It’s the middle of the night, and you hear a squeaking sound coming from your attic. You get up to investigate, and as soon as you pull the attic ladder down, a swarm of winged-rodents come flying out ...

Each night around sunset, in one of the most upscale parts of the city, the bats get ready to fly. They’re Mexican free-tailed bats, a small species found up and down North, Central and South America.