Kori bustard

Species of bustard native to Africa

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. In fact, 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 then 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.

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. 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. 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. 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. The juvenile is similar in appearance to the female, but is browner with more spotting on the mantle, with shorter crest and neck plumes. and a wingspan of Male birds may typically weigh between The average weight of adult males of the nominate race in Namibia (20 specimens) was , while A. k. struthiunculus males were found to average Males in Serengeti National Park had appreciably higher weights, however, averaging The larger excepted males can scale up to and a few exceptional specimens may weigh up to at least Reports of outsized specimens weighing , and even "almost" 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. As a whole, other species, such as Dalmatian pelican (Pelecanus crispus), Andean condor (Vultur gryphus) and trumpeter swan (Cygnus buccinator), in which the larger males might match the average weight of the largest bustards and may weigh more on average between the sexes as they are less sexually dimorphic in mass than the giant bustards. Other than a mute swan (Cygnus olor), the maximum size of the large bustards exceeds that of other flying birds. The standard measurements of the male include a wing chord of , a tail measures from , a culmen from and a tarsus from Meanwhile, the female's standard measurements are a wing chord of , a tail of , a culmen from and a tarsus from Body mass can vary considerably based upon rain conditions.

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. Kenya may hold the largest population of kori bustards of any country and it can even border on abundant in the North Eastern Province. This species occurs in open grassy areas, often characterized by sandy soil, especially Kalahari sands, and short grass usually near the cover of isolated clumps of trees or bushes. Where this species occurs, annual rainfall is quite low, between They follow fires or herds of foraging ungulates, in order to pick their various foods out of the short grasses. They may also be found in cultivated areas, especially wheat fields with a few scattered trees.

Kori bustards spend most of their time on the ground, with up to 70% of their time being on foot, Additionally, adult and juvenile males move after the breeding season, whereas females do not appear to do so.]] The breeding seasons of the two subspecies of Kori bustards are distinguishable. In general, A. k. struthiunculus breeds from December to August and A. k. kori breeds from September to February. Breeding is closely tied with rainfall, and in drought years, may be greatly reduced or not even occur. Kori bustards engage in lek mating. All bustards have polygynous breeding habits, in which one male displays to attract several females, and mates with them all. Males display at regularly used sites, each male utilizing several dispersed leks or display areas. These displays usually take place in the mornings and evenings. The courtship displays of the males are impressive and elaborate, successfully advertising their presence to potential mates. Occasionally fights between males can be serious during the mating season when display areas are being contested, with the two competitors smashing into each other's bodies and stabbing each other with their bills. They may stand chest to chest, tails erect, bills locked and "push" one another for up to 30 minutes. Occasionally she stretches her legs and raises her wings overhead. The female regularly turns the eggs with her bill. The female's plumage is drab and earth colored, which makes her well camouflaged. She occasionally picks up pieces of vegetation and drops them on her back to render her camouflage more effective. Captive hatchlings weigh on their first day but grow quickly. Sometimes kori bustards are found with southern carmine bee eaters (Merops nubicoides) and northern carmine bee eaters (Merops nubicus) riding on their backs as they stride through the grass. The bee eaters make the most of their walking perch by hawking insects from the bustard's back that are disturbed by the bustard's wandering. This is regularly seen in Chobe National Park, Botswana but has only been reported once elsewhere. There is also one record of fork tailed drongos (Dicrurus adsimilis) perching on their backs in a similar manner. Additionally, there is a report that a pair of black backed jackals manage to take down an adult male kori bustard. Other mammalian predators, including warthogs (Phacochoerus spp. ), mongoose and baboons (Papio ssp.) may eat eggs and small chicks. At times, successful instances of a martial eagle killing an adult male kori bustards have been photographed. Chicks of up to largish size may be vulnerable to raptors such as Verreaux's eagle (Aquila verreauxii), tawny eagles (Aquila rapax), Verreaux's eagle owls (Bubo lacteus) and Cape eagle owls (Bubo capensis). The display of the adult male may make it more conspicuous to larger predators, such as hyenas or lions. In protected areas, they can be locally common. Poisons used to control locusts may also effect and collisions with overhead power wires regularly claim kori bustards.