Argentina (B), Bolivia (B), Brazil (B), Paraguay (B).
Eastern Bolivia (Santa Cruz), western Paraguay and southern Brazil (southern from Mato Grosso and Goiás) to southern Argentina (Mendoza and Río Negro); no definitive records from Uruguay, where probably occurs.
 
Population
Estimated population is 250 - 999 (2010) and decreasing.
Status EN
Habitat destruction through mechanised agriculture, intensive cattle-ranching, afforestation, invasive grasses, excessive use of pesticides and annual burning, and hunting are the main threats.
For more information see BirdLife International Species Factsheet.
Chaco Eagle (Buteogallus coronatus) [XC325758]
by Robson Silva e Silva from Tr\u00eas Lagoas, Mato Grosso do Sul, Brazil (call)
Chaco Eagle (Buteogallus coronatus) [XC775242]
by Jacob Wijpkema from Est Parraga, Yacuma, Beni Department, Bolivia (uncertain)
Subspecies
Closely related to Buteogallus. Sometimes considered to include Solitary Eagle (Buteogallus solitarius).
No subspecies.
Similar Species
Great Black-Hawk (Buteogallus urubitinga) which lacks a crest, is smaller and shorter-winged. Adult blacker, immature more heavily streaked brown below.
References
See References.