BIRDS OF THE BRITISH ISLES. 271 



THE Smew (Mergus albellus, Linnaeus) is a rare straggling 

 autumn and winter migrant to the British Isles, and inhabits 

 the Northern Palearctic Region. The adult male has the 

 forehead, crown, and crest (which is elongated) white ; 

 loral region, black ; patch on nape, black ; back, two cres- 

 centic black lines on sides of breast; secondaries and middle 

 wing-coverts, rich black, the latter fringed with white ; 

 primaries, blackish ; scapulars, white and greyish, with 

 black margins on outer webs; upper tail-coverts and tail, 

 slate-grey ; flanks and sides, vermiculated with black ; 

 plumage, otherwise white ; irides, reddish ; bill, slate colour, 

 lighter at tip ; legs and feet, grey ; webs, darker. Length, 

 from sixteen to seventeen inches. 



