Hanks began to learn all he could about bats and their habits, discovering that they were very beneficial. Poisoning them wasn't in anyone's best interest, he concluded. So he came up with the idea of a small, one-way bat excluder, an ingeniously simple device mounted directly over a bat exit hole, allowing bats to leave but not to return. He experimented with dozens of designs and today tailor-makes each excluder specifically for the job. And with as much as he has learned about the habits of house bats, Marshall Hanks has become an expert at knowing just where they are likely to enter a home.
Bats can enter attics through holes less than an inch in diameter.
High on a ladder, Hanks begins by bat-proofing a building with caulk, leaving open only a few strategic holes to be outfitted with his excluders. One of their most recent joint projects is evicting thousands of bats from several stadiums at the University of Florida in Gainesville. The effort has gained national attention because the university is also building alternative housing for the bats. The new roost is experimental and potentially will accommodate as many as 200,000 bats. While Hanks likes bats, he realizes that most people don't appreciate having large colonies in their home because bats can stain ceilings and cause odor problems.