INFRASOUND DETECTION BY THE HOMING PIGEON - BEHAVIORAL AUDIOGRAM

Homing pigeons could detect extremely low frequency sounds (infrasounds) as low as 0.05 Hz in a sound isolation chamber. Classically conditioned heart rate changes were used as a behavioral measure of sensitivity. An audiogram of thresholds was determined for 13 frequencies between 0.05 Hz and 200 Hz. Below 10 Hz, the pigeons are at least 50 dB more sensitive than humans. Surgical removal of middle ear or inner ear structures reduced or eliminated the infrasound responses. Natural infrasounds come from many sources including weather patterns, topographic features, and ocean wave activity. Infrasounds propagate long distances and can be detected hundreds or even thousands of km away from their sources. These laboratory experiments are part of a series designed to find out if homing pigeons can use outdoor infrasounds as cues for orientation and navigation. © 1979 Springer-Verlag.