SOUNDS: All calls are ultrasonic and therefore above the range of human hearing. On a bat detector (heterodyne) the calls of the soprano pipistrelle are similar in sound to the common pipistrelle. Produces very loud 'slaps' around 55 kHz. As the detector is gradually tuned up the range of frequencies above this frequency the slaps develop into 'clicks'. The pulse repetition rate seems very fast and erratic like a badly tuned car. Social calls can be heard throughout the active period. These are heard mainly around 22 kHz but range between 15 kHz and 45 kHz. They are very loud and like a rapid grating sound. They may be produced occasionally, or very rapidly. I have counted as many as 340 calls in one ten-minute period. However, this is an extreme example recorded during the mating season, when social activity reaches a peak. They are produced throughout the active season, commonly heard either during the mating season or at low insect densities. They can be emitted in very rapid succession, often during aerial chasing. Social calls are always produced during flight, never from a perch.

Click to hear the echolocation and social calls of the soprano pipistrelle slowed down 10 times

To hear the sound in an external media player please click here.

© Jon Russ 2001. Text refereed by Angela Ross & Lynne Rendle.

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