Skip to Content
Green news from the UC Division of Agriculture and Natural Resources
by Leslie Kruth
on November 11, 2016 at 8:12 PM
We do not have too few bats....we have way too many living in our house near the Bolinas coast. We love them because they really do keep the mosquitos down. HOWEVER, that said, they roost 5 stories up at the top of our eves and behind the old boards all over the south-western exposure of this building. They make a terrible mess which we fear may be hazardous to our health since their dropping cover the entrance to the building. We have tried various measures to keep them out since we know they only need a 5/8" opening and space in which to live. We put up a couple of bat boxes which they are now occupying. While slightly diminished, there are still too many and we know they are very happy and will continue to multiply. We took off one side of the building and replaced it with metal, but now we are looking for an alternative solution. We would like to keep the old redwood boards if possible. If we cover that side of the building with a 1/4" plastic mesh (assuming we can find it and an installer), will the bats eat thru it and all will be for naught? We are pretty desperate and resisting dastardly measures. As an expert can you help me? I would be happy to donate my bats to the Yolo Bypass!! Leslie
by Rachael Long
on November 12, 2016 at 12:03 PM
So glad to hear you like bats, but I agree, they don't belong in your house! Bats have a strong homing instinct and will return to the site where they were born every year. So, once you have them, they are tough to get rid of. In your case, I would recommend hiring a professional vertebrate pest control specialist to exclude your bats due to the high numbers, tricky areas to access, and the need to protect the bats. Bats generally have one young a year late spring and one has to be careful not to exclude the females from their young because the pups cannot fly until they are about 6 weeks old. Sometimes a colony will show up out of the blue and stay for a few weeks in the spring or fall; these again are migratory bats and if you leave them alone, they will move on. Yours, however, seem to be a maternity colony, where mothers are raising their young and they'll stay for many months and possibly year round. I'd be glad to talk with you further. Please email me at and we can figure a time to chat. Thanks for your interest!
Leave a Reply:

You are currently not signed in. If you have an account, then sign in now!
Anonymous users messages may be delayed.

Security Code: