The Role of Song Phonology and Syntax in Vocal Learning Preferences in the Song Sparrow, Melospiza melodia

Abstract

AbstractAre young songbirds ready to learn virtually any song, or are they predisposed to learn songs of their own species? To explore this question tests were conducted on the equipotentiality of auditory song learning stimuli in the song sparrow. 23 males reared as nestlings were exposed to tape recordings of their own and other species songs in early life and subsequent song production was analyzed for imitations. Birds exposed to natural song sparrow songs, including their fathers', and equal numbers of swamp sparrow songs, strongly preferred conspecific songs. They neither favored nor eschewed paternal songs despite having had access to them for 6–10 days as nestlings. In three other experiments synthetic songs were used in which some properties were held constant and others were systematically varied. Birds were exposed to 1–4 segmented songs varying in phrase order, tempo and syllable number, each synthesized in two versions, one from conspecific and the other from heterospecific (swamp sparrow) song syllables. With one‐segmented songs (alien syntax) subjects favored conspecific over heterospecific syllable songs. Heterospecific syllables were rendered more acceptable by incorporation into two‐segmented trilled songs (more song sparrow‐like syntax). Heterogeneous summation of phonological and syntactical cues appeared to occur. There was also evidence of interaction between phonology and syntax. When another phrase type, the note complex, was added, in three‐ and four‐segmented songs, a preference for conspecific syllables reappeared. Heterospecific syllables may be more readily accepted as a trilled sequence than without repetition, as in a note‐complex. When phrase structure within four‐segmented songs was varied, birds favored patterns most like normal conspecific song. We conclude that there are innate learning preferences in the song sparrow, based on note and syllabic structure (phonology and syllabic syntax), and temporal organization of phrases (segmental syntax), differing from those of the closely related swamp sparrow, Melospiza georgiana, in which song syntax plays no role in learning preferences.