Description: Hummingbird of high Andean and Puna environments, about 13 cm in length, with overall brown and white tones. Male: upperparts grayish-brown with a slight greenish sheen. Small white postocular spot. Throat bright emerald green, strongly iridescent, bordered below by a black band. Underparts mostly white. Shows a relatively narrow longitudinal rufous-brown or ochraceous band on the belly (may appear darker depending on light). Tail white, with central pair and outer edges of lateral rectrices bronzy-black. Female: grayish-brown back. Throat white to grayish with spotting sometimes forming lines. Underparts whitish with grayish tinge. Tail dark with 3–4 outer feathers showing white base and tip; ventrally white only at base and tip. Juvenile: duller, more grayish; base of mandible yellowish. Very similar to the Andean Hillstar (O. leucopleurus), with which it may locally overlap in NW Argentina. Male Andean Hillstar shows a broader, bluish belly band; females are nearly identical but tail pattern differs (more lateral white in Andean), and the Puna species has denser throat spotting. Outer tail feathers are broader than in the Andean. Both species may coexist in some areas and times of year, especially when descending in altitude during winter; isolated cases of hybridization have been reported.
Distribution: High Andes from southwestern Peru and western Bolivia to northern Chile and northwestern Argentina. In Argentina (O. e. estella): Jujuy, Salta, Tucumán, and Catamarca, mainly in Puna and Prepuna. Very localized populations in La Rioja. Largely resident within its range, with altitudinal movements in winter toward lower areas and adjacent valleys.
Habitat: Rocky valleys, arid slopes, and grasslands of Puna and Prepuna, generally between 2,400 and 5,000 m a.s.l. (most common between 3,500–4,500 m). Frequent near rocky outcrops, watercourses, stands of Puya, flowering shrubs, and edges of Polylepis woodlands. Also occurs in human constructions in Andean villages. During breeding, sexes may segregate: females territorial in shrubby ravines; males roam more widely across open grasslands.
Behavior: Usually solitary or in pairs. Territorial and aggressive toward other hummingbirds. Feeds both in flight and while perched, often clinging to flowers rather than prolonged hovering (pers. obs.). Uses exposed perches (branches, fences, rocks, structures). In austral winter may disperse to lower valleys; remains at high elevations even during brief snowfalls. Rests in torpor attached to vertical rock surfaces, caves, or deep crevices. Call a short, repeated “tsip.” During chases emits a sharp, rapid trill. During displays, males puff up throat feathers (pers. obs.).
Diet: Mainly nectar from high Andean shrubs and cacti (e.g., Chuquiraga, Barnadesia, Berberis, Buddleja, Ribes, Puya, Caiophora, Ligaria, cushion cacti). Supplements diet with arthropods captured from vegetation or in flight.
Breeding: Large, woolly cup-shaped nest (up to 7 cm wide and 8 cm deep), built by the female using plant fibers and wool (often from camelids), attached to corners of rock walls, banks, or under natural overhangs and structures. Occasionally beneath Puya leaves. Clutch of 2 eggs.
Conservation status: Not threatened at national or global level. A common species in suitable habitats.

Author of this compilation: Diego Carus y María Belén Dri – 03/04/2026