THE GULLS 



[ORDER : Charadriiformes. FAMILY : Laridce. SUBFAMILY : Larince] 

 PRELIMINARY CLASSIFIED NOTES 



[r. C. R. JOTJRDAIN. F. B. KIRKMAN. A. L. THOMSON. W. P. PYCRAFTJ 



BLACKHEADED-GULL [Larus ridibundus Linnaeus. Peewit-gull, 

 sea-maw, sea-crow, patch, redlegged-gull, turnock; rittock (Orkneys). 

 French, goeland rieur ; German, Loch-Move ; Italian, gdbbiano comune]. 



I. Description. The adult blackheaded-gull may readily be distinguished 

 at all seasons by the deep blood-red colour of the beak and legs, and the broad 

 margin of white along the front edge of the wing. The sexes are alike, and 

 there is a distinct seasonal change of coloration. Length 16 inches [406 '40 mm.]. 

 (PI. 103.) The breeding dress differs from that of the winter only in that the head 

 is covered except for a rim of small white feathers behind, and partly encircling 

 the eye by a " hood " of dark " coffee " brown, which is assumed in the spring 

 by a moult. The back and wing-coverts are of a delicate pearl-grey, the rest of the 

 plumage pure white, but the breast, during the breeding season, may be suffused 

 with a faint and evanescent rose-pink. The six outer primaries have a black 

 terminal band and a white tip, the rest of the feather being grey, save the three 

 outermost, which are white instead of grey. The white tips to these quills are 

 soon lost or greatly reduced by abrasion. In the winter the dark hood is lost, but 

 there is a patch of dark grey over the auriculars. The inside of the mouth is of 

 the same hue as the beak and legs, but paler. In the young in down the ground- 

 colour of the upper parts is of varying shades of buffish brown, with in many cases 

 a strong rufous tinge. This is relieved by black markings representing disin- 

 tegrated stripes. As with all disintegrating patterns, they vary individually, but 

 a median stripe on the crown, and two longitudinal lines down the hind-neck 

 and back can generally be traced, and commonly, also, a pair of lateral stripes. 

 The down plumage is followed by what further research may show to be in 



