About Stercorarius skua (Brünnich, 1764)
Great skuas (Stercorarius skua) measure 50–58 cm (20–23 in) in body length, with a wingspan of 125–140 cm (49–55 in). One study recorded an average weight of 1.27 kg (2 lb 13 oz) from 112 male great skuas, and an average weight of 1.41 kg (3 lb 2 oz) from 125 females. Adult great skuas are streaked greyish brown with a black cap, while juveniles are a warmer brown and have no streaking on their underparts. This species has a short, blunt tail and flies powerfully. Its call is a harsh hah-hah-hah-hah, and quacking and croaking sounds have also been observed.
Distinguishing the great skua from the other skuas found in the North Atlantic—the parasitic jaeger, pomarine jaeger, and long-tailed jaeger—is relatively straightforward. Even from a distance, the great skua's herring gull size, massive barrel-shaped chest, and white wing flashes are distinctive, and it is sometimes described as giving an impression similar to a common buzzard. Identification only becomes complicated when distinguishing the great skua from closely related large skuas native to the southern hemisphere.
Despite its common name, the great skua is marginally smaller on average than the three other large southern-hemisphere skuas, but this size difference is not large enough to reliably tell the groups apart by size in the field. Some taxonomic authorities still consider the great skua to be the same species as some of these southern skuas, and the group has sometimes been placed in the separate genus Catharacta. This taxonomic treatment is not commonly followed currently.
