Pivieressa

Identificazione

The grey plover is 27–30 cm (11–12 in) long with a wingspan of 71–83 cm (28–33 in) and a weight of 190–280 g (6.7–9.9 oz) (up to 345 g (12.2 oz) in preparation for migration). In spring and summer (late April or May to August), adults are spotted black and white on the back and wings. The face and neck are black with a white border; they have a black breast and belly and a white rump. The tail is white with black barring. The bill and legs are black. They moult to winter plumage in mid August to early September and retain this until April; this being a fairly plain grey above, with a grey-speckled breast and white belly. The juvenile and first-winter plumages, held by young birds from fledging until about one year old, are similar to the adult winter plumage but with the back feathers blacker with creamy white edging. In all plumages, the inner flanks and axillary feathers at the base of the underwing are black, a feature which readily distinguishes it from the other three Pluvialis species in flight. On the ground, it can also be told from the other Pluvialis species by its larger (24–34 mm, 0.94–1.34 in), heavier bill.

Tassonomia

The grey plover was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Tringa squatarola. It is now placed with three other plovers in the genus Pluvialis that was introduced by the French onithologist Mathurin Jacques Brisson in 1760. The genus name is Latin and means relating to rain, from pluvia, "rain". It was believed that they flocked when rain was imminent. The species name squatarola is a Latinised version of Sgatarola, a Venetian name for some kind of plover.<p>The English common name used for this species differs in different parts of the world. It is generally known as "grey plover" in the Old World and "black-bellied plover" in the New World.<p>Three subspecies are recognised:

Nome scientifico

Pluvialis squatarola

Autorità

(Linnaeus, 1758)

Ordine

Caradriformi

Famiglia

Caradriidi

Genere

Pluvialis

Areale e habitat

Areale riproduttivo

NA, PAL : high (locally low) Arctic coasts and is. (except Ellesmere I., Greenland, Scandinavia and is. from Svalbard to Severnaya Zemlya)

Areale non riproduttivo

Worldwide, temperate to tropical coasts (except remote is.)

Migrazione

Complete migrants

Comportamento

Young birds do not breed until two years old; they typically remain on the wintering grounds until their second summer.<p>They forage for food on beaches and tidal flats, usually by sight. The food consists of small molluscs, polychaete worms, crustaceans, and insects. It is less gregarious than the other Pluvialis species, not forming dense feeding flocks, instead feeding widely dispersed over beaches, with birds well spaced apart. They will however form dense flocks on high tide roosts.

Conservazione

Tendenza della popolazione

declining