214 A HANDBOOK OF EUROPEAN BIRDS. 
side of chest, margins of so f scapulars, primaries and some 
of secondaries black, the latter having white tips; innermost 
secondaries, vwmp, tail and vermiculations on flanks gvey ; 
plumage otherwise white ; the black head patches glossed with 
green ; bill, legs and feet slaty-grey, the webs darker ; irides 
reddish-brown. Length 16:5 to 17:5 inches; culmen 1°25 ; 
wing 7°5 to.7°75.; tail 3°3.; tarsus 1°3. 
Adult Female: Forehead, crown, nape and back of neck 
dull chestnut ; round the lower neck an obscure grey ring ; 
loral region black ; upper parts generally slate-grey, barred with 
pale grey and shading into nearly black on the rump; wings 
much as in the male. 
Adult Male in moulting dress: Resembles adult 
female but is distinguishable by the crescentic marks on the 
sides of the chest. 
Young in first plumage: Are very similar to adult 
females, but have brown lores and a more highly developed 
grey ring round the lower neck ; the lesser wing-coverts consi- 
derably marked with brown ; wing otherwise as in female. 
Distribution : Inhabits the northern portions of Europe 
and Asia, migrating southward in autumn. 
Habitat : Chiefly found on inland fresh waters, but also 
frequents estuaries or bays of the sea. 
