Genus XEMA.
Gen. Cuar. Beak short, slender, straight, laterally compressed,

7 its tip bent down; the lower
mandible somewhat angulated bene

ath. Nosérils very slender,

linear, Legs slender: tibice
naked on the lower part. Tazl forked.

LAUGHING GULL.

Xema ridibundus, Boje.

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
in it undergo at different seasons ; for example, the bill and legs are
spring from white to black or deep chocol

species comprised
bright red, and the head changes in
ate brown, which latter colouring is cert
breeding-season, and disappears on the approach of autumn; in young pass
through a very different gradation of plumage to that which obt }

ains among the Gulls in general. Independently
of these variations in the colouring, we may observe that the general contour of the

and elegant, the bill more feeble, and the tar.
for the purposes of nidification, always resortit

ainly confined to the
addition to this we find that the

species is much more light
si more slender ; they choose, moreover, a very different place
1g 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 isl

ands 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.

Tn 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 comeatly observed in a 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. 18,) is produced not by a process of
moulting, but by an alteration in the colour of the feathers. ae

The young of the year have the colour of the bill and tarsi much more obscure ; the top of the head anc
€ar-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. ‘ Sats et

The full plumage of maturity is not acquired until after the moulting of their second autumn, and is assumec
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.

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