How Does a Bat Get Into an Attic Through a Chimney Without a Chimney Cap?

Bats can get inside through tiny gaps

If you have discovered bats in your attic you might be extremely puzzled as to how they got in. If you don't have a cap on the chimney they might well have come in this way. Bats are good at crawling as well as flying. However there are plenty of other ways for bats to enter a property. In order to exclude bats in the future you need to find their entrance.

Facts About Bats

There are at least 1,100 species of bat worldwide and 46 in North America. Aside from the tropical fruit bats, these animals are extremely small. The most common bat in the United States--the little brown bat--reaches an adult length of just three inches including tail.

How Bats Get Into Attics

Because bats are so tiny they can crawl or fly through the smallest spaces. There only needs to be a gap half an inch wide for bats to get in. Tiny gaps are actually more attractive to bats than big spaces, because it means predators cannot follow them.

How To Find The Entrance

Watch the places where the bats emerge at dusk. Chances are they will not all be coming out through the chimney. You will see their main entrances. There may well be other gaps, especially in older properties, so next go and examine the walls very carefully. Look closely around windows and where the walls join the roof. If your thumb will fit through a gap then so will a bat.

What To Do Next

Bats are heavily protected in many areas and you certainly should not think about killing them. Don't try to exclude them during the breeding season either. This will leave the babies behind to starve. If the young are old enough they may try to escape and crawl down into other rooms. Outside the breeding season fit one-way bat excluders over the main entrances and a cap on the chimney. This allows the bats to get out, but not return. Then caulk up all the other gaps no matter how small.

References

• California Department of Fish and Game: Living With Bats
• U.S. Fish and Wildlife Service: Endangered Bats of America
• Colossal Cave Mountain Park: Bats, and More Bats
• Bat Conservation and Management: The Bats of Pennsylvania