About Circaetus cinereus Vieillot, 1818
The body plumage of Circaetus cinereus is uniformly fairly dark hazel brown, and some reports note it can show a purplish sheen in certain lighting. Body color extends across the wings, except for contrasting unmarked whitish-grey flight feathers. The relatively short tail, which is most easily visible in flight, has alternating brown and grayish-cream bars at all ages. Juveniles are similar in overall appearance and color, but typically have very sparse white feather bases. Juveniles from the southern portion of the species' range show heavier white speckling, particularly on the abdomen and head. This species has a large head and bare legs, a feature that distinguishes it from other brownish medium-sized eagles in Africa. While juvenile bateleurs can be confused with this species in low light, juvenile bateleurs have more varied coloration, brown eyes, a shorter tail, and shorter legs. The brown snake eagle is medium-sized among eagles, but it is the largest member of the Circaetus genus. Among living species in the Circaetinae subfamily, it is similar in size to the bateleur, and much smaller than the Philippine eagle. Its total length ranges from 66 to 78 cm (26 to 31 in), and its wingspan ranges from 160 to 185 cm (5 ft 3 in to 6 ft 1 in), though individuals may possibly reach a wingspan of up to 200 cm (6 ft 7 in). Recorded weights fall between 1.5 and 2.5 kg (3.3 and 5.5 lb), with an average weight of around 2.05 kg (4.5 lb). Despite its fairly large overall size, this species has a relatively small wing area; its wings are smaller than those of the bateleur, and even smaller than the wings of the much lighter black-breasted snake eagle. The brown snake eagle's call is a hoarse, guttural hok-hok-hok-hok. This call is usually given during territorial displays toward other members of the species, and it sometimes ends in a crowing kaaww. Pairs also use a soft kwee-oo call, likely as a contact call at the nest. This species has a wide distribution across Africa. In West Africa, its range covers southeastern Mauritania, Senegal, The Gambia, Guinea-Bissau, eastern and western Guinea, Sierra Leone, the northern inland parts of Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, and inland areas of Mali and Niger. From West Africa, its range extends east to southern Chad, southern Sudan, South Sudan, inland Eritrea, northern and central Ethiopia, and southern Somalia, then continues through most of Kenya, Uganda, and the southern Democratic Republic of the Congo, and south through southern Africa to roughly half of Namibia, all of Botswana and Zimbabwe, and northeastern and eastern South Africa. The brown snake eagle is not migratory, but it may be somewhat nomadic; there are records of individuals with territories up to 200 km (120 mi) apart, and one ringed bird is known to have traveled 2,100 km (1,300 mi), from South Africa to the Democratic Republic of the Congo. This species lives in open woods and wooded savanna, and most often prefers areas where gullies or wooded hillocks break up flat terrain. It apparently prefers somewhat more densely wooded areas than related snake eagle species. It can live at elevations ranging from sea level up to 2,000 m (6,600 ft).
