The Dark-breasted Spinetail is common from the lower tropical zone to 1,800m, ranging from the east slope of the Andes and into Amazonian Brazil. It is often found foraging secretively in reedy habitats near stream edges, or on river islands in shrubby habitats or woodland edges. Generally dark gray, the Dark-breasted Spinetail has rufous wing coverts and a rufous crown, from forehead to nape. It has a whitish throat and a narrow black bib between the throat and breast, but during displays, it raises its throat feathers making them appear black. The gray breast fades to a whitish belly and buff vent, and it has a relatively short, olive tail. The subspecies S. a. rodolphei is found in the northwestern corner of the species’ range, and is generally darker than the nominate race.