Large and slender tyrant flycatcher measuring 23–26 cm. It shows a completely black, straight and relatively thin bill, without a pale base and with a slight terminal hook. Pale iris. Head and upperparts brownish-gray, dark wings with pale edges, and underparts ranging from dirty white to ochraceous depending on subspecies. Its most distinctive feature is the mostly white tail, with the central pair of rectrices dark and the rest white. Juveniles have dark eyes and a yellowish base to the lower mandible.
Subspecies: Montanus (NW Argentina): smaller and notably paler, lacking cinnamon tones on the belly and often showing faint streaking on throat and neck. Maritimus (Cuyo, Patagonia, Central Sierras, Ventania): larger and darker, with cinnamon wash on belly and flanks, and slightly more black at the base of tail feathers.
Similar species: Differs from the rare Andean Gaucho (A. albicauda) by its completely black and slimmer bill and pale iris, whereas the Andean species has a thick, pale-based bill and dark eyes. Both share similar tail patterns. It also differs from the Common Gaucho (A. micropterus) and the Large Gaucho (A. lividus), which both have dark tails and more robust, bicolored bills.
Geographic distribution: The most widespread Agriornis, occurring from Colombia and Ecuador along the entire Andean chain southward through Peru, Bolivia, Chile and Argentina to Patagonia. In Argentina it is found in the NW, Cuyo, Patagonia and even Sierra de la Ventana in Buenos Aires province. Occupies a wide altitudinal range, from sea level to 4300–4500 m depending on the region. Southern populations move to temperate areas or toward Cuyo and Córdoba in winter. In the NW it is partially resident, making short movements linked to prey availability.
Habitat: Shrubby steppes, rocky hills, dry prepuna and stony slopes, as well as edges of high Andean grasslands and montane scrub. Common in areas with rocks, boulders and isolated structures used as perches. May occur in mountain towns, old buildings, antennas and fences.
Behavior: A very confiding bird that perches in exposed places and uses elevated lookout posts from which it scans and hunts. Moves with broad undulating flights, alternating glides with brief hovering pauses. Captures prey in flight or by dropping from a perch, and can walk on the ground while pursuing prey. Usually solitary or in pairs, defending large territories. Emits an ascending–then–descending whistle, especially at dawn from high perches.
Diet: Opportunistic hunter of large insects, spiders, small mammals, lizards, frogs, nestlings of other birds and occasionally eggs or seeds. Hunts from perches or by short gliding flights. May travel long distances among rocks while stalking. Diet varies with region and elevation but always includes small vertebrates.
Reproduction: Nests in rock crevices, low shrubs, cuts in cliffs or even isolated mountain structures. Nest is a large, loosely built cup of dry sticks lined with wool or fibers. Clutch usually consists of 2–3 eggs.
Conservation status: Species not considered threatened. It is the most common and widely distributed gaucho, though generally found in low densities due to its large territories.
Authors of this compilation: Diego Carus and Maria Belén Dri – 06/12/2025