Their upper plumage is buff and grey, finely barred with black, which allows them to blend in with their environment. The underparts may be pale buff, white or solid black. They have only three front toes, which are short, broad and well adapted for running. Males are more brightly colored than females.
Male kori bustards range in weight from 24 to 42 pounds (11 to 19 kilograms) and females are roughly half the size of the males. They stand about 5 feet (1.5 meters) tall.
Kori bustards are distributed throughout eastern and southern Africa. They inhabit wide, open grasslands and lightly wooded savanna.
During the height of the mating display, the male inflates his esophagus to as much as four times its normal size. The tail feathers are cocked to reveal as much of the white underfeathers as possible. The wings may droop down so much that the tips of the primaries touch the ground. During direct courtship of a female, the male will bow toward her with his neck inflated and bill snapping. He may also emit a low-pitched booming sound.
Kori bustards are omnivorous birds, although they tend to be more carnivorous than other species of bustards. Insects form a large portion of their diet, especially when they are chicks. They also eat a variety of small mammals, lizards, snakes, seeds and berries. They have been observed eating carrion.
At the Smithsonian's National Zoo, they are fed mice, meatballs, avian pellets, chopped vegetables, fruits and insects.
Kori bustards are a polygynous species—one male will mate with more than one female. Mating lasts no more than a few seconds, and once over, the male leaves and resumes displaying to attract another female. He plays no part in incubation or in the rearing of chicks. As with all bustards, the clutch of one to two eggs is laid on the ground in a shallow scrape the female has made. The eggs are pale olive in color with splotches of brown. Incubation is 23 to 24 days. The chicks hatched fully developed, and remain with the female well after the fledging period, which is at about five weeks. Kori bustards reach sexual maturity at about two years at the earliest.
The Zoo’s research with kori bustards focuses on behavior and reproduction with the goal of advancing the understanding of kori bustard biology and making recommendations to improve its survival, both in the wild and in human care. Since 1970, kori bustard ranges have shrunk more than 20 percent in East Africa and close to 10 percent in southern Africa. The distribution of this kori subspecies is becoming fragmented and is declining in numbers due to habitat destruction from agriculture, development, hunting and a slow reproduction rate. Local extinctions have been recorded.
Zoo scientists are studying the behavior and reproduction of adults, sub-adults and chicks; specifically, they are examining breeding displays, hormone patterns and copulation. Zoo scientists seek to understand kori bustard actions and responses during certain times of the day and seasons, and how their activities vary between the sexes. They also study how the birds interact with and react to Zoo visitors. The Zoo successfully bred this species for the first time in October 1997, and was only the third zoo in the United States to breed this species. The Zoo keeps the International Studbook for the species and manages the Species Survival Program.