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A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



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I. / v. n\ 



Juvenile. — Fore-head and lores buffish-white ; fore-part of 

 crown grey-brown, feathers fringed and tipped pale buff to buffish- 

 white ; rest of crown and back of neck rather darker brown with 

 narrower buff or buffish-white tips ; mantle, scapulars, and back 

 same, feathers with broader tips and penultimate dark shading, 

 bases brown-grey ; rump and upper tail-coverts white, lightly 

 tipped buff ; under-parts white, but grey-brown of upper -parts 

 encroaching on to sides of upper-breast ; tail white, broadly banded 

 brown-black at tips, extreme tips narrowly fringed buff to buffish- 

 white ; primaries : 2nd to 6th 

 like adult but browner black, 

 white on inner webs not so 

 sharply cut off and white tips 

 much smaller and absent from 

 2 or 4 outer feathers, 7th with 

 more black than adult, being 

 like 2nd to 6th but with longer 

 white tip and white on inner 

 web extended to tip and often 

 a white oval spot near tip of 

 outer web, shaft brown, 8th 

 white with shaft usually brown 

 and occasionally a brown-black 

 spot near tip of outer web, rest 

 of primaries white ; secondaries 

 white, inner ones dark grey 

 tipped white and innermost 

 brown edged buff as scapulars; 

 primary-coverts as adult but browner ; greater coverts dark slate- 

 grey tipped white, outer ones edged white, inner tipped buff and 

 innermost as rest of upper-parts ; median and lesser coverts as rest of 

 upper-parts. N.B. — Fore-head and tips of feathers of upper-parts 

 become whiter by wear. 



First winter. — Not examined. First summer. — Whole head a 

 mixture of white and lead-grey, some blackish-tipped feathers in 

 position of ring in adult ; back of neck tinged grey ; usually some 

 black at tips of some tail-feathers ; 7th primary- much as described 

 under juvenile ; one or two inner secondaries occasionally with 

 dark centres ; lesser wing-coverts sometimes dark-grey along edge 

 of wing ; rest of plumage as adult. N.B. — No moulting examples 

 available but there appears to be a complete moult in spring. 

 Birds with a few spots of black on tips of tail and 7th primary with 

 black at tip but otherwise like adult may be 2nd summer but are 

 more probably very forward birds in 1st summer. 



Measurements and structure. — $ wing 265-280 mm., tail : outer 

 feather 113-123, central 90-100, depth of fork 20-28, tarsus 32-36, 

 bill from feathers 23-27.5 (12 measured). $ wing 260-280. Juvenile 

 <J and $ wing 250-270, tail : outer 100-115, central 80-90, fork 

 20-28. Primaries : 1st narrow, pointed, and about two-thirds 



Tail of juvenile Sabine's Gull (Xema sabini). 



