Crateroscelis robusta

General description: 

Male nominate race is dark brown above, including upperwing and tail, with rufous wash on uppertail-coverts; chin and throat white, straw-coloured, pinkish orange or orange-brown; bill brown, legs grey-brown. Female is similar to male or duller. Juvenile resembles adult, but underparts van be reddish-brown or grey-brown, iris dark brown or grey-brown. Races vary markedly in colour and pattern, with two broad groups, those with grey underparts and those without: deficiens resembles nominate but deeper brown above, uppertail-coverts less rufous, underparts greyish, lacks slaty breastband; peninsularis is like previous, but more white on breast; ripleyi is like last, but greyish-toned, less rufou-brown, above; sanfordi is slightly larger, rich brown to olive-brown above, dull rufous-brown below (more like C. murina bud duller); bastille is like last, but upperparts dull dark olive, underparts slightly paler, with less contrast between light throat and darker breast and belly.

Conservation status: 

Not Threatened

Diagnostic description: 

Male nominate race is dark brown above, including upperwing and tail, with rufous wash on uppertail-coverts; chin and throat white, straw-coloured, pinkish orange or orange-brown; bill brown, legs grey-brown. Female is similar to male or duller. Juvenile resembles adult, but underparts van be reddish-brown or grey-brown, iris dark brown or grey-brown. Races vary markedly in colour and pattern, with two broad groups, those with grey underparts and those without: deficiens resembles nominate but deeper brown above, uppertail-coverts less rufous, underparts greyish, lacks slaty breastband; peninsularis is like previous, but more white on breast; ripleyi is like last, but greyish-toned, less rufou-brown, above; sanfordi is slightly larger, rich brown to olive-brown above, dull rufous-brown below (more like C. murina bud duller); bastille is like last, but upperparts dull dark olive, underparts slightly paler, with less contrast between light throat and darker breast and belly.

Size: 

12 cm

Phylogeny: 

Taxonomy: Gerygone robusta De Vis, 1898, Wharton Range, south-eastern New Guinea. Races form two groups, sanfordi and bastille brown below and the other four having grey underparts; whether groups differ vocally, however, is not known. Proposed race pratti (Mt Dayman, extreme SE New Guinea) normally merged with nominate. Six subspecies recognized. (source: Handbook of the Birds of World)

Distribution: 

Subspecies and Distribution:

    * ripleyi Mayr & Meyer de Schauensee, 1939 - Vogelkop (Tamrau Mts), in NW New Guinea. * peninsularis E. J. O. Hartert, 1930 - Arfak Mts, in Vogelkop (NW New Guinea). * sanfordi E. J. O. Hartert, 1930 - W New Guinea from Wandammen area, and Weyland Mts and Snow Mts, E to Jayawijaya Mts, Victor Emanuel Mts and Hindenburg Mts. * deficiens E. J. O. Hartert, 1930 - N New Guinea (Cyclops Mts). * bastille Diamond, 1969 - N New Guinea (Bewani Mts, Torricelli Mts). * robusta (De Vis, 1898) - E & SE New Guinea from Huon Peninsula (Saruwaged Mts), Sepik Mts and Herzog Mts E to Owen Stanley Range.
Habitat: 

Mountain forest, at c. 1250 – 3680 m; inhabits dense shrubby understorey of moss forest, occurring also in coarse kunai grass (Imperata) along forest edge, and in overgrown treefall areas. Becomes commoner at higher elevations, e.g. at 1645 m on Mt Karimui, but tails off as vegetation becomes dwarfed nearer tree-line. Replaced at lower elevations by C. murina. Narrow zone of overlap with both latter and C. nigrorufa in a few areas; ecological-separation mechanism unknown, but presumably through nich selection, with present species between mainly terrestrial C. murina and higher-foraging C. nigrorufa.

Trophic strategy: 

Insectivorous; no details of dietary items. Usually seen singly or in pairs, or in groups of three or four individuals, probably family parties. forages on ground and substage; creeps quietly through vegetation, easily overlooked unless calling. Often skulking but sometimes quite approachable, heard far more often than seen. Hops on ground and through shrubs, gleaning food items; will feed on narrow shady tracks adjacent to thick cover.

Reproduction: 

Few data. Netlings reported in Dec and Aug. Domed nest similar to that of Sericornis, lined with feathers; sites include under tree roots, in fork of small tree, under small cliff and in a landslip area. No other informations.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith