As temperatures drop and the leaves disappear from Michigan’s trees, many of us start wondering what happens to the wildlife around us, especially the bats that may have roosted in our homes during warmer months.
If you’ve heard scratching in your attic or found bat guano near your eaves, you’re not alone. So, when exactly do bats in Michigan settle down for the winter, and how does that affect homeowners?
Let’s get into it.
Key Takeaways
- Most bats in Michigan hibernate from late October to March in places like caves, attics, or wall voids.
- Hibernation depends on cold weather, local bat species, fat reserves, white-nose syndrome, and nearby food or habitat.
- Finding a hibernating bat means you should not disturb it and instead keep the area sealed and quiet.
- Pest Pros of Michigan can inspect your home and schedule humane bat exclusion when spring activity begins again.
When Do Bats in Michigan Hibernate for the Winter?
Most bats in Michigan begin hibernating in late October and stay in hibernation through March or even early April. This window can vary depending on the weather and the bat species involved.
During these colder months, bats enter a state called torpor, which helps them conserve energy by slowing down their body functions. You probably won’t see them flying during winter because they depend on stable, undisturbed environments, called hibernacula, to survive the cold.
If your home in Lansing and Ann Arbor offers a quiet, dark space that doesn’t freeze, it could become a bat roost without your knowledge.
What Affects When Bats Hibernate in Michigan?
If you’re trying to figure out when bats might start hibernating near your home, there’s more than just the temperature to think about.
Here’s what to watch for:
Cold Weather
The drop in temperature is one of the biggest triggers for bat hibernation.
In Michigan, the first hard frosts usually show up in October, which signals to bats that it’s time to find shelter. As soon as insect activity drops, they follow their instincts to find a place to shelter.
Bat Species
Different bat species in Michigan hibernate differently.
The little brown bat and big brown bat, for example, are among the most common hibernators found in homes. Big brown bats can sometimes overwinter in buildings and become active during warmer spells.
Migratory species like the red bat, hoary bat, and silver-haired bat typically head south before winter hits.
White-Nose Syndrome
White-nose syndrome is a devastating fungal disease that has hit Michigan’s bat population hard, especially species like the tricolored bat, northern long-eared bat, and Indiana bat.
This disease changes where and how bats hibernate, sometimes forcing them to seek alternative roosts that may not offer the protection they need, like your attic.
Local Bat Habitat
Homes near forests, wetlands, or bodies of water are more likely to have bats nearby. That’s because these areas offer food in the summer and potential spots in the winter.
Homeowners in areas like Lapeer or along the Grand River may be more likely to find hibernating bats on their property.
What to Do if You Find a Hibernating Bat on Your Property
If you find a bat hibernating in your home or garage, what you do next is important. Here’s what you can do to handle the situation safely and responsibly:
Stay Calm and Don’t Disturb the Bat
First off, don’t panic. Bats in torpor aren’t aggressive. They’re vulnerable and slow-moving. The best move is to avoid touching them altogether.
Disturbing hibernating bats can cause them to wake up and burn through their fat reserves too quickly, which can be fatal to them.
Close Off the Area
If you find bats in your attic or garage, keep the space sealed off from the rest of your home. Close doors and avoid using the space if possible.
This limits human-bat contact and helps them stay undisturbed until they naturally leave in spring.
Contact a Professional for Bat Removal
Never try to remove hibernating bats on your own.
Wildlife removal in winter requires experience, and in many cases, permits from agencies like the Michigan Department of Natural Resources or the U.S. Fish and Wildlife Service, especially if protected species are involved.
A professional can assess the situation and help with humane bat exclusion when the time is right.
Don’t Attempt Bat Exclusion in Winter
Bat exclusion, sealing entry points to keep bats out, should never be done in winter when they are hibernating. Doing so can trap them inside your home, where they may die or end up in your living space.
Spring and late summer are better times for this work, when they are active and can leave on their own.
Prep for Future Seasons
If you’ve found bats hibernating in your home, chances are they’ll be back.
Now’s a good time to schedule an inspection for spring. Sealing entry points and installing a bat house away from your home can guide them to a better roost next time.
Don’t Wait Until Spring if You Suspect Hibernating Bats
Bats are a vital part of Michigan’s ecosystem, but they don’t belong in your attic.
If you suspect you’re hosting a colony of bats this winter, or you’ve seen guano, heard scratching, or noticed an entry point, your best bet is to get expert advice.
At Pest Pros of Michigan, we offer bat control and removal that’s safe, humane, and aligned with DNR guidelines. Our local techs know what to look for and when to act, so you’re not left guessing through the winter months.
Let’s make sure your home stays yours this season, without unexpected guests.
Reach out now for a bat inspection or to talk about setting up exclusion work for spring.
