COMMON GUILLEMOT. 153 
—The commonest and the smallest of the Divers, and varying 
greatly in their plumage, according to age andseason. It breeds 
on the Scottish mainland, in Shetland, in the Hebrides, and until 
lately in the Orkneys. The eggs are said to be always deposited 
very near the water’s edge. They are two in number, of a greenish 
brown colour, spotted with very dark brown, but, as Mr. Yarrell 
states, when the egg has been long sat upon the brown ground- 
colour is apt to assume a chestnut, or dark reddish-brown tint. 
IiT.—ALCAD A, 
279. COMMON GUILLEMOT—(Uria troiie). 
Foolish Guillemot, Willock, Tinkershere, Tarrock, Scout, Sea- 
Hen, Murre, Lavy.—The first on the list of our Rockbirds, as 
they are often called. It is remarkable in several particulars 
connected with its breeding peculiarities. It makes no nest and 
lays but one egg, but that an egg of huge dimensions as con- 
trasted with the size of the bird itself; besides which, it is almost 
impossible out of a collection of many scores to pick out half a 
“dozen that are precisely alike, either in ground-colour or general 
markings. The eggs are laid on the ledges of rocky precipices 
overhanging the sea, on various parts of the British coasts. I 
have frequently seen the Willocks under the impulse of a sudden 
‘alarm—for instance, the firmg of a gun in the close vicinity of 
their egg-bestrown ledges—fly off in very large numbers and 
with every symptom of precipitation. But no egg is ever dis- 
lodged ; a circumstance which some have sought to account for 
on the supposition that they must be cemented to the rock! 
The explanation really is, it would seem, that the shape of the 
eges is such that, instead of rolling off in any direction, as a 
ball would do on being sufficiently moved, they simply turn round 
and round within the length of their own axis. It would serve 
