We had the great pleasure this week of taking part in the 30-hour Sutton Park BioBlitz. Last night we met at 8.30 at the visitors’ centre where we (and members of the public) boarded a bus and were driven to the other side of the reserve. We began a bat walk taking in several different types of habitat, and in spite of the cold, we weren’t disappointed by what we heard!
The image in the video above is called a sonogram – basically a picture of a sound wave made when you plot the frequency (how high pitched the call is) over time (how long the call lasts). You can listen to the sounds that go with the image by pressing play. It’s possible to use software to tell us something called the ‘peak frequency’ (the pitch at which the call was the loudest). The peak frequency is what helps us to narrow down what species we have heard, as different species of bats call at different frequencies (a bit like planes in the sky flying at different heights to avoid each other!). These calls have a peak frequency of 21kHz (kilohertz), which means that they are likely to be noctule bats. The two other similar UK species (Leislers and Serotine) echolocate just a bit higher, at around 22-25kHz. These calls are from just one of several species we heard on our walk, including Soprano Pipistrelle, Common Pipistrelle, and possibly Brown Long Eared bat and Serotine – we still have some recordings to go through to confirm the last two! We also know that there is a thriving population of Daubenton’s Bats at Sutton Park. All in all, it seems that Sutton Park is a fantastic site for bat watching, and we can’t wait to go back later in the summer for more!