Song Sparrow males use female-typical vocalizations in fall

Abstract

In many species of north temperate-zone passerines, females do not sing, but rather use female-specific calls for acoustic communication. In a resident population in Washington state, banded adult male Song Sparrows (Melospiza melodia) outside the breeding season used a vocalization (chitter call) previously believed to be used only by females. This phenomenon has not been observed previously because most field studies of temperate passerines are confined to the breeding season. In this population, juvenile males attempt to establish territories in fall when they do not yet sing fully crystallized songs. Use of female-typical vocalizations by adult males outside the breeding season may allow adults of both sexes to communicate about territories to juvenile males who cannot yet sing the full adult songs males typically use to communicate territorial boundaries.