116 BRITISH BIRDS' NESTS. 



GULL, GREAT BLACK-BACKED. 



Description of Parent Birds. — Length about thirty 

 inches. Bill of medium length, large and powerful ; 

 pale yellow, excepting a portion of the under man- 

 dible, which is orange ; upper mandible turned 

 down at the tip. Irides straw-yellow. Head and 

 neck all round snowy-white. Back and wings 

 black, vdth exception of the tips of the quills, 

 which are white. Upper tail-coverts and tail- 

 quills white. Breast and all under parts pure 

 white. Legs, toes, and webs pale flesh-colour. 



The female is similar, but somewhat smaller. 



Situation and Locality. — On the ledges of mari- 

 time cliffs, on the tops of rocky islets in the sea 

 and fresh-water lakes, known as rock-stacks ; also 

 on the ground, in marshes and moors ; on the 

 coasts of Dorset, Cornwall, Scilly, and Lundy ; on 

 the Welsh coast, but most abundant on the western 

 and northern shores of Scotland and the islands 

 lying round about ; also in Ireland. Our illustration 

 was obtained near the summit of a small rock-stack 

 in a Highland sea-loch. 



Materials. — Seaweed, heather, wool, and dry 

 grass in variable quantities. Sometimes they are 

 almost entirely absent. 



Eggs. — Two to three, generally the latter 

 number. Yellowish-brown or stone-colour to light 

 olive-brown, blotched with slate-grey and dark 

 brown. The spots are not very large, and generally 

 distributed over the surface of the Qgg. Size about 

 3-1 by 2-1 in. The large size of the eggs and the 

 small sj)ots are distinguishing characteristics. 



Time. — May and June. 



Beniarls. — Eesident, but wandering during the- 



