If you see a bat in your garden, don't loose your mind. As you may have heard, bats are very beneficial. They are one of North America's most 
exotic exterminators. They just love to munch on mosquitoes, black flies, and other insects.
You can attract a colony by hanging bat houses, and by planting night blooming flowers. Bat houses should be placed on the South wall of a 
structure and about 15 feet from the ground. Bats will need a good supply of water. Half a mile from a lake or stream will be sufficient. One more very important point: Do not hang the bat house in a tree. The tree is prone to harbor predators. They might not spot your bat house for a while but once they move in they’re extremely loyal to their roost and will return year after year. If you have bats, consider yourself lucky. They don't bite, or swoop after you, and you are more likely to get rabies from the raccoon in your garbage can.