Chortoscirtes serengeti

The calling song of the recorded male consists of long, uninterrupted sequences of pairs o f syllables (Fig. 7; syllable repetition rate 43.7 Hz, repetition rate of syllable pairs 9 Hz; T = 22 ◦ C). This type of song is produced for many minutes or even hours (longest recorded sequence 3.5 min). The syllables have durations of 12–15 ms and contain 9–13 impulses, the first syllable of each pair slightly shorter with fewer impulses than the second (Fig. 7C). This type of continuous buzzing song is also heard in the field (when using a bat detector). However, sometimes a completely different signal can be registered, called a short- song. The first time it was heard was from many animals in the field in an evening after a strong rain. It was then recorded in a captive animal after a disturbance and was followed by the continuous song re-starting. Finally, the same type of song was recorded in the evening and sporadically throughout the whole night after an animal had been placed in the laboratory in Germany. At about 9 am the animal began the continuous song, and the short-song could only be heard before the start of a long sequence (Fig. 7A). Each echeme of the short-song contained 11–13 syllables pr oduced at a homogeneous rate of 39 Hz (T = 20 ◦ C). The intervals between the echemes were quite variable (2–8 s), but sometimes two echemes followed each other without any interval. The function of this signal can only be speculated on. As in the other Chortoscirtes species, the calling song is nearly exclusively in the ultrasonic range. In a recording with a 300-kHz sampling rate (animal in a gaze cage, distance to microphone about 0.6 m) the peak frequency was 33 kHz (range 10 dB below peak 21–41 kHz, in other recordings up to 60 kHz) (Fig. 6). [1]

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