A small warbler characteristic of the Yungas, measuring approximately 13 cm in length. It has overall olive-green upperparts and bright, fairly uniform yellow on the throat, breast, and belly. It is distinguished by a broad, bright yellow supercilium that extends clearly beyond the eye, a conspicuous pale yellow crescent on the lower eyelid, and a short blackish eye line extending only slightly past the eye. The crown is uniformly olive, lacking conspicuous bands or markings. The bill is short and blackish, while the legs are pale yellowish to pale orange. Its overall appearance is that of a predominantly yellow warbler with a very distinctive facial expression created by the contrast between the broad yellow supercilium and the short dark eye line. The sexes are alike. Juveniles are browner, with olive tones mainly restricted to the wings and tail, duller underparts, and paler bill and legs. It may be confused primarily with the Capped Warbler (Myiothlypis culicivora), which has a black crown with a conspicuous chestnut central patch, absent in the Yellow-browed Warbler. In addition, the Capped Warbler is usually found at lower elevations within the Yungas, whereas the Yellow-browed Warbler is more characteristic of montane forests.
Geographic distribution: Distributed along the Andes from central and southern Peru through Bolivia to northwestern Argentina. In Argentina, it is restricted to the Yungas of Jujuy and Salta, where it mainly inhabits montane areas between approximately 900 and 1,900 m above sea level, although it may occasionally be recorded at higher elevations. There is no evidence of significant migratory movements, and it is considered a resident species throughout its range.
Habitat: A characteristic inhabitant of the Yungas, especially montane rainforest and humid montane forests. It frequents dense understory, moist ravines, and areas near streams, where it usually remains concealed among shrubs, vines, and dense understory vegetation.
Diet: Feeds mainly on small arthropods, including insects, larvae, spiders, and other invertebrates. It usually forages alone or in pairs, actively searching through low foliage and understory vegetation with short hops and brief flights. It frequently joins mixed-species flocks of understory insectivorous birds.
Behavior: Usually observed alone or in pairs. It is an active yet relatively inconspicuous species, spending much of its time within the dense understory foliage, where it is more often detected by its vocalizations than by sight. It typically moves close to the ground, usually less than two meters above it, searching through shrubs and vegetation near watercourses. Its song consists of a long series of sharp, rapid notes that begin by rising in pitch and then descend, producing a somewhat irregular and explosive sequence.
Nesting: Very poorly known. The presence of juveniles during the austral summer suggests that breeding takes place between spring and summer. Details regarding nest construction, egg laying, and incubation remain poorly documented.
Conservation status: Classified nationally as Not Threatened (NA) and internationally as Least Concern (LC). Although it has a relatively restricted distribution associated with the Yungas, it can be locally common in suitable habitats. The degradation and fragmentation of montane forests constitute its main potential threat.
Author of this compilation: María Belén Dri and Diego Carús – 07/15/2026