296 BRITISH BIRDS. 



Genus LARUS. 



The genus Larus was recognized by Linnseus in 1766, in the twelfth 

 edition of his ' Systema Naturae/ i. p. 224. The Common Gull (Larus 

 canus] is generally regarded as the type; but no reason can be assigned for 

 such a course, except that it has been so regarded by the majority of 

 authors. 



The Gulls may generally be distinguished from the Skuas and the Terns 

 by their even tails ; but Ross's Gull has the cuneate tail of a Skua, and 

 Sabine's Gull has the forked tail of a Tern. The bill of the Gulls is also 

 intermediate between that of the Skuas, which is more hooked, and that 

 of the Terns, which is less so : in the Skuas the line of the gape rapidly 

 curves downwards beyond the nostrils ; in the Gulls the curve is more 

 gradual ; and in the Terns the degree of curvature scarcely alters from 

 the base to the tip. As in the Terns, the slit of the nostrils in the Gulls 

 is nearly longitudinal, whilst it is diagonal in the Skuas. 



This genus may be regarded as cosmopolitan ; it contains about fifty 

 species, six of which have been removed into four little genera in my 

 opinion most unnecessarily, even by a " lumper," like Saunders ; whilst 

 in the hands of a " splitter/' like Bonaparte, the Gulls are divided into no 

 fewer than eighteen genera. 



The Gulls frequent inland sheets of water, but are more often seen on 

 or near the sea. Except during the breeding-season they are great 

 wanderers, roaming hither and thither in search of their finny prey. 

 Their food principally consists of fish ; but this fare is varied with worms, 

 insects, crustaceans, and even carrion, small mammals, and birds. Their 

 flight is extremely buoyant, graceful, and well sustained. Upon the 

 ground they walk somewhat clumsily, but they swim with ease. Their 

 notes are harsh. They are generally gregarious throughout the year. 

 They make more or less bulky nests, generally on the ground, but occa- 

 sionally on cliffs, and even, in some cases, in trees ; and their eggs closely 

 resemble those of the Plovers and Sandpipers. 



The subjoined key will enable the student to discriminate between any 

 species of British Gull, with the following possible exceptions : 



Large examples of immature Herring-Gulls are difficult to distinguish 

 from small examples of immature Great Black-backed Gulls and from 

 large examples of immature Lesser Black-backed Gulls, but may generally 

 be recognized by their paler coloration, especially that of the basal half 

 of the tail, which is nearly white. 



