Sound order discrimination in two species of birds-Taeniopygia guttata and Melopsittacus undulatus.

Recent psychophysical experiments have shown that zebra finches (Taeniopygia guttata-a songbird) are surprisingly insensitive to syllable sequence changes in their species-specific motifs while budgerigars (Melopsittacus undulatus-a psittacine) do much better when tested on exactly the same sounds. This is unexpected since zebra finch males learn the order of syllables in their songs when young and sing the same song throughout adulthood. Here we probe the limits of this species difference by testing birds on an order change involving just two syllables, hereafter called bi-syllable phrases. Results show budgerigars still perform better than zebra finches on an order change involving just two syllables. An analysis of response latencies shows that both species respond to an order change in a bi-syllable motif at the onset of the first syllable rather than listening to the entire sequence before responding. Additional tests with one syllable omitted or doubled, or with white noise bursts substituted for syllables, indicate that the first syllable in the sequence has a dominant effect on subsequent discrimination of changes in a bi-syllable pattern. These results are surprising in that zebra finch males sing their full motif syllable sequence with a high degree of stereotypy throughout life, suggesting that this consistency in production may not rely on perceptual mechanisms for processing syllable order in adulthood. Budgerigars, on the other hand, are quite sensitive to bi-syllable order changes, an ability that may be related to useful information being encoded in the sequence of syllables in their natural song. (PsycInfo Database Record (c) 2023 APA, all rights reserved).