Boys and their toys.

In September and October male bats will be spending time feeding ready for the winter and hibernation, but they will also be trying to attract females to their harem. Male Common Pipistrelle bats add 'chonking' sounds to their echolocation, associated with mating. The most succesful males will gather bigger harems of female during this period.



When going out with a hetrodyne bat detector it is possible to hear these 'chonking' sounds. By recording the ultrasound calls through a frequency division or time expansion bat detector it is possible to analyse the sound on a computer. I have recently been recording Common Pipistrelle bats at a roost with a Batbox Duet frequency division bat detector. This detector analyses all of the ultrasound and divides the frequency by 10 in order to make it audible. The information can then be put into a program, I use batscan, to produce a a sonogram, a graph of the sound frquencies of the call.

This call shows the lower frequency 'chonk' sounds that the bat is making, as well as the normal echolocation calls.