2O8 BRITISH BIRDS. 



mottled and barred above with white ; rump and under 

 parts chiefly white. Length 12*50; wing 6*50. Young: 

 similar to adults in winter plumage, but bill is dusky-slate ; 

 iris darker ; feet dark brown. 



Breeds on the rocky coasts of Scotland and Ireland, but 

 on the English coasts very few birds are to be found even 

 in winter. Eggs : 2 ; greyish-white, spotted and blotched 

 with deep brown and ash-grey ; 2*35 by 1*60 



GENUS CCV. MERGULUS, Vieillot (1816). 



380. Mergulus alle (Linn.). LITTLE AUK. 

 Hab. Coasts of North Atlantic, within Arctic' Circle. 

 A very irregular winter visitor, but sometimes occurring 



in large numbers, particularly along the east coast. It is 

 easily recognised by its small size,black and white plumage, 

 and short, stout bill. Length 775 ; wing 4*50. 



GENUS CCVI FRATERCULA, Brisson (1760). 

 Bill higher than long (in breeding season), much com- 

 pressed and transversely grooved; nostrils basal, marginal. 



381. Fratereula aretiea (Linn.). PUFFIN. 

 Hab. Coasts and islands of North Atlantic. 



Adult : crown, nape, a collar round throat, and upper 

 parts black, lighter on wings ; sides of head, cheeks, chin 

 and under parts white ; bill variegated with red, yellow 

 and grey. In winter the outer sheath of bill is lost, its 

 size being proportionately reduced. Length about 1 1 oo ; 

 wing 6*00. Young : duller and with face grey ; bill as in 

 adults in winter. 



Breeds in great numbers on all our coasts with the 

 exception of the portion from the Humber to Hants. A 

 single egg is laid in crevices of rocks or in a burrow in the 

 soil ; at first white ; surface rough ; 2'2o by 1*60. 



