The Gulls. 



193 



The Gulls.— cj;y/«- Larifuf{mes. 



At first sight a Gull would seem to be different from a Plover in no small degree, 

 but anatomists have shewn that the two groups possess many characters in common, 

 so that it is impossible to draw a wide distinction between them in the Natural 

 System. However much they may be related, there is one character which at once 

 distinguishes the Gulls from the Plovers and Snipes, and that is — the webbed feet of 

 the former. The Gulls have two well-marked Families, viz., the Lni-idn or Gulls 

 and Terns, and the Stercorariiclo' or Skuas. The former have no cere at the base 

 of the bill, and have two notches in the hinder end of the breast-bone. The first 

 Sub-family oi Laridii consists of the Terns or Sea-Swallows, and the latter differ in 

 their more or less forked tail, and in the shape of the bill, which is usually slight and 

 slender, with the two mandibles nearly equal in length. P'lrst of all we have the Marsh- 

 Terns [Hydrochelidon], consisting of small species, of wide range in both Hemispheres. 

 This species has the upper surface slaty-grey, and the under 



surface leaden-black. In winter the under surface is white, as 



well as the forehead, 



THE 



BL.'\CK TERN. 



(Hydrochelidun 



111 or a.) 



hinder 



the liincler crown 

 and nape being 

 black. It can always be distinguished 

 from the other small Marsh-Terns 

 which come to our shores, by the 

 pale grey under wing-coverts, and in 

 winter the rump and tail are grey like 

 the back. The Black Tern formerly 

 bred in the marshes of the eastern 

 counties of England, but now only 

 visits us on migration, many of the 

 young birds being found along our 

 rivers in autumn. It nests in the 

 marshes of Central I-^urope, as far 

 east as Central Asia, and winters 

 off the coasts of Africa, resorting 

 to the marsli-lands and nesting 



Thk Black Tern. 

 The Sooty Tern. 



13 



