The Long-Tailed or Buffous Skua — Stercorarius Parasiticus (Linnæus)
This is a rare species to all our shores, but a few, chiefly immature birds, visit the east coast yearly, and in some seasons become quite common. It is a circumpolar species, breeding on the tundras throughout Europe, Asia, and America, and migrating in winter as far south as the basin of the Mediterranean.
In its habits it resembles other Skuas, but in addition to robbing Gulls, it feeds largely on beetles and worms, and the young eat a large quantity of crowberries when in their summer-quarters.
The adult has the top of the head black, cheeks and hind neck buffish yellow, mantle and tail, the two central feathers of which are much elongated, grey brown, wings darker. Under parts chiefly white, brownish on the flanks and belly. Length 23 in.; tail 8·5 in.; wing 11·9 in.
Immature birds are barred above and below with brown and yellowish white. It is sometimes rather difficult to distinguish between the young of this and the preceding species; the present species is, however, always much greyer and less rufous, and has the shafts of the two outer primaries white, the rest being dusky, whereas in the Arctic Skua the shafts of all the primaries are white.