The Chaco eagle (Buteogallus coronatus) or crowned solitary eagle, is an endangered bird of prey from eastern and central South America. Typically it is known simply as the crowned eagle which leads to potential confusion with the African Stephanoaetus coronatus. Due to its rarity, not much is known about its biology or population. Description The Chaco eagle is a large raptor with a mostly dull and silvery grey body plumage. Its short black tail has a broad white medial band as well as a white tip and both its cere and legs are yellow. As its name indicates, the Crowned Solitary Eagle has a crest of darker grey feathers. The juvenile also has a crest but its colour dark brown, except for it creamy head and underbody which are both have grey streaks. It is one of the largest raptors in the Neotropics and normally weighs around . Its total length can reach and it has a wingspan of . Taxonomy Buteogallus coronatus is monotypic, meaning that there are no subspecies. Vieillot first named it Harpyia coronata in 1817. It was subsequently reclassified by Lafresnaye in 1842 under the Harpyphaliatus genus and was renamed Harpyhaliatus coronatus. At the time, the Solitary Eagle (Buteogallus solitarius) was considered to be a subspecies of Harpyhaliatus coronatus until phylogenetic analyses of their DNA showed that they are, in fact, sister species. These analyses also indicated that another species, the Great Black Hawk (Buteogallus anthracinus), is also a sister species. They were all reclassified under the Buteogallus genus. Habitat and Distribution Distribution This bird is endemic to the Americas and can be found in eastern and central South America. It is present in southern and central Brazil, Bolivia, Paraguay and its range extends to Northern Patagonia in Argentina. The status of the Chaco Eagle is uncertain in Uruguay, where it hasn't been seen in decades and is believed to be extinct. It has been extirpated from portions of its historical range and is found in very low density throughout its range, making it one of the rarest and most threatened raptors in the Neotropical region. Only 250-999 mature individuals are left, while the total individual count of the species reaches 375-1499 birds. Habitat The Chaco Eagle can be found in semi open habitats such as open mixed grasslands, brushlands, savannahs, marshes and open woodlands. Also, the presence of large trees in the habitat is very