512 GULL TRIBE. 



genus of the subfamily is represented by three species, of which the black skimmer 

 (Rhynchops nigra), distinguished by its dark beak, is North American, while the 

 yellow-beaked skimmer (R. albicollis) is Indian, the third species inhabiting the 

 Nile and Red Sea littoral. The American species has been observed flying close 

 to the water, with the lower half of the beak immersed beneath the surface, 

 doubtless searching for food. 



The gulls proper, as distinguished from the other members of 



the order, form the third subfamily (Larince) of the typical family ; 

 the great majority of them belonging to the genus Larus, although the kittiwake 

 and an allied species from the North Pacific are separated as Rissa ; while Sabine's 

 gull and a kindred but very rare form from the Galapagos Islands constitute the 

 genus Xema ; and Ross's gull (Rhodostethia rossi) and the ivory gull (Pagophila 

 eburnea) respectively represent distinct generic types. As a subfamily, the gulls 

 are characterised by the upper mandible of the beak being longer than the 

 lower one, over which its tip is bent down; while the tail is usually squared, 

 although in one genus it is forked, and in a second wedge-shaped. Some of the 

 smaller gulls, like so many of the terns, assume a dark head and neck in the 

 summer-plumage. 



Fork-Tailed Sabine's gull (Xema sabinei), together with the Galapagos 



Gulls. forked-tailed gull (X. furcatum), may be at once distinguished by 

 the forking of the tail, a character in which they agree with the great majority 

 of the terns, as they also do in the assumption of a dark head during the breeding- 

 season. Not a very uncommon straggler especially in the immature state to 

 the British Islands, Sabine's gull breeds in Arctic America and Siberia, generally 

 in company with the Arctic tern ; two eggs being laid by the female on the bare 

 ground. Of the second and larger species but little is known, only a few examples 

 having found their way into European collections. 



Gull ^ S ^ ie f r k e d tail serves to distinguish the members of the last 



genus, so the single representative (Rhodostethia rossi) of the 

 present one is equally well demarcated by the wedge-like contour of the same 

 appendage. It is likewise characterised by its small dove-like beak : while the 

 delicate pink hue of its plumage is also a striking feature, although one shared by 

 some other members of the subfamily. Formerly rare in collections, this gull has 

 more recently been obtained abundantly off Point Barren; but its true polar 

 haunts appear to be as yet undiscovered, although it has been seen in summer 

 in Boothia Felix and Franz-Josef Land. 



icai Gulls Represented by nearly half a hundred species, the typical gulls 



of the genus Larus differ from both the preceding by the squared 

 tail, while they are further characterised by the full development of the first or 

 hind-toe. The genus includes both the largest and the smallest representatives of 

 the subfamily ; and while some species assume a dark head in the breeding-season, 

 others lose all trace of dark tints in this region when adult. The smallest of the 

 dark-headed species visiting the British Islands is the little gull (L. mimitus), easily 

 recognised by its diminutive size, and, when in flight, by the slaty black under 

 surface of the wings. A straggler to Southern Norway, this gull is common in the 

 Mediterranean countries, ranging eastwards to the Caucasus, and thence northwards 



