It is found in Bolivia, Colombia, Ecuador, Peru, and Venezuela. Its natural habitats are subtropical or tropical moist montane forests and degraded former forest.
Over most of this species’ range, which encompasses much of the Andean chain, except the west slope in Colombia, the Superciliaried Hemispingus is characterized by its olive upperparts, yellow underparts and white supercilium, which contrasts with the dark cheeks. However, in northern and central Peru, ‘sandwiched’ between yellow-bellied populations, there is a gray-backed and white-bellied population, which might briefly be confused with the sympatric Drab Hemispingus (Hemispingus xanthophthalmus), but for the pale irides and lack of any supercilium in the latter species. Elsewhere over the species’ broad range, the yellow-bellied forms of Superciliaried Hemispingus could easily be confused with the Citrine Warbler (Basileuterus luteoviridis), or one of the other olive-backed species of Hemispingus with an obvious supercilium.
It is 13–14 cm of length ; 11–17 g. Overall, rather variable. Nominate race has forecrown and cheek dusky, long narrow white supercilium; rest of crown, nape and upperparts, including tail and upperwing-coverts, olive-green, primary coverts blackish; flight-feathers blackish, outer primaries edged olive-yellow, inner ones olive-green; throat and underparts bright yellow, flanks tinged olive; iris reddish-brown; bill fairly small and slender, grey, sometimes duskier above and paler below; legs dark grey. Sexes similar.Immature (or subadult) is duller, with less contrasting head pattern, more olive on breast and sides. Race chrysophrys differs from nominate in having yellow (not white) supercilium, olive forecrown and duller cheek; nigrifrons is like nominate, but more dusky on forecrown and cheek; maculifrons differs in pale greyish-olive forecrown and cheek; leucogastrus is distinctive, crown, cheek and upperparts all grey, supercilium white, whitish below, some dusky mottling on side of throat, heavy grey tinge on breast, buff tinge on undertail-coverts; insignis is like last, but generally paler, with faint yellow tinge on undertail-coverts; urubambae is much like nominate but slightly paler below, forecrown blackish, eyestripe typically with traces of yellow towards rear.
Formerly treated in Hemispingus but recently found to be part of the Thlypopsis clade (1). Races can be organized into three groups in two ways: either “superciliaris group” with yellow underparts, “leucogastra group” with white underparts, and single-taxon “urubambae group” again with yellow underparts (no intergrades between groups found); or, as followed here, “chrysophrys group” with yellow eyebrow, “superciliaris group” as above but plus the disjunct urubambae and minus chrysophrys, and the “leucogastra group”. “Leap-frog” plumage pattern (yellow underparts in populations on each side of grey population) and supercilium yellow in far N and white elsewhere are curious circumstances, suggesting that more than one species is involved, but vocally they are very alike. Race leucogastra misspelt in HBW/BirdLife Checklist. Seven subspecies currently recognized.
Distribution and habitat
It is found in Bolivia, Colombia, Ecuador, Peru, and Venezuela.
It lives in the canopy and on the edges of humid montane forests of altitude, mainly between 2200 and 3200 meters above sea level.
Solitary, in pairs or family groups in canopy, occasionally lower at borders; regularly with mixed flocks. Forages for arthropods by gleaning from green leaves.