2372 The Zoologist — November, 1870. 



wing from the carpus only 4'50 long. Mirror of renewed feathers, 

 almost or quite pure white, but small ; under wing-coverts and axillars 

 pure white. Head and neck all around, rump, and whole under parts 

 marbled with black and white in equal quantity, the bird looking as if 

 dusted over with flour. Back black, most of the feathers lightly 

 bordered with white, the scapulars more largely white. A still further 

 increase of white produces the following: — 



Adult, winter plumage. — Wings and tail black, the mirror and 

 under wing-coverts faultlessly white. Head and neck all around, 

 rump and entire under parts pure white ; the back (and frequently the 

 crown and back of neck) black, more or less variegated with white. 

 Audubon figures this condition very nearly. 



The change in spring — mostly occurring during April and May — 

 is the reverse of that already described as the autumnal moult. 



Fledglings. — (Labrador, July, 18(j0, E. Cones, Mus. Smiths. 

 Length about 6 00 ; bill "50 ; tarsus "60 ; middle toe and claw "90, etc. 

 Wholly covered with soft woolly puffy down, fuliginous brownish black ; 

 bill and feet brownish black. 



Young, first plumage. — Traces of the down on various parts of the 

 body; the bird probably just beginning to fly ; length about 1000, 

 wing 1150; bill 100, black ; tarsus l'2o ; reddish dusky, as also are 

 the toes. Upper parts plumbeous or sooty black, scarcely varied with 

 white. Mirror beginning to appear, as white spotting on a blackish 

 ground. Entire under parts white, thickly marbled, rayed and 

 undulated with light touches of dusky. 



This state tends to pass directly into a condition exceedingly similar 

 to, if not identical with, that of the adults in winter. But birds of the 

 first winter may, at least early in the season, be distinguished from old 

 ones by a certain " feel " of the plumage, and a shorter, weaker bill, 

 less developed as to its ridges and angles. 



Accidental variations. — The foregoing descriptions apply to the 

 various stages of plumage, which are strictly normal in character, and 

 which, though unending in precise degree, and varying with almost 

 every individual, merge insensibly into each other. The species is, 

 however, also very subject to accidental and entirely abnormal varia- 

 tions. Of these, albinism is the most common. (Spec, in Mus. Acad. 

 Philad.). Entirely milk-white, without a trace of black ; bill and feet 

 light-coloured ; eyes probably pink in life. The opposite condition 

 of melanism is described by authors. This consists in the total 

 absence of white on the wings; and is apparently of infrequent 



