Bat Deaths Soar: Scientists Don't Know Why

A mysterious ailment called “White-nose syndrome” continues to decimate bat populations across the Northeast. A new outbreak has just been confirmed in New Hampshire. Scientists have begun collecting tissue from infected caves, creating a genetic record of bat colonies that could vanish completely. 

As part of a collaboration with Northeast stations, Brian Mann with North Country Public Radio reports:

Snow is falling on Vermont’s Aeolus Mountain as Scott Darling, a biologist with the state Fish and Wildlife Department loads a box of bio-hazard suits onto a snow machine.

White nose-syndrome doesn’t affect people, but he said bat caves these days can be nasty places.

“If it’s like last year, I’d rather not have my body on dead bats,” said Darling.

In 2007, scientists in neighboring New York first discovered thousands of dead and dying bats, their faces dusted with a white fungus. Many had left hibernation early, hungry, and searching for food.

Researchers still don't know if the fungus is a symptom or the primary cause of the die-off. But they’re convinced that this bat colony is one of the epicenters of the outbreak.

“I really don’t feel like I’ve seen anything like this before,” said Rose Paul of the Vermont Nature Conservancy, which owns Aeolus Cave. “It’s different. It’s so fast, and so drastic.”

Standing on a pair of snowshoes, Paul pointed to bats flitting through the frigid air, clinging to trees. 

“They shouldn’t be flying around in the middle of winter. That’s just a death knell for them.”

Listening closely, one can hear the flutter of black bat wings against the white snow.

Just a few years ago, before white nose hit, Aeolus cave was once home to thousands of bats - as many as 200,000 according to some estimates. In summer, diseased animals scattered to forage sites all across the Northeast - possibly spreading this ailment as far away as Cape Cod. 

“We have big respirators with us if you really feel somewhat nauseous down there,” said Darling as he picked his way down into the cave mouth.

There’s a sour, sickening smell. Carcasses are piled everywhere, mounds of tiny decaying bodies - carpets of bodies over the floor - even frozen into icicles.  

“This is just far more than I expected, it’s way more, so many more dead bats than there were last year,” said Darling, clearly shaken, as he folded dead bats into a plastic bag. He whispered to avoid disturbing the animals that were still alive, “and we still have another month and a half to go.”

Another month before spring, when surviving bats can escape the cold. 

This fall, researchers identified the white fungus that gives this disease its name - a major breakthrough.  But they’re still not sure how it’s spreading or how it’s killing these animals. Part of the effort now has shifted to collecting tissue samples - not to find a cure but to create a record of vanishing colonies.

“We can look at these collections as documenting what used to be and what simply isn’t there anymore,” said Nancy Simmons of the American Museum of Natural History, who created a new archive where these specimens will be shipped.

In some colonies, 80 to 90 percent of the bats are already dead. The disease appeared for the first time this winter in New Hampshire and also as far away as West Virginia, considered vital habitat for bats.

New caves are being identified so fast that researchers are struggling to keep track of all the infected sites.

Suzi Von Oettingen is a biologist with the US Fish and Wildlife Service.  
 
“Not only are we getting new maps every week - but two weeks ago we got three maps in one day,” she said.  “We do have ideas - we have pie in the sky ideas.  Is there an organic fungicide that we could apply to small sites? I mean, we are trying to be creative.”

She said scientists have begun talking about possible remedies - but only out of desperation.

“You know, if we have the ability to run small experiments right away that are totally hare-brained, I say go for it.  Because we just can’t run out of time.”

But the clock is ticking. Scientists hate flying blind like this. But with so many dead animals, and so many places, they say they have no choice.