Adults are 11–13 cm long and weigh about 12 g. The subspecies vary greatly, with upperparts ranging from dull greyish-brown to rich rufescent-brown, and the underparts ranging from brown, over buff and pale grey, to pure white. All subspecies have blackish barring to the wings and tail, and some also to the flanks. All subspecies show a faint eye-ring and eyebrow and have a long, thin bill with a blackish upper mandible, and a black-tipped yellowish or pale grey lower mandible. The legs are pinkish or grey. The short tail is typically held cocked.
This bird's rich bubbly song is commonly heard during the nesting season but rarely afterwards. There is marked geographical variation in its song, though somewhat more gradual than in the birds' outward appearance which can strikingly differ e.g. on neighboring islands in the Caribbean. Birds from far north and south of the species' range nonetheless have songs that differ markedly.