Bustards

(Otididae)

Class Aves

Order Gruiformes

Suborder Otidides

Family Otidae

Thumbnail description
Medium size to very large terrestrial birds, with long legs and necks and fairly short straight bills

Size
15.75–47.25 in (40–120 cm); 1–42.2 lb (0.45–19 kg)

Number of genera, species
11 genera; 26 species

Habitat
Level or gently undulating grasslands, steppes, semideserts, and open savanna woodlands

Conservation status
Endangered: 3 species; Vulnerable: 1 species; Near Threatened: 6 species

Distribution
Africa, southern Europe, south and Southeast Asia, New Guinea and Australia

Evolution and systematics

Bustards are linked ancestrally to cranes and their relatives (Gruiformes). Genetic studies place them in their own suborder, Otidides, whose divergence from the Gruides is estimated at 70 million years ago. Although conspicuous courtship displays imply a link with cranes, the evolutionary isolation of bustards finds manifestation in various morphological anomalies. These include the absence of a hind toe and preen gland, hexagonal rather than transverse tarsal scutellation, and unique dense powder-down.

Taxonomic relationships within the family are contested. The large bustards are grouped in Otis, Neotis, and Ardeotis, and these are possibly related to the smaller Chlamydotis and Tetrax. Diminutive Tetrax, long combined with the far larger Otis by taxonomists, might be related to Sypheotides, to which it more closely equates in terms of size, flight-feather modification, and display. Some recent appraisals combine 14 relatively small species within the genus Eupodotis, but an alternative treatment retains only five species in this grouping, separating the remainder into Afrotis, Lissotis, Lophotis, Houbaropsis, and Sypheotides.

Physical characteristics

Bustards combine stout bodies carried horizontally with long legs and necks, the latter supporting flat-crowned heads and short, straight bills. As a result of an exclusively terrestrial lifestyle, they have no hind toe. They tend to escape danger by flying, and consequently their feet are relatively small, and their wings are large and strong. Mature male Otis and Ardeotis bustards regularly reach over 3.3 ft (1 m) in height, and as some approach 44 lb (20 kg), they are among the heaviest of flying birds. In these genera, females tend to be twothirds the height and one-third the weight of their respective males. In smaller bustard species, the difference in size between the sexes is less pronounced.

Bustard plumage is largely cryptic: the upperparts are brown or finely barred, so that a crouching bird is camouflaged. The underparts are often white in open-country species, and sometimes black in species that inhabit taller vegetation (counter-shading being less of a consideration). Many species have patches of white and black in the wing that are concealed when standing or sitting but conspicuous in flight. Males are generally brighter or more strikingly patterned than females, at least in the breeding season, but sexes are similar in Eupodotis. In Otis, Ardeotis, Neotis, Chalmydotis, Lissotis, and Houbaropsis, males develop filamentous plumes that are used in courtship displays. The most elaborate are in Chlamydotis (elongated erectile piebald plumes on breast, neck, and crown), Otis (white moustachial plumes), and Sypheotides (long bare-shafted, spatulate-tipped cheek feathers).

Distribution

Bustards are confined to the Old World. A glance at patterns of bustard diversity suggests that they originated in Africa, where 21 species occur. Sixteen of these are purely Afrotropical, and another two only fractionally enter the

North African portion of the Palearctic region. Within Africa, there are two distinct centers of speciation. One is in East Africa, between the Horn and the Nile, the other is in southern Africa south of the Zambezi. Of four species with chiefly Palearctic distributions, two are widespread in Europe and Asia, with portions of their ranges in North Africa. One is entirely North African; another is almost entirely Asian, extending from Egypt and the Middle East to China (these two forms, the Houbara bustard Chlamydotis undulata and Macqueen's bustard C. macqueenii, are often treated as conspecific). Three more species are Oriental (all centered on the Indian subcontinent, one with an outlying population in Indochina), and one species is Australasian, occurring in Australia and southern New Guinea.

Habitat

Bustards inhabit temperate and tropical semideserts, grassy plains, and open low-stature woodland. The majority (19 species) are most commonly associated with flat or gently undulating open landscapes, generally with vegetation sufficiently low to allow them a view over long distances. Many African bustards (Eupodotis, Lophotis, and Lissotis) tolerate varying degrees of wooded cover, including acacia woodland and thorny thickets, and the floricans (Sypheotides and Houbaropsis) are regularly found in tall grassland. A huge area of habitat suitable for bustards has been converted to cultivation, especially in Europe and the Indian subcontinent. Fortunately, many species tolerate nonintensively farmed land.

Behavior

Most bustards are found walking slowly across open terrain. Several species are at least partially gregarious. The great bustard (Otis tarda) has been recorded in groups of over 50, and nonbreeding aggregations of the little bustard (Tetrax tetrax) can number in the thousands. The desert-adapted forms, such as Chlamydotis, are probably the most solitary. A few species gather at loose leks. Foraging bustards are regularly found near herds of grazing herbivores. Presumably they benefit from reductions in predation pressure or elevations in foraging success, as they hunt insects disturbed by the mammals.

It is unlikely that any bustard species is entirely sedentary, and many are clearly nomadic or migratory. Those that breed in Asia undertake long distance migrations to escape harsh winters. The lesser florican (Sypheotides indica) performs regular migrations in response to rainfall in India, and the same is true of several African species.

Feeding ecology and diet

Bustards are omnivorous and opportunistic. Most species have a diet predominately of vegetable matter. They eat fresh shoots, flowers, and leaves of herbaceous plants; excavate for soft roots and bulbs; and take fruit and seeds when available. In cultivated areas they consume a variety of crops. Insects are also an important food, at least seasonally. The timing of breeding tends to synchronize chick emergence with maximum insect abundance. Although beetles and grasshoppers are the main invertebrate prey items, many other arthropods

are taken if available. Bustards also consume small vertebrates such as reptiles and rodents, particularly those killed or injured in bush fires or traffic. Bustards can thrive without water for long periods, but drink freely when water is available.

Reproductive biology

The breeding season tends to coincide with periods of high rainfall. At its outset, males of many species perform magnificent displays, often from traditionally favored locations. In general, pair bonds between male and female bustards appear to be absent, as females visit displaying males and then leave to incubate the eggs and raise the chicks alone. Sexual maturation is slowest and sexual dimorphism most pronounced in species with dispersed leks or solitary territorial males: males take up to six years to reach full size and possess plumage ornamentation absent in females.

The displaying great bustard selects an elevated site and then inflates his gular sac and raises his tail, exposing white undertail-coverts. The inner secondaries are then twisted over and fanned so that, at the height of his splendid performance, having apparently turned himself inside out, the gleam of white plumage is visible several miles away. The kori bustard (Ardeotis kori) grossly inflates his neck plumage, cocks his tail, and emits a low booming call. Many smaller bustards, particularly those that inhabit taller vegetation, incorporate vertical display leaps or short flights into courtship behavior so that they are visible from a distance.

The nest is a bare scrape into which one to six (usually two to four) eggs are laid. Incubation is 20–22 days in the little bustard, 24–25 days in the great bustard, and presumably between these extremes in all other species. Incubation starts with the first egg, leading to asynchronous hatching. The precocial young (hatched covered with down and open eyes) can usually walk after a few hours.

Conservation status

In the face of agricultural intensification, pesticide use, hunting, and disturbance, bustard populations are falling and their distributions shrinking. Four species are currently considered Threatened: the widespread great bustard and all three bustards from the Oriental region. Six more bustards are treated as Near Threatened: little, Denham's (Neotis denhami), Nubian (N. nuba), Houbara, little brown (Eupodotis humilis), and blue bustard (E. caerulescens). [This assessment treats Houbara and Macqueen's bustards as conspecific.] All remaining large species are suffering declines and extinction at the local level. The most threatened species are the two floricans and the great Indian bustard (Ardeotis nigriceps). They are confined to India and Indochina, where heavy hunting pressure and degradation of suitable habitat has savagely reduced their populations.

Although small numbers of each of these species breed and survive within protected areas, their future hangs in the balance. In general, bustards are at greater risk than many animals because populations in all but the very largest reserves are not viable. Low population densities, and their nomadic or migratory lifestyles, mean that current protected area networks do not comfortably meet their needs.

Significance to humans

Bustards bring economic and ecological benefits. Depredation of insect plagues and other crop pests by bustards improves agricultural productivity, and they are likely to play an important role in seed dispersal. In return, most species have suffered grievously at the hands of man. A heavy toll is exacted in many regions by hunting, to the point that Asian populations face a serious threat of extinction. The most significant method is the use by Arabian dignitaries of trained falcons to hunt bustards. The modern version of "traditional" entourages, equipped with teams of falcons and the latest technology, trawl across Middle Eastern deserts for the Macqueen's bustard. With numbers falling, the falconers have expanded their activities throughout North Africa, partly shifting their attention to Arabian (Ardeotis arabs) and Nubian bustards. A similar scale of persecution is reported from Cambodia, where Bengal floricans (Houbaropsis bengalensis) are a favorite source of food.

Species accounts

List of Species

Great bustard

Otis tarda

taxonomy

Otis tarda Linnaeus, 1758, Poland. Two subspecies recognized.

other common names

French: Grande outarde; German: Großtrappe; Spanish: Avutarda Euroasiática.

physical characteristics

Male: 41 in (105 cm), 13–40 lb (5.8–18 kg); female: 30 in (75 cm), 7–12 lb (3.3–5.3 kg). Back and tail barred black and gold; white underneath. Female and nonbreeding male head and neck are pale blue-gray; breeding male has white and russet on neck and whitish chin barbs.

distribution

O. t. tarda: northern Morocco and Iberia, Germany, Hungary, southern Ukraine; also breeds Turkey, western Iran, and southwestern Russia, through Kazakhstan to Kyrgyzstan, wintering from southern Turkey and Syria through southern Azerbaijan and northern Iran to Uzbekistan and Tadjikistan; O. t. dybowski: southeastern Russia, Mongolia, and northern China.

habitat

Level or gently undulating open short-grass plains, generally favoring undisturbed areas.

behavior

Usually lives in nonterritorial sex-segregated groups, these sometimes large in winter. In breeding season dominant males display spectacularly on dispersed leks. Migratory in part of range.

feeding ecology and diet

Plant material and invertebrates, occasionally amphibians, reptiles, or young birds.

reproductive biology

Two to three eggs laid in bare scrape, where incubated by female for about 25 days; fledging period 30–35 days. First breeding occurs at 5–6 years in males and 2–3 years in females.

conservation status

Vulnerable. Populations have declined and fragmented. Main threats are agricultural intensification, disturbance, pesticide use, and hunting.

significance to humans

Appears in European heraldic imagery and insignia; now the figurehead of a major grassland conservation program in Iberia.

Great Indian bustard

Ardeotis nigriceps

taxonomy

Otis nigriceps Vigors, 1831, Himalayas. Monotypic.

other common names

English: Indian bustard; French: Outarde à tête noire; German: Hindutrappe; Spanish: Avutarda India. Monotypic.

physical characteristics

Male: 47 in (120 cm), 18–32 lb (8–14.5 kg); female: 35 in (90 cm), 7.8–15 lb (3.5–6.75 kg). Extensive black crown; head, neck, and breast white with fine dark gray barring and indistinct black breast band. Back and wings brown with fine dark vermiculations. Black panel on wing spotted with white.

distribution

Western and central India.

habitat

Rolling grassland with some shrubby vegetation, or sandy semidesert. Visits cultivation.

behavior

Solitary or in small groups. Males display on well-separated territories in the breeding season; no pair bonds.

feeding ecology and diet

Consumes grains, shoots, and berries in season, as well as arthropods, small reptiles, and mammals.

reproductive biology

One egg (sometimes two) incubated for about 27 days in bare scrape by female only; fledging period 35–40 days.

conservation status

Endangered. Probably fewer than 1,000 birds survive. Irrigation of semideserts, agricultural intensification, disturbance, and hunting continue to press this species toward extinction.

significance to humans

Symbol of the Bombay Natural History Society, India's largest wildlife and conservation organization.

Houbara bustard

Chlamydotis undulata

taxonomy

Psophia undulata Jacquin, 1784. Three subspecies.

other common names

English: Ruffed bustard; French: Outarde houbara; German: Kragentrappe; Spanish: Avutarda Hubara.

physical characteristics

Male: 25.5–29.5 in (65–75 cm), 4–7 lb (1.8–3.2 kg); female: 21.5–25.5 in (55–65 cm), 2.7–3.8 lb (1.2–1.7 kg). Buff crown

with white erectile feathers along center. Pale grayish buff head and neck with black erectile plumes down side of neck to breast. Back pale sandy buff, mottled and lined with darker brown. Female has reduced neck plumes, otherwise similar.

distribution

C. u. fuertaventurae: eastern Canary islands; C. u. undulata: Morocco to north central Egypt (not eastern Nile Valley or Sinai).

habitat

Arid semidesert with tussock grass, sandy grassland, and stony plains with scattered low shrubs; regularly on cultivation in nonbreeding season.

behavior

Essentially solitary and nonmigratory (but locally nomadic). Males display in breeding season; no pair bonds.

feeding ecology and diet

Vegetable matter, insects, and small reptiles.

reproductive biology

Main breeding season March and April. Clutch usually 2–3 eggs, laid in bare scrape and incubated for 24–28 days by female; fledging period about 35 days.

conservation status

Expanded species (including macqueenii) considered Near Threatened. Although undulata is less severely hunted than its Asiatic cousin, numbers are probably much lower overall, and hunting pressure increasing. Population of race fuertaventurae: about 700 individuals.

significance to humans

Favored quarry of Arab dignitaries who hunt with falcons and guns.

Blue bustard

Eupodotis caerulescens

taxonomy

Otis caerulescens Vieillot, 1820, "Kaffraria" = eastern Cape Province. Monotypic.

other common names

English: Blue korhaan; French: Outarde plombée; German: Blautrappe; Spanish: Sisón Azulado.

physical characteristics

21.5 in (55 cm); 2.5–3.5 lb (1.1–1.6 kg). Blue-gray neck and underparts.

distribution

Eastern and central South Africa and Lesotho.

habitat

High rolling grasslands and croplands, usually above 4,900 ft (1,500 m).

behavior

Pairs or small groups of up to six appear to be sedentary and group territorial, the young staying with adults for up to two years.

feeding ecology and diet

Plant matter, invertebrates, and small reptiles. Visits recently burned grasslands and plowed fields.

reproductive biology

Main breeding period October–November, 1–3 eggs laid on bare scrape in grassland, incubated for 24–28 days. Mature offspring from last brood probably cooperate in breeding attempts.

conservation status

Near Threatened. Declining in some areas through agricultural intensification, but population is thought to exceed 10,000 individuals.

significance to humans

None known.

White-quilled bustard

Afrotis afraoides

taxonomy

Otis afraïdes A. Smith, 1831, flats near Orange River. Three subspecies.

other common names

English: White-quilled korhaan; French: Outarde à miroir blanc; German: Weißflügeltrappe; Spanish: Sisón Negro Aliclaro.

physical characteristics

19.7 in (50 cm); 1.5 lb (0.7 kg). Black neck and underparts, with gold and brown barred spot on crown, white collar behind neck, and white ear-coverts. Wings and back barred dark brown on whitish; white on primaries is conspicuous in flight.

distribution

A. a. etoschae: northwestern Namibia and northern Botswana; A. a. damarensis: Namibia and central Botswana; A. a. afraoides: southeastern Botswana through northern and northeastern South Africa to Lesotho.

Flat grassland with sward of 19.7–39.4 in (50–100 cm), semi-desert scrub, grassy dunes, and arid savanna. Tolerates heavily grazed areas.

behavior

Generally solitary; males display on territories using stylized flights accompanied by loud calling.

feeding ecology and diet

Variety of plant and animal material, including insects, seeds, flowers, and leaves.

reproductive biology

Breeds almost throughout year, but mainly September to March. Lays one, sometimes two, eggs on bare ground. Incubation period 19–21 days in captivity.

conservation status

Not threatened. Common in most of range.

significance to humans

None known.

Bengal florican

Houbaropsis bengalensis

taxonomy

Otis bengalensis Gmelin, 1789, Bengal. Sometimes merged with Eupodotis. Two subspecies.

other common names

French: Outarde du Bengale; German: Barttrappe; Spanish: Sisón Bengali.

physical characteristics

Male: 25 in (64 cm), 2.8–3.8 lb (1.25–1.7 kg); female: 27 in (68 cm), 3.8–5 lb (1.7–2.25 kg). Back and tail buffy brown, vermiculated with black pattern. Male has head, neck, and underparts black. Female has buffy head and underparts.

distribution

H. b. bengalensis: along border of southern Nepal and India, east to lowlands of Assam; H. b. blandini: central and southern Cambodia, southern Vietnam.

habitat

Flat grasslands, often with scattered shrubs, or in recently burned patches. Visits cultivation.

behavior

Both races dispersive, b. blandini probably with regular short distance migration. On breeding grounds, males make display flights from traditional sites.

feeding ecology and diet

Mainly vegetable matter in the nonbreeding season, invertebrates in the breeding season.

reproductive biology

One to two eggs laid in March to June (India) on bare scrape where incubated for 25–28 days. No pair bond; female responsible for all incubation and chick rearing.

conservation status

Endangered. Total population thought to be around 500 individuals in India/Nepal, but unquantified Indochinese population possibly contains several thousand birds. Conversion of grasslands and heavy hunting in some areas are the main threats.

significance to humans

Important food source in Cambodia.

Little bustard

Tetrax tetrax

taxonomy

Otis tetrax Linnaeus, 1758, France. Monotypic.

other common names

French: Outarde canepetière; German: Zwergtrappe; Spanish: Sisón Común.

physical characteristics

17 in (43 cm); male: 1.7–2.2 lb (0.8–1 kg); female: 1.5–2 lb (0.7–0.95 g). Upperparts buffy brown, lightly vermiculated with black; tail white mottled with three bars. Breeding male has blue-gray face, black neck and breast, with white V at foreneck and white band across breast, and white undersides. Female has buff face, neck, and breast, with streaking and barring on breast. Nonbreeding male is similar to female.

distribution

Western Mediterranean basin, Turkey, Ukraine, and southwestern Russia through Kazakhstan and Kyrgyzstan, extreme northwestern China and extreme northern Iran. Eastern populations winter to Iran, Azerbaijan, and Afghanistan.

habitat

Flat or rolling short-grass plains, stony semideserts, pasture, and fallow land.

behavior

Highly gregarious in mixed-sex groups outside breeding season. Males give crepuscular jumping display in breeding season.

feeding ecology and diet

Invertebrates and plant material, the former predominate in summer, the latter in winter.

reproductive biology

Two to six eggs laid February to June in bare scrape, usually in grassy cover; incubated by female 20–22 days, remaining with her until first autumn.

conservation status

Near Threatened. Although over 100,000 individuals probably survive, there has been a massive decline almost throughout its range, particularly in the east where habitat modification continues, and hunting is not controlled.

significance to humans

Favorite food item and target of hunters in many countries.

Resources

Books

BirdLife International. Threatened Birds of Asia. Barcelona: Lynx Edicions, 2001.

Collar, N. J. "Family Otididae (Bustards)." In Handbook of Birds of the World. Vol. 3, edited by del Hoyo, J., A. Elliott, and J. Sargatal. Barcelona: Lynx Edicions, 1996.

Goriup, P. D., and H. Vardhan, eds. Bustards in Decline. Jaipur: Tourism and Wildlife Society of India, 1983.

Johnsgard, P. A. Bustards, Hemipodes and Sandgrouse: Birds of Dry Places. Oxford: Oxford University Press, 1991.

Periodicals

Allan, D. G. "The World's Bustards: A Looming Crisis." Quagga 24 (1988): 5–9.

Gaucher, P., P. Paillat, C. Chappuis, M. Saint Jalme, F. Lotfikhah, and M. Wink. "Taxonomy of the Houbara Bustard Chlamydotis undulata Subspecies Considered on the Basis of Sexual Display and Genetic Divergence." Ibis 138 (1996): 273–282.

Johnsgard, P. A. "Bustards: Stalkers of the Dry Plains." Zoonooz 63, no. 7 (1990): 4–11.

Wightman, J. "Bustards (Behavior, Display, Reproduction, Habitat)." Animals 11 (1968): 341–343.

Joseph Andrew Tobias, PhD