Asked July 27, 2017, 1:00 PM EDT

We have an ever-growing bat colony that lives (as best we can tell) under the tiles in our roof and tucked into every available nook and cranny between the house and roof line. We also suspect that they are in parts of the attic. What can we do to encourage them to move on? Our main complaint is the bat guano that is getting on the deck, windows, etc. We love bats and certainly do not want to hurt them, but the guano is pretty gross. Also, what started out as a cute little group of bats now numbers in the many hundreds (if not thousand). Thanks for any ideas!

Deschutes County Oregon wildlife damage management bats

1 Response

Thank you for your question about how to safely evict bats from your house.The process relies on excluding them from the structure by covering all possible entries and installing one-way devices so that they can exit but not re-enter.

“It is important not to disturb roosting bats at any time of the year. In the spring, disturbing a maternity colony when flightless young are present may cause young bats to be dropped to their deaths, or abandoned, by panicked females. Because some bats hibernate in buildings during the winter months, batproof a building only when you are sure no bats are hibernating in it. If bats are found hibernating inside after October 15, they should be left alone until early spring (prior to the birthing period in May) after the weather has warmed enough for insects to be out regularly. Meanwhile, seal all potential entry points into human living spaces, and develop a plan so the exclusion process can be accomplished effectively in spring (see “Bats Roosting in Buildings”).”

The above excerpt is from “Living with Wildlife – Bats” ( where you’ll find additional detailed information. Tactics for preventing conflict with bats are explained on page 4, for excluding bats on page 5.

If you prefer to hire a professional to do the exclusion, see the list of Certified Wildlife Control Operators in Oregon at

Thank you for your concern about these small beneficial animals.