The Great Indian bustard is a large terrestrial bird with a horizontal body and long bare legs, giving it an ostrich-like appearance; this bird is among the heaviest of the flying birds. It is unmistakable with its black cap contrasting with the pale head and neck. The body is brownish with a black patch spotted in white. The male is deep sandy buff-colored and during the breeding season has a black breast band. The crown of the head is black and crested and is puffed up by displaying males. In the female which is smaller than the male, the head and neck are not pure white and the breast band is either rudimentary, broken, or absent. Male of the Great Indian bustard also have a well-developed gular pouch which is inflated when calling during display and helps produce the deep resonant calls.
These birds are found in India and Pakistan. They are most often found in arid and semi-arid grasslands, open country with thorn scrub, and tall grass interspersed with cultivation.
Great Indian bustards are diurnal birds, usually active in the early morning and evening hours. During the breeding season, they spend time together, and after the monsoons, populations typically disperse and make local movements.
Great Indian bustards are omnivores preferring to feed on insects and beetles. They will also eat grass seeds, berries, rodents, and reptiles. In cultivated areas, these birds feed on crops such as exposed groundnut, millets, and pods of legumes. Great Indian bustards drink water if it is available and will sometimes sit down to drink or suck water followed by raising up their heads at an angle.
Great Indian bustards have a polygynous mating system, where each male mates with a number of females. During the breeding season which occurs between March and September, males gather into a special group called "lek", performing displays in order to attract females. During this time males inflate and display fluffy white feathers. Territorial fights between males may involve strutting next to each other, leaping against each other with legs against each other, and landing down to lock the opponent's head under their neck. During courtship display, the male inflates the gular sac which opens under the tongue, inflating it so that a large wobbly bag appears to hang down from the neck. The tail is held cocked up over the body. The male also raises the tail and folds it on its back. The male periodically produces a resonant deep, booming call that may be heard for nearly 500m. After mating the female lays a single egg in an unlined scrape on the ground. Only the females are involved in the incubation and care of the young. In order to protect their nets and chicks, females may use a distraction display that involves flying zigzag with dangling legs. When threatened, they may also carry their chicks under the wing.
The Great Indian bustard is critically endangered, mainly because it has been extirpated from 90% of its former range mainly by hunting and habitat loss. In the past, they were heavily hunted for their meat and for sport, and, today, poaching of the species may continue. In some places, such as Rajasthan, increased irrigation by the Indira Gandhi canal has led to increased agriculture and the altered habitat has led to the disappearance of Great Indian bustards from these regions. Some populations migrate to Pakistan where hunting pressure is high. Other serious threats to the species include the development of roads and electric power lines in the desert that lead to collision-related mortality. Proposed expansion of renewable energy infrastructure, which may involve deploying solar panels over large areas of desert and grasslands is another threat to the bird's habitat.
According to the IUCN Red List, the total population size of the Great Indian bustard is 50-249 mature individuals. Currently, this species is classified as Critically Endangered (CR) on the IUCN Red List and its numbers today are decreasing.