The frequency sensitivity of hearing in the grey swiftlet, Collocalia spodiopygia, was determined by neuronal recordings from the auditory midbrain (MLD). The most sensitive best frequency response thresholds occurred between 0.8 and 4.7 kHz, with the upper frequency limit near 6 kHz. Spectral analysis of echolocation click pairs revealed energy peaks between 3.0 and 8.0kHz for the foreclick, compared to 4.0-6.0 kHz for the principal click. The relationship between good hearing sensitivity and click energy peaks in the swiftlet extends about an octave higher than it does in the oilbird (Steatornis caripensis).
- © 1987 by Company of Biologists