Svasso piccolo

Identificazione

The black-necked grebe usually measures between 28 and 34 centimetres (11 and 13 in) in length and weighs 265 to 450 grams (9.3 to 15.9 oz). The bird has a wingspan range of 20.5–21.6 in (52–55 cm). The nominate subspecies in breeding plumage has the head, neck, breast, and upper parts coloured black to blackish brown, with the exception of the ochre-coloured fan of feathers extending behind the eye over the eye-coverts and sides of the nape. This eye is mostly red, with a narrow and paler yellow ring on the inner parts of the eye and an orange-yellow to pinkish-red orbital ring. The thin, upturned bill, on the other hand, is black, and is connected to the eye by a blackish line starting at the gape. Sometimes, the foreneck can be found to be mostly tinged brown. The upperwing is blackish to drab brown in colour and has a white patch formed by the secondaries and part of the inner primaries. The flanks are coloured tawny rufous to maroon-chestnut and have the occasional blackish fleck. The underwing and abdomen is white, with an exception to the former being the dark tertials and the mostly pale grey-brown outer primaries. The legs are a dark greenish grey. The sexes are similar.<p>In non-breeding plumage, the nominate has greyish-black upper parts, cap, nape, and hindneck, with the colour on the upper portion of the latter being contained in a vertical stripe. The dark colour of the cap reaches below the eye and can be seen, diffused, to the ear-coverts. Behind the ear-coverts on the sides of the neck, there are white ovals. The rest of the neck is grey to brownish-grey in colour and has white that varies in amount. The breast is white, and the abdomen is whitish. The flanks are coloured in a mix of blackish-grey with white flecks. The colour of the bill when not breeding differs from that of the breeding plumage, with the former being significantly more grey.<p>The juvenile black-necked grebe is similar to the non-breeding adult. There are differences, however, including the fact that the dark areas are usually more brownish in the juvenile, with less black. The lores are often tinged pale grey, with whitish marks behind the eye. On the sides of the head and upper neck, there is a buffy or tawny tinge. The chick is downy and has a blackish-grey head with stripes and spots that are white or pale buff-grey. The throat and foreneck are largely pale. The upper parts are mostly dark grey in colour, and the abdomen is white.<p>The subspecies californicus usually has a longer bill compared to the nominate, and has brown-grey inner primaries during the breeding season. When not breeding, the nominate has diffuse and pale lores less often than Podiceps nigricollis californicus. The other subspecies, P. n. gurneyi, is the smallest of the three subspecies, in addition to having a greyer head and upper parts. The adult of this subspecies also has a rufous-brown tinge on its lesser wing-coverts. It also lacks a non-breeding plumage, in addition to the tufts on the side of its head being paler.<p>When breeding, the black-necked grebe gives a quiet "ooeek"[needs IPA] that ascends in pitch from an already high pitch. This call is also used as a territorial call, in addition to a low and fast trill, which itself is also used during courtship. Another call is a short "puuii" or "wit".[needs IPA] This grebe is silent when it is not the breeding season and when it is feeding or resting.

Tassonomia

This species was first described by Carl Ludwig Hablitz in 1783 as Colymbus caspicus, from a bird in Bandar-e Anzali. This was originally thought to be a synonym for the horned grebe, until Erwin Stresemann discovered that the description applied more to the black-necked grebe in 1948. Before this, the earliest description was thought to be by Christian Ludwig Brehm in 1831, who gave this bird its current scientific name of Podiceps nigricollis from a German bird. To resolve this, the International Commission on Zoological Nomenclature suppressed the name C. caspicus. The genus name Dytes is sometimes used for this species, a placement which was formalized by Robert Ridgway in 1881.<p>This bird is closely related to the silvery grebe and the Junin grebe. The extinct Colombian grebe is sometimes considered to be a subspecies of this species, in addition to three other extant subspecies:<p>The generic name, Podiceps, comes from two Latin words: podicis, meaning 'vent' or 'anus', and pes meaning 'foot'. This is a reference to the attachment point of the bird's legs—at the extreme back end of its body. The specific epithet nigricollis is Latin for 'black-necked': niger means 'black' and collis means 'neck'. The subspecies epithet californicus comes from "California", while gurneyi comes from the name of British ornithologist John Henry Gurney Sr.<p>"Black-necked grebe" has been designated the official name by the International Ornithological Committee (IOC). Both common names for this species refer to features visible when the bird is in its breeding plumage; in such plumage, it has an all-black neck and a spray of golden plumes on each side of its head. The name "eared grebe" is nearly a century older than the name "black-necked grebe". The latter was first used in 1912 by Ernst Hartert, in an effort to bring the common name of the species in line with its scientific name. The name "eared grebe" is still used in North America to refer to this bird.

Nome scientifico

Podiceps nigricollis

Autorità

Brehm, CL, 1831

Ordine

Podicipediformes

Famiglia

Podicipedidi

Genere

Podiceps

Areale e habitat

This species breeds in vegetated areas of freshwater lakes across Europe, Asia, Africa, northern South America and the southwest and western United States. After breeding, this bird migrates to saline lakes to moult. Then, after completing the moult and waiting for sometimes several months, it migrates to winter in places such as the south-western Palearctic and the eastern parts of both Africa and Asia. It also winters in southern Africa, another place where it breeds. In the Americas, it winters as far south as Guatemala, although the wintering population there is mainly restricted to islands in the Gulf of California, the Salton Sea, and Baja California. When not breeding, its habitat is primarily saline lakes and coastal estuaries.

Areale riproduttivo

PAL, AF, NA, MA : temperate Eurasia to Russian Far East and ne China; e, s Africa; sw Canada and w, wc USA to c Mexico

Areale non riproduttivo

to coasts of n Africa, Arabian Pen., Black and Caspian seas, nw Indian subcontinent, se China, Korean Pen. and Japan; s Mexico and ec US

Migrazione

Migratori completi

Comportamento

Comportamento migratorio: Migratori completi.

Conservazione

Tendenza della popolazione

unknown