Great bustard

The great bustard (Otis tarda) was once quite common in the United Kingdom, but had been hunted to extinction by the 1840s. However, it is now making a remarkable comeback, have recently bred here for the first time in more than 170 years.

Great bustards are inland grassland birds that are native to the steppes of Russia and the high plains of Spain. Their reintroduction to Britain (from Russian stock) has therefore been attempted on Wiltshire’s Salisbury Plain, well away from human populations, although they do have to share their domain with the Army, which uses the Plain for firing practice. The Army has, however, proved to be the perfect guardian for the great bustard population by keeping other humans far distant, and, of course, not firing at the great bustards!

  

Great bustards are rarely seen in Great Britain, not only because of their limited range on a small area of Salisbury Plain, but also because they are very shy birds that are intensely aware of human presence and can hide away very easily in the long grass. However, the Salisbury Plain colony has been closely monitored since releases began in 2004, and the arrival of chicks bred in their new home was first noted in 2009.

Appearance

It is a large bird, with males reaching 102 centimetres (40 inches) in length. Females are smaller, at around 80 centimetres (31 inches). The wingspan is up to 240 centimetres (94 inches). The great bustard is like a goose in shape, but much larger and heavier. Some birds can weigh up to 20 kilograms (44 pounds), making it the world’s heaviest flying bird.

The body is reddish-brown above (with black markings) and white below, the wings being white with black edges and tips. The neck is long and thick, and the head and neck are grey, merging into brown at the base of the neck. Male birds have wispy “moustaches” that grow longer during the breeding season when they are used as part of the bird’s mating display. The feet are notable for not having an opposable rear toe, which means that great bustards are unable to perch. However, this is not a problem for a bird whose natural environment consists of wide, treeless plains.

Behaviour

Although it is a very capable flyer, with slow beats of its powerful wings, the great bustard usually prefers to stay on the ground, where it is a fast runner. It was this reluctance to fly that led to it being a target for hunters, as it provided “sport” for pursuit by dogs.

Great bustards have quite a varied diet, mainly insects and plant food but also invertebrates and small mammals such as voles. However, young birds are also prey for larger mammals such as foxes and badgers, and to birds of prey, and it is common for only 20% of young birds to reach maturity. Those that do survive can live for 15 or 20 years.

Courtship

In the spring, the male great bustard performs an elaborate courtship that involves use of the moustaches mentioned above as well as inflating the throat pouch and fanning the tail. The males may have to fight each other for the right to perform this display, which is the main reason why male birds have a higher mortality rate than females. The courtship display is known as “lekking”, and it is highly competitive because the females can be very choosy, visiting a number of males before deciding on their mate.

One unusual feature of the mating process is that it is not done to form pair bonds, as the successful males may mate with a number of females, and females will mate with other males in successive years.

There is often a marked age difference between males and females at mating, because males only become sexually mature at around five to six years of age whereas the females do so at two years.

Breeding

Although great bustards tend to congregate in flocks, nesting birds do not stay close together, with the nests being spread around quite a large area. The raising of young is an entirely female affair, with the male role ending after mating. The nest is a scrape in the ground, lined with a few strands of vegetation. One, two or three eggs are laid in April or May and incubated for up to 28 days. The young are able to move from the nest very soon after hatching, although they cannot feed themselves immediately. Despite their independence in some respects, they stay very close to their mother for a considerable time, and may still form a family group until the next breeding season comes around. Within six months the chicks will be about three-quarters fully grown.

© John Welford