What are Great Bustards?

Introduction

The Great Bustard (Otis tarda) is a large bird in the Bustard family, unrelated to other large bird species such as turkeys or geese. Great Bustards can (and do) fly, despite being the heaviest flying animal alive today. Great Bustards can be found across Europe, as far south as Spain and as far to the north as the Russian steppes.

Most members of the Bustard family are smaller than the Great Bustard which is dwarfed only by the Kori Bustard. Male Great Bustards grow about 30% larger than the females, reaching up to 1 meter tall and weighing up to 16Kg (the heaviest recorded Great Bustard weighed in at 21Kg).

The conservation status of the Great Bustard is listed as vulnerable, with populations in many countries being in decline and having been extinct in the UK for over 180 years.

Appearance

Huge, heavily built and robust but stately in appearance, adult bustard males can be identified by their bulging neck, heavy chest and characteristically cocked tail which adds to their stocky appearance. Shape is similar to a large goose, but the bustard is much larger with considerably longer legs and a straighter neck.

The head and neck are a pale blue-grey, the body and tail rufous brown with black bars, and underparts white. The wings of the Great Bustard are mostly white with dark secondary feathers.

Males in breeding plumage grow large white moustachial whiskers (20 cm) and become more vividly coloured on their back and tail, also developing a band of russet coloured feathers on their lower neck and breast, amount dependent on age.

Size

There is a marked difference in size between male and females, termed sexual size dimorphism. Great Bustards actually exhibit the largest sexual size dimorphism of any bird species and even most other mammals, birds, reptiles, amphibians, and fishes! Female Great Bustards can be as much as 50% smaller than males.

Males: Standing height 90-105 cm. Wingspan 210-250 cm. Weight 8-16 kg
Females: Standing height 75-85 cm. Wingspan 170-190 cm. Weight 3.5-5 kg.

Voice

Adults usually silent but males can sometimes be heard when fighting in breeding season. They use a variety of gruff nasal barks and also a soft “umb, umb” sound sometimes heard as the gular (throat) pouch is inflated and deflated during display. The young also have a number of calls including a high plaintive whistle, first heard from the egg prior to hatching which continues until chicks are several months old.

Nominate form

Otis tarda tarda Linnaeus, 1758. Iberia, Morocco, Turkey, and central and south-east Europe east to central Siberia.

Extralimital form

Otis tarda dybowskii Taczanowski, 1874.East Asia, from the eastern Altai and Lake Baykal to northern China. Order: Gruiformes (12 Families) Family: Otididae (Bustards) – 25 species in 9 genera.

Common name

It is thought that ‘Bustard’ is derived from ‘Bustarde’ and ‘Bistard’ which date back to at least the fourteenth century, having been recorded as a surname in 1391. Most sources state that this is derived from the Latin avis tarda c.77, meaning slow bird. This became abetarda or betarda in Portuguese, avutarda in Spanish, ottarda in Italian and oustarde and bistarde in Old French. It is suggested that the English is derived from a blend of the two French words with the form Bistard found in some 16th and 17th century sources. Great Bustards had traditional local names in different parts of the country such as Sussex where they were called ‘Shepherds Wild Turkey’.

Scientific name

The name Otis is Greek for ear, as in ear of wheat or barely. Each spring male Great Bustards grow whiskers which closely resemble the ears of wheat. The name, tarda, is Latin, meaning slow. The Great Bustard is often stately but the word tarda is rather surprising as this species is actually rather fleet of foot and has a surprisingly fast flight. In their first official list of British birds, published in 1883, the British Ornithologists Union state that tarda is a “Celtic or Basque word, bearing no relation to tardus = slow”, although, they do not say what the word means. It is possible that tarda is in fact the original name from a language spoken in Spain before the arrival of Romans. On being taken into Latin, it naturally seemed to mean slow.