Black-Chested Buzzard-Eagle

The Black-chested Buzzard-eagle (Geranoaetus melanoleucus) is a bird of prey of the hawk and eagle family (Accipitridae). It lives in open regions of South America. This species is also known as the Black Buzzard-eagle, Grey Buzzard-eagle or analogously with "eagle" or "eagle-buzzard" replacing "buzzard-eagle", or as the Chilean Blue Eagle. It is sometimes placed in thegenus Buteo.

With a total length of c.25-30 in (about 62–80 cm) and weighing around 70 oz (2 kg), it is a huge eagle-like "buzzard" ("hawk" in American terminology). It is rather long- and broad-winged, with a wingspan of about 70–80 in (175–200 cm), and the slightly tapering tail is short by comparison and colored black, with grey tips in fresh plumage. The adult has a white underside, sometimes with fine blackish stripes; its upperparts are dark grey with a blackish, brownish or bluish hue. The feathers of the neck and the lowest dark feathers of the breast are somewhat elongated. Adults have an ash-grey-and-white zone on the wings, the silvery white seen clearly from afar. The female is distinguished by a reddish-cinnamon hue to the upper- and underwing secondaries and is considerably larger than the male.

The immature plumage is reminiscent of that of the Great Black Hawk (Buteogallus urubitinga). Its upperparts are deep brown, sometimes almost black, and it has no light wing patch. The underside is white or light buff with heavy dark streaks on the breast and dark bars on the belly and thighs. It does not acquire the full adult plumage until 4–5 years old.

It is not very vocal, calling usually in flight and when close to the nest. Some calls resemble a wild human laugh, others are a curlew-like whistle. Occasionally flying birds give a high-pitched vocalization "kukukukuku".

The Black-chested Buzzard-eagle is readily identified in flight by its short wedge-shaped tail scarcely protruding from its long, broad wings. It is usually easy to make out the generally white underparts with the dark chest-band and tail if the birds are adult. Yet as this bird is usually encountered in the wild when it soars, you are less likely to see its grey upperparts.