Bats are struggling with a strange syndrome
Over the last decade, bats have been struggling with a strange disease called white-nose syndrome, caused by a cold-loving fungus that attacks bats in their winter hibernation sites, growing on muzzles and wings.
Walking across the lawn alongside the Schuylkill Center’s main building on a lovely evening in mid-May, a bat flew across the sky above me. Now I love bats, knowing they are mosquito-eating machines, but seeing this one made me feel wistful, for it is both the first and only bat I have seen thus far this year.
And that shouldn’t be the case. A forest like the Schuylkill Center’s should be teeming with bats.
Over the last decade, bats have been struggling with a strange disease called white-nose syndrome, caused by a cold-loving fungus that attacks bats in their winter hibernation sites, growing on muzzles and wings. The fungus cause the hibernating bats to awaken from their deep sleep in the cold weather, and tragically the bats cannot get back into their hibernation state, cannot find food — and die. Biologists have seen bats leaving their caves in cold winter weather to find food, which they cannot do, as their food (flying insects) is unavailable and their furless wings freeze in frigid weather.
While biologists don’t know if the non-native fungus entered the U.S. from Asia or Europe where bat populations have long ago evolved to adapt to it, the disease was first spotted in this country in upstate New York in 2006, where it quickly decimated bats, and has since been spreading across America ever since, now reaching as far as Minnesota, Oklahoma and Arkansas. It spread through Pennsylvania early in its American journey.
“Local bat populations have declined,” said Brenda Malinics, a noted bat conservationist and advocate who rehabilitates injured bats and works closely with the Schuylkill Center’s own Wildlife Clinic. “I’m just not seeing as many flying nor are we getting as many intakes. The decline has been increasing over the past 10 years.”
Deb Welter agreed. The founder of Diamond Rock Wildlife Rehabilitation Clinic, she noted, “We used to admit about 20 bat pups each summer, but each year since, the number has gone down. Last year, I admitted only two.” She’s only admitted three little browns in the last five years, less than one annually.
Rick Schubert has directed our Roxborough clinic for the last decade and fully concurs.
“We used to get maybe a dozen little brown bats a year,” he told me last week, “but I haven’t seen one in two or three years. Not one.”
For Rick, this is an ecological issue.
“Bats are a keystone species,” he noted, performing critical ecological services in keeping populations of night-flying insects in check. In a world of worries over the Zika virus being spread by mosquitoes, bats are crucial links in local food chains.
Little brown bats, the most common of the state’s nine bat species, have been especially hard hit by white nose, as they hibernate over the winter in colonies, the fungus quickly spreading throughout the group. So if there is any good news locally, most of Philadelphia’s bats are big brown bats, larger cousins of the little, a species that hibernates in smaller numbers in attics and trees. Welter said, “They are not in caves where they hibernate in large numbers and are susceptible to the syndrome.”
While Malinics is “not aware of any promising leads to control or stop the syndrome,” there are survivors, who perhaps will build up resistance over time. Still, some 98 percent of our state’s little brown bats have become victims to the syndrome.
In late May, I enjoyed a Phillies night game — well, OK, they lost, but I did see a Ryan Howard double, increasingly a rarity, and a Tyler Goeddel rocket to first nailing a runner who was tagging up — but I was completely unnerved scanning the bright lights above the stadium. In years past, I would watch bats cavorting in the stadium’s lights almost as closely as I watched the game itself, bats cruising through the lights picking off the moths and flies that were swarming there.
That night last month, I couldn’t find one sin- gle bat. Which made that one I saw at the Schuylkill Center only two weeks earlier all the more precious. Mike Weilbacher directs the Schuylkill Center for Environmental Education, can be reached at mike@ schuylkillcenter.org and tweets @SCEEMike. He’d especially love to know any reports of bats you see in the area.