Lower Moor bat walk 4th May 2024 - audio recordings

Over 20 people took part in a bat walk at Wiltshire Wildlife Trust's Lower Moor reserve. I handed out 10 π•pistrelles so people could hear bats time-expanded or heterodyne, and had a pippyg stuck into my rucksack strap to record bat activity at 384kHz/16. Here's the results - a quite quiet night, things didn't really kick off until after 9.15, but there was enough activity to keep everyone entertained and delighted, and we had 5 confirmed species. I've heterodyned the recordings to show how the Magenta users experienced things, and also time-expanded 16x to illustrate the π•pistrelle experience.


Things to note - the higher pitch of Soprano Pipistrelle is immediately apparent when time-expanding. Most of the time with a bit of ear training you can ID a pipistrelle after a single call is picked up by the detector.

Hear how much the Noctule sounds like a distant owl.

Also note the qualitative difference of the Daubenton's and the Brown Long-Eared bats with their giant, fast FM downsweeps. Even when the Pipistrelles are sweeping strongly due to flying in a cluttered environment, their calls clearly have a terminal pitch - as in, they stop sweeping down and end on an identifiable note. Ditto (most of the time!) the Noctule. But the Daubenton's and Long-Eared bats don't really produce a note at all, just a "zip" down through the ultrasonic spectrum.