A small bird of upper montane and subalpine forest canopy and bushes. Dull brown upperparts, whitish underparts and yellowish tinged head, neck and upper chest. Note the white, beady eye, grizzled cheek and relatively short bill. Forages very actively and constantly, often in mixed flocks with Large and Papuan Scrubwrens. Similar to Brown-breasted Gerygone, but Papuan Thornbill is more common higher up and avoids more open habitats. Voice, various high-pitch chips and squeaks.