RAZOR-BILL 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 lon ' 

 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 faintly indicated, 

 and do not acquire their purity of colour and well-defined 

 form until after it has attained the spring or black-head 

 plumage. 



PLATE 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, General 

 and upper part of the neck, brownish-black, becoming t i on> 

 browner in tint as the summer advances. Upper plu- Summer 

 mage black. The secondary quills tipped with white, P luma ge- 

 and forming a bar across the wings. Under plumage 

 pure white. Tail black, wedge-shaped and pointed. 

 Legs and toes black. 



