How to Discourage a Bat From Your Attic

Step outside as evening descends and watch the windows, vents and other possible openings into your attic. If you do have bats in the attic, you can see how they are getting in and out as they leave at night for food. You can also confirm their presence by looking for guano, or bat droppings. This waste crushes easily and contains shiny bits, which are pieces of undigested insects. Guano is distinguished from bird droppings because it is not chalky or white.

Make sure all the bats are out of the attic. If you can't wait until winter, when bats leave buildings for their winter roost sites, use staples or duct tape to affix bird netting around all holes or cracks larger than 1/4 inch -- bats can squeeze through openings that small. However, don't tape or staple the bottom of the squares of netting. This way, bats flying out of the attic will hit the netting and fall downward and then fly away. They won't be able to get back in, however.

Permanently seal any holes or cracks after the netting has been up for a couple of days and you are sure there aren't any more bats in your attic. The Connecticut Department of Environmental Protection recommends caulk, fine screens or petroleum-soaked rope to seal off any entrance holes.

Install a bat house to lure the bats outside, and have your own colony of insect killers. You can build your own bat house or buy one as a premade kit.