124 
allen’s naturalist’s library 
like the liack ; 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 w'hite, excejiting those round the bend 
of the wing, which are blackish; bill black ; feet dark crimson; 
claws black. Total length, ii’S inches; culmen, 1-4; wing, 
6'i ; tail, i'8; tarsus, i-25. 
Adult Female. — Similar to the male. Total length, 12-0 
inches; culmen, i‘3; wing, 6‘3 ; tail, i’7Sl tarsus, i'2. 
Adult in Winter Plumage. — Diflers 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 summer 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 with dusky 
blackish edgings to the feathers, these being more distinct on 
the flanks, llie scapulars are also edged and tipiied with white, 
giving a mottled appearance, which, however, varies very much 
in extent. 'I’he 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 19 th 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. 
