The great skua is a large, heavy seabird, roughly the size of a herring gull. At a distance the great skua looks stout and dark with streaks or dapples of gold/yellow and a dark grey cap. They show white wing flashes in flight. The beak is powerful and hooked and both bill and legs are black.

Behaviour

The great skua is a predatory seabird that will hunt small birds, rodents and rabbits; it is aggressive, harassing birds as large as gannets to steal a free meal.

Great skuas breed on coastal moorland and rocky islands, usually laying two spotted olive-brown eggs in simple grass-lined shallow depressions. The young remain close to the nest and are fed by the parents until they are fledged after six or seven weeks. Great skuas become sexually mature when they are seven or eight years of age and regularly stay with the same partner for life.

Due to its size, aggressive nature and fierce defence of its nest, the great skua has hardly anything to fear from predators. They are not fearful of humans; adults will dive-bomb anyone trespassing too close to their nests. When not threatened, they typically stand on elevated mounds or rocks, overlooking and observing their breeding ground.

This skua’s call is a harsh ‘hah-hah-hah-hah’.

Size

• Length:  50-58 cm
• Wingspan: 125-140 cm
• Average weight: 1.28 kg (male); 1.4 kg (female)
• Average lifespan: 15 years

Status

Classified in the UK as Amber under the Birds of Conservation Concern 4: the Red List for Birds (2015); protected by The Wildlife and Countryside Act 1981. The Avian influenza virus affected large numbers of Great Skuas across the Scottish islands in the summers of 2021 and 2022; details of the population level impacts are, as yet unknown.

Distribution

Scotland represents the southern limit of great skua breeding distribution. It breeds on Scottish islands, predominantly, the Northern Isles, with some individuals breeding on mainland Scotland. Can be seen on rare occasions on passage southwards in the North Sea, close to coastal headlands in adverse weather conditions, as they migrate to wintering grounds off the coasts of Spain and Africa.

When to see

Best seen during the breeding season (late March to mid-July), in localised areas in Scotland, such as Shetland (e.g., Isle of Foula) and Orkney, where 90% of the breeding population can be found.

Facts

• The great skua is also known as the ‘Bonxie’, a Shetland name of Norse origin.
• The English and species name ‘skua’ is believed to originate from the Faroese skúvuror skúgvur and is the only known bird name to originate from the Faroes that has come into regular use elsewhere.