Congress Avenue Bridge bat emergence

From spring through fall each year, an estimated up to 1.5 million Mexican free‑tailed bats emerge at dusk from under the Ann W. Richards Congress Avenue Bridge. This nightly emergence is documented as the largest urban bat colony in North America and has been studied by Bat Conservation International and researchers. The emergence draws nightly crowds and boat tours on Lady Bird Lake and is a well‑known piece of Austin local lore and culture.