Polygyny Leads to Disproportionate Recruitment in Urban Cooper’s Hawks (Accipiter cooperii)

Excluding harriers (Circus spp.) and the Boreal Owl (Aegolius funereus), polygyny is rare in most species of raptors and more often occurs under conditions of food abundance and in rodent-eating birds of prey (Korpimäki 1988,Korpimäki and Hakkarainen 2012, Simmons et al. 1986, Rosenfield et al. 2007a). We genetically confirmed paternity of a male Cooper’s Hawk (Accipiter cooperii) in successful polygyny in a high density population in the city of Grand Forks, North Dakota, where the predominant prey for this species is birds (Rosenfield et al. 2007a, T. Driscoll unpubl. data). To our knowledge, ours was the first study to report polygyny in Cooper’s Hawks, and the first documentation of successful polygyny in Accipiter; that is, all three young fledged in each of two simultaneous nests in 2006. The male’s reproductive output may have been enhanced in...