Sub-Family STERCORARIINÆ (Robber Gulls)
THE GREAT SKUA
STERCORARIUS CATARRHÁCTES
Upper plumage brown, of several shades; shafts of the quills, basal half of the primaries, and shafts of the tail-feathers, white; under, reddish grey, tinged with brown; two central tail-feathers but slightly elongated, not tapering; tarsus two and a half inches long, somewhat rough at the back. Length twenty-five inches. Eggs olive-brown, blotched with brown.
The Skuas, called also Skua Gulls, are sufficiently distinguished from the true Gulls by their strong hooked bills and talons, and by the habits of daring and voracity founded on these characters. The present species, though called common, is only to be so considered in high latitudes; for it is very rarely seen on the coasts of England, and has become scarce even in the Shetland Islands, where it was at one time frequent. Mr. Dunn[53] says: "I never saw this bird in Orkney, and there are only three places in Shetland where it breeds—viz. Foula, Rona's Hill, and the Isle of Mist; in the latter place it is by no means numerous, and is strictly preserved by the landlords, on whose property it may have settled, from a superstition that it will defend their flocks from the attacks of the Eagle. That it will attack the Eagle if he approaches their nests is a fact I have witnessed: I once saw a pair completely beat off a large Eagle from their breeding-place, on Rona's Hill. The flight of the Skua is stronger and more rapid than that of any other Gull. It is a great favourite with the fishermen, frequently accompanying their boats to the fishing-ground, or Haaf, which they consider a lucky omen; and in return for its attendance, they give it the refuse of the fish which are caught. The Skua Gull does not associate in groups; and it is seldom that more than a pair are seen together. During the breeding season it is highly courageous; and will strike furiously at, and will even pursue, any one who may happen to approach its nest, which is constructed among the heath or moss; the female laying two eggs."
Some authors state that the Common Skua obtains its livelihood by levying contributions on the White Gulls, compelling them to disgorge their prey, and catching it before it reaches the water; but Dr. Edmonston, who had great opportunities of watching the habits of these birds, says that they do not adopt the practises correctly attributed to the Arctic Gull, or Richardson's Skua. The voice of the Common Skua is said to resemble that of a young Gull, being sharp and shrill; and it is from the resemblance of its cry to that of the word Skua, or Skui, that it obtains its popular name. That it is remarkably courageous and daring, all accounts agree. Mr. Low says that, when the inhabitants are looking after their sheep on the hills, the Skua often attacks them in such a manner that they are obliged to defend themselves with their cudgels held above their heads, on which it often kills itself; and Captain Vetch, In the Memoirs of the Wernerian Society, says that it not only drives away Ravens and Eagles, but that the larger quadrupeds, such as horses and sheep, which venture near its nest, are immediately put to flight. Its northern name is Bonxie.
[53] Ornithologist's Guide to Orkney and Shetland, p. 112.
TWIST-TAILED OR POMATORHINE SKUA
STERCORARIUS POMATORHINUS