Female choice for song characteristics in the house finch

Song has been proposed to function in mate choice, and such a role has been demonstrated experimentally in a number of species. We presented captive female house finches, Carpodacus mexicanus, with a choice of two songs, each of which was identical except for a single parameter that had been either accentuated or minimized. To ensure that our playback tapes offered choices within the normal range of variation in house finch song, we recorded wild male finches, then created playback tapes using values for the song parameters under consideration that were above or below the mean for the local population, but within the natural range of variation. We presented females that had not previously mated with choices between songs that (1) were long or short, (2) were given at fast or slow rates, and (3) included a large or small repertoire of unique song elements. Females showed significant preferences for long songs and for songs presented at a faster rate, but there was no significant preference for large or small repertoires of unique song elements. Song length and rate each seem likely to indicate a male's energy reserves, and thus could be important sources of information for females choosing mates.