At Exclusive Batproofing, we have successfully bat proofed 1000's of homes. Our bat friendly process of exclusion was developed in the 1970's by the nations leading bat specialists Marshall Hanks and Dr. Merlin Tuttle who went on to establish the organization Bat Conservation International based in Austin, Texas. Using this method, the bats are allowed to exit the structure through a one way device that we make called the Excluder. We mount the Excluder at the exit points being used, allowing them to leave the structure generally for feeding (every night or two) without any hindrance. Because of their longevity (30 yrs.), and reluctance to change living quarters, all other possible reentry sites need to be sealed to prevent the bats from finding a new way into the structure. This includes any crack 1/4" wide by 1" long, (the width of a pencil by one inch long), or a hole roughly the size of your thumbnail. Within a few days all the bats living in the structure will exit through the Excluders and, because of their inability to reenter, will out of necessity move on to find a new place to call home.