Great Bustard

The great bustard (Otis tarda) is a member of the bustard family and the sole extant representative of the genus Otis. This avian species is notable for its substantial size and sexual dimorphism, with males being significantly larger than females. The adult male is one of the heaviest living flying animals, boasting a wingspan of up to 2.7 meters and weighing as much as 18 kg, with some specimens reaching even greater weights. Females are considerably smaller, weighing between 3.1 to 8 kg. The plumage of males is characterized by brown and black barring above and white below, with a long grey neck and head. During the breeding season, males display long white neck bristles. Females have a more muted coloration, aiding their camouflage in open habitats.

Identification Tips

The great bustard is distinguished by its heavy build, long legs, and barrel-chested body. Males have a striking appearance with chestnut and golden hues on the breast and back, and a flamboyant display of white plumage during mating rituals. Females and immature birds are more subdued in color, with buff breasts and brownish plumage. The eastern subspecies exhibits more extensive grey coloring in both sexes.

Habitat

Great bustards favor open grasslands and farmland, thriving in flat or rolling landscapes with undisturbed cultivation. They show a preference for areas with crops like cereals, vineyards, and fodder plants, particularly during the breeding season when they avoid human activity.

Distribution

The species breeds across a range from northern Morocco and South and Central Europe to temperate Central and East Asia. The majority of the world's population is found in central Spain, with significant numbers also in southern Russia and the Great Hungarian Plain.

Behaviour

Great bustards are gregarious, forming large flocks in winter. They exhibit a stately slow walk and prefer to run rather than fly when disturbed. Both sexes are generally silent, but males can produce booming and grunting sounds during display, while females may vocalize guttural calls at the nest.

Song & Calls

The great bustard is typically quiet, but during the breeding season, males may emit deep grunts and booming noises as part of their display, while females communicate with their brood using soft trilling calls.

Breeding

Breeding occurs in March, with males displaying elaborate rituals to attract females. The female lays one to three eggs in a shallow ground scrape, which she incubates alone for 21 to 28 days. Chicks are precocial and leave the nest shortly after hatching, remaining with their mother until the following breeding season.

Similar Species

The great bustard can be confused with other bustard species such as the MacQueen's, houbara, and little bustards. However, none of these species match the great bustard's size or plumage coloration, making it essentially unmistakable.

Diet and Feeding

Great bustards are omnivorous, with a diet that varies seasonally. They consume green plant material, invertebrates, and seeds, with preferences for alfalfa, legumes, crucifers, and various grains. Insects are a crucial food source for young bustards in summer.

Conservation status

As of 2023, the great bustard is classified as Endangered on the IUCN Red List. The species faces threats from habitat loss due to intensive agriculture, human disturbance, and collisions with power lines and vehicles. Conservation efforts are underway in various parts of its range to address these threats and protect the species.