Small high-Andean seedeater about 12 cm long, with dull tones and a grayish conical bill. Male: short white eyebrow and very noticeable white eyering. Upperparts grayish-brown with streaked back and uniformly gray rump. Grayish chest and whitish belly, paler toward the abdomen. Wings dark brownish with pale edges. Female: browner, with pale streaks on crown, chest, and flanks; whitish belly with few to no streaks. Juvenile: similar to the female but duller. Compared with the sympatric Plumbeous Sierra Finch (G. unicolor), the Small Sierra Finch (G. plebejus) is smaller, has a distinct white eyebrow, a streaked back, and a whitish belly, whereas the Plumbeous is uniformly lead-gray, lacks eyebrow, is larger, and the female has heavily streaked chest and belly.
Geographical distribution: Andes from southern Peru, western Bolivia, northern Chile, and northwestern to west-central Argentina, reaching as far as Mendoza; also in the central sierras. In Argentina, subspecies plebejus: Jujuy, Salta, Catamarca, La Rioja, Tucumán (Aconquija and Cumbres Calchaquíes), San Juan, Mendoza, and Pampa de Achala (Córdoba and San Luis). Found between 1,800–4,500 m. Local altitudinal migration in winter.
Habitat: Typical inhabitant of Puna and high-Andean slopes, present in rocky areas, stony grasslands, scattered shrublands, and edges of wetlands. Also in ravines and rocky outcrops over high-altitude grasslands in the upper ecotone of the Yungas.
Behavior: Fairly terrestrial, walking and hopping among stones in search of seeds. Seen alone, in pairs, or small groups, often mixing with other high-Andean seedeaters. Short, low flight. Sings from shrubs or rocks, especially at dawn. Emits a very sharp, metallic and dry trill followed by “chip” notes.
Diet: Seeds and small arthropods, foraged on the ground or low vegetation. Frequently joins mixed flocks with the Olive-yellow Finch (Sicalis olivascens) and other seedeaters.
Reproduction: The nest is a simple cup made of fibers, hair, or wool, hidden in rocky crevices, among stones, or in tall grasses. Lays 2–3 bluish eggs with brown spots.
Conservation status: Not considered threatened. Common to abundant throughout its range.
Authors of this compilation: Diego Carus and Maria Belén Dri – 06/12/2025