398 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



First winter and summer. — Like juvenile but more glossy on 

 upper-parts and usually rather brown on throat and breast, but 

 owing to individual variation of juvenile and partial character 

 of moult no certain difference is noticeable. In some examples new 

 pure white feathers grow on belly which in these examples becomes 

 purer white than in juvenile.* The juvenile body -plumage is very 

 partially (chiefly head and neck) moulted Aug.-Dec. Always 

 distinguishable from older birds by juvenile greater wing -coverts 

 which are somewhat pointed and have whitish tips. 



Second winter and summer. — A very gradual moult eventually 

 involving whole plumage commences March (when bird is nearly 

 a year old), and is usually not complete before Oct. Bird is then 

 much like adult winter on upper-parts but not so glossy blue and 

 rather more tinged brown on crown and neck ; chin brown or dull 

 white, feathers tipped brown ; throat and upper-breast brown, 

 sometimes feathers with a good deal of brownish -white on edges and 

 some feathers often tipped blue-black ; rest of under-parts showing 

 good deal of white basal part of feathers and not uniform as in 

 adult and gloss not so bright and greener with brownish tinge ; a 

 few white hair -like filoplumes on head, neck, and thighs. 



Third winter and summer. — Apparently like adults, but in 

 summer it seems that white feathers on crown and neck are not so 

 plentiful and are more hair -like with few rami, while white feathers 

 on thighs are less plentiful. 



Measurements and structure. — £ wing 330-360 mm. (adult), 

 330-370 (immature), tail 144-168, tarsus 68-82, bill from feathers 

 66-82 (ad.), 70-86 (immature). (24 British measured.) $ wing 

 330-345 (ad.), 325-365 (imm.), bill 69-73 (ad.), 65-77 (imm.). 

 Primaries : 2nd and 3rd about equal and longest, 1st 5-10 mm. 

 shorter, 4th 5-15 shorter, 5th 35-50 shorter, 6th 55-72 shorter ; 

 2nd to 4th emarginated outer, and 1st to 3rd inner webs. Second- 

 aries with tips rounded in adult but with point at extreme tip in 

 juvenile, innermost reaching to about 4th primary. Tail much 

 rounded, 14 feathers, narrow and very stiff, tips rounded in adult 

 but more pointed in juvenile when unworn. Bill strong but rather 

 slender, nearly straight but ridge of upper mandible slightly 

 concave and tip decurved with sharp point projecting below under 

 mandible, sides of bill somewhat scaly, but in juvenile smooth, 

 near base of upper mandible a transverse "hinge." Nostrils com- 

 pletely closed by ossification but in downy nestling open and slit- 

 like. Skin of lores, round eyes and gape, sides of base of lower 

 mandible and sides and apex of angle of lower mandible bare. 

 Tibia feathered to tarsal joint. All four toes in same plane (1st 



* The specimen described. {Brit. B., in, p. 385, etc.) by Mr. F. W. 

 Frohawk, who has kindly allowed me to re-examine it, is unusually white on 

 the under-parts and is a bird in its first summer (June), i.e. a year old. Another 

 example (Aug.) in Tring Mus. is equally white and undoubtedly in juvenile 

 plumage. 



