On Thursday I met up with Denise & David from the Herefordshire Mammal Group, John from the Shropshire Bat Group, members of BrumBats and the Sutton Park Rangers for an evening bat survey using mist nets and harp traps.
Harp traps are basically an arrangement of nylon strings in a rectangular, upright frame (like a harp – or one of those egg slicer things from the ’70s and ’80s!). Ultrasonic lures are played nearby to attract bats, which fly into the soft nylon strings and plop into a catching bag at the bottom. Mist nets (if you’ve ever been to a bird ringing demonstration you will have seen some) are soft, fine nets that are strung between poles in areas likely for bats to fly. The nets have pockets, into which the bats fall.
The bats are retrieved by licenced, experienced bat handlers and ‘processed’ – their species, weight, forearm length, age and breeding status is written down, before being released back into the woodland. So how did we do?
During the night (from 9pm – 1am) we caught a total of 55 bats of three species: 27 soprano pipistrelles, 20 Daubenton’s, 5 common pipistrelles and 3 unidentified pipistrelles. We also set up bat detectors, which recorded many (a few thousand) bat calls, which included a Noctule, a possible Serotine, an unknown Myotis species and also some calls consistent with Nathusius pipistrelle (but we would need more evidence to confirm the species).
We had a truly fantastic night. I get to handle bats of many species on a regular basis doing bat care, but there is something very special about this type of survey work, and it was a real privelege to take part.
Huge thanks again to Denise, David and John for making it happen!