Live near a wetland or river? Then chances are your home will attract bats, particularly if the home is older, has an open chimney or attic vents. Now bats in your yard are a wonderful thing: A single bat will eat her entire weight in insects in one evening. Bats are a safe, natural environmentally friendly insecticide. We live on a river, yet we enjoy bug-free evenings all summer long.
Bats in your home present a problem, however. While bats do not often bite and are rarely rabid, they are carriers of rabies. Pets, cats in particular, are in special danger from bats; your pets will chase the bats and naturally the bat will bite. One of our cats once caught a bat in midair. He scooped the bat out of the air and put the bat in his mouth, all in one incredibly fast movement. Thankfully, he was not bitten, but he easily could have been. Also, bat feces (or guano) is quite toxic.
To prevent bats from roosting in your attic, you need to check several things. Bats are a species protected by the Environmental Protection Agency (EPA) so an exterminator will not put down any form of chemical to prevent bats from roosting. When we discovered that a roost of bats were tenanting our attic, we made calls to several exterminators and environmental and wildlife organizations. We were given this advice.
- Stake out the perimeter of your house.
- Sit outside, one person on each side of the house in the evening before dusk. Being nocturnal, bats go out in the evening, just before dark.
- Watch when dusk falls to see if bats are exiting your house and identify where they exit your house.
- Place screens over attic vents. Don't not seal them completely; attic vents are necessary to keep the attic from accumulating toxic furnace gases such as carbon monoxide.
- Place a screen over the chimney, especially if it unused. (Newer homes have narrow PVC tubes to vent the furnace; if your furnace has been replaced, your unused chimney will be a perfect access way for bats.
- Seal up any gaps in windows, siding, ceiling tiles or walls. Use caulk or silicone to seal up cracks in walls. Bats can enter and exit through cracks no wider than one half an inch.
- Place a substance with an unpleasant fragrance in your attic. Choose something non-toxic. Strong mint, menthol or eucalyptus is a scent many animals do not like. Don't use sugary mint or you'll have ants next. We prefer to use Vick's VapoRub. These smells are entirely harmless to bats and pets, but they are very annoying and effective in keeping them away.
- Some people recommend placing mothballs in the attic, but mothballs are really a very strong smelling toxin. Mothballs are made either from naphthalene, more commonly known as naphtha, and the other is para-Dichlorobenzene, which is a form of benzene (a poison that was used for removing stains). Do not use mothballs to prevent bats from nesting. The fumes cause breathing problems and are particularly harmful for children and pets.
If you have bats in your area, let them do their job and keep the insect population down. But be sure to keep them out of the house. For more information on what to do should a bat make it into your house, read How To Get a Bat Out of Your House.
Marilisa Sachteleben is a special general education teacher, happily married wife and mother of four. She writes for several online communities.