Congress Avenue Bridge Bat Colony

Overview

The Congress Avenue Bridge is home to the largest urban bat colony in North America. Each evening from March through October, approximately 1.5 million Mexican free-tailed bats emerge from beneath the bridge in a spectacular aerial display.

Highlights

• 1.5 Million Bats: The colony is the largest urban bat population in North America.
• Nightly Emergence: Bats stream out at dusk in a dark ribbon visible from blocks away.
• Bat Boat Tours: Several operators offer viewing from Lady Bird Lake.

History

The bats first colonized the bridge following its 1980 reconstruction, which created ideal crevice roosting habitat. Initially considered pests, public opinion shifted after Bat Conservation International educated the community about the colony's ecological value.

Visitor Tips

• Best viewing is from the bridge's east sidewalk or the lawn on the south bank.
• Peak season is August when the colony is largest and pups are learning to fly.
• Duration: 30–60 minutes.