Male Promiscuity and Female Adultery by the Rook Corvus frugilegus

Abstract

Promiscuity has been shown to occur among many colonial, monogamous bird species, among them the rook C. frugilegus. The male rook achieves a selective advantage in adapting a mixed reproductive strategy, i.e., beside being strongly monogamous it also is a promiscuous bird. The young females copulated significantly more often with promiscuous males than the old females, at least during the period when the eggs had the greatest chance of becoming fertilized. The female rook may benefit by accepting several males as fathers for their offspring and may copulate willingly with some of the promiscuous males.