Silvicola di Roberts

Identificazione

Roberts's warbler resembles the related species in the genus Prinia in being long-tailed warbler-like birds. This species differs from that genus by 8 rather than 10 feathers in the tail which has a more stepped profile than the graduated profile of Prinia. It is a dark-grey warbler which bears the closest resemblance to is the tawny-flanked prinia (P. subflava) but differs in having a grey throat, pale eye and lake of brown edges to feathers of the upperparts. The upperpart of the head with the rest of the upperparts being dull olive brown, the flight feathers of the wing are dark brown and the tail is brown. The underparts are grey to rufous grey and are paler in the non breeding season and in the juveniles the eye is dark.. The length of Roberts's warbler is 13 to 14 cm (5.1 to 5.5 in).

Tassonomia

Roberts's warbler was first formally described as Prinia robertsi in 1946 by the British ornithologist Constantine Walter Benson, although it had originally been identified as a distinct species at Mount Selinda by Charles Swynnerton in 1906. Benson gave the type locality as Vumba. In 1991 Phillip Clancey proposed the new monospecific genus Oreophilias as, among other features which differed, this species had 8 tail feathers rather than the 10 present in species in the genus Prinia. Clancey suggested that Oreophilias was a more basal taxon thena Prinia because of the lower number of retrices. Roberts's warbler belongs to the family Cisticolidae, which includes the cisticolas, prinias, apalises, tailorbirds, eremomelas and other groups of “African” warblers, formerly classified within the Old World warbler family Sylviidae. The Cisticolidae is now classified in the superfamily Sylvioidea, part of the Corvides clade within the suborder Passeri in the order Passeriformes. This species is monotypic with no subspecies.

Nome scientifico

Oreophilais robertsi

Autorità

(Benson, 1946)

Ordine

Passeriformi

Famiglia

Cisticolidae

Genere

Oreophilais

Areale e habitat

Robert's warbler is endemic to the Eastern Highlands of Zimbabwe where it is found from the Chimanimani Mountains in the south to Nyanga in the north, typically at altitudes above 1,200 m (3,900 ft), where it appears to replace the tawny-flanked prinia, although the two species overlap with Roberts's warbler preferring denser cover than the prinia. Its range extends into adjacent parts of Mozambique but it has not been recorded from Mount Gorongosa. It prefers forest along streams, clearings, dense stands of bracken, Erica and briar (Smilax) along forest edges.

Migrazione

Resident species

Conservazione

Robert's warbler is classified as a species of Least Concern by the International Union for Conservation of Nature. It does have a restricted range but this does not seem to approach the thresholds for the species to be classified as Vulnerable. The population, although not know, is apparently stable and is thought to be large enough to justify its classification as Least Concern.

Tendenza della popolazione

stable