The Black-faced Grassquit, Tiaris bicolor, is a small bird formerly placed with the Emberizidae. It is now recognized as a tanager closely related to Darwins finches. It breeds in the West Indies except Cuba, on Tobago but not Trinidad, and along the northern coasts of Colombia and Venezuela.
This is a common bird in long grass or scrub in open or semi-open areas, including roadsides and ricefields. It makes a domed grass nest, lined with finer grasses, and placed low in a bush or on a bank. The typical clutch is two or three whitish eggs blotched with reddish brown. Both sexes build the nest and feed the young.
Adult Black-faced Grassquits are 10.2cm long and weigh 10.5g. They have a short conical black bill with an obvious curve to the culmen. The male is olive green above, paler grey-olive below, and has a black head and breast. Female and immature birds have dull olive-grey upperparts and head, and paler grey underparts becoming whiter on the belly.
Males on the South American mainland have more extensively black underparts, shading to a grey belly.
The Black-faced Grassquit feeds mainly on seeds, especially of grasses and weeds. It is often found in small groups, but is solitary at evening roosts.
The male has a display flight in which he flies for short distances, vibrating his wings and giving a buzzing dik-zeezeezee call.