Systematics

Orange-breasted Falcon is monotypic; there is no described geographic variation.

For many years the prevailing view was that Orange-breasted Falcon was most closely related to Peregrine Falcon (Falco peregrinus) and allied species (Stresemann 1924, Hellmayr and Conover 1949, Wetmore 1965, Stresemann and Amadon 1979, Amadon and Bull 1988, Sibley and Monroe 1990). These authors were aware of the similarity in plumage between the Orange-breasted Falcon and Bat Falcon (Falco rufigularis), but suggested that the larger size of the Orange-breasted (closer to that of the Peregrine), and that its relative proportions (such as the middle two with claw longer than the tarsus; and the central rectrices slightly longer than the outer rectrices; Wetmore 1965) supported a relationship to the Peregrine Falcon. Cade (1982) and White et al.  (1994) proposed that the Orange-breasted Falco is more closely related to Bat Falcon, based on perceived similarities in behavior and in vocalizations (in addition to the plumage similarities). Wink and Sauer-Gürth (2004) concluded, based on phylogenetic analysis of mitochondrial DNA, that the Orange-breasted Falcon belonged to a group of falcons related to the Eurasian Hobby (Falco subbuteo), and not to the Peregrine group; but this analysis did not include Bat Falcon.