Bats live their silent lives around us as we sleep, quietly going about their work as the primary predators of night-flying insects.
As consumers of vast numbers of pests, they rank among humanity's most valuable allies. According to Dr. Merlin D. Tuttle, founder of Bat Conservation International (BCI), a single little brown bat can catch hundreds of mosquito-sized insects an hour (between 3,000 and 7,000 mosquitoes in a night!), and a typical colony of Big Brown bats can protect local farmers from the costly attacks of 18 million root-worms each summer.
"Bats are not blind. They are very clean animals. They do not get caught in people's hair or eat through the attic of your house. Bats will not interfere with feeding backyard birds," says Doug Gelbert, a long time bat aficionado. Further dispelling myths surrounding bats, Mr. Gelbert says "Like all mammals, bats can contract rabies but few, less than one half of one per cent, actually do; that is far fewer than cases of rabies contracted from family pets."
Bats are an ideal neighbor to have in a suburban backyard, diminishing the mosquito population by thousands of insects each night.
Indiana State University biologist John Whitaker published a 1995 study of bats and their diets. His data suggest that farmers might effectively employ bats against beetle scourges such as cucumber beetles, the larvae of which severely damage corn, melons and other crops. "Farmers interested in sustainable growing methods are turning to natural controls, and some are integrating bats into successful pest management programs," Whitaker reports. While little research is available quantifying the impact of bats on crop productivity, some data provide encouraging information about the diet of common bats and their relation to agricultural insect pests.
If you recognize the benefits of attracting bats to your property, providing a roost or bat housing is a good first step. BCI, a nonprofit organization, offers technical assistance in this regard. BCI guidelines recommend that bat houses should be at least two feet tall, 14 inches or more wide, and have a 3-6 inch landing area below the entrance. Houses should include roosting chambers, with the chambers spaced 3/4 inch to 1 inch apart; the small spacing reduces wasp use. Rough wood surfaces or surfaces covered with durable plastic screening allow the bats to cling to the roost. The BCI warns against using pressure-treated wood but builders should use quality materials. "It often takes several years for bats to colonize the house and with already declining bat populations it is unwise to disturb a bat house for repairs," advises Dr. Tuttle.
Bat house builders find temperature control to be important, particularly in areas with hot summers. So houses should include wide front vents and 6-inch tall side vents. Three coats of outdoor paint help protect the exterior, but the recommended color varies according to climate. Bat houses can be placed 15 to 20" off the ground, preferably on a pole to protect against predators. "When mounting houses, place the boxes so they receive at least six hours of direct daily sun and the houses should be within 1/4 mile of a water source," recommends Tuttle.
- bats are mammals that produce only one or two live young each year
- young bats are fed on milk and nurtured by their mothers until they are able to forage on their own
- a community of bats will create complex relationships among themselves and can easily identify bats from another colony
- bats are the only mammals that can truly fly
- bats use echolocation to move about in complete darkness, easily tracking down their tiny prey and avoiding collisions with objects and other bats on their own erratic flight paths
- the Big Brown bat, common in the Midwest lives throughout the continental US. The Little Brown bat is prevalent in all states except Louisiana, Texas and Florida
©2007 Brenda Thoma
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