The Pomatorhine Skua — Stercorarius Pomatorhinus (Temminck)
This bird, especially when immature, is not very rare on our eastern shores during the autumn migration in September and October, a few even wintering off our south coast. On the return migration in spring it is very rarely seen.
It breeds in Eastern Siberia and thence eastward across Arctic America to Greenland.
The adult has the head sooty black. The hind neck whitish with straw yellow acuminate feathers. Upper parts brown, two central tail feathers longer than the rest and twisted vertically. Under parts whitish, except the flanks and abdomen, which are brown. Length 21 in.; wing 14·25 in.
The young bird in its first autumn is brown mottled and barred with dull rufous. It takes more than a year to assume the full adult plumage.