On summer nights at dusk in Austin, Texas, people gather like hobos under the Congress Avenue Bridge. Children run around while their parents sit on blankets. What’s the attraction: an ongoing fireworks extravaganza? No, it’s the nightly emergence of the largest urban bat colony in North America. People let out a collective "aaah" as some 1.5 million Mexican free-tails fly out like an unfurling black ribbon, heading for dinner in the farm fields and Hill Country of central Texas. Flying at up to 60 miles per hour, they"ll cover 100 miles a night, returning to their roost before dawn. Each bat will consume up to 1,200 mosquito-sized insects per night; the entire colony will eat 10,000 to 30,000 pounds of insects—saving farmers from using tons of pesticides.
In the 1980s, when the creatures first moved under the bridge, horrified citizens demanded that the colony be eradicated. But Bat Conservation International (BCI) launched a campaign that turned public attitudes around. Bats now get all the insects they can eat and Austinites get nearly mosquito-free backyard barbecues.
Bats around the world are benefiting from increased educational efforts. "Public awareness is much greater," says Jim Kennedy, BCI’s assistant director of the North American Bat Conservation Partnership. "You don’t have as many people believing those old fallacies—that bats are blind, always carry rabies or get in your hair."
But bats are still in trouble: Of the 45 North American species, more than half are endangered or threatened. The main problem is human disturbance and vandalism of the caves and abandoned mines where they hibernate. Roosting in large numbers in some of the few suitable remaining caves, bats are highly vulnerable to habitat destruction and human disturbance.
One such tragedy occurred in 2000, when some Tennessee teenagers entered Wolf River Cave and attacked a hibernating colony of 2,400 bats. Picking the helpless creatures off the wall, they killed 38 federally endangered gray and Indiana bats. "After that incident, we helped gate the cave," says Kennedy. After a brief development scare last July, BCI helped the Southeastern Cave Conservancy and the Nature Conservancy of Tennessee purchase the property. There are only 300,000 Indiana bats left range-wide, down from tens of millions in this country 150 years ago.
Bats are also threatened by habitat loss. Many caves had been altered by commercial development, which has warmed them too much for cold-loving bats. Nectar-eating bats are suffering from disturbance of roosts and destruction of food sources. The lesser long-nosed bat, for example, may be affected by over-harvesting of the declining agave plant. The bat is the primary pollinator of the agave, from which tequila is made. No bats, no margaritas? In Texas, it doesn’t get any more basic than that.