Argentina (B), Belize (B), Bolivia (B), Brazil (B), Colombia (B), Costa Rica (B), Ecuador (B), El Salvador (B), French Guiana (B), Guatemala (B), Guyana (B), Honduras (B), Mexico (B), Nicaragua (B), Panama (B), Paraguay (B), Peru (B), Suriname (B), Trinidad and Tobago (B), USA (B), Venezuela (B).
Population
Estimated population is 2,000,000 (2011).
Grey-lined Hawk (Buteo nitidus) [XC438185]
by Fernando Igor de Godoy from Santa Marta, Magdalena, Colombia (call)
Grey-lined Hawk (Buteo nitidus) [XC446716]
by Rosendo Manuel Fraga from Cujubim, Rond\u00f4nia, Brazil (song)
Subspecies
Asturina nitida and Asturina plagiata (Sibley and Monroe 1990, 1993) have been lumped as nitidus following AOU (1998) and moved to the genus Buteo following AOU (2006). Gender agreement of Buteo nitidus follows David and Gosselin (2002a).
Sometimes placed in Asturina, partly due to distinctive moult pattern; appears to form clade with Roadside Hawk (Rupornis magnirostris), Ridgway's Hawk (Buteo ridgwayi) and Red-shouldered Hawk (Buteo lineatus), and this group may be more closely allied to Leucopternis than to Buteo. Subspecies plagiatus sometimes awarded specific status, due to differences in size and plumage, but evidence remains rather weak.
The following 5 subspecies are recognised:
plagiatus (Schlegel, 1862) - Lowlands of south-western US to north-western Costa Rica.
costaricensis (Swann, 1922) - South-western Costa Rica to northern Colombia and western Ecuador.
nitidus (Latham, 1790) - Eastern Colombia and eastern Ecuador, east to Venezuela and the Guianas, and south through Amazonian Brazil to northern Maranhío.
pallidus (Todd, 1915) - South-central Brazil (Piauí to Rio de Janeiro and Mato Grosso) and eastern Bolivia, south to Paraguay and north-central Argentina (Tucumán and Chaco).
blakei Hellmayr & Conover, 1949 - South-western Costa Rica to northern Colombia and western Ecuador.