Bats are the single most important controller of night-flying insects, including mosquitoes, moths, and beetles. For example, a single little brown bat can catch up to 600 mosquitoes in an hour. Watching bats fly around light posts catching bugs can be an interesting nighttime activity. A bat house in your yard will help attract bats and provide them with much-needed roosting habitat. The house should be placed on a pole at least 15 feet high in a spot that receives sun most of the day.
Tree trunks are usually too shady for bat boxes.
Some bat species such as gray bats, red bats, and hoary bats will use shrubs and trees for roosting under loose bark or in cavities. Many species of bats migrate in the fall and hibernate throughout the winter months in caves, mines, or buildings. If disturbed during hibernation, their metabolism is increased, depleting fat reserves and reducing their chances of survival. As with all wildlife, bats should be watched, but not handled or chased. Generally, bats are shy of humans and will not attack or fly after a person.