Backyard Conservation - Beneficial Bats
Do mosquitoes bother you? Do you hate using insect repellants and aerosol foggers? Have you found that bug zapper to be somewhat less than effective--and a real annoyance? Maybe it is time to consider a bat colony! While myths have turned these fuzzy creatures into monsters, bats really are important, useful members of the ecosystem.
In the United States and Canada there are no vampire bats. While some bats carry rabies, the number of carriers is far lower than in many other wild animals such as raccoons. Besides, rabies kill bats quickly so they rarely show the aggressiveness seen in rabid dogs or cats. Even the less than half of one percent of bats that carry rabies normally bite only in self-defense and pose little threat to people who do not handle them.
A colony of 150 big brown bats can protect local farmers from up to 33 million or more rootworms each summer. The 20 million Mexican free-tails from Bracken Cave, Texas, eat approximately 200 tons of insects nightly. Best of all, a single little brown bat can catch more than 1,200 mosquitoes-sized insects in one hour!
Loss of natural roosts--such as tree cavities or caves--has impacted our most common species of bats. Providing an alternate roost can encourage bats to your yard and keep them from seeking shelter in attics.
Suggestions for providing shelter
Bat houses can be purchased or you can make your own. Books containing plans can be purchased at many bookstores or you can visit the Bat Conservation International, Inc. website for criteria for successful bat houses and answers to frequently asked bat house questions.
The best-designed houses are 24 to 36 inches tall, 16 to 24 inches wide, and 4 to 5 inches deep. Most houses have 1 to 4 (three-quarter inch wide) roosting chambers. Rough lumber allows bats to cling more easily.
Houses should be placed at least 10 feet above the ground, 15 to 20 feet is better. Houses placed on poles or on buildings are preferable to those hung on trees.
Bat houses mounted on poles or sides of buildings provide the best protection against predators. Try to locate the house 20 to 25 feet from the nearest tree. Using three-quarter inch roosting spaces helps limit colonization by wasps.
Houses should be placed so they receive at least 6 hours of sun a day (more in northern climates), but are protected from bright lights at night.
Greatest success will be in areas where water is within a quarter of a mile and there is diverse habitat, including natural vegetation.
Bat houses will be most successfully colonized the first year if they are installed before migrating bats return in the spring.
As with all wildlife, bats should not be handled. If a bat is close enough to pick up, it may be sick and should be left alone. You should not attract bats to places where curious children may try to handle them.
While fear of bats persists in the United States, the Chinese consider bats a symbol of good luck and some Native American cultures considered them powerful deities. Given a chance, bats can be a fascinating and beneficial addition to the wildlife in your neighborhood as they swoop around at dusk devouring annoying insect pests.
For more information on wildlife habitat and other Backyard Conservation practices, contact your local conservation district or the Natural Resources Conservation Service. Or call 1-888-LANDCARE (toll free) for a free colorful Backyard Conservation booklet and tip sheets.
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