White-nose syndrome has been decimating bat populations.

Here’s what we can do

Posted 7/15/20

If you’ve spent a lot of summers here, you remember the bats.

They skimmed through the night, swooping by people out for a walk and gobbling up mosquitoes. Or they lived in our houses and …

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White-nose syndrome has been decimating bat populations.

Here’s what we can do


If you’ve spent a lot of summers here, you remember the bats.

They skimmed through the night, swooping by people out for a walk and gobbling up mosquitoes. Or they lived in our houses and surprised us with evening visits. Summers recently have been quiet. Where did the bats go?

The question drew a lot of replies on a local forum recently, with people sharing their love of bats, their personal counts of bats they’ve seen and more.

People obviously care. So we reached out to Dr. Merlin Tuttle, ecologist, conservationist and bat photographer, who has studied bats for more than 60 years, and asked what happened.

“Your bats have declined,” he agreed, on the phone from Texas. “The little brown bat was the most significant. But the good news is that they’re beginning to recover.”

What is killing millions of bats is white-nose syndrome, caused by the fungus Pseudogymnoascus destructans that has devastated some bat species by 90 percent or more, Dr. Tuttle said. He calls it “the most serious wildlife disease epidemic in American history.”

This matters. Bats are a vitally important part of the ecosystem (see why bats matter below).

The disease is called white-nose because of “the visible white fungal growth on infected bats’ muzzles and wings,” according to the National Park Service. It was identified in North America in the mid-2000s and has spread rapidly, sometimes by humans and sometimes by bats.

In New York, the Department of Environmental Conservation is supporting research efforts aimed at understanding the white-nose syndrome disease and efforts to develop a management strategy. But at the moment, they say, the best hope is that the bats will adapt to the disease.

Example: A colony in New York state had 1,200 bats. Then white-nose arrived. “The population dropped to less than 100. But it’s starting to show recovery,” Tuttle said.

In Pennsylvania, he wrote on his site,, you can find “innovative attempts to improve hibernation roosting opportunities. Initial results from modifications designed to lower and stabilize temperatures have been encouraging.”

That’s important because white-nose kills bats by disrupting their hibernation. Infected bats wake up more often. Bat body temperatures average about 40 degrees during hibernation, but when awakened those temps climb to 100 degrees, Dr. Tuttle said. And “some bats hibernate more than six months out of the year.”

 Bats store up fat to use during hibernation, and if they use up the reserves on waking up, they can starve to death before hibernation is done (

He stresses that not all bat species are susceptible; there are only a few in our area, but that includes the little brown bats (yes, that’s their name; in Latin, it’s Myotis lucifugus), who have been hit hard. Slowly, and with work by bat specialists, they’re starting to recover.

Other states might be a different story, and federal protection of some bat species is being considered.

A major part of the problem, which goes back decades, Dr. Tuttle said, is that key places for hibernation (like caves) have become unavailable to bats, “forcing millions of them into less optimal sites.” Caves get used for commercial purposes—at first, food storage, and later tourism or recreation—and that destroys the delicate balance of temperature and humidity that bats need. “Once they lost the key sites... they expended more energy on hibernation.”

Another concern is that when people saw what was wrong, they rushed in to help, and—despite the best of intentions—made matters worse, Dr. Tuttle said. Humans can carry the fungus out on their clothing or gear, or bats can pick it up from cave walls. And then they track it into other caves.

But humans can help bats recover.

First, the caves. “There are options even at commercial caves,” Dr. Tuttle said. “Bats can be protected and habitats can be restored.” He described a cave where visitors walk by bats, who have grown accustomed to the activity. “The bats have now become a key part of the experience.” It’s a chance for people to see bats in real life.

Remember the Pennsylvania experiments in improved places for hibernation? Indian Caverns in Spruce Creek, PA, has closed permanently to create a haven for bats. Bats are seeking colder temperatures, says wildlife biologist Greg Turner, who, along with biologists Dr. Brent Sewall and Dr. Barrie Overton, plus researcher Marianne Gagnon, have created an environment in Indian Caverns cool enough to keep bats hibernating and thus keep them healthier. It’s the first project of its kind, and a scientific work in progress, but it gives bat-lovers hope. Second, there are ways you can help: spread knowledge and become a citizen scientist (see more information on the right).

“Bats can be protected,” Dr. Tuttle summed up, “and habitats can be restored.” Which means that humans have a chance to make things right.

For further knowledge: (PA-specific) (NY-specific)

Bats matter

Merlin Tuttle has dedicated his decades-long career to changing people’s minds about bats. We’ve generally stopped seeing them as airborne vampires; now, more and more people are seeing them as kind of cute. Granted, we need to stop blaming bats for every scary disease that comes around, but for all that progress (let’s get to possums next?) we can thank Tuttle and other bat scientists and researchers. Here are a few bat facts, just in case you haven’t been listening:

  • Bats can eat as much as a thousand mosquitoes an hour, ridding us of not just an evening nuisance but a major source of disease.
  • Bats are the world’s most effective long-distance pollinator.
  • In their job as pest control champions, bats are estimated to save farmers more than 22 billion dollars annually.
  • Bat poop is a natural fertilizer, but untouched piles of guano are also home to “entire ecosystems of life found nowhere else.”

Calling Citizen Scientists and bat enthusiasts

Do you care about bats? Merlin Tuttle has some suggestions.

First off, “Try to protect old mines,” he said. “That can be one of the most important things you can do.”

You can put up bat houses. Dr. Tuttle has current information about proper bat houses:

“Bat houses are a big help,” he said, adding that, if they’re well done, they can house thousands of bats. But don’t start with a whole development. “I recommend putting up one or two, and then expand.” And then share your knowledge! “It opens up opportunities to talk.”

You can even make a bat cave, though no one would say it is easy, or cheap—but it is interesting all the ways humans can help bats:

Become a citizen scientist. Contact the Appalachian Bat Count and help them monitor Pennsylvania’s summer bat colonies (

New York State has a program, too. The Department of Environmental Conservation runs a volunteer-based statewide monitoring project in the summertime. Volunteer opportunities at DEC can be found at

And for real bat fans, go beyond just counting bats and start identifying them. Ultrasonic song meters let you record bat sounds, and, with training, identify the bats you hear:

bats, northeast, new york, pennsylvania, white-nose syndrome


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