Goin' bats in Austin: America's largest urban bat population takes off

It's almost dusk in downtown Austin, Texas, and Congress Avenue bridge is packed. Leaning over the railing, hundreds of shorts-clad students, tourists and locals are pointing their cameras awkwardly toward the bridge's belly. A guy hawking ice cream bars barks to the crowd, but even a chilly Sno-Cone on a hot summer night can't move anyone to reach for his wallet.

No one wants to miss the bats.

A million and a half Mexican free-tailed bats--a number so incomprehensible that you just have to see it for yourself--live beneath the bridge. Every evening from March to November, the creatures take a cue from the dipping sun and take to the sky en masse. At first, a few dozen bats dart out over Town Lake on an erratic recon mission, eliciting didja-see-thats from the crowd. But then--show time!--thick ribbons of fluttering, undulating animals unspool from the bridge supports at 60 miles per hour.

Even people who don't know much, if anything, about bats ("Will they get in my hair? Do they bite?") find these bridge dwellers way cool. Their amazing exodus gets total strangers swapping questions: "Where are the bats going?" "What will they eat?" Before this better-than-any-IMAX show is over, you might not know those answers, but you will know that the collegian on your left has seen the bats five times, and that next month he's bringing his mom.

BAT CENTRAL

A destination city known for its tech industry and music scene, Austin epitomizes the adage "If you build it, they will come." That was never more true than in 1980, when city engineers rebuilt the 946-foot Congress Avenue bridge, and Austin's bat population took off. In about five years' time, the handful of bats that already called the bridge home multiplied by tens of thousands. Attracted by the new, perfectly-bat-sized expansion joints beneath the bridge, the 4-inch animals with the 12-inch wingspans formed a colony that became the talk of the Texas capital.

A few squeamish Austinites demanded that the colony be destroyed. But Merlin Tuttle, founder of the nonprofit educational group Bat Conservation international (BCI), went to Austin's who's who and quickly got out the word: Forget what you know from the movies, he urged. These bats aren't out for blood.

BIG EATERS

Mexican free-tailed bats are, in fact, gentle, passive creatures, says Barbara French, a conservation biologist with BCI. The nocturnal mammals have an enormous appetite for agricultural pests and can eat up to their own body weight in bugs. Austin's bridge colony devours up to 30,000 pounds of mosquitoes, moths and other crop killers nightly. Using echolocation to navigate, the bats can travel up to 30 miles from the roost, flying as high as two miles over waterways and farms. At dawn, the animals return to the bridge in groups, having eaten the human equivalent of 50 pizzas each.

The bats spend the daylight hours hanging upside down, clustered tightly together, in their roost. Throughout the day, though, visitors standing on or near the bridge can hear the animals chittering. "They're social little guys," says French, who has studied their vocalizations. Listen closely, and you can hear buzzes, chirps, trills, beeps and clicks.

Austin's is a maternity colony, which means that most of the bats are females. In June, each gives birth to one pink, hairless pup. About half a million baby bats will take to Austin's skies by summer's end. August is the best bat-viewing month.

By the time the colony seeks warmer weather in Mexico each November, more than 100,000 tourists from all over the world will have poured $8 million into the local economy. Recognizing what an asset the bat colony is to Austin, BCI and local businesses work earnestly to preserve it. Signs ask that you look but don't touch the bats, and a fence encourages sightseers to keep a respectful distance from the colony, At the picnic-friendly Bat Observation Center adjacent to the bridge, visitors can learn more about the bats through educational kiosks or by talking to a BCI expert on summer weekends (June through August). During the year, BCI experts teach elementary school students about bat conservation.

Y'ALL COME

It's been 25 years since the tiny flying mammals swooped into Austin by the thousands and a newspaper headline screamed "Bat Colonies Sink Teeth Into City." This diverse metropolis of 650,000 residents--many of whom live and die by the motto "Keep Austin Weird"--is now affectionately nicknamed "Bat Capital of America." Talk about an attitude adjustment: The Austin American-Statesman, the local newspaper once responsible for anti-bat articles, now sponsors the Bat Observation Center. The public library hosts an annual Bat Week. Austin's hockey team is the ice Bats. And in 1998, the city erected a massive sculpture of a Mexican free-tailed bat--with a 20-foot wingspan.

"The Austin colony is a perfect model of how to protect a species," says French. "It's become a source of revenue for the city." Everyone in Austin benefits from the bats: the local farmers who sell their produce at the eco-chic Central Market; the hotel and restaurant owners whose lakeside suites and dining rooms swell with tourists each summer; and the visitors and residents who enjoy mosquito-free outdoor activities such as the annual Austin City Limits Music Festival. In 2004, the three-day event brought about 75,000 sweaty people to potentially buggy Zilker Park.