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. 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.
Rough lumber allows bats to cling more easily.
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. Greatest success will be in areas where water is within a quarter of a mile and there is diverse habitat, including natural vegetation.