About Synallaxis spixi P.L.Sclater, 1856
Spix's spinetail (Synallaxis spixi P.L.Sclater, 1856) measures 16 to 17 cm (6.3 to 6.7 in) long and weighs approximately 12 to 15 g (0.42 to 0.53 oz). Males and females have identical plumage. Adults have a pale gray supercilium on an otherwise grayish brown face. Their crown is rufous, while their back, rump, and uppertail coverts are dark brown. Their lesser wing coverts are rufous, their median and greater wing coverts are dark brown with wide rufous edges, and their flight feathers are dark brown. Their dark brown tail is graduated, and the central tail feathers have pointed tips. Their throat is grayish white, and the lower throat feathers are black with grayish edges. Their breast is brownish gray, their belly is a paler shade of brownish gray, and their flanks and undertail coverts are browner than the belly. Their iris ranges from reddish brown to pale orange, their maxilla is black, their mandible is gray, and their legs and feet range from gray to greenish gray. Juveniles have a grayish brown crown, ochraceous brown underparts, and a less distinct throat patch than the nominate subspecies. Spix's spinetail is distributed from Minas Gerais and Espírito Santo in southeastern Brazil, south through eastern Paraguay and almost all of Uruguay, to Buenos Aires Province in Argentina. It lives in a wide variety of landscapes within the Atlantic Forest biome, and typically stays low in dense undergrowth. Habitats it occupies include fields and pastures, gallery forest, campo rupestres, restinga, savanna, and brushy second growth. Its elevation range extends from near sea level to 2,200 m (7,200 ft); in Brazil, its maximum recorded elevation is 2,050 m (6,700 ft).
