Little Brown Bats

little brown bat in a crack on the side of a house

The Guest House portico bat in 2007

Living, as we do, in an old country house, we often hear strange noises.

On an August evening, my husband Bruce and I sat in the living room reading. Shortly after 8:00 p.m., we heard unusual sounds coming from either the kitchen or sitting room.

We looked up at each other and then resumed reading. Both of us were engrossed in our books and didn’t feel like moving.

After all, many times we had investigated a noise and found nothing.

Then, there were more noises.

“I hope it’s not a bear,” I whispered to Bruce, remembering an attempted bear and cubs break-in back in June. “We’d better check it out.”

Because it was a wet night, it was already dark, and we couldn’t see a thing until Bruce switched on the sitting room lights. Then we ducked as a bat circled the room, narrowly missing the plates on our seven-foot-high plate rail.

Bruce opened the veranda door, but the bat continued its circling flight inside. As the minutes passed, I worried that mosquitoes, which had earlier driven us from the veranda, might get into the house.

But the bat was probably scooping up any that dared to enter and paid no attention to our feeble attempts to herd it out the door.

location of the bat in the previous photo

Location of the bat in the previous photo

Twice the bat barely missed the open door and once it landed for a few seconds on the wall, giving us a good look at its lustrous brown fur, but mostly it kept circling at plate rail height.

Bruce and I moved closer, he on one side of the door, I on the other, and I ducked reflexively every time the bat neared my head, even though I knew that its echolocation ability would keep it from hitting me.

Finally, it swooshed through the open door, and we breathed a sigh of relief. I was also elated that at least one little brown bat had escaped the white-nose syndrome (WNS), a fungus that has killed at least 95% of little brown bats throughout eastern North America since February 2006 when the disease was first discovered in a cave in Schoharie County, New York.

This cold-loving fungus Pseudogymnoascus destuctans only affects hibernating cave bats, which include the already Federally-Endangered Indiana bat, as well as the State-Threatened eastern small-footed bat, big brown bat, eastern long-eared bat, and tri-colored bat, but the little brown bat, also called little brown myotis, common bat, and cave bat, along with the eastern long-eared and tri-colored bats, is especially susceptible to the disease.

Dee Ann Reeder, A Bucknell University professor who has been studying bats in her bat vivarium even before the disease appeared, has been trying to understand how bats are affected and has been using little brown bats as her test subjects.

In a two-year captive study, she found WNS affected female little brown bats more than males and that bats kept in colder temperatures survived longer than those in warmer temperatures.

Little brown bats hibernating at Woodward Cave in central PA, February 2006

Little brown bats hibernating at Woodward Cave in central PA, February 2006

Reeder has worked closely with Greg Turner, PGC’s Endangered and Threatened Mammals Section Supervisor, to try to mitigate the disease, but this fuzzy white fungal growth around a bat’s muzzle, ears, and wing membranes thrives in winter hibernaculums—natural caves and old mines in Pennsylvania, such as the gated Hartman Limestone Mine at Canoe Creek State Park.

Back in 2008, when the PGC conducted its biannual count of bats at that mine, there were thousands of healthy, hibernating, mostly little brown bats. Three years later, they counted 38 total bats. And other hibernaculums throughout the state also contained few live bats.

Because bats cluster together in winter hibernaculums, the disease spreads easily from bat to bat. WNS causes them to rouse every few days instead of every few weeks as they used to do. The small size of little brown bats means they have less fat reserves to begin with so they quickly lose their fat reserves and starve.

They also lose more water through evaporation, and when they emerged, starved and dehydrated, for instance, from the Hartman Limestone Mine, they ate snow. In addition, little brown bats have suppressed immune systems during hibernation, which makes them more vulnerable to the fungus. Thus, once nicknamed the common bat, they are now rare.

Hibernating bats among the stalactites in Woodward Cave

Hibernating bats among the stalactites in Woodward Cave

Scientists say the best case scenario would be a full recovery of the bat population in 200 years! As of April 2015, the cave bats in 26 states and 5 Canadian provinces have been infected with WNS and still the disease rages westward at a frightening pace.

This is a huge wildlife disaster, certainly the worst in my lifetime, and all because some cavers, probably from Europe, where cave bats have evolved with the disease, brought the fungal spores over on their clothes.

Lately, there have been a few bright spots in this dismal picture. In 2014 the Hartman Limestone Mine cave bat count was 155, and this year 71 bats. Although the numbers are still low, according to Greg Turner, bats are coming into hibernation heavier, even the few juveniles, and they have fewer skin lesions on their wings. They also spread themselves out in hibernaculums. But all such changes may be due simply because there are few bats left to compete with for food and space.

Knowing all this, I welcomed our little brown bat visitor. One bat eats between 800,000 and 1 million insects a year including moths, wasps, gnats, midges, beetles, mayflies and especially mosquitoes, scooping up prey with its wings while flying or grabbing prey with its mouth.

Little brown bats have both day and night roosts during spring, summer and early fall. They like to roost near ponds, lakes, rivers or streams in buildings or trees, under rocks and woodpiles, and in caves. Females and their young occupy warm nursery roosts in natural hollows, buildings, such as old churches, at Canoe Creek State Park, for example, and attics.

A bat on the side of a concrete block

A bat on the side of a concrete block outside our barn, 2007

They sleep almost 20 hours in a 24 hour cycle, saving their energy for when insect prey is most abundant—from dusk to two to three hours later and again for a shorter period before dawn. Flying at between 13 and 22 miles an hour, they hunt their prey using echolocation, a process in which they orient themselves by emitting high-frequency sounds and then interpreting the reflected sound waves.

They mate in autumn before hibernation, but fertilization occurs after the females emerge from hibernation the following spring. After a gestation period of 50 to 60 days, a single pup is born to a female in late May or early June.

Born with their eyes closed, the young hang in the nursery roost while their mothers hunt for food. The rest of the time, for two weeks, they cling to their mother’s nipple until they are two weeks old. At three weeks of age they learn to fly, and a week later they are adult-sized—between 3.1 and 3.7 inches with a wingspan of 8.6 to 10.5 inches.

Female little brown bats are larger than males, but all adults need to eat half their body weight each night, and new mothers more than their body weight. One study in New Hampshire of pregnant and nursing mothers found that they ate 7 insects per minute.

Before WNS, we could sit out on our unscreened veranda even after dark and rarely see or hear a mosquito. A few male little brown bats roosted in our barn and in openings under our roof and the guesthouse portico roof. We often watched them flying over our field and imagined them scooping up water from our stream.

Close-up of the little brown bat in the previous photo

Close-up of the little brown bat in the previous photo

Now the mosquitoes force us inside every evening. Farmers, who may not have realized how many harmful insects bats eat, will be forced to use more pesticides.

Little brown bats have few predators, although occasionally a snake, raccoon, skunk, or cat may enter a hibernaculum and kill a few. They’ve also been caught on barbed wire fences or in burdock bristles.

Before WNS, humans wiped out entire cave or attic nursery populations, but bat education by dedicated people such as Cal Butchkoski, a wildlife biologist for the PGC who spent countless hours at Canoe Creek State Park and other venues, presenting excellent programs on bats, and Environmental Educator Heidi Mullendore at the park who organized several successful Bat Festivals there, had begun to change peoples’ minds about bats. The PGC had also gated many vulnerable winter hibernaculums throughout the commonwealth.

Now it is illegal to kill even one bat of any species. With 6 million gone, “every bat we find is precious and needs to be conserved,” Dee Ann Reeder says.


All photos by Dave Bonta.

Another Batty August

On a warm August evening, my husband Bruce and I sat in our living room, reading quietly. Suddenly, we were not alone. A bat, flying close to our heads, circled the room.

Bruce called our son Dave up from the guesthouse to help shepherd the bat outside through the open front door, but it wouldn’t shepherd. Round and round the bat went as they tried to guide it out with jackets used like matador capes. Always it missed the open door because it flew too close to the ceiling.

Several times the bat landed on top of our books in the bookcase and peered down at us. By then, I had gotten my binoculars, which gave me a close-up look at its little face. Its expression reminded me of a naughty child hiding from its parents.

After fifteen minutes of watching the men in fruitless pursuit of the bat, I searched around for something else to persuade it to leave. I handed my old mop to Bruce who held it near the ceiling above the open door. The next time the bat circled toward that corner of the room, Bruce wiggled the mop slightly. That caused the bat to swoop lower, sense the open door, and swoop out into the night. Bruce quickly closed the screen door, and as we looked outside we could see the bat circling our front porch, no doubt already in pursuit of the mosquitoes that had driven us inside earlier in the evening.

It seems as if every August a bat finds its way into our old farmhouse. Last August’s visitor was a little brown bat or myotis, one of Pennsylvania’s most common bats. Probably it was a youngster or “pup” that was exploring the nooks and crannies of our house in search of a roosting place.

Our batty August continued when our granddaughter Eva arrived for a short visit. She and I, and her mother Luz, planned to attend Canoe Creek State Park’s Third Annual Bat Festival. The brainchild of Heidi Boyle, the energetic environmental educator for the park, the free festival highlights bats in a series of family-oriented programs ranging from bat games for kids and information about bat caves, to meeting live bats and watching the evening emergence of a bat maternity colony. That colony, incidentally, is the largest known maternity colony of little brown bats east of the Mississippi River.

It had been fifteen years since I had attended a bat program at the park. Then Roy Boyle had been park naturalist, and he and park superintendent Terry Wentz had been part of a crew that had climbed to the second floor of a nearby old country church to get some idea of the bat population there, which nearby residents told them had been present for many summers. At that time, they estimated the maternity colony held 5,600 little brown bat mothers and pups.

Since then Canoe Creek State Park, the church, which the park later bought, and the nearby gated Hartman Limestone Mine that protects thousands of hibernating bats in the winter, have become world famous for their bats and bat research. (See my column for August 1996).

Back in 1988, though, Roy Boyle and Pennsylvania Game Commission wildlife technician Cal Butchkoski, otherwise known as the “Bat Man of Pennsylvania,” initiated the first bat program at the park. Rumors of their fabulous program had reached me, and I spent an evening watching Butchkoski and Boyle convert 125 bat-haters into bat-lovers within the hour.

While the kids were willing, their parents were not. “I hate those things,” one woman confided loudly to another before the program began. And when Butchkoski started the program by asking, “What comes into your mind when I say ‘bat?’,” two women yelled, “Kill!”

Remembering that, I was amazed when we arrived at the bat festival. More than six hundred men, women, and children had come from as far away as Pittsburgh and Philadelphia. Many were bat enthusiasts, eager to learn more about their favorite critters. While I attended the kid-friendly programs with Eva, my daughter-in-law, who knew nothing about bats, went to the adult-oriented programs.

Eva and I crammed ourselves into the standing-room-only crowd at the park’s education center to learn about caves from Ann Molosky of nearby Lincoln Caverns and to build a model of a bat cave out of a Big Mac container. The enthusiasm was high and remained so at the next activity–bat games for kids.

In the meantime, Luz joined a group that learned how Game Commission scientists use telemetry to track bats for research. She followed that up by attending a program on the Indiana bat by Cal Butchkoski. Butchkoski’s great discovery, since my last visit, had been that federally-endangered Indiana bats, which are known to hibernate in the Hartman Limestone Mine, were using the “Bat Condo” he had erected near the church, bat boxes, and the church itself as maternity roosts.

“Up until that point in time, Indiana bats had never been documented using a manmade structure as a maternity roost,” said Jerry Hassinger, Wildlife Diversity supervisor for the PGC’s Bureau of Wildlife Management until his recent retirement.

Typically, Indiana bat summer maternity roosts are found in tree cavities or under loose bark. Using telemetry on the Indiana bats they found in the church, Butchkoski and Hassinger discovered that those same bats also used trees as alternate or secondary roosts even though they gave birth and raised their young in the manmade structures. Further research revealed that Indiana bats foraged mainly in a nearby large block of mature lowland forest, habitat that is harder and harder to find because it is popular for development.

Bat Festival attendees had the chance to visit the Bat Condo, church, and Hartman Mine, all of which remain important components in the PGC’s bat research. But probably the most popular program at the festival occurred near dusk.

Hundreds of people made their way to the bat church and settled themselves in the old graveyard to watch the nightly emergence of the bats. While naturalist Stan Kotala told us about the bat maternity colony, Cal Butchkoski showed us what was happening inside the church. Previously he had set up infrared cameras with infrared lighting in the church that sent a signal to a receiver outside the church. He then plugged the receiver into a video projector that produced the images on a screen for us to watch of bats flying about inside the church before emerging.

Finally, though, as daylight faded, first a few bats flew outside through a second story back window, then more and more–a river of bats that fluttered off to “act as an all-natural pesticide,” in the words of Michael Gannon, an associate professor of biology at Penn State Altoona who also uses the Canoe Creek bats in his research on bat calls. Gannon says that, “A single little brown bat can catch 300 to 3,000 insects per night, and a nursing mother little brown bat eats half her body weight or more each night.” No wonder the farmers living near the park use less pesticides than farmers in the rest of the state.

My granddaughter Eva was enthralled at the emergence, along with all the other children in the audience, but they were probably unaware that they were witnessing a once common natural phenomenon few people today have the privilege of seeing.

Bat numbers are dwindling for many reasons. Most people still think “kill” when they see one. In addition to human persecution, as well as habitat destruction, bats, in our part of the Appalachians, face still another hazard–wind turbine farms. Developed as an environmentally-friendly alternative to conventional power plants, the graceful, white turbines rise more than 340 feet above the ground at both the Meyersdale, Pennsylvania and Backbone Mountain, West Virginia wind farms.

Already castigated for causing too many bird deaths, the discovery of thousands of dead bats at those facilities was an unexpected shock. But bat conservationists have swung into action in an effort to discover why bats are dying and what can be done to prevent their deaths. A collaborative research initiative called the Bats and Wind Energy Cooperative has been developed with Bat Conservation International, the U.S. Fish and Wildlife Service, the American Wind Energy Association, and the U.S. Department of Energy’s National Renewable Energy Laboratory. Last summer they conducted daily searches at both facilities and found that the turbines’ ultrasonic emissions did not attract bats as previously suspected and that more bats died during nights of low wind speed. At the Meyersdale facility more adult and male bats were killed than juveniles or females. Altogether, at Meyersdale, between July 31 and September 11, searchers found 290 bat bodies of seven species–hoary, eastern red, eastern pipistrelle, silver-haired, big brown, little brown, and northern long-eared. In addition, the researchers concluded that bats are dying all year long at the site, not just during migration.

The mystery continues, and so will the research until scientists figure out, as Merlin Tuttle of Bat Conservation International puts it, why wind turbines are “bat veg-o-matics.”

Our own batty August ended with Dave’s and Eva’s bat watching at the guesthouse portico one night as a couple little brown bats swooped around the portico light catching insects.
Then one bat climbed into the crack between the end of the guesthouse roof and the side of the house to groom itself. Training a flashlight on the bat, they watched what Dave said looked like “a big-eared mouse chewing on a tiny umbrella.”

As he later wrote in his Via Negativa blog post entitled “Little Brown Myotis:” “Only when he worked on the surface of an open wing did we get a look at his face, dimly visible through the thin membrane of skin…He spent most of his time on the wings, with only a few nibbles at his abdomen…When the bat finished grooming, he turned his listening face full on us for a few seconds, then, rather than flying out the way he came, scuttled up feet first through a crack in the [roof] tiles and disappeared.”

Needless to say, Eva will not forget her batty August and neither will we.

For information about the upcoming Fourth Bat Festival, check Canoe Creek State Park’s online Calendar of Events or call the park at 814-695-6807.