Razor-BiLti AUK. NATATORES. ALCA. 437 
supplied in Scotland, and sparingly also along the English 
coast, from the colonies that breed in higher latitudes; and 
which birds, during the months of November, December, 
and January, are met with in the plumage of the supposed 
Alca Pica. Upon the approach of spring these return to the 
north, where they renew the black upon the head and neck, 
in which state all the breeding birds are found, and are then 
perfectly similar to those which, also returning from the 
south, make our shores their summer quarters. In disposi- 
tion they are rather more wary than the Guillemots, and do 
not always admit of so near an approach. They dive and 
swim equally well with the latter, and their food is of the 
same nature, consisting principally of sprats, and other spe- 
cies of the genus Clupea. A few breed every year on the 
Fern Islands in company with the Guillemots, and, as the Food. 
egg is very similar in size, shape and colour, it is not easily Incuba- 
to be distinguished. The bill of the young bird when it 
first quits the rock is narrow, and shews scarcely any ap- 
pearance of the transverse furrows which are so strongly 
marked in the old one. The white streaks that pass from 
the base of the bill to each eye are also faintiy indicated, 
and do not acquire their purity of colour and well-defined 
form until after it has attained the spring or black-head 
plumage. 
Pirate 83. Fig. 1. Represents the bird of the natural size, 
and in the black-headed plumage. 
Bill very hooked at the tip ; the sides transversely furrow- 
ed; the middle furrow white. Streaks from the base 
of the upper mandible to the eyes pure white. Head, 
and upper part of the neck, brownish-black, becoming 
browner in tint as the summer advances. Upper plu- 
mage black. The secondary quills tipped with white, 
and forming a bar across the wings. Under plumage 
pure white. Tail black, wedge-shaped and_ pointed. 
Legs and toes black. 
tion, &c. 
General 
descrip- 
tion. 
Summer 
plumage. 
