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Congo serpent eagle
The Congo serpent eagle (''Dryotriorchis spectabilis'') is a species of bird of prey in the family Accipitridae, and is placed in the monotypic genus ''Dryotriorchis''. This species is found in western and central Africa, with its range stretching from Sierra Leone south to Angola and west to the Democratic Republic of the Congo. It occurs in upper and lower Guinean forests, which are dense rainforests. This serpent eagle specializes in hunting in these forests’ dark understories. It has two subspecies, the nominate subspecies ''Dryotriorchis spectabilis spectabilis'' and ''Dryotriorchis spectabilis batesi''. Though monotypic, it appears to be very closely related to ''Circaetus''. This hawk is a medium-sized bird with distinctive short, rounded wings and a long, rounded tail. It is varying shades of brown on its back and has a slight crest. Its breast is white with variable amounts of a rufous wash and, in the nominate subspecies, is covered in round, blackish spots. The subspecies ''D. s. batesi'' only has these dots on its flanks. The Congo serpent eagle closely resembles Cassin's hawk-eagle, and some ornithologists believe that this likeness is a rare example of avian mimicry. It is a very vocal raptor, and often is one of the most heard species in its habitat.
This serpent eagle feeds on snakes, chameleons, and toads, and hunts these species by dropping onto them from a perch in the understory. Its excellent eyesight enables it to hunt in the dark forest. Very little is known about its breeding habits, though it is suspected to breed from June to December. The Congo serpent eagle is listed as a species of Least Concern due to its large range and population. This species has been kept as a pet.
==Taxonomy==
The Congo serpent eagle was first described in 1863 by Hermann Schlegel as ''Astur spectabilis'' from a specimen collected near Elmina, Ghana.〔Brown 1982, p. 350〕 Schlegel published his description in ''Nederlandsch Tijdschrift voor De Dierkunde'' and placed this species within the goshawks.〔 In 1874 George Ernest Shelley, who had access to more specimens, realized that this bird wasn't a goshawk and moved the species into its own monotypic genus, ''Dryotriorchis''.〔 ''Dryotriorchis'' is a distinct genus due to its short wings, long tail, short crest, and oval nostrils.〔 The word "Dryo-" is from the Greek for "oak" and "triorchis" from the Greek for "hawk", specifically a kind of hawk thought to have three testicles.〔 It is believed that the genus is more closely related to ''Circaetus'' than ''Terathopius'', and it is possibly a link between these and the Asian genus ''Spilornis''.〔 The syrinx morphology is distinctly like those of accipiter hawks but shows similarities to features found in ''Nisaetus''. Two subspecies are known: the nominate subspecies ''Dryotriorchis spectabilis spectabilis'' and ''D. s. batesi''.〔 ''D. s. batesi'' was originally described as a separate species, ''Dryotriorchis batesi'', by Richard Bowdler Sharpe in 1904 due to its unspotted breast. Sharpe named the subspecies in honor of G. L. Bates, who shipped him specimens from Cameroon.〔 This species is also known as the West African Serpent eagle and the African Serpent-eagle.〔Ferguson-Lees 2001, p. 128〕〔Thiollay 1994, p. 134〕
The Congo serpent eagle is superficially similar in plumage and size to Cassin's hawk-eagle, which has an overlapping range with the serpent eagle. It has been suggested that the Congo serpent eagle evolved to mimic the Cassin's hawk-eagle, which could give the serpent eagle several advantages, possibly including the ability to trick its reptilian prey into not fleeing, lowering its own predation, and/or minimizing mobbing by birds through its resemblance to a predator of birds.〔 ''D. s. spectabilis'' more closely resembles the immature Cassin's hawk-eagle, while ''D. s. batesi'' resembles the adult.〔 This is one of very few suspected examples of avian mimicry.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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