Once you've humanely removed a bat from inside your house or evicted them from your attic, how can you keep bats from coming back indoors? Make sure they have plenty of places to live outdoors.
Bats are gaining an appreciation for their ecological contributions as pollinators, seed dispersers and insect predators. They’re also fascinating animals to watch. Sadly, though, bats are suffering from habitat loss and other hazards.
Protect natural habitats
Give bats places to stay by protecting and planting native vegetation, and leave dead trees standing as shelter, when it's safe to do so. Those with caves or abandoned mines on their property can provide fencing and signs to keep people from disturbing hibernating bats.
To the bat house!
Put up a bat house to reap the benefits of having bats nearby. Whether you buy one or build your own, here are a few suggestions:
Bat house size and features:
- More than 24” tall with 1 to 4 chambers, at least 20” tall and 14” wide
- Chambers 3/4” - 1” deep
- Horizontal grooves inside chambers, 1/4” - 1/2” apart
- Landing plate with grooves
- Shingled roof
- Open bottom
- Painted or stained surfaces and sealed seams
- Mount on a building or metal pole.
- Do not place above a window, door, walkway or deck.
- Mount with a 2” - 4” spacer and a long backboard.
- Place a shallow tray below for droppings.
- Choose a spot with at least 7 morning hours of sun, except in particularly hot regions.
- Mount houses on poles back-to-back, facing north and south.
- Choose a spot near water and diverse habitat, 20’ from the nearest tree branch or other potential perch for aerial predators.
- Avoid spots near air conditioner units, air vents or burn barrels.
- If vandalism is likely, choose a safer location.
- Monitor for predators, hornets and overheating in summer.
- Clean out any wasp or mud dauber nests each winter.
- Caulk, paint and stain every 3 to 5 years.
- Move or modify the house if no bats occupy it for 2 years.
Prevent bats from entering your home
Look for loose-fitting doors or windows, unscreened chimneys, or gaps in walls. Bats only need a gap of 3/4" to 1" to enter. Plug any gaps with door draft guards, hardware cloth, steel wool or caulking.
If you need to evict bats from your home, do so in early spring or in fall, when flightless young will not be present. Install a bat house as part of the project.
Worried about disease?
Don't let the threat of rabies prevent you from protecting bats. Bats are rarely rabid—and they are unlikely to be aggressive. Bats who do contract rabies die quickly, so they don't cause an ongoing threat. Follow normal safety practices: Do not handle bats with bare hands, warn children not to handle bats, and vaccinate dogs and cats for rabies.
- Bat Conservation International has a Bat House Builder’s Handbook and a Building Homes for Bats DVD, as well as ready-made boxes and kits, in their online catalog.