124 ALLEN S NATURALISTS LIBRARY 



like the back ; median and greater coverts pure white, with a 

 line of black along the base of the latter, this black band 

 mostly concealed by the median series ; all the under wing- 

 coverts and axillaries white, excepting those round the bend 

 of the wing, which are blackish; bill black; feet dark crimson; 

 claws black. Total length, 11-5 inches; culmen, 1*4; wing, 

 6"i ; tail, 1*8; tarsus, 1-25. 



Adult Female. — Similar to the male. Total length, 12*0 

 inches; culmen, 1-3; wing, 6-3; tail, r75; tarsus, 1*2. 



Adult in Winter Plumage. — Differs from the summer plumage 

 in being white below, the flank-feathers showing black bars, 

 which impart a mottled appearance to the sides of the body. 

 The white plumage is assumed by a direct moult, so that in 

 autumn the birds are often found curiously speckled, when the 

 new white plumes are appearing in the midst of the remains of 

 the black sunmier dress. The crown, neck, and upper tail- 

 coverts are margined with hoary white ; bill black ; feet carmine. 



Young Birds. — Easily recognisable by the black ends to the 

 wing-coverts, and after the moult this character at once distin- 

 guishes the young from the fully adult birds, the pure white 

 patch on the wing being a sure sign of an old bird. The 

 young have the under surface of the body mottled w^ith dusky 

 blackish edgings to the feathers, these being more distinct on 

 the flanks. The scapulars are also edged and tipped with white, 

 giving a mottled appearance, which, however, varies very much 

 in extent. The feet are vermilion red in the young birds. 

 It has been surmised that the old birds, having once attained 

 their black plumage, never lose it in winter, but this is a 

 mistake. At the same time, it is evident, as I have also been 

 assured by Mr. J. G. Millais, that the white breast lasts but for 

 a few weeks, and a specimen killed by Mr. Nikolai Hanson 

 near Christiansund on the 19th of December has lost most of the 

 whitish edgings to the feathers of the upper surface, and is 

 evidently beginning to assume the full black plumage on the 

 back. 



Young in First Plumage. — Dingy black above, and not showing 

 any hoary margins till after the first moult. 



Nestling. — Covered with silky down of a sooty brown colour. 



