Grandule del Namaqua

Identificazione

The sandgrouse is a medium-sized bird with a plump body, small head and short legs. It grows to a length of about 28 centimetres (11 in). The male has an orangish buff head, throat and chest delineated by a conspicuous narrow band of white and dark brown. The back and wings are mottled brown with large white specks and there are two long black filaments extending from the olive-brown tail. The colouring of the female and juvenile is more cryptic being generally various shades of brown patterned with white specks. It could be confused with the double-banded sandgrouse (Pterocles bicinctus) and Burchell's sandgrouse (Pterocles burchelli), which share the same range.

Tassonomia

The Namaqua sandgrouse was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the grouse like birds in the genus Tetrao and coined the binomial name Tetrao namaqua. Gmelin based his description on the "Namaqua grous" that had been described in 1783 by the English ornithologist John Latham in his A General Synopsis of Birds. The Namaqua sandgrouse is now placed with 13 other species in genus Pterocles that was introduced in 1815 by the Dutch zoologist Coenraad Jacob Temminck. The genus name combines the Ancient Greek pteron meaning "wing" with -klēs meaning "notable" or "splendid". The specific epithet namaqua is from Namaqualand, a region in Namibia and South Africa, the type locality. The species is monotypic: no subspecies are recognised.

Nome scientifico

Pterocles namaqua

Autorità

(Gmelin, JF, 1789)

Ordine

Pterocliformes

Famiglia

Pteroclidae

Genere

Pterocles

Areale e habitat

The Namaqua sandgrouse can be found in various arid parts of South Africa and its neighbouring lands. It is common in the Kalahari Desert, the Nama Karoo (in central and western South Africa), and in parts of the Western Cape. In addition, it is also found in Namibia (especially in the Namib Desert), Zimbabwe, Botswana and Angola.<p>It favours deserts and other arid areas. In order to survive, this bird needs only seeds, some gravel, and easy access to some sort of fresh water source. Their habitat usually has rough vegetation and tussock-type grasses.

Migrazione

Complete migrants

Comportamento

Outside the breeding season, the sandgrouse are gregarious. The birds converge on watering holes in the early morning and several dozens or even hundreds of individuals may congregate in one place. They also tend to spend the night in groups, congregating about an hour before dusk. They split up during the day into much smaller groups to feed.<p>Their principal diet is seeds but they also eat leaves, flowers, small fruit, insects and molluscs. They forage by exploring loose soil with their beaks and flicking it away sideways.<p>Breeding takes place at any time of the year and is dependent on rainfall. Usually the nests are solitary but sometimes several pairs of birds choose sites near each other. The nest is a scrape in the earth, scantily lined with dried plant material. Two or three pinkish-grey eggs with brown markings are laid over the course of a few days. Incubation starts after the last egg has been laid and lasts about 22 days. The female does the incubation by day and the male does a longer shift at night, starting about two hours before sunset and finishing two hours after dawn. The chicks are precocial and able to leave the nest on the day they are hatched. The male brings them water absorbed on the specially adapted feathers of his breast. The chicks grow rapidly; they are fully feathered at three weeks and able to fly at six.

Conservazione

Tendenza della popolazione

stable