Kinship, promiscuity, and communal breeding in the acorn woodpecker

1. Acorn woodpeckers typically live in permanent social groups in which most adults help to incubate and feed the young of a single nest. The selective basis of communal breeding in this species is examined. 2. At the study area in New Mexico, most juveniles did not remain on their natal territories during subsequent breeding seasons. There was also a high rate of turnover among adults within each group. The groups were not...