Ardeotis kori

Geographic Range

Ardeotis kori lives throughout eastern and southern sub-Saharan Africa. There are two populations of Kori bustards, which are separated by the miombo woodland of Central Africa. The southern population is composed of the subspecies Ardeotis kori kori , which lives in parts of Zimbabwe, Botswana, Namibia, South Africa, Mozambique and southern Angola. The northeastern African population is composed of the subspecies Ardeotis kori struthiunculus , which inhabits parts of Somalia, Ethiopia, Sudan, Kenya, Uganda and Tanzania.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

Habitat

Kori bustards are found in dry habitats such as savannas, grasslands and semi-deserts. They are usually found near water sources and in areas with light tree cover, where they take shelter from the heat of the day. They do not inhabit entirely wooded areas.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland

Physical Description

Kori bustards have large necks, crested heads, greyish brown backs, vermiculated grey necks and breasts, whitish bellies, black and white spotted patterns on the shoulder and sides of their necks, and black and white bars on their tails. Their bills, legs, feet, and eyes are all yellowish. The two subspecies are similar in appearance, but the southern subspecies is slightly larger and has a few differences in facial plumage. Kori bustards are easily distinguished from other bustards by their size, crest and lack of rufous on the hind neck. In flight, the distinguishing characteristic is grey speckled underwings without white markings.

Kori bustards are the heaviest flying birds in Africa, with males weighing 10 to 19 kilograms and females weighing 5.5 to 5.7 kg. They range in length from 105 to 128 cm and have a wingspan of 75 to 76 cm in males and 60 to 65 cm in females. The sexes have similar plumage, although individual patterns may differ. Females are about half the size of males. Juvenile males have shorter head crests, paler eyes, and a darker mantle than adult males. Juvenile females also have shorter crests and paler eyes as compared to adult females.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

During the breeding season, males perform elaborate displays, including deep booming calls, inflating their esophagus up to four times its usual size, erecting neck feathers, and fanning the tail to expose their white under tail coverts. These displays can last for several days and can be performed singly or in a group. Once a female has chosen a male, actual copulation is quite brief, lasting only a few seconds.

Although the mating system of Kori bustards is unclear, males continue courtship dances after their initial copulation and do not invest in incubation and rearing, suggesting that they are polygynous. Courtship feeding in white-bellied bustards ( Eupodotis senegalensis ) suggests monogamous pairing in some bustards, but this has not been reported in Kori bustards.

The breeding season is different in the two subspecies of Kori bustards. In general, A. k. struthiunculus breeds from December to August and A. k. kori breeds from September to February. Recorded laying dates vary considerably. For example, laying dates were recorded from April to June in Somalia and from March to June in Ethiopia. In southern Africa, laying dates were reported from September to December in Zimbabwe and from November to January in Namibia. Breeding success is heavily dependent upon rainfall and in times of drought breeding is reduced significantly. Sexual maturity is usually reached after 3 years in both sexes.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

The nest, a scrape in the ground usually near a clump of grass, holds one to two eggs that are incubated solely by the female for approximately 23 days. Once hatched, the chicks are precocial and cared for by the female, although the male is sometimes present. Fledgling occurs after 4 to 5 weeks, but the chicks remain with the mother until the following year.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • protecting
    • female

Lifespan/Longevity

There is little information about lifespans in the wild, but in captivity Kori bustards have been documented to live as long as 26 years.

Behavior

Kori bustards are usually found alone or in small groups, but occasionally associate in larger flocks. They prefer not to fly and are commonly seen walking quickly with large strides or hiding from the hot sun under trees. They lack a hind toe and thus are restricted to terrestrial habitats. They have no preen gland, but instead produce powder down and practice dust bathing. Although Kori bustards don’t seem to make regular migrations, they are thought to make small migrations in response to rainfall and food supply. Additionally, adult and juvenile males move after breeding season, whereas females don’t appear to do so.

• Key Behaviors
• terricolous
• flies
• diurnal diurnal
• motile motile
• nomadic nomadic
• social social

Communication and Perception

Kori bustards are generally quiet, but when surprised may make a sort of bark or snoring noise. They have been observed growling when their young are threatened. In courtship displays, males make a low roaring noise and perform visual displays, inflating their throats, erecting their neck feathers and fanning their tails. This display shows off the brilliant white undertail coverts and can be seen up to 1 km away.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Kori bustards are omnivorous with an extremely varied diet including insects, reptiles, small rodents, birds, carrion, seeds, berries and roots. Insects make up a large portion of their diets, especially when they are. They forage on the ground and are drawn to bush fires where they eat insects killed in the blaze. They are known to consume the gum from Acacia trees, either for the gum itself or for the insects inside the gum. Kori bustards drink water in an unusual manner: instead of scooping up water as most birds do, they actually suck up the water.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• mammals
• reptiles
• carrion carrion
• insects

• Plant Foods
• roots and tubers
• seeds, grains, and nuts
• fruit
• sap or other plant fluids

Predation

Many species prey on Kori bustards including lions, leopards, caracals, jackals, and eagles. Kori bustard chicks are quite vulnerable to predation and exhibit high mortality rates, although they have cryptic plumage. When alarmed, Kori bustards make barking calls and bend forward and spread their tail and wings to appear larger. Adults will growl when their young are threatened by predators.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Kori bustards have a mutualistic association with carmine bee-eaters ( Merops nubicus ), which often perch on their backs. As a Kori bustard forages they stir up insects that the bee-eaters capture. Kori bustards may get some benefit in return from the bee-eaters, such as help in detecting predators.

Economic Importance for Humans: Positive

Kori bustards are interesting birds to watch because of their size, plumage and courtship display patterns. Because of this, they may enhance the tourism industry in the many African countries in which they live. They are also hunted for their meat.

• Positive Impacts
• food food
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no reported negative effects of Kori bustards on humans.

Conservation Status

Despite some decline in Kori bustard populations and habitat fragmentation, they are still common in some areas. Kori bustards are considered a species of least concern according to the IUCN redlist because their decline, although not quantified, appears to be below 30% over the last ten years. Despite their least concern status, multiple threats face this species including habitat destruction from farming, livestock grazing, human encroachment, collisions with power lines, and poaching. Although still common in major game reserves and a few other areas, they are uncommon in many areas where they once thrived and are declining throughout their range. This is of particular concern because of their low fecundity and decreased breeding in dry years.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Jill Bible (author), Stanford University, Terry Root (editor, instructor), Stanford University.

References

Hallager, S., J. Boylan. 2004. "Kori Bustard Species Survival Plan Husbandry Manual" (On-line pdf). Accessed May 13, 2007 at http://www.gruitag.org/uploads/media/kori_bustard_husbandry_manual.pdf .

Harrison, J., D. Allan, L. Underhill, M. Herremans, A. Tree, V. Parker, C. Brown. 1997. The atlas of southern African birds. Vol. 1: Non-passerines . Johannesburg: BirdLife South Africa.

2007. "BirdLife International" (On-line). Accessed May 13, 2007 at http://www.birdlife.org .