Length: 53 – 58 cm
Wingspan: 125 – 140 cm
Weight: 1.2 – 2 kg
Great skuas in breeding plumage have brown upperparts, mantle, scapulars, and upperwing coverts with paler spots and streaks. The flight feathers are dark with white bases on the primaries, which are conspicuous in flight. The tail is black and shows narrow pale edges on the rectrices in fresh plumage.
The underparts from the chin to the undertail coverts are buff, brown, or grey, and sometimes rufous. They may have a broad, dark breast band. The belly and undertail coverts are dark brown with dark grey primary and greater coverts with darker tips.
The plumage on the head varies. Some great skuas have a dark brown crown with paler yellow streaks on the sides of the head. The head may also be pale grey-brown with dark marks around the eyes and ear coverts. The rear of the ear coverts is lighter. There are irregular white, yellow, or buff spots on the crown and the lores, forehead, and chin are usually paler than the rest of the head. There may be pale grey, pale yellow, or golden streaks on the nape, sides of neck, chin and throat.
Great skuas have black bills, sometimes with a paler grey tip, the eyes are dark brown, and the legs and webbed feet are black.
In winter the plumage is similar but the head is darker brown with pale streaks on the sides of the neck and darker marks around the eyes. Male and female are similar and they tend to get paler with age.
Juveniles resemble the adults, although they are darker with less streaks and markings. The body plumage varies from chestnut to brown and the white patch on the wing is less conspicuous.
Great skuas start breeding in May, nesting in loose colonies. Then nest is a scrape on flat or gently ground, lined with dry grasses.
Great skuas lay 2 pale olive-brown eggs with dark brown spots which are incubated for 28-32 days by both sexes, but mainly the female. The chicks are precocial and covered with pale pinkish-grey down. They leave the nest 24-48 hours after hatching and fledge at 40-50 days. They are sexually mature at 7-8 years.
Great skuas eat mainly fish that they catch by surface-plunging. However, they are opportunistic feeders and will also steal food from other seabirds by forcing them to regurgitate food.
They will also eat dead birds, smaller mammals, and live birds, and will take chicks and eggs too.
Where to see them
Great skuas arrive for breeding in the UK in April and leave in July. They can also be seen on passage until November. The breed on coastal rocky islands and moorland, and throughout the rest of the year can be found by the coast, often in the colonies of other birds, or taking food from the surface of the sea.
Dries Van de Loock/xeno-canto
Did you know?
In Shetland, great skuas, are known as bonxies, a name of unknown origin. The indie rock band, Stornoway, called their final album Bonxie after the bird, a nod to lead singer Brian Biggs’ academic background in ornithology.