Every summer, a million and a half bats in Austin, Texas make themselves at home.

The Congress Avenue Bridge has become, quite accidentally, the largest urban bat colony in the world. When engineers finished its reconstruction in 1980, it turned out that the crevices underneath the bridge doubled as perfect bat housing. When Mexican free-tail bats began their yearly migration north the next spring, they moved in by the thousands.

Austin freaked. Bats have a very bad reputation, thanks in equal part to both rabies and Béla Lugosi, and people demanded that the housing be demolished. Luckily, a group by the name of Bat Conservation International made an appearance, and explained to Austinites that, minus a nasty guano habit, bats are actually both brilliant and adorable. And the ones now living in their midst eat anywhere from ten to twenty thousand pounds of insects per night.

Nowadays, the Congress Avenue Bridge brings in 100,000 tourists annually. The mostly female colony starts moving in around March, and each female gives birth to a single pup by early June. The pups mature over the next five weeks, until eventually they can leave the roost with their mothers en masse, and take Austin’s insect population by storm.

Congress Avenue Bridge Frequently Asked Questions