When can I exclude bats from my belfry? And other related questions...

Asked July 23, 2018, 4:37 PM EDT

OK, its not my belfry, its my attic. Can you tell me the timing for performing a bat exclusion from the attic? I know it must be after the pups are fledged. I imagine it varies by species. I don't know the species I am most likely to have. My house is in Capes Meares, Tillamook County, just a couple blocks from the ocean. Another unknown to me is whether they are hibernating in my attic during the winter, or if they most likely leave for other climates. If they leave, I could seal up the holes during the winter, but I don't want to trap them in that manner. These are dormers with the finish material applied to the underside of the rafters. So there is no access to the roosting area. They are entering by way of small holes where the dormer vents meet the roof. I do have some bat cone one-way devices that I intend to use for the exclusion project. Is this the best device? If I succeed with exclusion, I wish to install bat houses around the property to encourage them to stay in the neighborhood. Do you have advice about that?

Tillamook County Oregon

1 Response

Here's a recent response to a similar question from Dana Sanchez Associate Professor and Extension Wildlife Specialist:

"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 http://icwdm.org/handbook/mammals/mam_d5.pdf 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."

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