Little brown bats almost gone, not forgotten

Photo
Greg Funka | Staff Photographer

A single bat dips and weaves over Chautauqua Lake.

It is a remarkable sight. The creature makes such tight turns that it seems ungoverned by inertia. It flies low over the water, leaving a thin wake behind it as it picks bugs out of the air, making tiny corrections in its flight path based on where its echolocation indicates there’s an insect. It may eat half of its body weight tonight.

The acrobatic feats themselves aren’t remarkable; it is, after all, what bats do. But this bat — remarkably — is alone.

Seeing one bat is like seeing one ant; it just seems wrong. Ten years ago it may have been 10 bats circling over the water, like a mobile with invisible strings. But that was before the arrival of Geomyces destructans laid waste to millions of little brown bats.

Geomyces destructans is a scary name for a scary mold. It thrives in cold temperatures and covers the surfaces of caves and mines that bats use as hibernaculum. As bats sleep through the cold winter, their heart rates and breathing rates slow to elephantine levels. The mold begins to cover the bats, just as it covers everything else. It grows on their wings and muzzles like a deadly frost, causing an ailment called white nose syndrome.

Sometimes there is a visible white dust on the nose and wings, but not always. Most of the bodies of the deceased are emaciated.

The bats have died at an alarming rate, and they won’t be making a dramatic comeback anytime soon.

Before WNS, the most common bat in New York skies was the little brown bat (Myotis lucifugus). The little brown bat population has been affected the most by the mold, reduced by at least 90 percent.

Researchers believe that the bats don’t die from the mold itself, but from the exhaustion that it causes. When animals hibernate, their metabolisms slow, allowing them to live on the calories they have stored up. Any disruption of their slumber causes their metabolisms to speed back up, burning through those precious calories before it’s warm enough for them to find more food. The mold seems to rouse the bats, burning valuable calories. Some bats are desperate enough to leave the caves to look for food, which is nowhere to be found in the sleeping world of winter.

* * *

“The spread and impact have been stunning in the rate they have happened.” —Carl Herzog

Carl Herzog is a biologist with the New York State Department of Environmental Conservation. The first signs of WNS, he said, were seen in 2006. Since then, it has only accelerated. Each year, the affected area grows in concentric circles, like a map in an old newsreel tracking the movements of a marching army.

WNS is now present in 17 states and in Canada.

It is believed that the mold originated in Europe or Asia and was brought here either by human beings or by a bat who carried the disease. (If it was a bat, it was a stowaway, as bats can’t fly across the Atlantic Ocean.) European bats have been unaffected by the mold, but it is unclear if this is because of genetic or environmental factors. Once here, the mold found the perfect hosts to carry it into new caves and mines. In a cruel irony, the bats carried the seeds — technically, spores — of their own destruction, spreading the mold through contact with other bats in densely populated caves and mines, according to the New York State Department of Environmental Conservation.

The best thing bat lovers can do for the bat population, Herzog said, is to let them sleep through the winter. If someone comes across a hibernacula, they should get out as soon as possible to avoid waking the sleeping bats, who may at that very moment be quietly fighting for their lives. Those who enter bat habitats, including hikers and spelunkers, should take all suggested precautions, including decontamination procedures and avoiding caves and mines that have been closed to the public.

* * *

 “They better not go away, or I will be outmof a job.” —Caroline “The Bat Lady” Van Kirk Bissell

There is something about the bat that resonates in Chautauqua. Like the town itself, bats seem to exist on their own terms. For years, there was a tiny bat hidden inside of each issue of The Chautauquan Daily, waiting to be found by observant readers. Like most of the little browns, he is now gone.

Caroline Van Kirk Bissell runs the Bat Chats on Wednesday afternoons for the Chautauqua Bird, Tree & Garden Club. She is affectionately known as “the bat lady” and sports a bat T-shirt and matching bat jewelry. When a resident has an issue with a bat in a living room, Bissell gets a call to come help remove the little thing humanely.

She believes that the lack of bats is causing another flying creature to surge in numbers: the mosquito.

“People in Chautauqua have noticed a huge difference,” she said. “Week Two, I had nine mosquito bites, which is unheard of. People are coming up to me and complaining as if I have control over it.”

Bissell said that a group from York University in Toronto estimated there were 10,000 bats on the grounds before the arrival of WNS. According to the Adirondack Ecological Center, 100 little browns can eat 42 pounds of insects in four months. If the York numbers are accurate, at the height of the little brown population, the bats were eating more than two tons of mosquitos each season, more than the weight of the average American car. That comes out to more than 500,000,000 bugs.

The bats may be disappearing, but interest among Chautauquans is still high. During Week Five, 40 people were in attendance at Bissell’s Bat Chat, including a young girl who has been to the last three. She has soaked up the information like a sponge, answering all of the questions during her second session. For the young girl’s third session, Bissell jokingly banned her from answering any more. The bats may be going away, but their place in the town’s imagination is secure.

* * *

“It is the greatest disease-driven decline of wildlife populations ever documented.” —Dr. Jeremy Coleman

Dr. Jeremy Coleman is the national WNS coordinator for the U.S. Fish and Wildlife Service. While most people spend the first few days at a new job learning the ropes, Coleman spent his trying to wrap his mind around the possibility that Northeastern bats may become extinct.

Bats have a fairly long life cycle, with some living for more than 10 years. Unlike most rodents, bats typically only have one pup a year. If this type of sickness had affected most rodent populations, it would have been relatively short-lived.

“If there is going to be a recovery of the populations of little brown bats,” Coleman said, “it will take decades and maybe won’t happen in our lifetimes.”

In spite of what he has seen, Coleman hasn’t given up on the bats just yet.

“I have to stay hopeful that we will be able to do something and see the recovery of bat populations,” he said. “If we didn’t have that hope and goal to strive for, we would be unable to do our jobs here.”

It’s not all bad news. Herzog and Coleman agree that some little brown bat populations seem to be surviving, although it is unclear why. It is possible that their chosen hibernaculum have a different humidity level, or some other characteristic which may inhibit the mold from growing at the same rate as in the lethal caves and mines. If the survival ability is genetic, there may be hope yet for the little brown bats.

A single bat dips and weaves over Chautauqua Lake. It is a remarkable sight.

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