Successful Introgressive Breeding of a Ferruginous Hawk × Red-Tailed Hawk Hybrid with a Red-Tailed Hawk

Abstract

Hybridization in wild raptors is uncommon, but direct observations of successful hybridization exist. Subsequent introgressive hybridization (i.e., hybrid backcrossing), however, is less commonly reported in the raptor literature. We document (1) an interspecific Ferruginous Hawk (Buteo regalis) breeding attempt, and (2) introgressive hybridization within the genus Buteo. We found photographic evidence of a successful breeding attempt between a Ferruginous Hawk and Red-tailed Hawk (Buteo jamaicensis) in Wayne County, Utah, USA. Subsequent photographic observations in 2011 of adult and juvenile Ferruginous Hawk × Red-tailed Hawk hybrids indicate that this hybrid pair may have bred successfully multiple times. In 2017, we photographed an adult Ferruginous Hawk × Red-tailed Hawk hybrid breeding successfully with a Red-tailed Hawk near the same area where the original hybrid pair was documented. Our observations demonstrate that at least some Buteo hybrids are fertile and capable of reproduction; however, we do not know if the second-generation hybrids are fertile.