Adults of the nominate subspecies have a buff supercilium with speckles at its front, blackish brown lores and ear coverts, and a whitish malar area with dark scallops.

Their belly is paler and browner than the breast and has a white center, and their flanks and undertail coverts are rich dark brown with some whitish feather tips.

Subspecies C. o. hornensis is less richly colored than the nominate, with darker gray upperparts and grayer (less brown) underparts.

Subspecies C. o. hornensis is found on Chile's Desolación Island and on Chilean and Argentine Tierra del Fuego and the Cape Horn Archipelago.

[2] The grey-flanked cinclodes inhabits open grassy and rocky landscapes, and in mountains is often found near streams.

Subspecies C. o. hornensis is partially migratory, with some individuals moving north onto the mainland after the breeding season.

[1] It is considered uncommon to fairly common and its habitat "is subject to only minimal human disturbance other than grazing".