Imprinting studies have traditionally stressed the importance of visual features in the formation of early postnatal attachments. However, recent studies by Johnston & Gottlieb (1981, 1985) have demonstrated that visually imprinted preferences can be altered by the maternal call. Thus, in the present study the interaction between natural visual and auditory stimulation in the control of filial behavior was examined in bobwhite quail chicks during the first 4 days of postnatal life.

Previous research has revealed that bobwhite quail hatchlings are differentially responsive to their species-specific maternal call in the period right before and immediately following hatching (Heaton, Miller & Goodwin, 1978). Results from this study indicate that quail chicks begin to lose this naive preference for their maternal call over a non-conspecific call (a domestic chicken maternal call) by 72 hrs following hatch, and do not respond to either the bobwhite call or chicken call by 96 hrs following hatch. However, differential responsiveness to the bobwhite call can be reinstated in bobwhite chicks at 72 hrs and 96 firs following hatching if the birds are provided with integrated audiovisual stimulation (i.e., a quail hen model emitting the maternal call). These results suggest that in the initial stages of postnatal development, species identification in bobwhite quail is based primarily on the auditory component of maternal stimulation. Later in development, combined auditory and visual stimulation appears necessary to control species-specific filial behavior despite the fact that auditory cues remain dominant over visual cues.

These findings conform well to what is known about the neuroembryological development of sensory systems, in that the auditory system of birds (and mammals) develops in advance of the visual system. This prenatal sequence of sensory system development appears to influence the sequence of early postnatal perceptual preferences in precocial avian neonates.