Bat Colony Exclusion

Bats are extremely beneficial animals, but we understand why you might not want to share your house with them. If you are reading this page, it's likely that you have bats living in your house, and more specifically in your attic. At night, those same bats are eating thousands of insects in and around your yard, helping your garden and making it more enjoyable for you to be outside in the evening.

We at the Organization for Bat Conservation suggest that when doing a bat exclusion you make sure to provide an alternate home for bats by putting up a bat house. It's very likely that the bats are roosting in your house because there aren't better options available. Bats often prefer dead or dying trees as a place to sleep during the day. Unfortunately bat habitat such as dead trees, are often cut down or destroyed providing fewer options for bats. We don't expect you to share your house with bats, rather we hope that you'll provide them with a safe place to live outside of your home and in return they will feast on the nighttime insects in your backyard.

So, how do you get the bats out of your house? There are safe and humane methods to follow for a do-it-yourself plan or you may want to hire a local company to do the exclusion for you. Please be sure to verify that the exclusion services provided are humane and effective. OBC recommends Critter Catchers for your bat removal needs for those in Southeast Michigan. If you have just one bat in your house, please refer to our steps here.

Please Note: NEVER conduct bat exclusions between the months of May to August. The pups are not able to fly until late summer. A summer exclusion may cause baby bats (pups) to become separated from their mothers, trapped in your home and resulting in death.

Basic Steps for a Proper Bat Exclusion:

  1. With a group of family members and friends, find out how bats are getting into your house. Each of you will stand at a different location around the house just before sunset. This will allow you to see what crevices bats are using to enter/exit your house, plus give you a good idea of how many bats are residing in your home. Bats don't all leave at the same time, so be sure to watch for them for 30-60 minutes after sunset. Bats may use multiple entry points so it's best to watch for several nights, until you are confident of their exit location(s).
  2. Mount a bat house near one or more of the openings. This can be on your house, or nearby on a pole. Please review our bat house section for more bat house information. It is best to mount the bat house a week or more before doing the exclusion, allowing the bats to be aware of their other roosting option(s).
  3. During the day, cover all openings that the bats are using with a sheet or cone of plastic mesh. Attach the mesh on the sides and top, but leave the bottom open. The mesh should be attached loosely enough to allow the bats to exit. Duct tape or staples can be used to attach the mesh.
  4. At dusk the bats will begin to exit your house. They are able to crawl out from under or through the mesh, but will not be able to enter upon their return. Instead they will search for a nearby roosting location, often times the bat house you mounted.
  5. Leave the mesh in place for 5-7 days to ensure that all bats have left your house. Be sure that they have not found a new opening into your house by watching at sunset and also, if possible take a look in your attic (or their roosting location in your house) during the day. If all bats have vacated your house, permanently seal all openings.

The bats may not choose to use the bat houses you have provided for them, or it may take some time until the bat houses are occupied. Either way, be sure to leave the bat houses up so they are available for the bats when they choose to start using it.

Never physically remove and relocate the bats. Bats are wild animals and should not be handled. They are also protected, important species and should not be harmed.

© 2012 Organization for Bat Conservation
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