Chestnut-throated Spinetail

The chestnut-throated spinetail is about 13 to 15 cm (5.1 to 5.9 in) long and weighs about 14 to 17 g (0.49 to 0.60 oz). Adult males of the nominate subspecies have a deep rufous-chestnut forecrown, face, and throat. Their hindcrown, nape, and back are chestnut strongly washed with olive-brown, and their rump and uppertail coverts are dark brown. Their wing coverts are mostly chestnut and their flight feathers dark fuscous. Their tail is slaty-black; it is graduated and the feathers are pointed. Their breast is deep rufous-chestnut, their belly and undertail coverts are gray tinged with olive-brown, and their flanks are slightly darker than their belly. Their iris is ivory gray to dark brown, their maxilla black, their mandible dark gray, and their legs and feet dusky olive to brownish gray. Adult females have slightly paler throat and belly than males. Juveniles have darker and more olivaceous upperparts than adults, with only a hint of rufous. Their throat is whitish with dusky tips on the feathers; their lower breast and belly feathers have faint brown edges. Their mandible is whitish. Subspecies S. c. napoensis has more rufous on its forehead than the nominate, with paler edges on the flight feathers and a darker belly. Subspecies S. c. saturata is paler overall and browner above than the nominate, with a more orange-rufous throat and breast and a paler gray belly.

The chestnut-throated spinetail has a disjunct distribution. The nominate subspecies is the most widespread of the three; it is found in the central Amazon Basin in the Brazilian states of Rondônia, Mato Grosso, Pará, and Tocantins. Subspecies S. c. napoensis is found in southern Colombia's Putumayo Department and in Ecuador's Sucumbíos and Napo provinces. Subspecies S. c. saturata is found in northern and central Peru and in northern Bolivia. The separate populations of the chestnut-throated spinetail inhabit different landscapes. In Amazonian Brazil it mostly occurs in terra firme forest, and mostly in stands of Chusquea bamboo. The disjunct populations further west occur mostly in thick vegetation in the understorey of the edges of lowland and foothill primary forest and within secondary forest, with no particular association with bamboo.

The chestnut-throated spinetail feeds on arthropods. It typically forages in pairs, usually keeping in dense vegetation, and usually within about 3 m (10 ft) of the ground. It does sometimes forage on the ground and as high as 8 m (26 ft) above it.