354 
LAUID.E. 
colouring of course rendering this the more^easy. In many 
collections I have seen Gulls’ eggs labelled as those of the 
Skua, and although it is in most cases easy to detect the im- 
position, it is very difficult to define the precise points of 
distinction. Generally speaking, the egg of the Skua is finer 
in texture, rather more glossy, and smoother to the touch, and 
more frequently either of a clayey or purplish brovni colour ; 
the spots are fainter and more scattered, and, if we were 
looking at an artificial production, we should say that the mark- 
ings had been more carefully laid on, and softened away at the 
edges. The dark variety, tinged with purplish brown, does not, 
so far as I am aware, occur in any Gulls’ eggs. The specimens 
which are most difficult to identify are those of the pale 
bluish green and nearly spotless variety, for which similar ones 
from the nests of the Lesser Black-backed and Herring Gulls 
are often substituted ; but the finer texture in genuine speci- 
mens is in most cases a trustworthy guide. One of the most 
beautiful varieties I have seen is a pale greenish blue, with a few 
streaks and blotches of dark brown and light brownish grey ; 
but these light-coloured eggs always occur late in the season, 
after the birds have been repeatedly robbed. The measurement 
may be called two inches and seven-eighths by two inches. 
The Great Skua,s are usually seen singly or in pairs, except 
during the early summer, when they are assembled at the breed- 
ing grounds; upon these occasions I have seen considerable 
numbers about the same spot, but even then they were chiefly 
in pairs, except when they became mixed up by accident. At 
such times, when the young are about, the birds become very 
daring, sometimes even knocking a man’s hat from his head. 
A dog has no chance with them, for they buffet him so severely 
in their rapid swoops that he soon has to retire discomfited. I 
once had four of them sailing in circles close round my head 
as I stood upon the crown of the highest hill in Unst, Saxaford, 
and could almost touch them with my gun, the sound of which, 
by the way, did not seem to cause them much alarm ; perhaps 
tliey divined liow little they had to fear, so far as I was con- 
