"A thoroughly alternative night out"

Angus Watson has a delightful short piece at the FT on taking a public bat walk in Regent's Park:

We were given bat-detectors, walkie-talkie-sized machines which make the squeaks audible. You swing the detector about until you hear a squeak, then follow the sound to find the bat. So off we went into the cool Regent’s Park night, about 30 of us, ranging from three- to 60-years-old, plus bat experts.

After a few false sightings, the detectors led us to the first bat, a little pipistrelle flitting overhead, and soon we’d found a whole cloud of bats by the boating lake. They swirled above us, chasing insects like spacecraft in a Star Wars dogfight. Through the detectors, we could hear their alien “bukka-bukka-bukka” hunting calls. Intermittently, a bat’s cries would accelerate into a raspberry sound, then go silent, revealing that the bat had zeroed in, then chomped an insect.