Audibility Thresholds of the Blue Jay

Abstract

-The audibility thresholds of two Blue Jays were measured behaviorally using operant conditioning and psychophysical techniques. The jays responded to pure tones between 0.25 and 10 kHz. Their thresholds are similar to those reported for seven other passerines. This indicates that passerines are somewhat less sensitive than man in the detection of sounds in the 1 to 4 kHz range and considerably less sensitive than man to sounds above and below this range. Received 8 February 1977, accepted 28 August 1977. THE field study of avian vocal behavior usually involves arbitrary decisions about the audibility of a call to the birds being studied. The present study grew out of the suspicion that Blue Jays (Cyanocitta cristata) were not hearing calls that were audible to the observer. Is man more acute than birds at detecting a bird's call? In order to compare avian and human auditory sensitivity, the pure tone hearing thresholds of each must be known. We adopted standard operant conditioning and psychophysical procedures to measure the Blue Jay's hearing. The standard function for humans was published by Sivian and White in 1933, and audibility thresholds for several other bird species have been reported (Trainer 1946, Schwartzkopff 1949, Dooling et al. 1971, Dooling and Saunders 1975, Heinz et al. 1975, Sinnott 1975).