Perception of species-specific contact calls by budgerigars (Melopsittacus undulatus).

Three budgerigars were trained with operant techniques to discriminate examples of species-specific contact calls. Budgerigars were also tested on vocalizations from another avian species--the canary (Serinus canarius). Budgerigars showed an equivalent ability to discriminate and remember both budgerigar and canary calls. Additional tests showed that both temporal and spectral cues were important in the discrimination of species-specific calls by the budgerigar. However, spectral cues occurring in the region of 2.0-4.0 kHz appear to be critical for the discrimination. These experiments support the notion of a generalized, but highly sophisticated, perceptual learning system in the budgerigar for the processing of vocal signals.