HUANJIA ZHANG: Many people in Pennsylvania may have noticed that, nowadays, it is not easy to encounter bats any more at night during the summer. My guest today has spent years working with bats in Pennsylvania, and he will talk to us about the story behind the dramatic declination of bat populations in Pennsylvania.
Mike Scafini is the endangered mammal specialist of the Pennsylvania Game Commission. Mike works with all non-game mammals including everything from bats to Northern Flying Squirrels, Allegheny woodrats, water shrews and other small mammals that people don’t normally think of when it comes to the Pennsylvania wildlife.
Hey Mike, how are you today?
MIKE SCAFINI: Pretty good, how are you doing?
HUANJIA ZHANG: I am good, thank you! Thanks for joining me today.
So, at the beginning at the talk, I want to start with “misunderstanding”. Perhaps, no other mammals in the Northeast are as misunderstood as bats. Because of their dark, small, flying and nocturnal features, bats, unfortunately, have been considered vicious animals that bite and can carry diseases. Could you please tell us whether these rumors about bats are true?
MIKE SCAFINI: Well… yea, there are a lot of misconceptions about bats. From you know all the horror movies you see, and the things you see on the news. But actually up close, bats are pretty cute. You mentioned drinking blood, that’s vampire bats, that’s central and South America.
We owe a lot to bats, they are the only predators of night flying insects. I have seen a lot of different figures saying bats can eat 45 insects in a single evening, which equals to a million insects in an entire year. So, the agriculture industry in PA owes a lot to bats. They eat your crop pests and they eat all your nuisance pests like flies and mosquitos that people don’t want around the summer time and so yea… we owe a lot to bats and they are really not scary once you see what they are all about and see them up close.
HUANJIA ZHANG: There are nine species of bats commonly living in Pennsylvania. Among the nine species of bats, six of them, which include the little brown bat, big brown bat, eastern pipistrelle bat, northern long-eared bat, Indiana bat, and eastern small-footed bat, are short distance hibernating bats, meaning that they don’t make long migratory trips when winter comes. Instead, they will hibernate in Pennsylvania or in adjacent states. The rest of our bat species, which are silver-haired bat, eastern red bat, and hoary bat, in contrast, will migrate to the south when winter approaches, some birds.
The population of hibernating bats in Pennsylvania, has dramatically declined over the past decade.
MIKE SCAFINI: Back to the six species again, we have three of them; well actually four of them; are actually 99% declined.
HUANJIA ZHANG: The terrible drop in hibernating bats in Pennsylvania, and along the entire east coast of North America is primarily caused by a new bat disease called white nose syndrome.
MIKE SCAFINI: White nose is a bat that’s been infected with Pseudogymnoascus destructans, which is a fungus and it’s believed to be transferred from Europe. It is proposed that it came from humans that went caving to Europe and brought it back to New York State. And since then, it spread up and down the east cost and moved its way westward even up into Canada. Bats that get infected with this fungus, it irritates them when they are hibernating. So, they become dehydrated, they wake up more often, and oftentimes they will fly out in the middle of winter when it’s cold and there is no insects to eat and that’s primarily the cause of all these deaths.
I have a figure here in front me that shows our hibernacula surveys: it compared those sites that we checked before white nose and we also have surveys after white nose in PA. So each year, we survey more sites, each winter. And so we have more sites to compare with the pre-white nose years. And each year four of our species: little brown, Indiana, long-eared, and tri-colored have really not rebounded. Their numbers, for examples, we have Altenburg County in central part of the PA; we have a site called canoe-creek mine. It had at one point hit a high of 34,000 bats, and now we are at between 70 and 80 total.
HUANJIA ZHANG: Unfortunately, there is no cure for white nose syndrome for bats right now, but scientists are working hard to find the cure.
MIKE SCAFINI: There is actually; we had an interesting experiment that’s worth mentioning. There are kinda two different things and I will tell you the one we are more involved with—it’s called PEG 8000, Polyethalglyco 8000. I guess it’s found in the pharmaceutical community a lot. It’s what it does is to trick the fungi into thinking its water stressed, so it doesn’t grow. And we kinda set up an experiment with three cages, seven bats in each cage. One was control, one had this PEG 8000 applied to one of their wings and the other one had the PEG applied to the roost itself on the wall. And what we saw was the one that we applied to the wing it didn’t make any difference, it still got the PD fungus, it didn’t have any effect. And the one we applied to the roost, they were fine; they didn’t pick up the spore. So, we were thinking the PEG 8000 could be almost a roost cleaning application. It would be near impossible to treat a whole cave, but being that bats are creature of habits, they go back to some of the same spots in the cave. So if we could treat maybe the main spots where they go each winter, where they all congregate together, we may have beyond something as first.
HUANJIA ZHANG: So far we have talked about the decline of hibernating bats, what about the non-hibernating bats? Are they also being threatened?
MIKE SCAFINI: We also have the migratory bats, and they are being hit by wind farms. That’s part of what I did my graduate work on. There is a wind farm in Schuylkill county where I did what they called post-construction mortality surveys. And just an estimate of a roughly 12/13 turbine wind farm is killing 500 or more bats every summer. So, there have been different ideas of why that is: they are following the top where they think that the turbine is a tree to roost on. But so far, they haven’t come up with…they come up with some ways to help slow the turbine blades when wind speeds are low, which is when bats typically fly, and the turbine isn’t creating that much of energy anyway. So they come up with some different way to curtail the impact, but between white nose for the hibernating bats and turbines for migratory bats, and then just the normal fact that bats are really slow reproducers—most of their species only have one pup per year. Big browns and red bats can have two, but for the most part, with this kind of decline it is hard for them to rebound. Just from natural death and all these other factors, that’s been a pretty steady decline.
HUANJIA ZHANG: Sometimes bats come into our backyards or into the house. What should people do if bats visit their home?
MIKE SCAFINI: The bats in homes is something that we more see as a problem in the summer. I get emails left and right in the summer time: people that have bats in their homes and they want them out, or bats in their barn. Essentially, bats form maternity colonies in the summer to raise their pups, so, when it’s the hottest months of the year, that’s when females are with their pups—June and July. When you see them in your home, there are different things that you can do. One option is to call us and we can try to direct you to someone—cuz we can’t really response to all calls, we can kinda guide you through the process—we can it eviction and exclusion. Eviction is where you put a one-way door, say, if you know where the opening is, if they are coming into your attic, there will be a door where they can fly out but not back in. The only problem with that is you can’t do it when there are flyless pups. So, like I said, they are forming maternity colonies. So, there is a window time in the middle of the summer that this won’t work—you’ll be trapping bats inside and the adults fly out to feed the pups are gonna try whatever they will to get back in, but otherwise, it’s a really good technique—once all the bats fly through that door, you can the seal any openings.
HUANJIA ZHANG: As Pennsylvania residents, we are constantly hearing depressing stories of endangered or threatened wildlife and diseases that affect bats. What do you think are things we can do here in central PA to help protect bat populations?
MIKE SCAFINI: Some of the big things that you can do, hum, the one like I mentioned is the Appalachian bat count. That gives us a handle on not only where the bats are, a good majority of the year during the summer, but also if they are reproducing. Because the ABC counts are designed to count before and after they (bats) have their pups. So, we can actually see how much they are reproducing. So, kinda give us this idea in the handle on bat populations, where they are, that’s probably the biggest that they can do, is participating that program.