778 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



throat and ear-coverts, otherwise plumage appears to be like 

 summer. 



Nestling. — Closely covered with soft down with silky hair-like 

 tips. Upper-parts yellowish-brown or pinkish-brown, under-parts 

 paler and greyish in centre. 



Juvenile. — Whole upper-parts and wing-coverts brown-black, 

 most feathers slightly tipped rufous to paler brown ; sides of head 

 brown-black ; throat rather browner ; rest of under-parts brown 

 more or less mottled rufous ; under wing-coverts and axillaries 

 black-brown mostly slightly tipped pale brown to rufous ; tail 

 black, extreme concealed base white, tips w T hen not worn very 

 narrowly edged pale brown ; primaries and secondaries as adult but 

 white on outer primaries less extensive ; feathers of neck normal 

 not lanceolate as in adult summer. 



First summer. — Apparently much like juvenile and judging by 

 one example in full moult (Sept.) birds in second winter are also 

 like juvenile. What appear to be second summer birds are more 

 like adult but upper-parts more uniform and darker with narrow 

 pale centres to the feathers and very little rufous, neck-feathers also 

 darker and with narrower straw-coloured shaft-streaks, under- 

 parts darker brown and less rufous and flanks more uniform. N.B. 

 — Owing to want of material, especially moulting birds, it is 

 impossible to trace the sequence of plumages satisfactorily. 



Measurements and structure. — £ wing 385-405 mm., tail : 

 central 140-155, outer 10-25 shorter, tarsus 65-72, bill from 

 feathers 47-55 (12 measured). $ wing 380-405 (one 415), bill 48-51. 

 Primaries : 1st narrow, pointed and about three-fourths primary- 

 coverts, 2nd longest, 3rd 5-10 mm. shorter, 4th 20-25 shorter, 5th 

 40-45 shorter ; outer web of 2nd narrow. Outer secondaries shorter 

 than 11th primary, tips fairly square, tips of rest sharply sloped off, 

 innermost about as long as 7th primary. Tail rounded, 12 feathers, 

 tips slightly rounded, central pair projecting, and tips rather more 

 rounded. About one-fourth of tibia bare, tarsus somewhat com- 

 pressed, toes rather long, hind one elevated, free and minute, but 

 with large strong claw, three front ones connected by straight webs, 

 claw of inner toe very strong and much curved, that of middle toe 

 less curved and somewhat dilated, that of outer toe comparatively 

 small. Bill very stout, broad at base, compressed at tip which in 

 upper mandible is strongly decurved and projects considerably 

 beyond under mandible, gonys gently sloped up, angle not prominent, 

 basal half, or rather more, of upper mandible covered by a thin 

 plate or saddle-like shield, partially covering oblong nostrils. 



Soft parts. — Bill, legs and feet dull black, in juv. base of bill 

 and tarsus greyer ; iris dark brown. 



Characters and allied forms. — Other forms inhabit southern 

 hemisphere. Large size, comparatively short tail, and white patch 

 on primaries distinguish this from other British Skuas. 



Field -characters. — Short tail combined with large size, heavy 



