Protecting Summer Hang-Outs For Bats

The foot of an endangered Indiana bat. Credit: Adam Mann, Environmental Solutions and Innova

Most people think of bats only as cave-dwelling night creatures that sometimes mistake your attic for a hideout. But bats don’t spend all their time in winter hibernation or asleep in dark, dusty corners. In fact, where they spend their waking hours matters a great deal.

Researchers from The Nature Conservancy are trying to help protect the bat’s vital role in the ecosystem by answering the question:  where do bats like to spend the summer?

In August I joined lead researcher and GIS expert August Froehlich at dusk near a soybean field in Norwalk, Ohio. We were there to check out some bats in their summer digs.

Shagbark hickory used as a roost by an Indiana bat maternity colony in Indiana. Credit: Joey Weber, Indiana State University.
This shagbark hickory is the roost site for a colony of Indiana bats. Credit: Joey Weber, Indiana State University

Since bat calls aren’t audible to the human ear, Froehlich’s team uses a bat detector that translates the calls into audible chirps. He was looking for the bat “hotspots.” Where were the bats hanging out? This is important to know because bat mothers raise their pups during the summer, and protecting these spots is crucial to the survival of the species. And bats aren’t doing so well. Hit hard by white-nose syndrome, bat populations are in decline in Ohio and across the country.

Froehlich’s team has created a bat map to predict summer habitat, especially that of the endangered Indiana bat.  “All large development projects, road projects, anything that requires a permit, basically, has to check to make sure if they’re going to impact Indiana bat habitat,” said Froehlich. Thus, developers end up spending inordinate amounts of time and money trying to make sure that they’re not hurting the Indiana bat. “This project is an attempt to try to get ahead of that,” he said, so that they can better understand the habitat needs of the endangered bat.


To test the map’s accuracy, Froehlich spent his summer on late-night car trips, like the one he invited me to join. Hazards on and driving slowly, we waited to hear the chirps. As we drove back and forth along the Huron River, it took some time for the bat detector to light up. When we approached a bridge over a forested river crossing, Froehlich stopped and put a finger to his lips.

As we paused on the bridge, the hiss of the wind against the detector’s microphone slowly gave way to a chorus of faint chirps. Bats were out and breakfasting. Back in the lab, Froehlich will be able to analyze the digital sound recordings to discern the species of bats we heard.

The goal of the bat map is to identify areas like this. It factors in proximity to agricultural land, woods, development, and more. This information can then be used as a guide for prioritizing which spots to protect.

Tim Krynak, a naturalist at the Cleveland Metroparks, holds Baby, a rescued brown bat.
Tim Krynak, a naturalist at the Cleveland Metroparks, holds Baby, a rescued brown bat.

After hearing bats from a distance I wanted to see some up close, so I met with naturalist Tim Krynak and Baby, his rescue bat who now educates visitors to the Cleveland Metroparks.

To me, Baby looked like a flying mouse with really distinct feet, but Krynak hates to hear him (or any other bat, for that matter) described like that. Kryank has a real soft spot for his favorite creature, and it saddens him to see the widespread decline of their populations, especially since bats provide a lot of ecosystem services that benefit humans.

Bats are the prime controller of night-flying insects, he said, eating nearly their whole body weight in bugs every night. “A lot of those night-flying insects humans consider ‘pests,’ so by helping the bat population, we're helping control these night-flying insects, which then relates to our plants at home as well as our agricultural community,” said Krynak. He cited a recent study from Texas-based Bat Conservation International that found a colony of big brown bats controlled pests on a 100-acre farm as effectively as pesticides. “It's better for the environment, cheaper for the farmers just by encouraging bats in their area,” said Krynak.

Bats also help regenerate forests, disperse seeds, pollinate flowers, and keep the entire ecosystem in good health. Their guano makes good fertilizer, and they have even been a help to medicine.

A bat skeleton is on display at the Cleveland Metroparks.
A bat skeleton is on display at the Cleveland Metroparks.

Karen Hallberg is a wildlife biologist with the U.S. Fish and Wildlife Service in Columbus, Ohio. The Nature Conservancy’s bat map research lands on her desk. It’s her job to work with developers to minimize impacts to the endangered Indiana bat. They’ll take this research into consideration when making land-use decisions. “It’s going to be one of the many tools we use to evaluate these project impacts,” she said.

It could also work like a swing vote. “We will look at this model in a special situation where it’s difficult to make a decision whether impacts are likely or not,” said Hallberg.

She added that protecting bat habitat has a ripple effect. It doesn’t just benefit the bats but also improves stream quality, nutrient cycling, and other important natural functions.

Environmental science disputes the bats’ bad public wrap: far from being creepy “flying mice,” they are in fact a vital part of a healthy ecosystem.

Want to relocate a colony from your attic, or encourage bats in your neighborhood?  Learn how to build your own backyard bat box.