Bats in my attic

Asked August 21, 2019, 4:57 PM EDT

I have bats in my attic. I don't want to kick them out this year, just want to seal it up once they're gone for the season. When will they migrate so I can start getting it done? Also, what size openings can they get through? Don't know the species, as I learned of this from a worker who had to get into the attic. I'll put up bat boxes (using your expert guidance in other publications) to give them alternate housing next year. Thanks, Marian Alter

Lane County Oregon

1 Response


Thanks for your interest in protecting bats while excluding them from your attic. Our wildlife expert Dr. Dana Sanchez is away, but here are some insights that she's shared in past that should hopefully get you pointed in the right direction:

  • "By late August the bats (adults and young) should be gone or in the process of leaving the seasonal roost. The task of excluding the bats will be simplified if you watch for their use of exits shortly after sundown (to 1st hour of dark) as they leave to feed for the night. That would help identify specifically where they're entering/exiting. This pamphlet is getting some years on it but their descriptions (pages 19-20) of building check-valves (1-way exits) and long-term exclusion solutions can be helpful for addressing your building's particular situation." (originally written for Linn County but likely your area has similar migration times)
  • "Bat Conservation International has compiled an excellent booklet on managing bats in buildings that could be very helpful-
  • Another option would be to engage a trained and licensed Wildlife Control Operator to assess the situation and provide either guidance on how to remove and exclude the bats, or to actually perform the work."
I hope that helps you plan next steps. Please reach out if we can assist further.