Tucked inside the crevices under the bridge were three quarters of a million bachelor free-tailed bats. They made Austin the summer home of the largest urban bat population in the world. As the sun cast dark shadows into the river, two crew boats crept, side by side. Could they see the bats when they passed under the bridge, I wondered? Sweethearts stood on the bridge and tightly clutched each other’s hands, waiting for the emergence. Sodium lights from the Hyatt Hotel cast a sinister shadow over the water. Suddenly, smoke belched from underneath the bridge. No, not smoke but a column of bats. Then two columns bolted and flew in parallel, like the tracks of a hunted pair of coyotes. Bats kept spewing out, and soon four columns stretched miles across the sky. A few strays dove and fed near us, passing like angry soldiers. The night was noticeably free from insects, but that was no surprise. These bats would eat five thousand pounds of insects that one night alone.