Four skuas
There are four species of skua which occur in the UK each year. Two breed: the big, butch Great Skua and the elegant Arctic Skua. The other two are scarce birds seen on passage. Separation of the smaller three species can be tricky, especially with younger birds, and ID is complicated by the birds appearing in more or less distinct colour morphs, meaning there is considerable variation. Here we illustrate just adults or near adults (in pale morph for the smaller species). To identify younger birds or dark morphs flying at sea, consult the field guides or search online…
Great Skua
The largest skua and the easiest to identify. It is roughly Herring Gull sized and though superficially looking like a juvenile gull (particularly a large one), it is much darker plumaged and has obvious white flashes in the dark wings which beat more powerfully than any gull, giving a sense of power and menace! The tail is short with a just about imperceptible central projection.
Arctic Skua
Intermediate among smaller skuas (and most numerous), the Arctic Skua is less deep chested than the Pomarine with a clean contact between the dark underwing and white flanks/belly. Small white wing flashes, very limited on upper wing. The upper breast band is similar to the Pomarine Skua’s. The central tail streamers are long, thin and pointed.
Pomarine Skua
The largest of the three smaller species, and mostly found as pale morphs, Pomarine Skuas look deep chested and adults have smudgy ‘contact’ between the dark underwing and the white flanks/ belly. The upper breast band is more or less ‘complete’. Small white wing flashes, but also show on upper wing. On birds with intact tails, the tail streamers are long and ‘spoon-shaped’.
Long-tailed Skua
The smallest, most elegant of the skuas, adult (pale) Long-tailed Skuas are distinctive and not hard to identify. The flanks and lower belly are continuously dark with the underwings. White wing flashes are tiny and just the outer shaft of upper wing. The upper breast band is absent. Tail streamers are very long indeed, considerably longer than those of Arctic Skuas.