Red-shouldered Spinetail

The red-shouldered spinetail is 18 to 19 cm (7.1 to 7.5 in) long and weighs 25 to 26 g (0.88 to 0.92 oz). The sexes are thought to have the same plumage. Adults have uniform fuscous brown face, crown, back, rump, and uppertail coverts. Their wing coverts are dull chestnut and their flight feathers brownish gray. Their tail is blackish; it is long and the feathers have blunt tips. Their chin and throat are black. The rest of their underparts are brownish gray with a buffier center to the belly. Their iris is orange to rufescent, their bill black to blackish brown, and their legs and feet gray. Voice: The red-shouldered spinetail's song is "a loud, fast, accelerating series that fades towards end...usually introduced with 1–4 quiet, widely spaced dry notes". Pairs exchange "tre-tré" or "tchí-krr" calls while foraging. The species' alarm call is a "high, shrill 'quebéc' ".