TWIST-TAILED OR POMATORHINE SKUA 289 
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 practices 
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 
ito 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 imme- 
diately put to flight. Its northern name is Bonxie. 
TWIST-TAILED OR POMATORHINE SKUA 
STERCORARIUS POMATORHINUS 
Upper plumage uniform dark brown; feathers of the nape long, tapering 
lustrous ; sides of the face and under plumage white; a collar of brown 
spots on the breast, and similar spots on the flanks ; shafts of the quills 
and tail-feathers white, except at the tip; two central tail-feathers 
projecting three inches, not tapering ; tarsus two inches long, rough at 
the back, with projecting scales. Length twenty-one inches. Young 
birds— upper plumage dusky brown, mottled with reddish yellow; 
under, yellowish white, thickly set with brown spots and bars. Eggs 
ash-green, spotted with dusky. 
THE habits of this bird vary but little from those of the other species. 
Its home is in the Arctic seas, from which it strays southwards in 
winter, and has been occasionally seen on our coasts. The follow- 
B.B. U 
