Family: Accipitridae
Genus: Dryotriorchis
Species: D. spectabilis
Subspecies: D. s. batesi, D. s. spectabilis

Congo Serpent Eagles are medium-sized eagles that occur in densely forested areas throughout western and central Africa. D. spectabilis is the only member of the genus Dryotriorchis, which is closely related to genus Circaetus.

Physical Description:

Congo Serpent Eagles have rounded wings, a long tail, a slight crest, and a short beak. They are dark brown from above, and the underparts are white with brown spots and barring. The head is light brown with dark streaks across the cheeks and throat, and the eyes are yellow-brown. The cere, legs, and feet are yellow. The tail is light brown with six thick black bars and the feathers are dark and barred with white tips.

The nominate subspecies D. s. spectabilis is heavily marked and has a reddish hue. D. s. batesi, by contrast, only has marks along the flanks and thighs. Congo Serpent Eagles are unique raptors in that they do not resemble other serpent eagles. Instead, they are more similar to Aquila africana (Cassin’s Hawk Eagle), which may be a form of mimicry as protection from other birds that would otherwise attack a serpent eagle.

Juveniles have a white head and back, with a pale brown tail and some black and brown spots.

The calls of Congo Serpent Eagles are similar to the meowing of a cat. Listen to a recording.

Size:

Length: 54-60 cm

Habitat and Distribution:

They live in dense lowland forest, often in the thickest parts of the understory. They occur in a range of 0-900 meters above sea level.

Congo Serpent Eagles are found throughout western and central Africa, from 9°N to 9°S, in countries including Guinea, Gabon, the Democratic Republic of the Congo, and northwest Angola. There are approximately 10,000 individuals over a range of 2,880,000 km².

Diet and Hunting:

They eat snakes, lizards, and amphibians, and possibly small mammals—the remains of mammals found from their stomachs may have been from the snakes the birds swallowed, not something they caught directly.

They have large eyes, which allow them to scan for movement in a dimly-lit forest. Once prey has been spotted, either on a tree trunk, in foliage, or on the ground, they swoop down and kill it with their beak or feet. They also hunt along roads and forest clearings and may perch over rivers for watersnakes.

Reproduction:

The breeding season is October-December in Gabon and June-November in the Democratic Republic of the Congo.

Incubation and nesting periods are unknown.

Conservation:

Although they have a large range, deforestation is a major threat to Congo Serpent Eagles, if it continues at its current pace. They are currently listed as Least Concern by BirdLife International.

Taxonomy:

Dryotriorchis spectabilis is the only member of the genus Dryotriorchis. It was considered to be closely related to the genus Spilornis and the species Eutriorchis astur (Madagascar Serpent Eagle), but studies of one nuclear intron and two mitochondrial genes showed that Dryotriorchis spectabilis is closer to the genus Circaetus.

Subspecies:

There are two subspecies: D. s. batesi, which lives in southern Cameroon, Gabon, Zaire, Uganda, and northern Angola, and D. s. spectabilis, which lives in Sierra Leone, Nigeria, and northwestern Cameroon.

Other Names:

African Serpent Eagle, West African Serpent Eagle, Slangehøg (Danish), Aafrika maduhaugus (Estonian), Aigle Serpentaire du Congo (French), Schlangenbussard (German), Aquila serpentaria del Congo (Italian), Hebiwashi (Japanese), Kongoslangehauk (Norwegian), Wezojad kongijski (Polish), Culebrera Congoleña (Spanish), Kongolesisk ormörn (Swedish).

Video of a Congo Serpent Eagle:

References:

http://www.arkive.org/congo-serpent-eagle/dryotriorchis-spectabilis/
http://avibase.bsc-eoc.org/species.jsp?avibaseid=3DA062BF0F062DDE
BirdLife International (2011) Species factsheet: Dryotriorchis spectabilis. Downloaded from http://www.birdlife.org on 29/10/2011.
Global Raptor Information Network. 2011. Species account: Congo Serpent Eagle Dryotriorchis spectabilis. Downloaded from http://www.globalraptors.org on 29 Oct. 2011
http://ibc.lynxeds.com/species/congo-serpent-eagle-dryotriorchis-spectabilis
http://www.planetofbirds.com/accipitriformes-accipitridae-congo-serpent-eagle-dryotriorchis-spectabilis
Ferguson-Lees, James, and Christie, David A. Raptors of the World. Houghton Mifflin Company, 2001.