Excluding bats from your home
Excluding bats from your home is not difficult. Even though bats are a vital part of the ecosystem, there is no reason you need to allow them to live in your home. They can be excluded from your dwelling by following these recommendations:
- Do not perform exclusions until late August after the pups have been weaned and are able to leave the roost on their own. You do not want to seal young animals inside a structure where they would die and lead to further health problems for you.
- Identify the entries the bats are using. Find them by looking for stained places on the sides of your house and watching in the evening for the bats to emerge. If there are many entries to the same roost, seal all but one.
- During the day while the bats are asleep in their roosts, create a one-way flap-valve by positioning netting (1/4" mesh or less) hanging loosely in front of the exit. (Nylon netting can be purchased by the foot in stores such as Home Depot.) Tape or tack the top and sides, but leave the bottom open with the netting hanging loosely down a foot below the entry. The bats will be able to leave, but not reenter.
- When the bats emerge, they will meet the netting and start climbing around trying to find a way out. Soon they will get out the bottom and go off to eat. But they are not clever enough to get back in the same way in the morning. You have created a "one-way door".
- Leave the netting up for 2-3 nights to make sure all the bats are out.
- After a few days, take the netting down and seal the holes. This is very important because the bats will return if they can! Any caulking can be used since, unlike rodents, bats do not gnaw holes, shred materials, build nests or cause structural damage to buildings.
- If you prefer, you can wait until late autumn and seal the entries without the one-way flap because the bats will have left for their hibernation sites.
- Think about providing an alternate home for these bats. Bat houses mounted close to the old entry are usually used quickly.
Nuisance Wildlife Control Operators These professionals are trained and regulated by WDFW to provide assistance for services that the department does not have the staffing or funding to provide itself. Because NWCOs are private businesses, they normally charge a fee for their services.
Washington State Department of Fish and Wildlife have tips for exclusion also, Living With Wildlife.