Great Bustards

The Great Bustard is a bird of superlatives. Males of this species reach 21 kg (45 lbs), making them the heaviest birds capable of flight. Females, however, weigh only 5-7 kg (11-15 lbs). Key to this dramatic difference - the most extreme sexual size difference seen in birds - is the unusual mating system of the Great Bustard.

Female bustards choose a mate on the basis of his appearance and mating display, which is performed at traditional sites each spring. The result of generations of female-choice? Super-sized males with striking red coloration, capable of performing a complex display involving contortion of the body and inflation of a specialized throat sac.

Unfortunately, severe population declines over the past 100 years mean that few people now observe the intricate display of the Great Bustard. The species has declined across its range, becoming extinct in some European countries.

The Asian subspecies of Great Bustard, found only in Mongolia, China, and Russian South Siberia, is of special concern. Though few surveys have been undertaken in Mongolia, the population has been estimated at just 1500 birds. These bustards are particularly at risk as Mongolia transitions from communism to a free-market economy, replete with road construction, increased natural resource development, and land privatization.

Threats to the Great Bustard are numerous. Bustard nests, simple scrapes in the ground, are destroyed by the activity of agricultural machinery in the fields they inhabit. The insect food base so important to the rapid growth of chicks is eliminated with pesticides. Though they are strong fliers, heavy-bodied bustards are not maneuverable enough to avoid collisions with powerlines. And though now illegal, hunting by humans also plays a role in these declines. Our team is working to quantify the risks to bustards in Central Asia, and we communicate with local people and conservation agencies to develop conservation plans.

Related Species

Other Bustard Species

Houbara Bustard. Evolutionarily, Houbara are a sister species to the Great Bustard. Like the populations of Great Bustard we research, Houbara bustards suffer a high rate of poaching. These chicken-sized birds also perform a captivating and unusual breeding display, jogging about with their eyes obscured by decorative feathers.

Great Indian Bustard. Roughly the size of the Great Bustards we study, the Great Indian Bustard is now considered critically endangered. Only 250 of these birds remain, due to habitat loss and hunting. Males of this species inflate a pendulous neck sack to produce booming noises to attract females.

Similar Species in North America

Although there are no members of the Bustard family in the New World, some species have a similar breeding biology or fill a similar ecological niche:

Turkey. Like Great Bustards, Wild Turkeys are heavy bodied. However, whereas Wild Turkeys fly only short distances, the Bustards we monitor are strong fliers that migrate long distances. The male Turkey, like the male Great Bustard, attracts females by contorting his tail and shivering his feathers. Turkeys were promoted by Benjamin Franklin as the national bird of the US. The Great Bustard, for its part, is the national bird of Hungary, and honored as well on the crest of Wiltshire in the UK.

Sage Grouse. Like Great Bustards, Sage Grouse gather on traditional breeding grounds called "leks" each spring to carry out their courtship displays. Bustards and Sage Grouse both prefer open habitats and suffer declines from land-use change and habitat loss.

Prairie Chickens are also lekking birds of open grasslands. The prairie chicken mating display involves leg stomping and strutting. This impressive performance is honored in dances of Native American Plains Indian tribes.