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A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



Tail of juvenile Kittiwake Gull (Rissa t. 

 tridactyla) showing slightly forked shape. 



rest of primaries ash-grey with white tips and inner edges of inner 

 webs ; secondaries white with basal part of outer webs ash-grey, 



innermost feathers darker grey, 

 outer webs with broad brown-black 

 streaks on distal halves ; primary- 

 coverts brown-black with grey inner 

 webs and inner feathers tipped grey ; 

 feathers along edge of wing brown- 

 black slightly fringed grey ; greater 

 coverts blue -grey with long white 

 tips ; median coverts same but only 

 fringed white ; lesser coverts and 

 inner median and greater blue -grey 

 broadly tipped black forming broad 

 black band down inner edge of 

 folded wing. 



First winter. — Like juvenile 

 with varying number of body- 

 feathers renewed, back of head and nape becoming more or less 

 blue-grey and some blue-grey feathers on back of neck and upper- 

 mantle but most are juvenile, black tips of which wear down to 

 some extent ; back blue-grey. The juvenile body -feathers are only 

 very partially moulted Oct. -No v. First summer. — A partial and 

 varying body-moult appears to take place in spring, but very few 

 are available for examination. Much like first winter but usually 

 more grey on nape ; hind-neck and upper-mantle white with no 

 black or only a few black-tipped feathers. 



Second winter and summer. — Like adults but often outer 

 primary-coverts with black streaks and 3rd primary with some 

 black on outer web. 



Measurements and structure. — ■$ wing 300-325 mm., tail 112- 

 127, tarsus 33-36, bill from feathers 33-38 (12 British measured). ? 

 wing 295-315, bill 33-35. Primaries : 1st narrow, pointed and 

 about two -thirds primary-coverts, 2nd longest, 3rd 2-5 mm. shorter, 

 4th 10-22 shorter, 5th 30-40 shorter. Rest of structure as Bona- 

 parte's Gull, but tarsus comparatively short, hind-toe very diminu- 

 tive and usually without a claw but occasionally this is present. 

 Tail in adult almost square but central feathers slightly shorter, in 

 juvenile tail definitely forked to depth of about 10 mm., but outer- 

 most feathers shorter than next. 



Soft parts. — Bill (ad.) pale greenish-yellow, yellower in summer, 

 (juv.) black ; inside mouth orange-red ; legs and feet (ad.) brown- 

 black, (juv. to 2nd winter) brown ; iris dark brown ; orbital ring 

 orange-red. 



Characters and allied forms. — R. t. pollicaris (Alaska, Bering 

 Sea) is larger and has longer black tips to primaries, juvenile has 

 black tips to feathers of nape. Size and in adult yellowish bill and 

 black legs, black-tipped primaries without white " mirrors," in young 



