The name “greenshank” means “green legged”, so it should come as no surprise to learn that the greenshank (Tringa nebularia) can be distinguished from its red-legged cousin, the redshank, by the greenish colour of its legs! Greenshanks and redshanks are waders that are closely related to sandpipers.
Distribution
The
greenshank is a northern bird, in that it breeds in western and northern
Scandinavia and northern Russia and Asia, but it is also migratory, with many European
and Asian birds wintering in southern Africa and Australasia.
In Britain,
the greenshank breeds in northern Scotland, a favoured area being the wild and
deserted flow country of Caithness and Sutherland. Wintering birds can be seen
further south, particularly Cornwall and Devon,
and passage migrants can turn up in virtually any coastal region of mainland Britain
Habitat
The preferred
breeding habitat of the greenshank is open forest or more sparsely wooded areas
in the sub-Arctic. In Scotland
At other
times greenshanks can be seen on lake margins, riverbanks and coastal marshes
and estuaries.
Appearance
The greenshank,
at 30-33 centimetres (12-13 inches) in length, is slightly larger than the redshank
and is taller and lankier. Its bill is longer and slightly upturned. As
mentioned above, the legs are greenish in tone, sometimes tending towards
yellow.
The plumage
is grey above and white below, the head being speckled grey and white, with the
speckling continued down the chest, particularly in summer. In flight, a white
arrow shape is noticeable up the back. The wings are narrower, longer and more
pointed than those of the redshank.
Behaviour
The greenshank
is usually seen either singly or in small groups. It flies strongly and
rapidly. When feeding on mud it will either peck from the surface or with side
to side sweeps of the bill. It also takes fish from open water, which it does
by plunging its head under water.
The greenshank
has a loud and carrying “teu-teu-teu” call, often heard in flight, and a repeated
“teu-i” whistle that constitutes its courting song, plus an excited “chip”.
Breeding
Greenshanks
return to their breeding grounds in April or May. The males claim their
territory with a song flight that involves flying very high and then tumbling
down again.
The nest
comprises a shallow hollow lined with grass or other plant material. The male
greenshank makes several scrapes in the ground and the female chooses which one
she wants for the nest.
The clutch,
laid in May or June, is normally of four eggs which are incubated mainly by the
female, with the male greenshank providing occasional relief. The chicks hatch
after 23-25 days and, as soon as they are dry, conceal themselves in the
surrounding vegetation, being tended by the adult birds although the chicks are
able to feed themselves. The female greenshank often abandons her family to
start her migration (in late June or July), with the young, which can fly at around
30 days, following later (before the end of August) with the male greenshank
accompanying them.
Only one
brood is raised each year.
Food
The
greenshank is unusual among waders in that fish is a regular part of its diet,
amounting to as much as a quarter of its food intake. Other food taken consists
of molluscs, worms and insects, such as water boatmen and beetles. When on the
coast it feeds on shrimps, crabs and ragworms as well as fish.
Conservation
status
Despite its
low population of breeding birds (estimated to be fewer than 1,500 pairs), the
greenshank has green conservation status in the United Kingdom. There has been
concern in recent years over developments in its traditional breeding areas,
with forestry and tourism having increased, but there have also been moves to
conserve this environment, which should help the greenshank and other birds
that live and breed in this very special and remote area.
Another
concern is that climate change will drive the greenshank further north, with
even northern Scotland becoming too warm to suit it.
©John Welford
No comments:
Post a Comment