Making a comeback: Researchers making progress in fighting deadly bat disease
Mollie Byrne recalls spending summers with her family at a camp on the Juniata River in Bedford County, in south central Pennsylvania.
In the evenings, visitors gathered near an old farmhouse to watch as thousands of bats emerged and flew into the night sky, providing a spectacular aerial show.
And then, around 2009, the bats disappeared.
“I was a kid at the time and I didn’t realize what was going on,” said Byrne, now 27 and a wildlife disease technician for the Pennsylvania Game Commission. “I wondered, where did they go? Then I found out white-nose syndrome was a thing and that it was wiping out bats. Mass mortality. It was really depressing news.”
White-nose syndrome is a fungus that hitchhiked from Europe to New York in 2007 and grows
on the bat’s noses, ears and wing membranes – causing a white fuzz – while colonies hibernate. It has decimated bat populations throughout the United States and began killing Pennsylvania cave bats around 2009.
The result: in Pennsylvania, a staggering 99% of all six species of hibernating bats in the state have died due to the disease.
“It was one of the biggest, most rapid declines in a species we will ever see. From a biological perspective, it happened sort of overnight,” Byrne said. “It’s shocking and incredibly sad.”
But some 18 years later, thanks to the efforts of national researchers – including the Pennsylvania Game Commission – there is a glimmer of hope in the battle to save bats.
Why should we care about bats?
Lots of reasons.
Bats, the only flying mammal, are insectivores – a single bat can eat as many as 1,000 insects in an hour – and provide free natural pest control, said Mike Scafini, an endangered mammals specialist with the Pennsylvania Game Commission.
By eating insects that can destroy crops, bats save farmers at least $3.7 billion in crop damage and pesticide costs annually, according to studies by the U.S. Geological Survey.
Bats also help reduce the population of disease-carrying mosquitoes and ticks, and other biting insects.
And that doesn’t take into account the critical importance of bats as plant and crop pollinators. They pollinate a variety of plants including peaches, cloves, bananas and agaves – a key ingredient in tequila.
Bats also help spread seeds for nuts, figs, and cacao, the main ingredient in chocolate.
These contributions that bats make to the U.S. economy aren’t known to many, other than those in communities of scientists, environmentalists, and bat enthusiasts.
There is no known cure for white-nose syndrome, but scientists and researchers throughout the country – including the Pennsylvania Game Commission – are working together to study the disease and determine how it can be controlled.
Scafini said the game commission, in collaboration with Pennsylvania universities and conservation agencies, is using two promising strategies to help the remaining bats in their fight for survival against the deadly fungus.
One method that has proven to be successful is spraying hibernacula – the shelters where bats hibernate – with PEG (polyethylene glycol), a petroleum-based, non-toxic compound found in products such as toothpaste and dandruff shampoo that coats the spores and keeps the fungus from growing.
That’s important because it means roosting bats don’t become infected as they hibernate. White-nose syndrome causes lesions on the bat’s body and causes them to awaken from winter hibernation early. That depletes a bat’s limited fat reserves, causing the bats to leave their hibernacula early in an attempt to forage for food that is not available. The bats often starve to death.
“We’ve been going to a few of our larger hibernacula sites and spraying with PEG in the fall before the bats return, and in the sites where we spray, we’re seeing a 70% to 80% reduction in white-nose in bats,” said Byrne.
Another tactic is to artificially cool the caves and hibernacula in order to stop the growth of the deadly fungus, which thrives in temperatures around 50 degrees. Researchers are structurally modifying the entrance to caves to improve airflow and reduce the temperature.
“We’ve done this at about half a dozen sites and had really good success, so we’re cautiously hopeful,” said Scafini.
Construction of the first artificial bat cave with temperature controls is underway in Southwestern Pennsylvania, although the game commission isn’t revealing the location.
Byrne and other technicians also are attaching transmitters to bats (tricky work, as some bats weigh as little as a couple of paperclips) to track them and find unknown colonies where the bats are roosting, so researchers can help them at those locations.
Their efforts are paying off, said Scafini, who is seeing signs of recovery.
For example, at a cave in Canoe Creek State Park in Blair County, the roosting population had plummeted from 32,000 to 72 bats. But these days, the population has climbed to 1,500 and is growing.
“We’ve seen increases at some sites, but it’s cautious optimism. “I’m hopeful as far as where we’re headed. We are doing some great stuff, a lot more proactive research and monitoring, and (the game commission) is leading the charge in a lot of these respects,” he said. “It gives me hope that what we’re doing is making a difference. Our more important colonies have gone up in numbers, but we don’t know how much of that’s consolidation, where survivors are finding each other, or if the population is increasing. They’re still infecting themselves in winter when they go back to their hibernacula, but not as badly.”
And bats – which have been around for 50 million years – are adapting, finding colder sites, with temperatures around 42 degrees or colder, to spend the winter.
“It’s kind of like seeing evolution in real-life, real-time,” said Byrne.
Still, bats are nowhere near out of the woods. Experts estimate it will take hundreds and hundreds of years for the bat population in Pennsylvania to recover to pre-white-nose syndrome numbers.
“Our goal is to get individual bats to survive and give them a chance,” said Byrne, but that’s not easy, she noted.
Bats reproduce slowly, typically producing one pup per year.
They face other challenges, too, Scavini said: habitat loss, climate change and wind turbines.
The Indiana bat, little brown bat, tri-colored bat, and the northern long-eared bat are listed as endangered and protected species, while the eastern small-footed bat is listed as threatened, according to the game commission.
“They’re getting hit with challenges from all directions,” Scafini said.
How can you help?
– First, learn about bats and help dispel myths about one of nature’s most misunderstood animals, said Byrne, dismayed that despite their plight and their contributions, bats are often feared or loathed. “We are a species of mammal, just like they are. We are co-existing. They deserve to be here just as much as we do,” she said. “Bats are really our friends. They have a bad reputation that is undeserved. They’re really curious. They’re not going to fly into your hair; they don’t suck blood.”
– Avoid places where bats hibernate; disturbing bats during hibernation can force them to use energy.
– Install a bat box to provide artificial roosting sites for bats, especially in urban areas or areas where natural roosting structures – such as trees – are limited. They provide a safe place for bats to raise their pups.
Over the past five years, CNX has installed about 15 bat houses in communities in the region, including North Strabane and South Strabane townships, Peters Township High School, Washington Park, Chartiers Township Park, Upper St. Clair parks, and St. Vincent College.
The boxes, about 12 feet high and in open areas that receive sunlight, have seven chambers and can hold about 200 bats.
“Given the fact that bats of Appalachia have been some of the hardest hit by white-nose syndrome, and several species are now listed as threatened or endangered, CNX has focused on educating the public on the importance of bats and the challenges they are facing,” said Daniel Bitz, CNX Director of Permitting. “Many local residents aren’t aware that a potential extinction event is happening in their backyards.”
– Remove unwanted bats humanely. If a bat accidentally flies into your home, remove it safely without harming the bat. If you contact a professional to help with bat removal, ask if they use humane methods.
– Participate in the game commission’s Appalachian bat count. Twice a year, the game commission holds a bat count to determine the population of bat colonies that roost in barns, abandoned houses, church steeples, and other locations.
Byrne, who feared when she started her career that the state’s bats would go extinct, said “there’s definitely reason for hope.
“For a long time it did feel like it was futile, like, oh, no, how are we going to come back from this? But we are seeing success. We are actually seeing all of these efforts coming to fruition in a way, and it’s incredibly rewarding,” said Byrne. “Bats are so important ecologically and economically. It’s cool to have a job where I’m physically seeing a species come back from the brink of extinction. It’s mind blowing. The work that we do matters, and it’s cool to be a part of it.”
Bat Facts
– There are over 1,400 species of bats worldwide. Bats can be found on nearly every part of the planet, except in extreme deserts and polar regions.
– Bats range in size from the Kitt’s hog-nosed bat, which weighs less than a penny, to the flying fox, which has a wingspan of up to six feet. The U.S. and Canada are home to 47 species of bats.
– Not all bats hibernate. Pennsylvania has three species of non-hibernating bats.
– Over 300 species of fruit, including bananas, avocados and mangoes, depend on bats for pollination.
– Bats are the only flying mammal. A bat’s wing resembles a modified human hand. The flexible skin membrane that extends between each long finger bone and movable joints make bats agile flyers.
– Most bats live less than 20 years in the wild, but scientists have documented six species that live more than 30 years.
– Like cats, bats clean themselves. Bats spend a lot of time grooming themselves.
– Baby bats are called pups. Like other mammals, mother bats feed their pups breastmilk, not insects. Most bats give birth to a single pup.
Source: U.S. Department of Interior