Widely spread across the phylogenetic tree in three avian orders, birds of prey are linked by their food habits and convergent evolution of talons and strong beaks. Second clutches/broods are rare among raptors; instead, a tendency to extend incubation beyond the time required for hatching has been documented in 12 species of the Accipitriformes, four of the Falconiformes, but only two of the Strigiformes (Margalida et al. 2006). With an average incubation period of 33 days (Arturo et al. 2014), the Great Horned Owl (Bubo virginianus) has not previously been reported to extend incubation. Furthermore, the species was previously known to lay a second clutch only after the death of the male early in incubation of the first clutch (Marti 1969).