A species-specific acoustic cue for selective song learning in the white-crowned sparrow

Abstract

Song learning in birds is paradoxical. Without tutoring, songbirds do not develop normal songs. Yet despite this inability, birds possess extensive foreknowledge, in a mechanistic sense, about the normal song of their species. When given a choice of tape recordings, young, naıve songbirds select sounds of their own species for imitation. We tape-tutored white-crowned sparrows, Zonotrichia leucophrys oriantha, with a set of manipulated songs to investigate whether the introductory whistle universally present in white-crowned sparrow song guides selective song learning in this species. Our results confirm that this whistle serves as a cue for song learning, enabling acquisition of normally rejected sounds of other species, including hermit thrush, Catharus guttatus, notes, which have a sound quality distinct from that of natural white-crowned sparrow phrases. Our results support the conclusion that sensory mechanisms rather than motor constraints are primarily responsible for the selectivity seen in song learning.