Each evening around sunset the Congress Avenue bats emerge like a black cloud from the crevices of the bridge. Covering the countryside in search of food, it is estimated that the bats consume from 10,000 to 30,000 pounds of insects.

Giving birth in June or July, the bats and pups hang around til October when they head back south. Watching the nightly forays for food is a favorite evening activity, especially in late summer.