LESSER BLACK-BACKED GULL 433 
The eggs, three in number, vary from a bluish to a 
brownish-green shade, blotched with dark brown: they are, 
on an average, smaller than those of the Herring-Gull. 
Incubation begins early in May. 
There are numerous colonies in the British Isles, though 
some are far distant from others. The Farne Islands, 
colonised also by several other species of sea-fowl, have 
a strong assemblage of these Gulls in the nesting-season. 
The Northern and Western Island-Groups of Scotland, as 
well as the moors of Northumberland and Cumberland (the 
latter as inland sites), may also be mentioned. 
In Ireland there is a large breeding-station in the co. 
Kildare, described by Mr. Palmer (‘ Irish Naturalist,’ 1898, 
p- 186), and Mr. Ussher mentions a bog-land breeding- 
ground in the co. Antrim, at an elevation of a thousand feet, 
which is tenanted also by Curlew. 
Geographical distribution.—Abroad, this Gull breeds in 
Northern Europe, as far north as Norway (though not in 
Iceland), and as far east as long. 45° EK. Southward it is 
found breeding in smaller numbers in the Channel Isles, 
along the coast of France, and in the Mediterranean. On 
migration, in autumn and winter, its range extends along 
the West African sea-board as far south as lat. 20° N. 
Eastward it occurs in Egypt, Nubia, the Red Sea and the 
Persian Gulf. 
DESCRIPTIVE CHARACTERS. 
PLUMAGE. Adult male nuptial.— Head, neck, breast, 
abdomen, and tail, white; back and wings, varying from 
dark greyish blue-black to black; scapulars and secondaries, 
broadly tipped with white; three outer primaries, dusky- 
black, with white tips, and greyish along the edges of the 
inner webs; first and second primaries have white ‘eyes’ 
near the tips; remaining primaries, chiefly lead-colour, 
barred with black and tipped with white. 
Adult female nuptial.—Similar in plumage to the male. 
Adult winter, male and female.—Differs from the nup- 
tial plumage in that the head and neck are streaked 
with greyish-brown. 
Immature, male and female.—In the immature chequered 
plumage, before the wings darken, the Lesser Black-backed 
Gull closely resembles the Herring-Gull of the same age. 
But even in the first season the back and wings of the 
former are darker and the primaries are nearly uniformly 
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