It is rather long- and broad-winged and the slightly tapering tail is short by comparison and colored black, with grey tips in fresh plumage.

[11] The black-chested buzzard-eagle is readily identified in flight by its short wedge-shaped tail scarcely protruding from its long, broad wings.

The alternative genus name Buteo is simply the Latin term used for these hawks in Ancient Rome, translating as "buzzard" (in the European sense).

[13] The earlier use of the specific epithet melanoleucus for the black-and-white hawk-eagle technically precludes its use for the black-chested buzzard-eagle, except when it is placed in Geranoaetus.

In fact, in the mid-20th century Buteo fuscescens was the prevailing name for the black-chested buzzard-eagle for some years,[14] but it was eventually dismissed as erroneous.

[10] This specific name was established – as Spizaetus fuscescens – by Vieillot for the immature of the black-chested buzzard-eagle at the very same time as he described the adult because he could not believe that such differently-colored birds were conspecific.

The barred hawk (L. princeps) looks similar to the black-chested buzzard-eagle in general color pattern, though the tail differs much in shape, size, and the bright white central band stands out.

The relationship of the black-chested buzzard-eagle to the prehistoric genera Titanohierax from the Caribbean and the Pan-American Amplibuteo also warrants more study.

[2] Some fossils have been placed in Geranoaetus, but those from North America have since been moved elsewhere: Bones indistinguishable from those of living black-chested buzzard-eagles were found in a spring deposit at the Baños de Ciego Montero in Cienfuegos Province, Cuba.

A partial left carpometacarpus – Specimen AMNH FR 6190 – as well as a fingerbone probably date from some time in the Pleistocene, during the last ice age.

Its contemporary close relatives in Cuba, as far as it is known, consisted of the gigantic eagle-like buteonine hawks which were clearly distinct by size alone, while the Pleistocene record of similar-sized birds from continental North America is from the far west.

[20][21][22] The black-chested buzzard-eagle is found in mountainous or hilly terrain with sparse vegetation, shrubland, or (in the south of its range) Nothofagus forest, where it spends a lot of time soaring in thermals and vertical drafts while looking for prey.

[2] It is most conspicuous in the mid-morning and afternoon when individuals will seek out places that provide the best soaring conditions, such as north and west-facing slopes and ridges.

Apparently, their main interest at these times is aerial play and display; they tend to ignore places where food is more plentiful or easily hunted in favor of simply soaring alone or in pairs in strong air currents.

[2] The food of this carnivore consists mainly of mid-sized mammals; the introduced European rabbit (Oryctolagus cuniculus) seems to have become a key prey item.

[2][3] While not aggressive under normal circumstances, the black-chested eagle-buzzard will fiercely attack humans if it considers itself or its offspring threatened.

[1] While it is rare and declining in places – e.g. in Rio Grande do Sul and Santa Catarina states in Brazil,[24] or in parts of Argentina – its habitat requirements mean that it will to some degree benefit from deforestation and it has for example colonized regions of the former Mata Atlântica forest in Alagoas.