Chestnut-rumped Thornbill

Identificazione

Length: 9.8 cm (9-11); wing span 15.5 cm (14-16.5); weight: 6 g.<p>Mid-sized thornbill similar in size and shape to inland thornbill (A. apicalis) and slaty-backed thornbill (A. robustirostris).Pale and plain with pale iris similar to buff-rumped (Acanthiza reguloides), western (A.inornata), slender-billed (A. iredalei) and yellow-rumped thornbills (A. chrysorrhoa).<p>Pale grey-brown upper, rich chestnut rump and mostly black tail with pale tips, pale mottled ear-coverts and rufous suffusion on forehead and crown. Plain whitish underbody. The sexes are alike, with no seasonal variation.<p>Slight geographic variations, birds of the more arid inland are paler and greyer above, with a slightly paler rump patch and cleaner white below than those in coastal and subcoastal regions. May be confused with other thornbills having a rufous-brown rump patch such as brown thornbill (A. pusilla), inland thornbill (A. apicalis) and slaty-backed thornbills (A. robustirostris).<p>The chestnut-rumped thornbill is gregarious, usually in small flocks, twos or threes and sometimes with other thornbills and small passerines. Active and restless, the chestnut-rumped thornbill forages in shrubs and trees, searching briskly, flitting and hopping in foliage and low branches, probing into crevices and bark. It also hops on the ground searching among fallen debris.<p>Flight similar to other thornbills, cover to cover in low undulating dashes.<p>Voice is penetrating, with a far-carrying song of similar phrases. It also mimics other birds.<p>Juveniles are similar to adults, but plainer with duller head pattern, and pale buff tail tips, not white. Iris is slightly duller, cream or greyish white. Nearly fledged juveniles have pale yellow gape.

Tassonomia

Described and classified by John Gould in 1838 in Synopsis of Birds of Australia, from a specimen collected in Liverpool Plains NSW.<p>Type, male, No17602 (525) is in the Academy of Natural Sciences, Philadelphia, United States. A specimen from the Gould collection is in the British Museum.<p>Mathews (1912) recognised a number of different subspecies of Acanthiza Uropygialis: A.u.ruthergleni, mellori, augusta, nea, murchisoni and condora, with A.u.kycheringi added in 1922. Campbell (1925) added subspecies Geobasilus uropygialis moora and G.u. erema. Where the genus Geobasileus, referred to ground feeding thornbills.<p>However, Mack (1936) and Mayr &amp; Serventy (1938) reorganised the species into two subspecies, A.u. uropygialis and A.u. augusta. Recent studies do not recognise subspecies but indicate that variations in plumage colouration are clinal.<p>Acanthiza had been previously placed in the family Pardalotidae, but are now part of the Acanthizidae.

Nome scientifico

Acanthiza uropygialis

Autorità

Gould, 1838

Ordine

Passeriformi

Famiglia

Acanthizidae

Genere

Acanthiza

Areale e habitat

Endemic to mainland Australia.<p>Qld: Widespread in S, to W of Great Divide, in South Western, South Central and W. South-Eastern Regions. Generally S of 23° S.<p>NSW &amp; ACT: Widespread W of Great Divide, including w. slopes of Northern Tablelands and southern Tablelands, Canberra.<p>Vic: Widespread in Mallee, Wimmera and North Districts N of 37°S.<p>SA: Widespread in many regions, but generally absent from SE (though a few records exist).<p>WA: Generally absent from Nullarbor Plain. Farther west largely absent from south coast, widespread in areas W of 123°E from 32°S North to 22°S in Pilbara region. Widespread in Gibson Desert, and scattered sites in Great Victoria Desert.<p>Chestnut-rumped thornbills are resident or sedentary, but some movement occurs. No large-scale movements are known, though some individuals occasionally move long distances. Non-breeding flocks disperse before breeding.<p>They are found in dry woodlands and shrublands, mainly of mulga and malleeeucalypts. Also in thickets, saltbush, bluebush, lignum, open pastoral country, among dead trees and stumps.They occur in arid and semi-arid zones extending to temperate and subtropical zones,in a wide variety of land forms including sand dunes, flood plains, rocky hillsides, plateaux and gorges.

Migrazione

Specie stanziale

Comportamento

Comportamento migratorio: Specie stanziale.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione