Song, mate choice and the question of kin recognition in a migratory songbird

Abstract

Songs of migratory indigo buntings, Passerina cyanea, were compared among kin for birds of known family history. In one population 9·7% of the banded nestlings were seen in a later year within 2 km of their birth site. Nearly all of the males that returned to their natal area had a song unlike their father's song. Four females mated with a male whose song was like their father's (two of the four mated with their father). The proportion of birds whose song was like their father's (or, for females, mated with a male with a song like their father's) was close to that expected by chance, based on the number of males with their father's song in the study area. Brothers, sisters, half-siblings and three-generation kin (maternal and paternal grandfathers compared with their grandsons and with their granddaughters' mates) had different songs. Birds within a song neighbourhood came from different natal song neighbourhoods and were not close relatives. The dispersal that accompanies long-distance seasonal migration and the disruption of family social bonds has the effect of dispersing relatives. Buntings do not appear to use songs to recognize kin in mate choice; songs are therefore not kinship markers in this species.