Western Gerygone

Identificazione

The western gerygone has plain, brownish-grey upperparts, with no prominent wing markings. The underparts are whitish, with variable amounts of grey on the throat and breast. The outer tail-feathers are conspicuously marked, with large, white patches at the base, a broad, blackish, subterminal tail band and white tips.<p>It is usually found singly or in pairs, in the mid to upper storey of trees and shrubs and is often located by its characteristic, persistent song. It can be very active when foraging. <p>The western gerygone is similar in appearance to several other Australian gerygones, which don't usually share its habitat. Its plumage can be distinguished from these species by the diagnostic large, white patches at base of its outer tail feathers.

Tassonomia

The western gerygone is a member of the family Acanthizidae (Thornbills and Allies), which has been split from the family Pardalotidae (Pardalotes).<p>It is a sister-species to the mangrove gerygone (Gerygone levigaster). The close relationship of this phylogenetic pair is suggested by analyses of both morphological characteristics and genetic loci. Populations of a common ancestor of the two species are thought to have diverged after becoming fragmented by severe aridity during the Pleistocene. These two species are now in secondary contact in the Carpentarian Basin, but occupy very different habitats and do not interbreed.<p>The common name western gerygone and scientific name Gerygone fusca are recognized by the taxonomies of the International Ornithological Congress, Clement's Checklist, the Handbook of the Birds of the World and Christidis and Boles.

Nome scientifico

Gerygone fusca

Autorità

(Gould, 1838)

Ordine

Passeriformi

Famiglia

Acanthizidae

Genere

Gerygone

Areale e habitat

The western gerygone is the most widespread gerygone species and is endemic to Australia. Its three subspecies show subtle differences in plumage and form geographically separate populations:<p>Nomadic individuals may travel far beyond this species' regular geographic limits.<p>Gerygone species are largely allopatric. They are usually separated from each other by their geographic distribution, or by their preference for different habitats. As it is the only gerygone of the Australian interior, the western gerygone does not overlap geographically with other gerygones throughout most of its range. <p>There are two island populations. Both are near Perth in Western Australia. Rottnest Island was colonized by the western gerygone in the 1950s. It was first observed on the island in 1955 and rapidly spread into all suitable habitat. On nearby Garden Island, which is closer to the Australian mainland, the species has been present since European records began.

Migrazione

Migratori completi

Comportamento

Comportamento migratorio: Migratori completi.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione