Illinois’ Bat Population: 5 Things You May Not Have Known

August is prime bat-watching season here in Northern Illinois, in case you're looking for evening entertainment.

If you happened to look up at the sky late last night or early this morning, you may have noticed some tiny, fast-moving creatures swooping and diving overhead, and it wasn't your imagination. Northern Illinois is home to plenty of bats, and summertime is prime time for seeing them at work.

But how much do you really know about Illinois' bats? Here are five things that might surprise you about these small, late-shift workers.

black bat

Let's Get Started On Illinois Bats 101

1. Illinois is home to 13 different species of bats.
And every one of them eats insects. Some species are permanent residents, while others migrate south for the winter. Eight species hibernate in Illinois, while five leave the state when cold weather arrives.

• Big brown bat
• Eastern red bat
• Hoary bat
• Silver-haired bat
• Evening bat
• Tri-colored bat (formerly called the eastern pipistrelle)
• Little brown bat
• Indiana bat
• Gray bat
• Southeastern myotis
• Northern long-eared bat 
• Eastern small-footed bat
• Rafinesque's big-eared bat

2. One bat can eat thousands of insects in a night.
Wildlife Illinois estimates that a single bat can consume as many as 3,000 insects in one night. That includes mosquitoes and agricultural pests, making bats nature's own little nighttime pest-control service.

3. Bats aren't blind. And they're not vampires.
All Illinois bats are insect-eaters, not blood-drinkers. They use echolocation to locate prey in the darkness, producing sounds and listening for the echoes to determine where that next meal is hiding. Bats are the only mammals capable of true flight.

birds on sky

But Wait, There's More

Let's get to the final two things that you may not know about Illinois' bats.

4. Illinois' bats have taken a serious hit.
Six of the state's 13 bat species are listed as endangered or threatened. One of the biggest threats is white-nose syndrome, a fungal disease first detected in Illinois during the winter of 2012-2013. It has devastated populations of several cave-hibernating species.

5. Bats aren't just creatures of the countryside.
Researchers have found bats, including the federally endangered northern long-eared bat, are living in surprisingly urban areas. Recent Illinois research found them in city environments, particularly where trees, streams and other green spaces provide habitat.

So the next time you see those little silhouettes darting across the evening sky, don't worry that they're going to end up in your hair. They won't. They're out actually doing your neighborhood a pretty big favor, 3000 or so bugs a night.