One of the most unique and celebrated attractions in Austin is a naturally occurring phenomenon and costs absolutely nothing to enjoy. The 1.5 million Mexican Free-tailed bats that live under the Congress Street Bridge from March to October emerge at dusk in a breathtaking display. This nightly (almost) occurrence can be viewed in a number of different ways, and is the kind of event that makes living in or visiting Austin so memorable.

Bats are much maligned and misunderstood in society. Often associated with vampires, belfries, and bad hair days, the bat holds a mystique of fright, and is tragically misunderstood. Although bats, like any other mammal, can carry rabies, and no one should ever touch a bat in nature, bats are an important part of our ecological system. According to Bat Conservation International, the Austin bats eat up to 20,000 pounds of insects every night!

Austin's bats migrate every spring from Mexico, and have made their home under the Congress Street Bridge by the thousands since 1980. Primarily female, the bats come to Austin to have their pups, usually in early June. They remain in residence under the bridge usually until mid-October, and each night they leave their roost to forage on the mosquitoes and flies and other bugs of Austin and its environs.

Two free viewing area provide different vantage points. Just under the bridge on the south side of the river is a dedicated park-like area provided by the adjacent Austin American-Statesman newspaper offices. Visitors can bring a picnic dinner on the grassy hill, and can read the posted information on the bat population's history and future. Others prefer to walk to the top bridge and secure a spot overlooking the river's eastern horizon. As the sun sets, soon the crowd will notice one or two brave bats flickering out into the dusk. The amount accelerates, and soon the air is thick with bats swirling out into the night. Visitors close to the bridge will get up close and personal with these fascinating but fast-moving creatures, watching them flutter by. Those with a view of the horizon will see columns and whorls of these little cuties silhouetted by the deepening shades of the twilight sky.

A number of boats are available to rent for bat viewing, from private riverboats to public platform boats, and the errant kayak, rowboat or canoe is sometimes found rising and falling with the river's flow near the bridge. Restaurants and hotels along the river also have patio dining with an excellent view of the show.

Although the best viewing is later in the summer, when the new pups have grown and begun to join the nightly flight, the bats put on a spectacular show most every night from spring to fall. Bat Conservation has a kiosk on the bridge with wonderful bat-related souvenirs and educational items, and they often have a naturalist on hand to explain further the wonder of Austin's unique and awesome Mexican Free-Tailed bats.