A small and compact swallow (13–14 cm) with a short, slightly forked tail. Upperparts glossy blackish-blue with a paler brownish-gray rump. Throat and breast smoky white grading to grayish white on the belly. Undertail coverts white. Underwing uniformly brown. Juvenile: browner above, cinnamon-washed forehead and throat, and a rufous-brown rump. Similar in shape and size to the Blue-and-white Swallow (Pygochelidon cyanoleuca), but that species shows pure white throat and belly, blue rump, and dark undertail coverts.
Geographical distribution: A high-Andean swallow distributed from south-central Peru, western Bolivia, extreme northern Chile, and northwestern Argentina (mainly Salta and Jujuy, with records in Catamarca). In Argentina it is local and scarce, associated with ravines and watercourses of the Puna and high-elevation grasslands. Common in the Abra de Santa Ana (Jujuy). Typical elevation: 3,000–4,600 m (occasionally descending to around 2,500 m in winter). Movements: high-Andean resident with possible altitudinal descents and post-breeding movements.
Habitat: High-Andean grasslands, banks along streams and rivers, bogs, wetlands, and lake edges; uses earthen banks for nesting.
Behavior: Active, with agile but not very fast flight; alternates stiff wingbeats with short glides. Common over water and over mammal herds that flush insects (vicuñas, llamas, livestock). Usually in small groups; may form larger flocks outside the breeding season. Vocalizations: short, harsh chirrs.
Diet: Insectivorous: catches flying insects, usually at low height (1–5 m) over water or open surfaces.
Breeding: Nests in caves and crevices of earthen banks, cliffs, and human structures; nests in cavities in banks or walls. May nest on cliffs shared with other Andean birds, such as the Andean Earthcreeper (U. validirostris).
Conservation status: Not threatened nationally (NA) and of Least Concern (LC) internationally, though localized and uncommon in Argentina.
Authors of this compilation: Diego Carus and Maria Belén Dri – 06/12/2025