Temporal variation in male Chaffinch song depends on the singer and the song type

摘要

Studies of variation in bird song within a species have tended to concentrate on repertoire size and on song rate, while other aspects of song delivery have received little attention even though they are also likely to play an important part in the signalling process. We here examine the pattern of delivery of individual males' repertoires in the chaffinch (Fringilla coelebs) to identify variation in a range of temporal parameters of song delivery. Coefficients of variation differed between song units and across hierarchical levels. Basic units (syllables) were delivered with great temporal precision. The larger building blocks of a song (the different phrases and the flourish) showed the highest variability while variation for song duration itself was intermediate. Most variables showed consistent differences between males, but there were also consistent differences between song types within a male's repertoire, as well as between the same song types as sung by different males. This suggests an interaction between a male's phenotype and song production, but because of consistent differences between song types within repertoires, there is potential for selection to act on aspects of song delivery both of the individual and of the song type (i.e. the culturally transmitted unit).