Audibility curve of bobwhite quail (Colinus virginianus).

Male Bobwhite quail (Colinus virginianus) (N:5) were initially handled, then trained upon hearing a 1.5-kc/s tone of 3-sec duration to approach a feeder-loudspeaker system and peck a response key for food reinforcement. Threshold testing in subsequent sessions using a method of limits established the species' audibility curve over 11 frequencies from .25-8 kc/s and at stimulus durations of 3 sec and for some at 200, 100, and 50 msec. A W-shaped audibility curve was obtained for the group with points of greatest sensitivity at 1 and 3.5 kc/s which were about 25 db more sensitive than the endpoints at .25 and 8 kc/s. These points of least and greatest sensitivity were not altered until the stimulus durations were shortened to 100 and 50 msec, respectively. To compare with regions of greatest sensitivity, sonographic representations of two major Bobwhite calls were drawn. There was a coincidence between the peak sensitivity at 1 kc/s and the major frequency in the adult "separation" call, and between the peak sensitivity at 3.5 kc/s and the chick "lost" call. Together, the audibility and sonographic data provided an interpretative base from which to suggest possible functional analysis of calls.