Ann W. Richards Congress Avenue Bridge - Mexican free‑tailed bat colony

The Ann W. Richards Congress Avenue Bridge in downtown Austin is home to a large colony of Mexican free‑tailed bats that roost in spaces beneath the bridge. Biologists and wildlife organizations have estimated the colony at times to number as many as 1.5 million bats, making it one of the largest urban bat colonies in the world. From spring through fall the bats emerge most evenings at sundown, drawing thousands of viewers and researchers to the bridge area; counts and crowd sizes vary by year and season.