258 
BLACK AND BRIDLED GUILLEMOTS. 
The testimony of Knox also might be cited to show 
that the scarcity of Guillemots, and other large water- 
birds, in some of their old breeding-places, may be attri- 
buted to the high prices given by collectors for their eggs. 
The Black Guillemot is inferior in size to the common 
species, generally measuring about thirteen inches in length. 
The plumage in summer is altogether black or dusky, with 
the exception of a large patch of white on each side. In 
winter the white overspreads a great part of the plumage ; 
so that this bird, like many others, assumes a very different 
appearance in the two seasons. The moult takes place in 
autumn, and is completed by the beginning of November. 
Early in spring another moult commences, which is com- 
pleted by the end of April. In these changes it is the 
dress of the summer, or breeding season, v/hich is always 
the handsomest ; and that of this bird is no exception to 
the rule, being glossed with green above, and warmed with 
a fine red tinge below. 
Like others of its genus, this is an open sea-bird, fre- 
quenting the rocky shores only for a limited period during 
the season of incubation. It is more confined to the 
northern parts of the British islands, than the common 
Guillemot, from which it differs in some of its habits. 
The other two species mentioned in the foregoing list are 
both rare birds with us, about which little need be said. 
The name Bridled appears to have been given to one on 
account of a white mark which encircles the eyes, and passes 
down the sides of the head. In every other respect it closely 
resembles the common species ; fifteen or sixteen inches is 
its usual length. Some naturalists, indeed, consider it but 
a variety of the same species ; it is sometimes called the 
Einged Guillemot. 
The species named after the naturalist Brunnich, who 
first described it in, his Ornitliologia Borealis^ is at once dis- 
tinguished from any other British member of this family by 
the shortness, stoutness, angularity, and greater depth of 
its bill, from which peculiarity it is sometimes called the 
Thick-lDilled Guillemot. In its liabits, as far as known, it 
does not differ from the common species, which it closely 
resembles in form and the colour of its plumage. But one 
