In-Air and Underwater Hearing in the Great Cormorant (Phalacrocorax carbo sinensis).

ABSTRACT

Hearing thresholds of a great cormorant (Phalacrocorax carbo) were measured in air and under water using psychophysics. The lowest thresholds were at 2 kHz (45 dB re 20 µPa root-mean-square [rms] in air and 79 dB re 1 µPa rms in water). Auditory brainstem response measurements on one anesthetized bird in air indicated an audiogram with a shape that resembled the one achieved by psychophysics. This study suggests that cormorants have rather poor in-air hearing abilities compared with other similar-size birds. The hearing capabilities in water are better than what would have been expected for a purely in-air adapted ear.