798 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



streaked brown ; axillaries brown tipped white ; under wing- 

 coverts mostly white, but greater ones hoary-brown and brown 

 bases of others showing here and there especially along edge of 

 wing ; tail and primaries as upper-parts but inner webs of primaries 

 pale brown becoming whitish basally ; secondaries with conspicuous 

 white tips ; wing-coverts as upper -parts. This plumage is acquired 

 by complete moult July-Nov., wing and tail-feathers being moulted 

 as in Razorbill and lowest series of median also dropped together 

 but rest of median and lesser coverts moulted normally. Summer. 

 — The body -feathers are again moulted Dec. to March or even April 

 but not wing -feathers, wing-coverts or tail. Head, neck and throat 

 all round chocolate-brown but centre of top of head and back of 

 neck blacker ; in " ringed " variety white line round eye and along 

 " furrow " very conspicuous ; rest of plumage as winter. 



Nestling (Plate 11). — Closely covered with down with fine hair- 

 like tips, rather coarser and decidedly longer on head and neck, 

 short on breast and belly. Head, neck and throat all round black 

 closely streaked with white hair -like down, and on chin and sides 

 of head somewhat spotted ; rest of upper -parts sooty-brown, upper- 

 mantle and wings mottled dull grey, down being tipped brownish- 

 grey ; under-parts below throat bumsh-white. N.B. — Coarse 

 white down on head and neck is composed of several filaments 

 partially enclosed within a sheath. 



Juvenile. — Upper-parts dark brown, feathers margined black- 

 brown giving a somewhat squamated appearance, rest of plumage 

 as adult winter but no brown streaks on flanks and all feathers of 

 very loose structure. As in Razorbill tail-feathers, primaries and 

 secondaries do not commence to grow until beginning of moult to 

 next plumage but primary-coverts and greater coverts give appear- 

 ance of miniature remiges. 



First winter. — Like adult winter but more often with white 

 showing across back of neck and usually less streaked on flanks, 

 but difficult to distinguish except by rather smaller bill. The 

 juvenile body-plumage and wing-coverts are moulted Aug.-Sept. 

 and at same time primaries, secondaries and tail grow. First 

 summer. — Moult of body later than in adult and continued often 

 until May. Like adult summer but usually with some white 

 feathers on chin and throat and wings and tail becoming pale brown 

 by abrasion in May and June.* 



Measurements and structure. — $ wing 193-204 mm., tail 41-48, 

 tarsus 33-37, biU from feathers 41-49, depth at nostrils 13-16 (12 

 British breeding birds measured). $ wing 191-203, bill length 

 42-45, depth 13-15. First winter J and $ wing 180-193, bill length 

 37-45, depth 13-15. Primaries : 1st longest, 2nd 2-5 mm. shorter, 



* I have seen live examples in May and June in very worn, pale brown 

 winter plumage from which it would appear that first summer birds some- 

 times do not attain the brown throat but I have not had skins of such" birds 

 for examination. — H.F.W. 



