140
THE ESSEX NATURALIST.
wigs, fragments of eggshells of Guillemot and Razorbill, grass,
and small stones, a very mixed diet.99
Specimens in the Essex Museum are composed of crab-frag-
ments, broken fragments of mussel shells, fish vertebrae and other
bones, including the pavement-like pharyngeal teeth of wrasse,
two entire legs of a small passerine bird, teeth and bones of a
young rabbit, grain-husks, the fibrous bark of the sea-mallow
(Lavatera), and a little sand.
Lesser Black-Backed Gull.
This Gull has been observed to throw up castings when in
captivity, and its pellets have been picked up at the nesting-
places. They were found to contain bones and fur of water vole,
fish-bones, crab remains and grain-husks.100
Pellets of this Gull (originally globular in shape, but now
disintegrated) in the Essex Museum collection are made up of
large numbers of comminuted fragments of shells of a mollusc
(Tellina sp.), including one perfect shell with adherent valves,
and also a few insect remains.
Great Black-Backed Gull.
Various records exist of pellets of this Gull being found
near the nest. Mr. O. V. Aplin, for instance, records finding
a pellet ''half as large again as a golf-ball, composed apparently
entirely of Puffins' feathers" by the side of a nest,101 and other
observers have found pellets in similar close juxtaposition to the
nest.'02
During the autumn of 1921 I found a casting, almost certainly
of this species of gull, on the saltings of Canvey Island, which was
entirely made up of fragments of crab's claws, but which was so
fragile as to crumble at a touch and so could not be preserved.
The recorded contents of the pellets include fur and bones of
young rabbits, crabs' claws, fur and bones of moles, voles and
shrews, the remains of mole being particularly abundant accord-
ing to one observer.
Larus dominicanus.
Mr. T. H. Potts, F.L.S., found castings in or about the nest of
this New Zealand gull, which contained remains of mussels.103
99 cf. Zoologist, 1880, p. 362; ibid. 1894, p. 343. British Birds, iv., p. 124. Zoologist, 1906,
p. 94, Glasgow Naturalist, ii., 1910, pp. 130-1.
100 Zoologist, 1895, p. 251; ibid. 1906, p. 94. Saunders's British Birds, 1889, p. 660.
101 Zoolog st, 1903, p. 201.
102 Zoologist, 1886, p. 95; ibid. 1890, p. 326.
103 Zoologist, 1875, p. 4487.