Identification

A small passerine, about 9.5–11 cm, almost uniformly yellowish-olive green, except for the black forehead and the white eye-ring typical of its genus. Subspecies Zosterops fuscicapilla crookshankii is slightly larger and has a wider eye-ring.

The nominate subspecies of Capped White-eye can be differentiated by its yellow underparts; all other white-eyes on New Guinea have whitish underparts.

Considering all species of white-eyes in the greater New Guinea region; the Biak White-eye (Zosterops mysorensis), Lemon-bellied White-eye (Zosterops chloris), Louisiade White-eye (Zosterops griseotinctus), and Tagula White-eye (Zosterops meeki) are confined to smaller islands for which there is only one species of white-eye present. On New Guinea, the Black-fronted White-eye (Zosterops minor) is widespread in intermediate hill altitudes, but absent in the lowlands (1 Diamond, J. M. (1985). New distributional records and taxa from the outlying mountain ranges of New Guinea. Emu 85(2):65–91. Close , 2 Rheindt, F. E. (2012). New avian records from the little-explored Fakfak Mountains and the Onin Peninsula (West Papua). Bulletin of the British Ornithologists’ Club 132(2):102–115. Close ), with both New Guinea White-eye (Zosterops novaeguineae) and Capped White-eye present in montane habitats (although New Guinea White-eye is, somewhat anomalously, also present in lowlands [3 Diamond, J., and K. D. Bishop (2015). Avifaunas of the Kumawa and Fakfak Mountains, Indonesian New Guinea. Bulletin of the British Ornithologists' Club 135(4):292–336. Close ]). The distributions of Capped White-eye and New Guinea White-eye in montane habitat do not seem to overlap very much, with Capped White-eye predominantly in the west of the New Guinea, and the New Guinea White-eye mainly in the east.

All three species (Black-fronted White-eye, Capped White-eye, and New Guinea White-eye) have been reported in the Kumawa Mountains, the Arfak Mountains, and both Capped White-eye and New Guinea White-eye have been reported from the Bird’s Head (Papua Barat) (3 Diamond, J., and K. D. Bishop (2015). Avifaunas of the Kumawa and Fakfak Mountains, Indonesian New Guinea. Bulletin of the British Ornithologists' Club 135(4):292–336. Close , 4 Pratt, T. K., and B. M. Beehler (2015) Birds of New Guinea. Second edition. Princeton University Press, Princeton, New Jersey, USA. Close ). On the D’Entrecasteaux archipelago, subspecies crookshanki replaces the Black-fronted White-eye (Zosterops minor) pallidogularis in forests above 800 m elevation (4 Pratt, T. K., and B. M. Beehler (2015) Birds of New Guinea. Second edition. Princeton University Press, Princeton, New Jersey, USA. Close ).

Wherever overlap occurs, all subspecies of the Capped White-eye are best differentiated by the yellow underparts (vs. white in all other species).

Although they do not overlap in distribution, the nominate subspecies is strikingly similar to the (formerly conspecific) Black-headed White-eye (Zosterops hypoxanthus), but the latter has the chin, throat, and underparts bright yellow (vs. yellowish olive green in the present species).