As the black-and-white hawk-eagle has not been placed in "Buteo" since long, Article 59.3 of the ICZN Code applies. According to this, a junior homonym replaced before 1961 is "not" rendered permanently invalid (as junior homonyms usually are) if "the substitute name is not in use" – which has been the case after Amadon's 1963 revision. Hence, in this case the scientific name "Buteo melanoleucus" can apply to the black-chested eagle-buzzard, even though the black-and-white hawk-eagle was described under exactly that name earlier, while the senior homonym "melanoleucus" still applies to the latter species when placed in "Spizaetus" according to the usual ICZN rules. Consequently, the proper name to use for each bird has through a number of coincidences become the senior synonym of the other species.