The Gulls. 
193 
The Gulls .—Order Lariformes. 
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 Lavida or Gulls 
and Terns, and the Stercorariidcc 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 of Laridce 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. First of all we have the Marsh- 
Terns (Hydvochelidon), 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 hinder 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 Europe, as far 
east as Central Asia, and winters 
off the coasts of Africa, resorting the Black Tern. 
to the marsh-lands and nesting The Sooty Tern. 
THE 
BLACK TERN. 
(Hydrochclidun 
nigra.) 
r 3 
