Bat sound diagrams, sonogramsBat sound diagrams with English subtitles
Bat sound analysis
With the time expansion technique the calls are recorded, and the file is displayed for instance 10 times slower. The time-expanded sound is analysed in a computer program and the diagram (sonogram, spectrogram) can be stored as a picture-file.
The spectrograms (frequency curves) below are recorded with a Petterson D240X bat detector, saved in a digital Roland R-05 recorder and analysed with the BatScan 9 computer software.
The spectrogram shows how the frequency changes over time. Yellow and red indicate high sound intensity.
Calls used for Echolocation
Brown long-eared bat (Plecotus auritus)
Barbastelle (Barbastella barbastellus)
The barbastelle typically use a double ecolacation call consisting of a loud call at 36 kHz to 28 kHz and a quieter call at 44 kHz to 29 kHz.
Barbastelle. Sometimes the quieter call type is omitted. Recordet at a woodland edge.
Whiskered bat/ Brandt's bat
It is nearly impossible to discriminate between Brandts bat and whiskered bat. Note the variations between calls