Brown Bat

Big brown bat hunting by echolocation. Note the large thumb in the middle of each wing. Photo courtesy of ODNR, Tim Daniel.

It was hard to get a good look at while it fluttered softly and silently. Eventually it landed, clinging to the white and green wallpaper. It looked so out of place, and my mother screamed as it took flight and dad tried to catch it with a broom. At the young age of 5 years, I was fascinated, and felt sorry it was trapped in our house. If you grew up in an older house or have stayed in a cabin, you may have had a similar bat encounter. Hopefully you had a better solution than a broom! (We eventually covered it with a shoebox, slid a large envelope underneath, and brought it outside. Note: Do not directly handle a bat with your bare hands, as a safety precaution.)

Bats can find their way into buildings through cracks and crevices, unscreened air vents, or maybe even an open door or window. Here in Ohio, from spring to fall, several species of insect-eating bats can be found in most areas with trees, fields, or water nearby. These tiny flying mammals use their excellent sense of hearing to hunt. Bats have an incredible capability to “see” by using echolocation. For example, big brown bats can emit two different frequency ranges at the same time, which allows them to determine the precise shape, size, and even distance from their target; all while in the dark! It truly is like seeing with their ears.

Bats belong to the order of mammals called Chiroptera, which means “hand wing.” Once a bat has located its prey, they use their wings and/or the membrane between their tail and legs to grab the insect and bring it to their mouth; all while in the air. It’s an incredible spectacle to watch them do this, but it happens so fast it’s hard to tell how it works. This video shows a bat using the membrane by its tail to bring the mealworm to its mouth.

Ohio has recorded 13 species of bats, but the two most common species you’re likely to encounter are the little brown bat (Myotis lucifugus) and big brown bat (Eptesicus fuscus). They are well named, with no major distinguishing features. Some of our other bats do stand out, such as red bat, which has red-brown fur, the silver-haired bat with a frosty gray color on the tip of its dark hairs, and the tri-colored bat with rose-colored forearms and dark black wing membranes.

All Ohio bat species share one thing in common: they are all extremely well adapted to catch & eat flying insects. Our bats consume midges, beetles, caddisflies, moths, mosquitoes, and more. Yes, mosquitoes! It has been estimated one little brown bat can eat 600 mosquitoes in an hour. If you have a patio or enjoy being outside on summer nights, you might appreciate having a bat colony nearby to keep those mosquitoes under control. Bats have been known to keep agricultural pests under control as well. They are most active at dusk and dawn, but bats may also forage throughout the night, especially the nursing mothers.

After hunting for a while, bats need to rest and digest. Their metabolisms are quite fast; it is estimated some species can completely digest their food in 35 minutes to an hour. Nighttime roosting sites are temporary, and bats usually rest by clinging to trees or eaves of buildings with their clawed feet. But they also need a daytime roost to sleep longer periods in a dark, protected place.

Ohio bats (and most in northeastern North America) typically spend summers feeding nightly and raising their young. When the season turns cold, and the insects are gone, bats survive winter by hibernating. Many will migrate to caves and abandoned mines, but some species overwinter in trees (such as red bats).

Bats in decline across North America
One of the major threats to bats is loss of habitat. Bats have lost roosting sites to deforestation, cave flooding, commercialization of caves, and general development. Unfortunately, loss of habitat isn’t the only challenge faced by these insect-eating machines. The large-scale use of pesticides seems to have caused a crisis. Chemicals can build up in their bodies over time. Recent findings suggest pesticides may interfere with bats’ immune systems.

Bat with WNS

Brown Bat with White Nose Syndrome. Photo courtesy of USFWS photo archive.

You may have heard of White Nose Syndrome (WNS); it is the name given to a phenomenon noticed since 2006 when hundreds of bats were found dead in a cave in New York state. The visible symptom is white fungal growth on the faces of hibernating bats. Since 2006, the fungus has spread to the Midwest, and most bat species are in sharp decline as a result. WNS affects hibernating bats in winter, and caves testing positive with the fungus have resulted in up to 90-95% mortality of the bats occupying the cave.

New research suggests that bats’ decreased immune function as a result of pesticides is making it harder for their bodies to cope with the fungus causing White Nose Syndrome.

“Two years after the honeybees started disappearing, so, too, did bats. The corpses of hibernating bats were first found blanketing caves in the northeastern United States in 2006. The disease that killed them, caused by a cold-loving fungus called Geomyces destructans — and dubbed White-Nose Syndrome for the tell-tale white fuzz it leaves on bats’ ears and noses — has since destroyed at least one million bats. University of Florida wildlife ecologist John Hayes calls it “the most precipitous wildlife decline in the past century in North America.”–Yale Environment 360

What you can do
While there is not much we can do to stop the spread of the fungus causing White Nose Syndrome, we can help ensure bats find summer habitat. Your backyard could be a great home for some species of bats, especially if your neighborhood isn’t spraying for mosquitoes or using large quantities of pesticides. Many people have installed bat houses on their property, which helps provide summer roosting sites and prevents bats from finding their way into your home or buildings nearby. If you are good with tools, bat houses are pretty simple to make. You can also purchase them as well.

Bat house description and plans offered by Organization for Bat Conservation:

Buying organic foods can also help bats. If you are able to invest in companies that do not use pesticides as part of their farming practices, you are helping bats as well as yourself (and countless other living things).

This season brings out all the myths and legends about bats and other misunderstood creatures of the night. You have heard bats are blind, or that they try to get in your hair and carry rabies. The fact is that there are many more reasons to appreciate bats than to fear them. To find out more about bats, check out this helpful website offered by Boston University, which covers facts, fiction, and so much more! — Colleen Sharkey

Colleen Sharkey has been a nature enthusiast and informal educator for more than 10 years. She lives in Columbus, near a couple of beautiful ravines that offer habitat to everything from nesting barred owls and red foxes to migrating warblers. Colleen is currently a Naturalist with Columbus and Franklin County Metro Parks.