Genus XEMA. 
Gun. Cuan. Beak short, slender, straight, laterally compressed, its tip bent down; the lower 
mandible somewhat angulated beneath. Nosérz/s very slender, linear. Legs slender; tebiw 
naked on the lower part. Taz/ forked. 
LAUGHING GULL. 
Xema ridibundus, Boze. 
La Mouette rieuse ou a Capuchin brun. 
Tue characters which distinguish the genus Xema of Dr. Leach from the genus Larus, consist not only in 
a decided difference of form, but in certain points of colouring, and the changes which the species comprised 
in it undergo at different seasons; for example, the bill and legs are bright red, and the head changes in 
spring from white to black or deep chocolate brown, which latter colouring is certainly confined to the 
breeding-season, and disappears on the approach of autumn; in addition to this we find that the young pass 
through a very different gradation of plumage to that which obtains among the Gulls in general. Independently 
of these variations in the colouring, we may observe that the general contour of the species is much more light 
and elegant, the bill more feeble, and the tarsi more slender; they choose, moreover, a very different place 
for the purposes of nidification, always resorting to low flat lands, often some distance from the sea, the nest 
being placed on the ground, whereas the generality of the Gulls build upon ledges of rock bordering 
the sea. 
Of all the species comprised in the present group which inhabit our island, the Laughing Gull is by far the 
most common and perhaps the most elegant of its genus. During the summer it resorts in immense flocks, 
for the purpose of nidification, to many of our marshy islands near the coast, after which it again returns to 
the sea, or the mouths of large rivers, and is found at this season round the whole of our coasts, but is not 
then to be distinguished by the bright chocolate colouring of the head, which character is so remarkable 
during the breeding-season. In general habits, manners, and mode of flight, it agrees with the rest of the 
Gulls; though, as its light form and long tarsi sufficiently indicate, its actions on the ground are much more 
nimble and rapid. It is said to be a bird of passage in Germany and France, but is found in the greatest 
abundance in Holland throughout every season of the year. Its food consists of various insects, worms, 
mollusca, and small fishes. ss 
In its full summer plumage the bill, naked skin round the eye, and tarsi, are bright red; the whole of the 
head and throat deep chocolate brown; the back and shoulders delicate grey; quills white on their outer 
edges, with the exception of the first, in which it is black, the extremities of all the rest being black slightly 
tipped with white; rump, tail, and whole of the under surface white. 
The winter plumage is similar to that of summer, with the exception of the chocolate hood, which is 
gradually exchanged for pure white, a change which Mr. Yarrell has correctly observed in his valuable paper 
“On the Laws which appear to influence the assumption and changes of plumage in Birds,” published in the 
Transactions of the Zoological Society of London, (vol. 1. part 1. p. 13,) is produced 1 not by a process of 
moulting, but by an alteration in the colour of the feathers. 
The young of the year have the colour of the bill and tarsi much more obscure; the top of the head and 
ear-coverts are mottled with brown, which is also the colour of the back and shoulders, each feather having a 
lighter margin; the tail is broadly edged with black. 
The full plumage of maturity is not acquired until after the moulting of their second autumn, and is assumed 
by gradations. ‘The sexes do not differ in their colouring. 
The Plate represents an adult, and a young bird of the year, of the natural size. 
