Great skua

Voice

Silent away from the colony: along the Dutch coast you will hear nothing, even from a bird passing close inshore. At the breeding sites in Scotland, the Faroes and Iceland it gives a hoarse, barking uk-uk-uk as it dives at walkers, and a long harsh scream during the wing-raising display. Anyone crossing Hermaness or Foula in June gets both the call and the bird itself, at once.

Identification

Huge and compact, with broad wings, a short wedge-shaped tail and a thick black hooked bill on a heavy head. The plumage is wholly dark brown with warm rufous and golden streaking on mantle, coverts and neck, so that at close range the bird looks streaked; at sea it simply reads as dark. The clincher in flight is the large, brilliant white flash at the base of the primaries, above and below the wing — far bigger and whiter than in any other skua. The central tail feathers are barely elongated and project a centimetre at most, so anyone looking for streamers here will be disappointed. Juveniles are plainer and colder brown with less streaking, a darker head and a blue-grey bill base.

Confusion species

Pomarine Jaeger is slimmer, with a longer hand, pale underparts in most birds and a far narrower white flash; its shape suggests a large gull, where a Great Skua suggests a buzzard out at sea. Parasitic and Long-tailed Jaegers are clearly smaller, finer and lighter in flight. A dark juvenile Great Black-backed Gull can mislead at range, but lacks the white primary flash and has a much longer tail and a pale bill base. The southern relatives from subantarctic waters are not to be expected in Europe.

Habitat

It breeds in loose colonies on coastal heath and tundra in Scotland, the Faroes, Iceland, Norway and Svalbard, usually near large seabird colonies. For the rest of the year it is pelagic, concentrating over shallow fishing grounds and behind trawlers. Its diet is stolen fish, carrion, fishery discards and seabirds it kills itself, up to the size of a Gannet; in the breeding season auk and storm-petrel colonies are a standing food supply.

Range and movements

Virtually the whole world population breeds in the North Atlantic, centred on Scotland and Iceland. Off the Dutch coast it is a passage migrant and winter visitor: the first birds appear in July, the peak runs from mid-September to mid-November, and several hundred winter on the North Sea, including over the Bruine Bank. In Spain it is seen in autumn and winter off the Atlantic coast of Galicia and in the Bay of Biscay, in smaller numbers as far as the Mediterranean.

• Resident
• Breeding (summer)
• Winter
• Passage
• Migration direction
• dark = core range, pale = thinly spread

Where and when to look

Seawatching on a north-westerly of force 6 or more in October gives the best chance; Great Skuas often come closer inshore than the other species and fly low and heavily over the waves. Watch for commotion far out: a Gannet that suddenly plunges with a brown bird on its tail is almost always this one. Outside gale days, a winter boat trip to the shallow banks of the southern North Sea produces reliable sightings.

Conservation status

Still Least Concern globally, but the species took a severe blow from highly pathogenic avian influenza in 2022: thousands died in the Scottish colonies, and subsequent counts showed declines of between a half and well over three quarters, which is why it was added to the UK red list. Reduced fishery discards and competition for sandeels also weigh on breeding success. Because virtually the entire world population nests in a handful of North Atlantic colonies, the species is vulnerable despite its favourable global status.