<Li> 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 . </Li> <P> 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 2 - 3 times less than the male . 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 . </P> <P> The male kori bustard is 120 to 150 cm (3 ft 11 in to 4 ft 11 in), stands 71--120 cm (2 ft 4 in--3 ft 11 in) tall and may have a wingspan about 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). 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, making the male kori and great not only the two largest bustards but also arguably the heaviest living flying animals . As a whole, other species, such as Dalmatian pelican (Pelecanus crispus), Andean condor (Vultur gryphus) and trumpeter swan (Cygnus buccinator), might weigh more on average between the sexes but are less sexually dimorphic in mass than the giant bustards . 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). Female length is from 80 to 120 cm (2 ft 7 in to 3 ft 11 in) and they usually stand 60 cm (2 ft 0 in) tall and have a wingspan of 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 . </P> <P> The size and dark crest are generally diagnostic amongst the bustards found in the kori bustard's range . However, East Africa holds the greatest diversity of bustards anywhere, including some other quite large species, and these have the potential to cause confusion . Kori bustards are distinguished from Denham's bustard (Neotis denhamii) and Ludwig's bustard (Neotis luwigii), both of which they sometimes forage with, by their greyer appearance and by their lack of a tawny red hind - neck and upper mantle . In flight it can be distinguished from both of these somewhat smaller bustards by not displaying any white markings on the upperwing, which is uniformly grey here . Both Stanley's and Ludwig's bustards lack the kori's dark crest . More similar to, and nearly the same size as, the kori is the closely related Arabian bustard (Ardeotis arabs) (despite its name, the latter species ranges well into East Africa). However, the Arabian species has white - tipped wing coverts, a browner back and very fine neck vermiculations and also lacks the black base to the neck and the black in the wing coverts as seen in the kori . </P>

How does the kori bustard change its appearance