Bats and sonograms
A recent development in the field identification of bats has been the introduction of two new types of bat detector that allow bat calls to be analysed by computer. These time expansion or frequency division detectors have the advantage of being able to pick up all the European species echolocating between 10 and 120kHz without the need to constantly retune the detector. The bat sounds are recorded onto a Minidisk and then downloaded into a computer where the echolocation calls can be analysed. Although it is not possible to identify all species – particularly Myotis bats, due to the similarity of their calls – this advance has enabled bat surveyors to identify the range of species present in an area without the need to resort to more intrusive methods.
This sonogram illustrates the social calls
of a soprano pipistrelle at around 30kHz.
There are two bats in this sonogram: a Kuhl’s pipistrelle echolocating at 40kHz and a
common pipistrelle at 45kHz. The recording was made in Provence during October 2002.
In this example, a Daubenton’s bat (the vertical lines) is feeding close to a soprano
pipistrelle that is echolocating at 55kHz with harmonics of the calls at around 170kHz.
You can listen to the Daubenton’s bat and soprano pipistrelle here.
(Please note that this .WAV file is 422K and may take some time to load.)
This sonogram shows a soprano pipistrelle
echolocating with a peak intensity at 55kHz.
A noctule with peak intensity
at 20kHz is illustrated here.
The vertical signals in this sonogram are characteristic
of a Myotis species, probably a Daubenton’s bat.
The cluster of red lines in the middle of this image denote a feeding “buzz”
from a soprano
pipistrelle. This distinctive sound on a bat detector occurs when a bat attempts to catch its prey.
Click here to listen to a common pipistrelle and serotine feeding in woodland in Danbury
Country Park. (Please note that this .WAV file is 431K and may take some time to load.)
This sonogram illustrates the social calls
There are two bats in this sonogram: a Kuhl’s pipistrelle echolocating at 40kHz and a 
In this example, a Daubenton’s bat (the vertical lines) is feeding close to a soprano 
This sonogram shows a soprano pipistrelle 
A noctule with peak intensity 
The vertical signals in this sonogram are characteristic 
The cluster of red lines in the middle of this image denote a feeding “buzz”
from a soprano