What Is the Right Way to Get Rid of a Bat Colony in My Chimney?

Seeing bats in the sky is one thing, but what if they are in your house?. antoni halim/Shutterstock

Q: I have a 100-year-old house — and a huge bat colony inside one of the chimneys. What is the green method to get rid of the bat colony?

Gary Gruby

A: I guess wearing a garlic necklace and screaming at the top of your lungs did not resolve the problem? Removing bats can be a tricky and somewhat dangerous task because they tend to prefer the highest points on a home, such as attics and chimneys. The humane approach to evicting bats involves creating exclusions, structures that allow bats to safely exit your home but not return. Once they have been evicted, you must seal those crevices that provided easy access. Bats can squeeze into a pretty tight space, so finding every hole at such a high elevation may be a dangerous and time-consuming process.

Bat Conservation International, an organization that celebrates all things batty, suggests sealing holes with water-based caulking rather than expanding foam, which can entangle bats as they attempt to exit. The organizatin's website is chock full of fascinating facts, tips and resources about bats. Along with instructions for creating exclusions, the site provides a list of professionals who pledge to use safe exclusion practices. I personally recommend calling in a pro, unless you are handy with a ladder or you fancy the idea of appearing on "America's Funniest Home Videos." If you do tackle the project solo, take note that bats typically do not exit at the same time. The exclusion process could take a few days.

When you do tackle this bat relocation exercise, make sure to wear gloves and avoid handling the animals with your bare hands. The chance of contacting rabies is rare, but you should consult a physician immediately if you are bitten.

You also need to create a safe place for bats to reside outside of your home. The National Wildlife Federation explains how and why to build a bat house for your flying roommates. You can also check out a copy of "The Bat House Builder’s Handbook" from your local library to get more step-by-step details on construction. Also, the conservation organization suggests holding off on exclusions between April and August when bats are giving birth and raising their pups. If you like gardening, bat poop makes great fertilizer, so your bat house could be a little gold mine for the garden. According to Bat Conservation International, bats provide natural pest control by eating insects and they play a vital role in dispensing seeds for various plants.