On certain summer nights, you can find Richard Fritsky slowly driving the backroads of northeast Pennsylvania with a specialized microphone attached to the roof of his car.

“The microphone picks up high-frequency sounds that bats make but are above human hearing,” he said. “I’ll drive so slowly, like only 20 miles a night, and record every noise and the computer that microphone is attached to identifies the type of bat and uses GPS to show exactly where they are flying.”

After 10 years of this study specifically and 17 years with the Pennsylvania Game Commission, the wildlife diversity biologist knows where bats spend much of their time.

“Whenever I cross a bridge or drive along a waterway, that is typically when my scanner is most likely to light up with bat activity,” he said. “I’ll find them in upland sites around unused buildings and vacant lots, near barns and old churches where they’ll find their way into attics. However, when I am riding along the Susquehanna River or one of its tributaries, I know that will likely be a hotspot for finding bats.”

Bats, bugs and

waterways

Throughout the world, bats provide a number of important uses, according to Fritsky, including pollination and seed dispersal. On certain summer nights, you can find Richard Fritsky slowly driving the backroads of northeast Pennsylvania with a specialized microphone attached to the roof of his car.

“There is a Mexican bat that pollinates cactus flowers that only bloom at night,” he said. “And fruit bats that carry the fruit around with them, and when they are done eating the flesh of the fruit, they’ll drop the rest, and in the process, disperse seeds.”

However, in Pennsylvania, bats are strictly insectivores.

“That means they all eat insects,” Fritsky said. “What better place to find insects consistently than around waterways?”

According to Matt Wilson, director of Susquehanna University’s Freshwater Research Institute, you can find approximately 500 insects on the bottom of a stream in the small headwaters area without many nutrients.

“In agricultural streams with more nutrients and energy available that number can be over 10,000,” he said. “This is not a case where more is better, but it does give you a sense of just how many insects are in streams.”

That is only amplified exponentially when you start talking about the Susquehanna River, Wilson added. It is a few hundred yards wide throughout its length, and still more than 100 yards for most of the length of either branch.

“Imagine standing on the bank of the river and looking across to the other side. Even if the river is narrow and only 100 yards (300 feet) wide and the width of your shoulders was one and a half feet with 500 insects per square foot, there are likely more than 225,000 insects in the river just between your shoulders,” he said. “In wider and more productive sections of the river, that number is easily in the millions.”

Fritsky pointed out that the sheer number of insects can be easier to visualize when taking in one of our waterways’ hatch events.

“We have one site we study on Hoover Island where there is a giant bat condo and the only way to get there is paddling across the river,” he said. “Sometimes, I am crossing over there in the dark and I am completely covered in mayflies. They are great protein for bats.”

Those hatch events do offer a prime opportunity for predators, including bats, to feast, according to Wilson.

“Most aquatic insects don’t have any real defenses (dobsonflies excluded) so they’ve evolved to emerge all at once to overwhelm predators so that a few survive long enough to mate and lay eggs. Sometimes this is determined by daylight length, sometimes it’s water temperature, sometimes is flow (if there was a flood or drought) and sometimes it’s a combination,” he said. “And when they do emerge all at once, most species need to find a place to rest on land and hide during the day – so all those insects between your shoulders are now heading for a home above your head! That’s why we see so many at once, when we see them.”

Species decimated

Because of their highly adaptive nighttime predatory skills, bats are ideal at keeping insect populations along waterways in balance. However, cave-dwelling bat species have been decimated over the past 15 years by White Nose Syndrome.

“It really is the biggest die-off of wildlife in North America in our lifetimes,” said Fritsky. “The reason we don’t hear about it much is because it’s bats. If we had a similar die-off of rabbits or deer, we’d hear so much more about it – it would be all over the news. We’re talking millions and millions of bats that have died off in the past decade-plus due to White Nose Syndrome. We’ve lost as much as 90 to 99 percent of certain species of bats from it.”

White Nose Syndrome is a fungus that was accidently brought to North America likely from sources in Europe, it is assumed, according to Fritsky, via caving equipment without knowing that contaminated a commercial cave in upstate New York near Albany.

“From there, it just spread and now is in 35 different states including across the Mississippi River and killing large numbers of our cave-dwelling bats,” he said.

The condition does not seem to impact tree-dwelling species that migrate south during the winter, which include the red bat, silver-haired bat and hoary bat.

“They’re all doing fine,” said Fritsky. “What aren’t doing well are the little brown bat, the big brown bat, the long-eared bat and the small-footed bat. Big brown bat populations have dropped by 90 percent. Little brown and Indiana bats are down as much as 99 percent. Just tiny fractions of their species remain.”

The silver lining, Fritsky added, is that we still have that small percentage of each species holding on.

“When this all started happening back in 2006, we didn’t know if we’d ever see bats again – if this would kill all our cave-dwelling bats off. We don’t know what is next or if they will rebound,” he said. “One of the biggest issues is that bats have a very low reproduction rate. They only have one pup a year and it takes them several years to be mature enough to start reproducing.”

Off balance?

So, with such a drastic loss in bat numbers, it is logical to assume that insect populations would continue to skyrocket. But, there is limited data at this time to make conclusive parallels.

“The game commission is primarily focused on mammal and bird species, so we haven’t done a lot of research on insect trends and I can’t show a definitive connection between the two populations,” said Fritsky. “There are still plenty of birds and other predators that eat insects, so perhaps they’ve shifted their diet to accommodate the potential increase. Farmers may have increased use of pesticides to offset crop pests and other variables may be at play.”

Wilson admitted that he and his colleagues typically look at the reverse phenomenon – how insects affect bats: “Because insects have evolved to emerge in large numbers and only a few typically survive, predation isn’t usually the limiting factor on their population size or the success of a species,” he said.

“I don’t think of it in terms of control, but in terms of balance. These species and these ecosystems have evolved together over tens or hundreds of millions of years, so removing one species will reverberate across both ecosystems,” Wilson added. “There is a research paper that was published about 20 years ago that I love for explaining this, with a title that uses the phrase ‘Tangled Webs.'”

Helping bats

In terms of helping bat populations weather the storm of White Nose Syndrome, the game commission is working to improve undergrown mine habitats to reduce temperatures because Fritsky and his colleagues have found that colder temperatures have proven to be more effective for success.

“For example, the New Angola tunnel which crosses under Interstate 81 near New Angola is a train tunnel that collapsed on one side when they built the interstate. Air can flow freely in and out of one end and temperatures stay around 50 degrees, but that is fairly warm for a hibernating bat,” said Fritsky. “They want to bring their body temperatures down to close to freezing as possible to conserve energy during winter, and then they warm up as they prepare to leave to find place to roost for summer.”

At this specific site, Fritsky and others have adjusted elements to change climate within the tunnel to improve the environment for the bats.

“We created a 50-foot mound out of rock and dirt in front of the tunnel which works as a catch, so as cold air falls off the hillside, it collects inside the tunnel. We also put in a gate on that keeps humans out but allows bats to go in and out freely,” he said. “We also had a driller drill a 300-foot hole from the median of I-81 all the way down to the back of the tunnel and put on a vent cover that we can open and close when we need to in order to help hot air escape, and that has really helped to bring temperatures down.”

As they improve conditions, they have noticed an increase in bats at the site.

“As we come across other places where this makes sense and the bats will benefit, we plan on doing this sort of thing a lot more,” he said.

On an individual basis, people can purchase bat boxes from the game commission or download plans to build their own and install them to provide additional habitat, but Fritsky doesn’t advise placing them close to your home.

“Although the rate is very low – like less than one percent, bats can still harbor rabies, so you don’t want to take that chance,” he said. “However, if you have an open field where you can place a bat box on a 4-by-4 pole in a place where there is a lot of sun, that is ideal. We want these boxes to be hot … that is why we paint them black and put them in the middle of open fields.”

If bats are in your home’s attic or basement and not coming into your living spaces or otherwise bothering you, Fritsky said you can leave them alone. However, if they are invading any living space, he advises getting help to seal any openings or make changes to reduce interaction.

“Lots of people do have them in their attics or basement of their homes and they may not even know they are there,” he said.

Ultimately, bats can be a very important part of our ecosystem and something we should work together to help conserve.

“A lot of people think wildlife is taken care of by a handful of people at the game commission, and while that is partially true, it can’t be done without people to spread the word about conservation as well as those who actively get involved with projects like bat boxes and bird boxes and whatever else they can do to improve the habitat,” Fritsky said. “It’s really an all-hands-on-deck effort. Everyone needs to chip in because bats really have had a hard time and they could use a hand.”

The Middle Susquehanna Riverkeeper Association serves an 11,000-square-mile watershed of the Susquehanna River, including Sullivan, Lycoming, Clinton, Union and Northumberland counties. Read more at www.middlesusquehannariverkeeper.org.