The kori bustard (Ardeotis kori) is the largest flying bird native to Africa. It is a member of the bustard family, which all belong to the order Otidiformes and are restricted in distribution to the Old World. It is one of the four species (ranging from Africa to India to Australia) in the large-bodied genus Ardeotis. The male kori bustard may be the heaviest living animal capable of flight. This species, like most bustards, is a ground-dwelling bird and an opportunistic omnivore. Male kori bustards, which can be more than twice as heavy as the female, attempt to breed with as many females as possible and take no part in the raising of the young. The nest is a shallow hollow in the earth, often disguised by nearby obstructive objects such as trees.
Taxonomy English naturalist William John Burchell described the kori bustard in 1822. The specific epithet kori is derived from the Tswana name for this bird – Kgori. Two subspecies are currently recognized:
Ardeotis kori kori – the relatively pale nominate race from Botswana, Zimbabwe, Namibia, southern Angola, South Africa and Mozambique. Ardeotis kori struthiunculus – the "Somali kori" distributed in Ethiopia, Uganda, South Sudan, Kenya and Tanzania. The two races are separated by the miombo woodlands of central Africa. This race has a more boldly patterned head and slightly more black and white patterning on the wings. The two races are similar in size, though A. k. struthiunculus may be slightly larger. This may be a distinct species. In older literature the species is named 'Large Crested Pauw' (Eupodotis kori).
Description
The kori bustard is cryptically coloured, being mostly grey and brown, finely patterned with black and white coloring. The upper parts and neck are a vermiculated black and greyish-buff colour. The ventral plumage is more boldly colored, with white, black and buff. The crest on its head is blackish in coloration, with less black on the female's crest. There is a white eye stripe above the eye. The chin, throat and neck are whitish with thin, fine black barring. A black collar at the base of the hind-neck extends onto the sides of the breast. The feathers around the neck are loose, giving the appearance of a thicker neck than they really have. The belly is white and the tail has broad bands of brownish-gray and white coloration. Their feathers contain light sensitive porphyrins, which gives their feathers a pinkish tinge at the base- especially noticeable when the feathers are shed suddenly. The head is large and the legs are relatively long. The eye is pale yellow, while the bill is light greenish horn coloured, relatively long, straight and rather flattened at the base. The legs are yellowish. The feet have three forward facing toes. Females are similar in plumage but are much smaller, measuring about 20–30% less in linear measurements and often weighing one third to half of the males. The female is visibly thinner legged and slimmer necked. The juvenile is similar in appearance to the female, but is browner with more spotting on the mantle, with shorter crest and neck plumes. Male juveniles are larger than females and can be the same overall size as the adult male but tends to be less bulky with a thinner neck, shorter head crest, paler eyes and a darker mantle.
Size
The male kori bustard has a length of 105 to 135 cm (3 ft 5 in to 4 ft 5 in) and a wingspan of 230 to 275 cm (7 ft 7 in to 9 ft 0 in). Male birds may typically weigh between 7 and 18 kg (15 and 40 lb). The average weight of adult males of the nominate race in Namibia (20 specimens) was 11.3 kg (25 lb), while A. k. struthiunculus males were found to average 10.9 kg (24 lb). Males in Serengeti National Park had appreciably higher weights, however, averaging 12.2 kg (27 lb). The larger excepted males can scale up to 16 to 19 kg (35 to 42 lb) and a few exceptional specimens may weigh up to at least 20 kg (44 lb). Reports of outsized specimens weighing 23 kg (51 lb), 34 kg (75 lb) and even "almost" 40 kg (88 lb) have been reported, but none of these giant sizes have been verified and some may be from unreliable sources. Among bustards, only male great bustards (Otis tarda) achieve similarly high weights (the mean mass of males in these species is roughly the same) making the male kori and great not only the two largest bustards but also arguably the heaviest living flying animals, with the kori bustard being Africa's second largest bird after the ostrich. The larger males of certain other species, such as the Dalmatian pelican (Pelecanus crispus), Andean condor (Vultur gryphus) and trumpeter swan (Cygnus buccinator), might match the average weight of the largest bustards, and these species may weigh more on average than the giant bustards as they are less sexually dimorphic in mass. Other than a 23 kg (51 lb) mute swan (Cygnus olor), the maximum size of the large bustards exceeds that of other flying birds. Other flying African birds (excluding rare vagrant pelicans and vultures to northernmost Africa) rival the average weight between the sexes of Kori bustards, namely great white pelicans (Pelecanus onocrotalus) and Cape vultures (Gyps coprotheres) while wattled cranes (Bugeranus carunculatus) lag slightly behind these on average. The female kori bustard weighs an average of 4.8 to 6.1 kg (11 to 13 lb), with a full range of 3 to 7 kg (6.6 to 15.4 lb). Females of the nominate race (35 specimens) in Namibia weighed a mean of 5.62 kg (12.4 lb), while females from A. k. struthiunculus weighed a mean of 5.9 kg (13 lb). Females in the Serengeti averaged slightly lighter at 5.15 kg (11.4 lb). Female length is from 90 to 112 cm (2 ft 11 in to 3 ft 8 in) while their wingspan is around 177 to 220 cm (5 ft 10 in to 7 ft 3 in). The standard measurements of the male include a wing chord of 69.5 to 83 cm (27.4 to 32.7 in), a tail measures from 35.8–44.7 cm (14.1–17.6 in), a culmen from 9.5 to 12.4 cm (3.7 to 4.9 in) and a tarsus from 20 to 24.7 cm (7.9 to 9.7 in). Meanwhile, the female's standard measurements are a wing chord of 58.5 to 66.5 cm (23.0 to 26.2 in), a tail of 30.7 to 39.5 cm (12.1 to 15.6 in), a culmen from 7 to 10.4 cm (2.8 to 4.1 in) and a tarsus from 16 to 19.5 cm (6.3 to 7.7 in). Body mass can vary considerably based upon rain conditions.
Similar species
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