Small warbler of approximately 13 cm, characteristic of the Yungas understory. It has olive-green upperparts and bright yellow underparts, with a slight olive tinge on the flanks. The head is highly distinctive: it shows a blackish crown with a conspicuous central orange-yellow stripe, partially hidden among the feathers, accompanied by a short yellow eyebrow, a marked dark eye line, and a subtle yellowish eye ring. The bill is black and the legs are pale orange-yellow. The sexes are similar. Juveniles have duller coloration, with a more olive head and upperparts, a less evident eyebrow, and less intensely yellow underparts.
It may be confused mainly with the Yellow-browed Warbler (Myiothlypis signata), although the latter lacks the characteristic black crown with a central orange-yellow stripe and has a much more developed eyebrow. While the Yellow-browed Warbler mainly inhabits upper montane forests, the Two-striped Warbler is typical of the lower elevations of the Yungas, with only a narrow zone of altitudinal overlap between both species.
It may also locally coexist with the Gray-and-gold Warbler (Myiothlypis culicivora), from which it is easily distinguished by its diffuse whitish eyebrow, grayish sides of the head and neck, and a brown crown with a gray central line and a hidden orange patch, in addition to its different vocalizations.
Geographic distribution: It has a discontinuous distribution in South America. Isolated populations are recognized in the southern Venezuelan tepuis, Guyana, and northern Brazil, as well as another widely distributed population along the eastern Andean slopes from southern Peru to Bolivia and northwestern Argentina. Three subspecies are recognized: Myiothlypis bivittata roraimae in the Guiana Shield, M. b. bivittata from southern Peru to central Bolivia, and M. b. argentinae in southern Bolivia (Tarija and Chuquisaca) and northwestern Argentina.
In Argentina, it is distributed in the Yungas of Jujuy and Salta. Recent observations and confirmation of historical records have verified its presence in Tucumán Province, particularly in piedmont and montane forest environments, considerably expanding knowledge of its southern distribution. Current records suggest that the species may be more widely distributed in the Tucumán Yungas than previously assumed. It is mainly recorded between 500 and 1,400 meters above sea level, although it may occasionally reach higher elevations.
Habitat: A characteristic inhabitant of the Yungas, especially piedmont and montane forests. It frequents dense understory, shrublands, stream edges, humid ravines, and areas with abundant low vegetation. It is usually found in well-preserved environments with a developed shrub layer, where it actively moves among low branches, vines, and riparian vegetation.
Feeding: It mainly consumes small arthropods, including insects, spiders, and their larvae. It forages alone, in pairs, or in small groups, actively searching through the lower vegetation layer using short hops and brief flights. It frequently performs acrobatic maneuvers to capture prey, including hovering or fluttering flights to catch insects on vegetation, among rocks, or even over small streams. It also occasionally joins mixed-species flocks of insectivorous birds.
Behavior: It is an active, curious, and relatively confiding species. It is generally observed alone, in pairs, or in small groups, constantly moving through the understory and vegetation near rivers and streams. It shows strong territorial behavior and often vocalizes in duets, with males and females responding to each other through sequences of rapid and variable notes. Its vocal repertoire is one of the most characteristic sounds of the piedmont Yungas understory.
Nesting: It nests mainly between late September and December. It builds a closed or semi-spherical nest made of plant fibers and other fine materials, generally placed close to the ground among dense understory vegetation. The clutch consists of two to four whitish or pinkish eggs, with brownish and grayish spots concentrated toward one pole. Both members of the pair participate in caring for the chicks.
Conservation status: This species is categorized as Not Threatened (NA) at the national level and as Least Concern (LC) internationally. Although it has a relatively restricted distribution in Argentina, it can be locally common and even abundant in suitable piedmont Yungas habitats. Degradation and fragmentation of the Yungas represent its main potential threat.
Author of this compilation: María Belén Dri and Diego Carús – 07/16/2026