Congress Avenue Bridge bat colony

The Ann W. Richards Congress Avenue Bridge in downtown Austin is home to the largest urban colony of Mexican free-tailed bats in North America. Each spring and summer the colony emerges nightly at dusk; estimates of the colony size vary, with counts ranging from several hundred thousand to over a million bats depending on the year and method. The nightly emergence has become a regular wildlife-viewing attraction and is studied by local biologists. The bridge and nearby viewing areas are managed to allow public observation while protecting the bats' habitat.