Hicks waves off a suggestion that the worst is over for bats. He begins listing other dead and devastated species — the passenger pigeon, the American chestnut — as he drives down a dark road, listening for signs of life.



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On the Net:



http://www.fws.gov/northeast/white_nose.html



http://www.batcon.org/



Copyright 2008 The Associated Press.

        

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