780 



A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



centre of tip by rami lying parallel to shaft and closely united) ; 

 some feathers of upper-mantle and some upper tail-coverts mottled 

 or tipped white and sometimes some barred black and white (upper 

 tail-coverts in adult with only occasionally one or two barred which 

 are apparently unmoulted winter feathers) ; rest of upper-parts 

 uniform black-brown ; chin white ; throat with some straw-yellow 

 tips at sides of neck ; upper-breast and flanks white, feathers barred 

 or tipped brown-black forming a narrow band (usually wider in 

 females) across fore-neck ; lower -flanks, vent and under tail- 

 coverts almost uniform black-brown but white bases of feathers 

 often not entirely concealed and sometimes some feathers mottled 

 and occasionally barred white ; rest of breast and belly white ; 

 under wing-coverts and axillaries black-brown, bases of axillaries 

 sometimes more or less white ; tail brown-black, extreme con- 

 cealed base white ; primaries and secondaries brown-black, inner 



Tail of the Pomatorhine Skua (Stercorarius pomarinus). 



webs paler brown, bases white extending on inner webs of outer 

 primaries beyond primary-coverts, shafts of outer 5 or 6 primaries 

 straw -white ; all wing-coverts uniform black-brown as upper- 

 parts. Dark form. — Whole upper -parts uniform brown-black, but 

 head blacker as well as back and sides of neck and ear -coverts and 

 throat, feathers of which are glossy and pointed and occasionally 

 tinged bronze ; whole under -parts black-brown uniform or with some 

 inconspicuous, very narrow, whitish fringes (all feathers of upper - 

 and under -parts with white bases) ; tail and wings as pale form but 

 rather blacker. This plumage is acquired by a complete body- 

 moult Feb -April, but wing -feathers, wing-coverts and tail appear 

 to be moulted only once commencing sometimes Oct., usually Nov., 

 and completing March or April. Body-moult to winter sometimes 

 commences July but usually August, finishing Dec. or Jan., and is 

 often not complete, varying number of summer feathers being re- 

 tained. Winter. — Pale form. — New feathers on back and sides of 

 neck, ear-coverts and throat barred brown-black and white and tips 

 rounded not pointed and yellow as in summer ; new feathers of 

 crown browner than summer and with small whitish tips ; new 

 feathers of mantle and some scapulars tipped white or pale buff but 

 some uniform ; some upper and under tail-coverts broadly barred 

 black-brown and white or tipped white, thus much like some 

 immature birds but upper and under wing-coverts and axillaries 



