192 THE ESSEX NATURALIST.
No one has succeeded in proving that the Great Northern
Diver breeds in Britain, but a visit to a tarn or loch among the
Scottish highlands or islands might be rewarded with a view
of the Red-throated or Black-throated Divers at home. The
two eggs are usually placed at the edge of the water or some-
times on a heap of material in it, so that the Divers, which are
awkward on land, may slip easily into that element which is
essential to them.
Of the thirty-one species of waders which have been
mentioned, only the Oyster-catcher, Ringed Plover, Lapwing,
Common Redshank and Snipe nest in Essex. Wherever there
is a. suitable bank of shingle along the coast you may find the
naturally protected eggs of the Ringed Plover resting in some
suitable depression. The Redshank on the other hand requires
a very different type of habitat. It resorts to the rough grass
of the marshy meadow to rear its family. The nests of others
must be sought beyond the confines of the County, and in some
cases long and difficult journeys would be necessary. The Golden
Plover, Dunlin, Curlew and Whimbrel can be found nesting on
the same lonely moorland within the boundaries of our islands,
although much to the north. Nearly half of the waders, ten
to be exact, have never been known to breed in Britain and
in some cases it is a far cry to their nesting haunts. For such
species as the Knot, Grev Plover, Curlew Sandpiper and Little
Stint, we should have to make acquaintance with the Siberian
tundras.
To gain experience of the nesting ways of the Common and
Little Tern we need go no farther than the Essex coast, and,
although they are not numerous, we shall find both species.
They have selected, however, different types of ground for
nesting purposes. The Little Tern demands a stretch of fine
shingle and sand, while the Common Tern prefers the short
turf of the saltings.
In spite of the fact that the Black-headed Gull is such an
abundant breeding species in the British Isles—many breed in
Essex—yet the results of the ringing enquiry suggest that most
of the birds which we see in winter come from abroad. The
Black-headed Gull is an adaptable bird. You may find a nesting
colony in a marsh near the sea or on a secluded tarn in the
mountains. The Kittiwake and Herring Gull are cliff-nesters,