White-tailed Shrike-Tyrant

The white-tailed shrike-tyrant is 25 to 28 cm (9.8 to 11 in) long. The sexes have the same plumage. The two subspecies are practically indistinguishable though A. a. pollens may be slightly larger than the nominate. Adults have a dark gray-brown crown, a narrow buff supercilium, and a streaked face. Their upperparts are dark gray-brown. Their wings are mostly dark gray-brown with paler edges on the flight feathers. Their underwing coverts are cinnamon-buff. Their central tail feathers are dark gray-brown and the rest are white with small dark marks at their tips. Their throat is white with blackish streaks, their upper breast and sides gray-brown, and their lower breast, belly, and vent whitish with a buff tinge. Both sexes have a brown to dark brown iris, a thick hooked bill with a black maxilla and a yellowish mandible, and black legs and feet.

The white-tailed shrike-tyrant has a disjunct distribution. Subspecies A. a. pollens is the more northerly of the two. It is found intermittently in the Andes of Ecuador. The nominate subspecies is found in the Andes of Peru from Piura Department to Pasco Department and then from southern Cuzco Department south through western Bolivia into the eastern parts of northern Chile's Tarapacá and Antofagasta regions. A separate population of it is in northwestern Argentina's Tucumán Province and perhaps a bit beyond. The white-tailed shrike-tyrant inhabits a variety of high elevation open landscapes. These include temperate zone shrubby grasslands, páramo, puna grassland, and montane scrublands. It favors areas with shrubs, rocks and boulder, or rocky slopes and cliffs. It also occurs around isolated and abandoned human structures, in Polylepis woodlands, and in Ecuador in farmland with introduced Eucalyptus trees. In elevation it ranges between 2,400 and 3,100 m (7,900 and 10,200 ft) in Ecuador and between 2,400 and 4,300 m (7,900 and 14,100 ft) in Peru. It ranges between 4,200 and 4,600 m (13,800 and 15,100 ft) in Chile; it is known only above 3,100 m (10,200 ft) in Argentina and its elevational range in Bolivia is unknown.

The white-tailed shrike-tyrant's diet has not been fully defined but it is known to feed on insects, small mammals, and small lizards. Other members of genus Agriornis feed on those items and other arthropods, small amphibians, and bird eggs and nestlings as well. It typically forages singly or in pairs and captures prey by dropping on it from a perch and in mid-air by "hawking".