Female serin (Serinus serinus) responses to song do not favour the predominant song syntax

Abstract

The predominant syntax of the serin song is sequential, whereby nonrepeated syllables follow a well-organised circular structure. This is an evolutionarily derived condition in serins, as most congener species use relatively more syllable repetitions. Repetition of syllables persists as a minor part of serin song, mostly at the beginning of songs. We investigated the possible existence of a female preference selecting for sequential syntax in the serin that could, explain its preponderance. Female preferences were assessed by analysis of their vocal responses and their operant eliciting of playbacks. Contrary to prediction, females tended to respond more to repetitive syntax, when choosing between the two natural serin syntaxes. This result could, however, be due to the syntactical and phonological similarities of the repetitive syntax and the species contact calls. When controlling for this possibility by giving the choice between repeated and sequential songs constructed from the same syllables in a second experiment, females expressed no preference. Taken together these experiments fail to link female preferences to the evolution of the serin sequential syntax. This result is discussed in the context of paucity of the evidence for a role of female choice in the evolution of song syntax in passerines.