Description: A 12.5–14 cm high-Andean siskin with a very thick, short, broad-based bill, unmistakable in the field. The male has a black head, throat, and upper chest, bordered by a yellow nape band that separates the hood from the olive-toned back. Bright yellow rump, whitish belly and undertail coverts, contrasting with yellowish flanks. Wings dark with a well-defined yellow wing panel and yellow bases on primaries and secondaries, visible in flight. Tail black with yellow bases on the outer rectrices. The female lacks the black hood; head and throat gray, brownish-olive tones on the back, and an olive-yellow rump. Underparts grayish with a whitish belly. Juvenile similar to the female but browner overall, sometimes showing early dark hooding. May coexist with the Hooded Siskin (S. magellanicus) and the Andean Siskin (S. uropygialis), but is always distinguished by the extremely large bill and the white central belly. The yellow rump is distinctive in both sexes.

Geographic distribution: Andes from south-central Peru, western Bolivia, and extreme northern Chile southward into northwestern and west-central Argentina. In Argentina it is associated with high-Andean environments featuring Polylepis woodlands and high shrublands, present in Jujuy, Salta, Tucumán, Catamarca, La Rioja, and Andean areas of Mendoza. Exhibits altitudinal migration and local movements. Some southern populations move northward or descend to lower elevations during winter. Usually found between 3,000 and 4,500 m, with records from 2,000 m in more austral sectors. In Tucumán it occurs in the Cumbres Calchaquíes above 3,900 m on large rocks around high-Andean meadows.

Habitat: High-Andean shrublands of the altiplano and prepuna, high ravines, rocky slopes with sparse vegetation, and Polylepis forests. Also inhabits wet meadows, stream edges, and areas near rural outposts and high-altitude corrals. Prefers open environments associated with low montane trees.

Behavior: Actively moves through trees and shrubs. Song lower-pitched and more nasal than other siskins, with rapid twitters and short variations. Often confiding and visible along shrub edges, Polylepis stands, and rocky outcrops.

Diet: Primarily seeds and Polylepis buds, taken acrobatically among branches, often hanging upside down. Also takes seeds of shrubs and herbs, flowers, and occasionally small invertebrates. Feeds in pairs and small groups, expanding to small flocks outside the breeding season.

Reproduction: Cup-shaped nest placed in shrubs or low trees, often in Polylepis, built with wool, plant fibers, and rootlets. Clutches of three whitish eggs with brown speckles. Incubation by the female.

Conservation status: National status: Not threatened. Locally common where Polylepis occurs but vulnerable to the loss of these woodlands.

Authors of this compilation: Diego Carus and Maria Belén Dri – 06/12/2025