Entity Display : Ardeotis kori

Ardeotis kori

Contributor:EcoPort ex-R. Ellis
QA and TEM

Bird

ID: 89231

Introduction

EcoPort ex-R. Ellis

2005-01-17

Image by Elliot, M-T

Authority	Burchell 1822

ID Standing

Classification	Aves : Gruiformes : Otididae (see lineages)

Synonyms	Ardeotis kori kori, Ardeotis kori struthiunculus, Otis kori Burchell 1822(full list)

Common names	avutarda kori, bustard kori, Giant Bustard, Gompou, Iseme, Kgori, Kgori, Kori Bustard, koritrapp, Koritrappe (full list)

Codes

Categories

Roles

A large, long-legged and long-necked terrestrial bird with three-toed feet. This bustard is cryptically coloured with a short tail. The male has an elaborate courtship display involving plumage transformation and a loud, booming call. This is the world's largest flying bird with the flight powerful with slow, deliberate wing beats.

Description	EcoPort ex-R. Ellis	2005-01-17
This is the worlds largest bustard and is one of the heaviest flying birds, being just heavier than the Mute Swan (Cygnus olor). It is the largest of the 22 species in the family Otididae of which 16 occur in Africa.

Field Appearance	The very large size of the male makes it unmistakable, being up to 120cm tall. It is long-legged, with a horizontal body and mainly buff coloured with dark vermiculations. Walks with a slow but certain and stately gait. The size, dark crest and lack of any rufous on the hind neck and upper mantle are diagnostic (Sinclair et al 1993). In flight its upperwing is uniformly speckled grey without any white areas at all.

Field Appearance

The very large size of the male makes it unmistakable, being up to 120cm tall. It is long-legged, with a horizontal body and mainly buff coloured with dark vermiculations. Walks with a slow but certain and stately gait.

The size, dark crest and lack of any rufous on the hind neck and upper mantle are diagnostic (Sinclair et al 1993). In flight its upperwing is uniformly speckled grey without any white areas at all.

Identification	A very large bird with a robust body, long neck and with a relatively large head. The legs are long with short toes and with the hind toe absent. The dorsal plumage is cryptically coloured, finely patterned with brown, grey, black and white colouring. The ventral plumage is more boldly coloured with white, black and buff colouring. The wings are long and broad, downcurved in flight. The tail is short to medium, grey-brown with two creamy-white bars towards the base. The sexes are similar in appearance and only differ slightly in their plumage but the males are about 20% larger than the females (Newman 1992). The upper parts and neck are vermiculate black and greyish-buff coloured (Williams 1995). The feathers of the neck are very lax giving the effect of a thick-necked bird. There is no rufous colouring on the hindneck (Maclean 1993)The neck and breast is finely barred and appears grey at a distance. The male has black feathers on the forehead and the sides of the crown extending into a black crest. This crest gives the bird a characteristic flat-crowned appearance. 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 upper breast. The chest and the belly are white. The back is brown with the upper wing coverts white mottled with black, giving a variable black and white panel when folded. The tail has wide bands of greyish-brown and white. The female is similar to the male but is only approximately half the size and has a more finely barred throat and less black on the crown.

Identification

A very large bird with a robust body, long neck and with a relatively large head. The legs are long with short toes and with the hind toe absent.

The dorsal plumage is cryptically coloured, finely patterned with brown, grey, black and white colouring. The ventral plumage is more boldly coloured with white, black and buff colouring. The wings are long and broad, downcurved in flight. The tail is short to medium, grey-brown with two creamy-white bars towards the base.

The sexes are similar in appearance and only differ slightly in their plumage but the males are about 20% larger than the females (Newman 1992). The upper parts and neck are vermiculate black and greyish-buff coloured (Williams 1995). The feathers of the neck are very lax giving the effect of a thick-necked bird. There is no rufous colouring on the hindneck (Maclean 1993)The neck and breast is finely barred and appears grey at a distance.

The male has black feathers on the forehead and the sides of the crown extending into a black crest. This crest gives the bird a characteristic flat-crowned appearance. 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 upper breast. The chest and the belly are white. The back is brown with the upper wing coverts white mottled with black, giving a variable black and white panel when folded. The tail has wide bands of greyish-brown and white.

The female is similar to the male but is only approximately half the size and has a more finely barred throat and less black on the crown.

Measurements	There is a marked difference in size between males and females – males average 71-76 cm in height, whereas females are typically 52.5-62 cm in height. Length: male 120-150 cm; female 105-120 cm. Wing: wingspan 220-250 cm; male 69.5-82.5 cm; female 58.5-66.5 cm. Tail: male 35.8-44.7 cm; female 30.7-39.5 cm. Tarsus: male 20-24.5 cm; female 16-19.5 cm. Culmen: male 9.5-12.4 cm; female 7.0-10.4 cm. Weight: male 8.4 -19.1 kg; female 4.3-6.6 kg. Weights are very dependant on environmental conditions and after a season of good rains the average female weighs about 6.1 kg, but in a dry year their average weights are much less, at 4.8 kg. The heaviest weight recorded for this bird is 19 kg, although heavier specimens have been claimed. Weights of 23 kg (Newman 1971) to almost 40 kg have been reported (Main 1987) but these need confirmation. Birds in the south of this species’ range (southern Africa) are appreciably heavier than those occurring nearer the equator (Liversidge 1991).

Measurements

There is a marked difference in size between males and females – males average 71-76 cm in height, whereas females are typically 52.5-62 cm in height.

Length: male 120-150 cm; female 105-120 cm.

Wing: wingspan 220-250 cm; male 69.5-82.5 cm; female 58.5-66.5 cm.

Tail: male 35.8-44.7 cm; female 30.7-39.5 cm.

Tarsus: male 20-24.5 cm; female 16-19.5 cm.

Culmen: male 9.5-12.4 cm; female 7.0-10.4 cm.

Weight: male 8.4 -19.1 kg; female 4.3-6.6 kg. Weights are very dependant on environmental conditions and after a season of good rains the average female weighs about 6.1 kg, but in a dry year their average weights are much less, at 4.8 kg.

The heaviest weight recorded for this bird is 19 kg, although heavier specimens have been claimed. Weights of 23 kg (Newman 1971) to almost 40 kg have been reported (Main 1987) but these need confirmation. Birds in the south of this species’ range (southern Africa) are appreciably heavier than those occurring nearer the equator (Liversidge 1991).

Bare parts	The eye is pale yellow. 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 (Newman 1992).

Juvenile	Immature birds are browner than the adults, the crest and neck plumes are shorter and they have more spotting on the mantle. They resemble the female.

Geographical variation	Two subspecies are recognized: Ardeotis kori kori – the nominate race from southern Africa; Ardeotis kori struthiunculus – the Somali Kori from north-eastern Africa which is slightly larger with a more boldly patterned head. This may be a distinct species.

Similar species	The female Kori Bustard is about the same size as the other bustards in southern Africa but lacks the rufous hind-neck of the other species (Liversidge 1991). Distinguished from Stanley’s Bustard (Neotis denhamii) and Ludwig’s Bustard (Neotis luwigii) by its slimmer and greyer appearance and by not having a tawny red hind-neck. In flight it can be distinguished from both these other bustards by not displaying any white markings on the upperwing which is uniformly grey (Sinclair et al 1993). Both these other bustard species lack the dark crest. Denham’s or Jackson’s Bustard (Neotis denhami) (often called Stanley’s Bustard in southern Africa) has a bright rufous back of the neck and co-occurs with the Kori Bustard in East Africa (Williams 1995). Heuglin’s Bustard (Neotis heuglinii) is another East African bustard which overlaps with the Kori Bustard (Williams 1995). This bird has the crown, sides of the face and the chin black in the male and the female has the sides of the face mixed black and white. Similar to the Arabian Bustard (Ardeotis arabs) but has a black base of the neck and black in wing coverts (Sinclair & Ryan 2003). In the Arabian Bustard the female is larger than the male (Williams 1995) and this species is browner on the back than the Kori Bustard, with the wing coverts tipped white and has very fine neck vermiculations. Overlaps with the Kori Bustard in East Africa.

Similar species

The female Kori Bustard is about the same size as the other bustards in southern Africa but lacks the rufous hind-neck of the other species (Liversidge 1991). Distinguished from Stanley’s Bustard (Neotis denhamii) and Ludwig’s Bustard (Neotis luwigii) by its slimmer and greyer appearance and by not having a tawny red hind-neck. In flight it can be distinguished from both these other bustards by not displaying any white markings on the upperwing which is uniformly grey (Sinclair et al 1993). Both these other bustard species lack the dark crest.

Denham’s or Jackson’s Bustard (Neotis denhami) (often called Stanley’s Bustard in southern Africa) has a bright rufous back of the neck and co-occurs with the Kori Bustard in East Africa (Williams 1995). Heuglin’s Bustard (Neotis heuglinii) is another East African bustard which overlaps with the Kori Bustard (Williams 1995). This bird has the crown, sides of the face and the chin black in the male and the female has the sides of the face mixed black and white.

Similar to the Arabian Bustard (Ardeotis arabs) but has a black base of the neck and black in wing coverts (Sinclair & Ryan 2003). In the Arabian Bustard the female is larger than the male (Williams 1995) and this species is browner on the back than the Kori Bustard, with the wing coverts tipped white and has very fine neck vermiculations. Overlaps with the Kori Bustard in East Africa.

Distribution & Occurrence	EcoPort ex-R. Ellis

Geographical distribution	The Kori Bustard occurs throughout southern Africa except for well-wooded and forested areas. A geographically disjunct population of Kori Bustards also occurs in the deserts and savannas of north-eastern Africa. In southern Africa they are common in Botswana and Namibia, extending into southern Angola and marginally into south-western Zambia. In Zimbabwe they are generally sparse but locally common, particularly on the central plateau. Their distribution range extends along the Limpopo River valley into southern Mozambique and the eastern lowveld of South Africa. In South Africa they are also infrequent to rare in the Free State, North West and Northern Cape Provinces, extending southwards into the interior of the Western and Eastern Cape Provinces. Absent from the coastal lowlands along the south and east of the country and from high mountainous areas. In north-east Africa the Kori Bustard is found in northern Tanzania, throughout Kenya (except the coastal region) and widespread in Ethiopia. Extends into the extreme north of Somalia and the extreme south of Sudan (Sinclair & Ryan 2003). Also occurs in Uganda (Williams 1995). It is most abundant in Kenya where it is widespread in the Northern Frontier Province.

Geographical distribution

The Kori Bustard occurs throughout southern Africa except for well-wooded and forested areas. A geographically disjunct population of Kori Bustards also occurs in the deserts and savannas of north-eastern Africa.

In southern Africa they are common in Botswana and Namibia, extending into southern Angola and marginally into south-western Zambia. In Zimbabwe they are generally sparse but locally common, particularly on the central plateau. Their distribution range extends along the Limpopo River valley into southern Mozambique and the eastern lowveld of South Africa. In South Africa they are also infrequent to rare in the Free State, North West and Northern Cape Provinces, extending southwards into the interior of the Western and Eastern Cape Provinces. Absent from the coastal lowlands along the south and east of the country and from high mountainous areas.

In north-east Africa the Kori Bustard is found in northern Tanzania, throughout Kenya (except the coastal region) and widespread in Ethiopia. Extends into the extreme north of Somalia and the extreme south of Sudan (Sinclair & Ryan 2003). Also occurs in Uganda (Williams 1995). It is most abundant in Kenya where it is widespread in the Northern Frontier Province.

Movements and migration	Mostly resident locally but with nomadic movements (Sinclair et al 1993). These migratory movements are probably influenced by rainfall and there is no evidence suggesting any regular pattern. These local migrations take place at night (Ginn et al 1989) but have not been mapped. In the Etosha National Park these birds have been recorded moving up to 85 km from mopane woodland to open grassland plains and returning again the following season.

Movements and migration

Mostly resident locally but with nomadic movements (Sinclair et al 1993). These migratory movements are probably influenced by rainfall and there is no evidence suggesting any regular pattern. These local migrations take place at night (Ginn et al 1989) but have not been mapped. In the Etosha National Park these birds have been recorded moving up to 85 km from mopane woodland to open grassland plains and returning again the following season.

Population & Demography	Sparse to locally common. Subject to population changes, which seem to be influenced by the effect of rainfall on its food resources. Thus it is more plentiful in some areas than others depending on the prevailing conditions.

Conservation status	Generally scarce, but can be locally fairly common, particularly in protected areas (Sinclair & Ryan 2003). Their numbers have been much reduced by hunting. Traditional hunters snare them with Acacia gum bait and traps. They are no longer classified as game birds although they are considered good eating (Newman 1971) and were regularly shot in the past. Habitat destruction in some areas, such as bush encroachment due to overgrazing by livestock, is also partly responsible for the decline in Kori Bustard populations. Poison used to control locusts may also contribute to declining populations. Collisions with overhead wires regularly account for deaths of this bird. The Kori Bustard is now generally uncommon outside major protected areas (Sinclair et al 1993) and is listed as Vulnerable in the South African Red Data Book (Maclean 1993).

Conservation status

Generally scarce, but can be locally fairly common, particularly in protected areas (Sinclair & Ryan 2003). Their numbers have been much reduced by hunting. Traditional hunters snare them with Acacia gum bait and traps. They are no longer classified as game birds although they are considered good eating (Newman 1971) and were regularly shot in the past. Habitat destruction in some areas, such as bush encroachment due to overgrazing by livestock, is also partly responsible for the decline in Kori Bustard populations. Poison used to control locusts may also contribute to declining populations. Collisions with overhead wires regularly account for deaths of this bird. The Kori Bustard is now generally uncommon outside major protected areas (Sinclair et al 1993) and is listed as Vulnerable in the South African Red Data Book (Maclean 1993).

General Ecology	EcoPort ex-R. Ellis	2005-01-17
Generally feeds during the morning and in the evening, spending the rest of the day standing still in any available shade (Ginn et al 1989).

Habitat	Occurs in open grassland plains, open dry bushveld and semi-desert areas. In the south they occur in the open plains of the karoo, highveld grassland, Kalahari sandveld, arid scrub, Namib Desert, lightly wooded savanna and bushveld (Maclean 1993). Rainfall varies between 100-600 mm. The Kori Bustard frequents flat terrain, often with sandy soil, especially Kalahari sands, and short grass (Ginn et al 1989), usually near the cover of isolated clumps of trees or bushes. It appears to be attracted to recently burnt areas. They are most common where game is plentiful, and prefer nesting on the ground after the herds have moved through their territory (Ginn et al 1989). It also occurs in cultivated fields such as wheat lands, particularly if these have a few isolated trees and shrubs. Breeding habitat is savanna in areas with sparse grass cover and scattered trees and shrubs (Tarboton 2001). When nesting they sometimes use hilly areas.

Habitat

Occurs in open grassland plains, open dry bushveld and semi-desert areas. In the south they occur in the open plains of the karoo, highveld grassland, Kalahari sandveld, arid scrub, Namib Desert, lightly wooded savanna and bushveld (Maclean 1993). Rainfall varies between 100-600 mm.

The Kori Bustard frequents flat terrain, often with sandy soil, especially Kalahari sands, and short grass (Ginn et al 1989), usually near the cover of isolated clumps of trees or bushes. It appears to be attracted to recently burnt areas. They are most common where game is plentiful, and prefer nesting on the ground after the herds have moved through their territory (Ginn et al 1989). It also occurs in cultivated fields such as wheat lands, particularly if these have a few isolated trees and shrubs.

Breeding habitat is savanna in areas with sparse grass cover and scattered trees and shrubs (Tarboton 2001). When nesting they sometimes use hilly areas.

Food and feeding	Forages by walking and pecking on the ground or in low bushes and trees. They feed mostly in the early morning and late afternoon and rest during the heat of the day. When foraging in a group they often walk in a loose line across the veld. They walk slowly and sedately when foraging. Kori Bustards are omnivorous birds. The diet is varied and insects such as locusts, grasshoppers, caterpillars and dung beetles are important food items. Often catches insects disturbed by grazing mammals and invertebrates occurring in their dung are important in their diet. This bustard often congregates at outbreaks of locusts and caterpillars. Other insects recorded in their diet include armoured ground crickets, termites, hymenopterans and solifuges. Scorpions and molluscs are also taken. Small vertebrates such as lizards, chameleons, snakes, mice and other small mammals, as well as birds’ eggs and nestlings constitute a large part of its diet. They will also take carrion and organisms killed in veld fires. Plant material is included in their diet and their large caecum indicates the importance of vegetable matter. This comprises seeds, berries, roots, bulbs, flowers and wild melons. They also take green leaves and grass. This bustard is very partial to Acacia gum (Ginn et al 1989). This liking has given rise to the Afrikaans common name Gompou or, literally translated, gum peacock. They actively swallow stones and grit, as well as man-made materials such as plastic and glass. Occasionally forages in the same area as Stanley’s (Neotis denhamii) and Ludwig’s Bustards (Neotis ludwigii).

Food and feeding

Forages by walking and pecking on the ground or in low bushes and trees. They feed mostly in the early morning and late afternoon and rest during the heat of the day. When foraging in a group they often walk in a loose line across the veld. They walk slowly and sedately when foraging.

Kori Bustards are omnivorous birds. The diet is varied and insects such as locusts, grasshoppers, caterpillars and dung beetles are important food items. Often catches insects disturbed by grazing mammals and invertebrates occurring in their dung are important in their diet. This bustard often congregates at outbreaks of locusts and caterpillars. Other insects recorded in their diet include armoured ground crickets, termites, hymenopterans and solifuges. Scorpions and molluscs are also taken.

Small vertebrates such as lizards, chameleons, snakes, mice and other small mammals, as well as birds’ eggs and nestlings constitute a large part of its diet. They will also take carrion and organisms killed in veld fires.

Plant material is included in their diet and their large caecum indicates the importance of vegetable matter. This comprises seeds, berries, roots, bulbs, flowers and wild melons. They also take green leaves and grass. This bustard is very partial to Acacia gum (Ginn et al 1989). This liking has given rise to the Afrikaans common name Gompou or, literally translated, gum peacock. They actively swallow stones and grit, as well as man-made materials such as plastic and glass.

Occasionally forages in the same area as Stanley’s (Neotis denhamii) and Ludwig’s Bustards (Neotis ludwigii).

Drinking	The Kori Bustard drinks regularly but access to water is probably not essential and they have been recorded more than 40 km from water. This bird has an unusual drinking action. They use a sucking action, rather than scooping water up with their bill. Often crouch down on their hocks to drink.

Predation	This bird has been reported to be preyed upon by Martial Eagle (Polemaetus bellicosus), Lion (Panthera leo), Leopard (Panthera pardus), Cheetah (Acinonyx jubatus), Caracal (Caracal caracal), Black-backed Jackal (Canis mesomelas) and African Python (Python sebae).

Pests and diseases	The chewing lice Otidoecus carpi, Otidoecus dimorphus and Otidoecus kori have been reported to be associated with the Kori Bustard (Dalgleish, 2003 (January 2005)).

Habits and Behaviour	EcoPort ex-R. Ellis

General habits	The Kori Bustard is a watchful and wary bird. Their behaviour varies however, and they are usually very shy, running or crouching at the first sign of danger; at other times they can be completely fearless of humans (Williams 1995). They have a hesitant manner of walking, taking slow steps and when they detect an intruder they try to escape detection by moving off quietly with the head held at an unusual angle of between 45° and 60° (Ginn et al 1989). The bill is usually angled upwards when walking (Maclean 1993). They appear reluctant to fly. It is normally silent and unobtrusive (to avoid detection by predators), but becomes conspicuous when it calls and when they execute their territorial and courtship displays (Steyn 1996). Kori Bustards spend most of their time walking, up to 70%. This walking involves foraging for food and these birds are typically observed walking across open habitat. They generally rest during the heat of the day.

General habits

The Kori Bustard is a watchful and wary bird. Their behaviour varies however, and they are usually very shy, running or crouching at the first sign of danger; at other times they can be completely fearless of humans (Williams 1995).

They have a hesitant manner of walking, taking slow steps and when they detect an intruder they try to escape detection by moving off quietly with the head held at an unusual angle of between 45° and 60° (Ginn et al 1989). The bill is usually angled upwards when walking (Maclean 1993). They appear reluctant to fly. It is normally silent and unobtrusive (to avoid detection by predators), but becomes conspicuous when it calls and when they execute their territorial and courtship displays (Steyn 1996).

Kori Bustards spend most of their time walking, up to 70%. This walking involves foraging for food and these birds are typically observed walking across open habitat. They generally rest during the heat of the day.

Communication/voice	This large bird has a loud, booming call which is often uttered just before dawn and can be heard from far away (Dennis et al 1997). This mating call is a deep, resonant ‘woum-woum-woum-woum’ (Ginn et al 1989) or ‘oom-oom-oom’ (Sinclair & Ryan 2003) or ‘wum, wum, wum, wum, wummm' (Newman 1992). This call ends with the bill snapping which is only audible at close range. They also utter a ‘ca-caa-ca’ or ‘kah, kah, kah’, repeated several times for up to 10 minutes. This call carries long distances. They utter a deep ‘vum’ on takeoff (Maclean 1993). Less vocal than other bustards (Williams 1995). This bird is generally silent but, when alarmed, both sexes emit a loud growling bark. This call is given by females with young and males during agnostic encounters.

Communication/voice

This large bird has a loud, booming call which is often uttered just before dawn and can be heard from far away (Dennis et al 1997). This mating call is a deep, resonant ‘woum-woum-woum-woum’ (Ginn et al 1989) or ‘oom-oom-oom’ (Sinclair & Ryan 2003) or ‘wum, wum, wum, wum, wummm' (Newman 1992). This call ends with the bill snapping which is only audible at close range. They also utter a ‘ca-caa-ca’ or ‘kah, kah, kah’, repeated several times for up to 10 minutes. This call carries long distances. They utter a deep ‘vum’ on takeoff (Maclean 1993).

Less vocal than other bustards (Williams 1995). This bird is generally silent but, when alarmed, both sexes emit a loud growling bark. This call is given by females with young and males during agnostic encounters.

Social	Generally solitary but occurs in pairs when breeding, the birds generally about 100 m apart from one another. Otherwise somewhat gregarious, sometimes 5 or 6, but flocks up to 40 or more birds are seen together (Maclean 1993). These aggregations may be at waterholes or widely distributed across open plains. It is of interest that these flocks are predominately single-sex groups. These groups are not cohesive over time, the birds remaining together for a few days only. It has been suggested that they function as temporary defence against predators.

Social

Generally solitary but occurs in pairs when breeding, the birds generally about 100 m apart from one another. Otherwise somewhat gregarious, sometimes 5 or 6, but flocks up to 40 or more birds are seen together (Maclean 1993). These aggregations may be at waterholes or widely distributed across open plains. It is of interest that these flocks are predominately single-sex groups. These groups are not cohesive over time, the birds remaining together for a few days only. It has been suggested that they function as temporary defence against predators.

Territorial	Males make territorial flights.

Flight	Their flight appears to be very heavy and laboured but is strong with the neck extended and the legs folded. It needs to run to take off and lands with spread wings which are only folded when the bird has slowed down to a walking speed (Ginn et al 1989). Can take off from a standing position (Maclean 1993). This bustard is not found in well-wooded and forested areas due to the fact that it needs a lot of open space in which to take off (Ginn et al 1989). When alarmed it will first run and, if pushed further, will take to the air on the run with much effort, its relatively short wings making heavy wingbeats. Once airborne it flies more easily with slow, measured wingbeats. It usually remains low and lands again within sight (Liversidge 1991).

Flight

Their flight appears to be very heavy and laboured but is strong with the neck extended and the legs folded. It needs to run to take off and lands with spread wings which are only folded when the bird has slowed down to a walking speed (Ginn et al 1989). Can take off from a standing position (Maclean 1993).

This bustard is not found in well-wooded and forested areas due to the fact that it needs a lot of open space in which to take off (Ginn et al 1989). When alarmed it will first run and, if pushed further, will take to the air on the run with much effort, its relatively short wings making heavy wingbeats. Once airborne it flies more easily with slow, measured wingbeats. It usually remains low and lands again within sight (Liversidge 1991).

Roosting	The Kori Bustard roosts on bare ground or in very short grass, crouching on the ground and remaining immobile throughout the night. They leave the roost a short while before dawn. They sometimes appear to roost communally.

Self-maintenance	Kori Bustards have no preen gland. To keep clean they produce a powder down. They regularly sun bathe and take dust baths.

Moulting

Antagonistic	Fighting between males occurs during the mating season when display areas are being contested. They stand chest-to-chest, tails erect, bills locked and ‘push’ one another for up to 30 minutes. When threatened or alarmed they sometimes resort to shock displays. In this defensive display the bird bows forward, lifts its tail feathers and spreads and inverts its wings, thus appearing larger in size to any potential predator. The Kori Bustard has been observed acting aggressively towards other animals at waterholes. They raise their crests, open their wings and peck aggressively. This interaction has been observed between Kori Bustards and Red-crested Korhaans (Eupodotis ruficrista), Springbok (Antidorcas marsupialis), Burchell’s Zebra (Equus burchelli) and Gemsbok (Oryx gazella).

Antagonistic

Fighting between males occurs during the mating season when display areas are being contested. They stand chest-to-chest, tails erect, bills locked and ‘push’ one another for up to 30 minutes.

When threatened or alarmed they sometimes resort to shock displays. In this defensive display the bird bows forward, lifts its tail feathers and spreads and inverts its wings, thus appearing larger in size to any potential predator.

The Kori Bustard has been observed acting aggressively towards other animals at waterholes. They raise their crests, open their wings and peck aggressively. This interaction has been observed between Kori Bustards and Red-crested Korhaans (Eupodotis ruficrista), Springbok (Antidorcas marsupialis), Burchell’s Zebra (Equus burchelli) and Gemsbok (Oryx gazella).

Interspecific interactions	Carmine Bee-eaters (Merops nubicoides) sometimes ride on the backs of Kori Bustards to hawk insects disturbed by the bustards (Ginn et al 1989). This is regularly seen in the Savuti area in Botswana but has only been reported once elsewhere. There is also one record of Fork-tailed Drongos (Dicrurus adsimilis) perching on their backs. In Tanzania Kori Bustards regularly attend Blue Wildebeest (connochaetes taurinus) herds and feed on the small mammals disturbed by them (Dean & MacDonald 1981).

Interspecific interactions

Carmine Bee-eaters (Merops nubicoides) sometimes ride on the backs of Kori Bustards to hawk insects disturbed by the bustards (Ginn et al 1989). This is regularly seen in the Savuti area in Botswana but has only been reported once elsewhere. There is also one record of Fork-tailed Drongos (Dicrurus adsimilis) perching on their backs. In Tanzania Kori Bustards regularly attend Blue Wildebeest (connochaetes taurinus) herds and feed on the small mammals disturbed by them (Dean & MacDonald 1981).

Breeding Biology	EcoPort ex-R. Ellis	2005-01-18
The males are polygynous and play no further part in reproduction once mating has taken place. (Steyn 1996). There is no evidence of monogamy despite reports of ‘pairs’. The breeding behaviour of this bird is difficult to study in the wild and accurate details have yet to be collected.

Courtship and displays	Males display at regularly used sites, each male with several dispersed leks or display areas (Tarboton 2001). 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. The males hold their heads backwards, with cheeks bulging, the crest is held erect, the bill open and they inflate their gular pouches, forming a white throat ‘balloon’. During this display the oesophagus inflates to as much as four times its normal size and resembles a balloon. They also puff out their frontal neck feathers which are splayed upwards showing their white underside. Their wings are drooped and their tails are raised upwards and forwards onto their backs like a turkey, the retrices being held vertically and their undertail coverts fluffed out. They enhance their performance with an exaggerated bouncing gait (Steyn 1996). When displaying they stride about with their necks puffed out, their tail fanned and their wings planed and pointed downwards (Dennis et al 1997). They also emit a low-pitched booming noise when the neck is at maximum inflation and snap their bills open and shut. Several males dispersed over a wide area gather to display but usually one is dominant and the others do not display in his presence and move away. The displaying males are visited by the females who presumably select the male with the most impressive display. In copulation the female lies down next to a displaying male. He stands over her for 5-10 minutes, stepping from side to side and pecking her head in a slow, deliberate fashion, tail and crest feathers raised. She recoils at each peck. He then lowers himself onto his tarsi and continues pecking her until he shuffles forward and mounts with wings spread. Copulation lasts seconds after which both stand apart and ruffle their plumage. The female then sometimes barks and the male continues with his display.

Courtship and displays

Males display at regularly used sites, each male with several dispersed leks or display areas (Tarboton 2001). 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.

The males hold their heads backwards, with cheeks bulging, the crest is held erect, the bill open and they inflate their gular pouches, forming a white throat ‘balloon’. During this display the oesophagus inflates to as much as four times its normal size and resembles a balloon. They also puff out their frontal neck feathers which are splayed upwards showing their white underside. Their wings are drooped and their tails are raised upwards and forwards onto their backs like a turkey, the retrices being held vertically and their undertail coverts fluffed out. They enhance their performance with an exaggerated bouncing gait (Steyn 1996). When displaying they stride about with their necks puffed out, their tail fanned and their wings planed and pointed downwards (Dennis et al 1997). They also emit a low-pitched booming noise when the neck is at maximum inflation and snap their bills open and shut.

Several males dispersed over a wide area gather to display but usually one is dominant and the others do not display in his presence and move away. The displaying males are visited by the females who presumably select the male with the most impressive display.

In copulation the female lies down next to a displaying male. He stands over her for 5-10 minutes, stepping from side to side and pecking her head in a slow, deliberate fashion, tail and crest feathers raised. She recoils at each peck. He then lowers himself onto his tarsi and continues pecking her until he shuffles forward and mounts with wings spread. Copulation lasts seconds after which both stand apart and ruffle their plumage. The female then sometimes barks and the male continues with his display.

Breeding Season	The breeding season falls between September and March in South Africa, but occurs mainly between October and December. However, the laying time varies, especially in the drier areas, and depends on prevailing local conditions.

Nest	The Kori Bustard lays its eggs on the ground in a shallow, unlined hollow, rather than a scrape. This nest is usually located within 4m of a tree or shrub, termite mound or an outcrop of rocks. Higher lying ground in sandy soil is often used (Tarboton 2001). The scrape is 300-450mm in diameter. When the incubating bird is on the nest the rocks and vegetation help to break up its outline. Nests are not easy to find, except by chance. The same site is sometimes reused in successive years. The Kori Bustard is a solitary nester and there is no evidence of territoriality amongst the females.

Nest

The Kori Bustard lays its eggs on the ground in a shallow, unlined hollow, rather than a scrape. This nest is usually located within 4m of a tree or shrub, termite mound or an outcrop of rocks. Higher lying ground in sandy soil is often used (Tarboton 2001). The scrape is 300-450mm in diameter. When the incubating bird is on the nest the rocks and vegetation help to break up its outline. Nests are not easy to find, except by chance. The same site is sometimes reused in successive years.

The Kori Bustard is a solitary nester and there is no evidence of territoriality amongst the females.

Eggs/Clutch

Normally 2 eggs are laid per clutch, less often only 1 (possibly in drier years) and seldom 3. They are laid at least 2 days apart. The eggs are characteristically elliptical or oval in shape and are glossy and waxy. They are cryptically coloured with the ground colour being dark buff, brown or olive and well marked and blotched with shades of brown, grey and pale purple (Tarboton 2001). The eggs are slightly glossed and pitted (Ginn et al 1989). Egg size is 83x60 mm. and weigh about 146 g.

Incubation

Only the female incubates the eggs. She remains on them for 98% of the daytime. She does not drink and remains close to the nest when she takes a break. Occasionally she stretches her legs and raises her wings overhead. The female regularly turns the eggs with her bill. She occasionally picks up pieces of vegetation and drops them on her back.

The female plumage is more drab than the male, helping her to remain undetected when incubating. Sometimes the sitting bird will flatten itself, relying on camouflage to remain undetected. She is extremely wary when at the nest, approaching it cautiously and leaving slowly in a crouched walk (Steyn 1996). If approached the incubating bird either slips unobtrusively from the nest or sits tight, only flying off at the last moment (Tarboton 2001).

The incubation period is between 23 and 30 days, 23-25 days in the wild and 27-30 in captivity.

Chick/Nestling

The young are precocial and nidifugous. The downy chicks are extremely cryptic and their markings on the head and back effectively camouflage them. The lores are tawny, the crown tawny mottled black. A broad white supercilium bordered with black meets on the nape, extending down the centre of the nape. The neck is white with irregular black stripes from behind the eye and from the base of the lower mandibles. The upper parts are tawny and black with 3 black lines running along the back. The underparts are whitish. They are ready to leave the nest soon after hatching and can feed themselves.

Parental care

The chicks are cared for only by the female. The young fly weakly at 4-5 weeks and can fly for several hundred metres at 3-4 months of age (Maclean 1993). The chicks stay with the mother until the start of the next year’s breeding season but only mature at 3 years.

The female performs a distraction display when her chick is threatened. She moves away, crouching and barking, drooping and shuffling her wings with her neck and body feathers fluffed out, crest erect and bill pointing upwards.

Breeding success

Hatching rates are relatively high, about 67%. Breeding success is linked to rainfall with fewer and smaller broods in dry years. In very dry years very few females breed and the brood sizes are smaller. Average brood size is 1.52 in wet years and 1.22 in dry years.

Chicks are killed at night by Black-backed Jackals (Canis mesomelas) and Leopards (Panthera pardus). Chicks and eggs are eaten by Martial Eagles (Polemaetus bellicosus, mongooses, Warthogs (Phacochoerus aethiopicus) and Chacma Baboons (Papio cynocephalus).

Notes	EcoPort ex-R. Ellis	2005-01-18
The Kori Bustard features in dances and songs of the San people of Botswana. Paintings of these bustards feature in San rock art. Etymology The specific epithet kori is derived from the Tswana name for this bird - Kgori.

Bibliography	EcoPort ex-R. Ellis	2005-01-18
Morgan-Davies A.M. (1965) On the Kori Bustard Ardeotis kori (Burchell) in northwestern Tanzania Steyn P. (1996) Nesting Birds : The breeding habits of southern African birds. Ginn P.J. McIlleron W.G. Milstein P. le S. (1989) The Complete Book of southern African birds. Tarboton W. (2001) A Guide to the Nests and Eggs of Southern African Birds. Sinclair I. Ryan P. (2003) A comprehensive illustrated field guide : Birds of Africa south of the Sahara. Dennis N. Knight M. Joyce P. (1997) The Kalahari: Survival in a Thirstland Wilderness. Liversidge R. (1991) The Birds Around Us - Birds of the Southern African Region. Dean WRJ MacDonald IAW (1981) A review of African birds feeding in association with mammals. Newman K. (1992) Newman's Birds of Southern Africa : Expanded Edition, Fourth Edition. Williams J.G. (1995) Collins Field Guide: Birds of East Africa. Sinclair I. Hockey P. Tarboton W. (1997) Sasol Birds of Southern Africa. Main M. (1987) Kalahari: Life's Variety in Dune and Delta. Newman K. (ed) (1971) Birdlife in southern Africa.

Links

EcoPort ex-R. Ellis

2005-01-27

Web Site	Comment
Birds and their Associated Chewing Lice (Dalgleish, 2003).	General Ecology - Pests & Diseases