Bats make great neighbors. One little brown bat, for example, can eat up to 600 flying insects per hour. That means a colony of just 10 bats can consume up to 60,000 flying insects every night. There is no better natural control of night flying insects, which includes mosquitoes and myriad garden pests.
But when bats actually move into the house, that's closer than even most avid nature lovers care to get. A recent e-mail, typical of notes I get this time of year, complained that bats were roosting in the attic. What's a homeowner to do when bats get too close for comfort?
Here are answers to some of the most common questions about bats I receive from readers each summer.
What kinds of bats roost in attics and barns? Little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) are the most likely species to occupy buildings in the northern two-thirds of the United States. Other possibilities include evening bats (Nycticeius humeralis) and eastern pipistrelles (Pipistrellus subflavus).
Will bats spend the winter in the attic? Big brown bats might. Other species either migrate south to a familiar hibernaculum, or they might hibernate in local caves.
Building a bat house
Where can I get plans to build a bat house? The best source of information about bats and bat houses is Bat Conservation International (www.batcon.org; Box 162603, Austin, TX 78716). Two small books published by BCI, The Bat House Builders Handbook ($8.95) and America's Neighborhood Bats ($10.95), answer virtually any question you may have about bats.
Where should I place a bat house? Based upon a BCI survey of bat house owners, bat houses are most likely to be occupied if they 1) are located less than one-quarter mile from a stream, river or lake larger than three acres, 2) receive at least four hours per day of sun, 3) are stained a dark color (to absorb heat), 4) are near orchards or other farmland and 5) are mounted on a pole or on the side of a building at least 15 feet above the ground. Place a well built bat house in an area that meets all five criteria, and your chances for success are excellent.
How can I get rid of a bat that gets into a living room or bedroom? Simply open a window or door. Bats have keen vision (they are not blind) and a sophisticated echolocation system, so they will find their way out at dusk.
Can bats be coaxed to move from my house to a bat house? Probably not. Bats are in the house because it meets their roosting needs, so they must be physically excluded. After you evict them, they may move into a bat house.
How do I exclude a colony of bats from my attic? Bats leave their roost at night to feed, so it's a relatively simple matter to plug all entrance holes to the house while they are gone. Unfortunately, that's not easy. Your best bet is to let a professional handle the job. Look under "wildlife damage control" in the Yellow Pages. Make sure sealing all entrances to the attic is part of the job and have the work guaranteed in writing.
Do bats carry rabies? Yes, like all mammals, bats can carry rabies. But few do. Most infected individuals die quickly; rabies epidemics in bat colonies are rare. A healthy bat will never be found grounded out in the open. Never touch or handle a bat, and your risk of contracting rabies from a bat is virtually zero.
According to BCI, bats pose little risk to human health. Since record keeping began 50 years ago, fewer than 20 Americans have contracted rabies from bats. Bee stings, vicious dogs, and food poisoning kill more each year.
Another disease associated with bats is histoplasmosis. This fungal disease is associated with the droppings of many animals, including birds and cats, as well as bats. Histoplasmosis does poorly in hot, dry places, so attic heat should control this problem.
XSend questions and comments to Scott Shalaway, R.D. 5, Cameron, W.Va. 26033 or via e-mail to sshalaway @aol.com