Storno di Tristram

Identificazione

Tristram's starling is 25 cm long (including a 9 cm tail), with a wingspan of 44–45 cm, and a weight of 100–140 g. The males have glossy iridescent black plumage with orange patches on the outer wing, which are particularly noticeable in flight. The bill and legs are black. Females and young birds are similar but duller and with a greyish head, lacking the plumage gloss.

Tassonomia

Nome scientifico

Onychognathus tristramii

Autorità

(Sclater, PL, 1858)

Ordine

Passeriformi

Famiglia

Sturnidi

Genere

Onychognathus

Areale e habitat

This bird is found in deserts in Israel, Jordan, northeastern Egypt (Sinai Peninsula), western Saudi Arabia, Yemen, and Oman, nesting mainly on rocky cliff faces. The species is becoming increasingly commensal with humans, feeding in towns and villages; this has enabled a recent northward spread in its distribution.

Migrazione

Resident species

Comportamento

Tristram's starlings are omnivorous, feeding on fruit and invertebrates (mainly insects such as beetles, flies, butterflies, and bees; but also small snails). They have also been observed grooming Nubian ibex and domestic livestock for parasites. Although they do not migrate for the most part, they fly relatively long distances compared to other resident birds, which likely makes them important seed dispersers for fleshy-fruited desert plants. In addition, they often forage for scraps in human settlements.<p>Tristram's starlings breed during the spring and early summer. They nest in existing cavities in rocky cliffs and also in urban buildings. Pairs are monogamous. The male courts the female by bringing her insects and twigs. They lay 2-4 eggs, which are blue with brown spots. Females incubate alone, but both parents feed the chicks. The young leave the nest about a month after hatching. Some pairs raise a second brood in later in the season, using the same nest.<p>Tristram's starling is a gregarious and noisy bird, with a call that resembles a wolf whistle. Outside the breeding season the starlings live in groups of between ten and a few hundred individuals. However, pairs remain together throughout the year, even when they join a larger group.

Conservazione

Tendenza della popolazione

stable