The Austin pink sunset fills the sky with color as the bats take center stage and exit the Congress Avenue Bridge.jpg
Ann W. Richards Congress Avenue Bridge is home to the world's largest urban bat colony, which is composed of Mexican free-tailed bats. The bats reside beneath the road deck in gaps between the concrete component structures. They are migratory, spending their summers in Austin and the winters in Mexico. According to Bat Conservation International, between 750,000 and 1.5 million bats reside underneath the bridge each summer. Since Austin's human population is about 750,000, there are more bats than people in Austin during summer.