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A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



apex (10-15 mm.) white, occasionally white subterminal spot on 

 inner web, grey of inner extending sometimes far towards tip but 

 varying, rest of primaries slate-grey to blackish slate-grey tipped 

 white, 5th and 6th with black subterminal band extending somewhat 

 up outer web with white line or patch at junction of grey and black, 

 7th with subterminal black band broken, often reduced to spot and 

 sometimes absent, rest with no black ; secondaries slate-grey with 



The Great Black-backed Gull (Lams marlnus). Second (outer) primary of : 1. Juvenile 

 and 1st winter. 2. 2nd winter. 3. 3rd winter. 4th. Adult. 



long white tips and mottled white on inner webs ; primary-coverts 

 and all wing-coverts slate-black but small coverts along edge and 

 bend of wing white. This plumage is acquired by complete moult 

 June to Nov. sometimes Dec. and occasionally outer primary still 

 with sheath in Jan. Summer. — The body-feathers are moulted 

 Jan-March, but not wing- or tail-feathers nor wing-coverts. As 

 winter but whole head and neck pure white, descending further on 

 to mantle than in winter. 



Nestling. — Like that of L. a. argentatus but black -brown 

 markings on head often smaller and ground-colour of upper -parts 

 usually paler or purer grey (not so buffish), under-parts also usually 

 slightly paler and centre of breast and belly whitish. 



Juvenile. — Like that of L. a. argentatus but under-parts white 

 and less mottled, brown markings being fewer and better defined 

 and markings of upper-parts slightly more contrasted ; tail-feathers 

 whiter with brown-black subterminal band narrower especially on 

 outer feathers and brown-black markings on proximal portion of 

 feathers usually fewer and on a clearer white ground. 



First winter. — Very much like L. a. argentatus but head and 

 under-parts rather whiter and less streaked and upper-parts usually 

 rather more barred with white or buff (new 1st winter feathers 

 being more buff than old juvenile). The juvenile body-feathers 



