Sharp-billed Canastero

The sharp-billed canastero or lesser canastero (Asthenes pyrrholeuca) is a species of bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is found in Argentina, Bolivia, Chile, Paraguay, and Uruguay, and has also occurred as a vagrant in Brazil. == Taxonomy and systematics == The sharp-billed canastero's taxonomy is unsettled. The International Ornithological Committee (IOC) and BirdLife International's Handbook of the Birds of the World (HBW) assign it two subspecies, the nominate A. p. pyrrholeuca (Vieillot, 1817) and A. p. sordida (Lesson, 1839). The Clements taxonomy adds two more, A. p. affinis (Berlepsch, 1906) and A. p. flavogularis (Gould, 1839). The IOC and HBW consider affinis to be a seasonal morph of sordida and flavogularis to be a seasonal morph of the nominate pyrrholeuca. This article follows the two-subspecies model. == Description == The sharp-billed canastero is 14 to 15 cm (5.5 to 5.9 in) long and weighs 12 to 14 g (0.42 to 0.49 oz). It is one of the smaller canasteros, with a pointed bill that is thinner than those of most others. The sexes have the same plumage. Adults of the nominate subspecies have a gray-brown face with a paler supercilium. Their crown is dull…