Bustards vary in size from 15 to 47 inches (40 to 120 centimeters) in length. They are among the heaviest flying birds, weighing 1 to 42.2 pounds (0.45 to 19 kilograms). Male bustards are generally larger than females, although there is less difference between the sexes in smaller bustard species. Bustards have stout bodies with long legs and long necks. The bills tend to be short and straight. Bustards have large wings and small feet with no hind toe. Since Bustards do not perch on tree branches, preferring instead to remain on the ground, hind toes are not needed. The large wings are helpful when flying away from potential predators.
Bustards are generally colored to blend in with their environments. The back is brownish, with either white or dark bellies. Some bustard species have white or black patches on the wings, which are hidden when the wings are folded and only revealed during flight. In some species of bustards males and females are similarly patterned, while males are brighter in other species. In a number of bustards, males also have long feathers on the head, neck, or chest that are used to attract females.
Bustards are found across much of the Old World, including Africa, Europe, and Asia, as well as in Australia.
Bustards are found primarily in grassland habitats with low vegetation where they are able to look out over long distances. Some bustards occupy taller grasslands or even slightly wooded areas. Bustards are also frequently found in cultivated fields.
Bustards are omnivores, consuming both plant and animal matter. They are opportunistic feeders who are often able to take advantage of any food. In most species, the diet consists mostly of plant matter, including leaves, shoots, flowers, roots and bulbs, fruit, and seeds. Individuals that occupy cultivated areas frequently eat crops as well. Bustardseat insects such as beetles and grasshoppers. Insects are a particularly important part of the diet during the breeding season, while chicks are being fed. Bustards sometimes eat larger animals as well, such as reptiles and rodents. In most cases, however, these animals are killed during fires or by traffic, rather than hunted by the bustards themselves.
Bustards are often seen foraging, or searching for food, near large herds of grazing mammals. This is probably because there is less danger from predators near other individuals. In addition, bustards may eat the insects which have been disturbed by the mammals.
BEHAVIOR AND REPRODUCTION
Bustards range from solitary, or, living alone, to highly social, forming groups of as many as thousands in the case of the little bustard. Bustards that occupy semi-desert habitats generally tend to be more solitary. Many species of bustards migrate, moving from a breeding habitat to a wintering habitat. Asian bustard species, in particular, frequently migrate to avoid harsh winter conditions.
Bustards often breed during the rainy season in their habitat. Males perform elaborate courtship displays to attract females. These can involve booming calls, showing off long feathers that only the males possess, fanning out the tail, and performing leaps. Males generally do not participate in either nest building, incubating (warming) the eggs, or raising chicks.
The female lays anywhere from one to six eggs at a time. These hatch after twenty to twenty-five days. Bustard young are precocial (pree-KOH-shul), meaning that they hatch at a fairly advanced stage of development. They are covered with down and are able to move, usually walking within a few hours of hatching.
BUSTARDS AND PEOPLE
Bustards play an important role in agriculture in some parts of their range by eating large numbers of insect pests. On the other hand, they are hunted in some parts of the world for food or sport. (In Asia, hunting has caused population declines in several species.) Some hunters use trained falcons to hunt bustards.
Of the twenty-six species of bustards in existence, four are considered Threatened with extinction and six are considered Near Threatened, in danger of becoming threatened. Most other species are also declining. Bustards are threatened primarily due to hunting (particularly in India and Indochina), habitat destruction, and pesticide use.