bats argest urban bat colony in North America argest urban bat colony in North America Bats in Austin revoada de 1 milhão e meio de morcegos annual migration from Mexico to Austin argest urban bat colony in North America bats fly Austin Bats Guide to bat season argest urban bat colony in North America Guide to Bat Season in Austin March to November 1.5 million free-tailed bats the largest urban bat colony in North America argest urban bat colony in North America as they migrate argest urban bat colony in North America Austin Bats Congress Avenue Bridge in Austin argest urban bat colony in North America vivid photographs creating a scene unlike any other