The Black-whiskered Vireo, Vireo altiloquus, is a small passerine bird, which breeds in southern Florida, USA, and the West Indies as far south as the offshore islands of Venezuela. It is a partial migrant, with northern birds wintering from the Greater Antilles to northern South America. This species has occurred as a rare vagrant to Costa Rica.
The breeding habitat is open deciduous wooded areas and cultivation, and in Florida also mangroves. The Black-whiskered Vireo builds a cup nest in a fork of a tree branch, and lays 2-3 white eggs.
This vireo is 14"?15 cm in length, has a 25 cm wingspan and weighs 17"?19 g. It has thick blue-grey legs and a stout bill.
The adult Black-whiskered Vireo has dull olive-green upperparts and white underparts, with yellowish on the flanks and under the tail. It has red eyes and a grey-brown crown with faint dusky edges. There is a dark line through the eyes and a white eyebrow stripe. There is a distinctive black line (the "whisker"?) on the neck sides. Juvenile birds are similar, but have brown-red eyes.
This species is similar to Red-eyed Vireo, but is duller and browner above, and is best distinguished by the black whisker mark. The song is a three-syllable whip, Tom Kelly, more abrupt than that of Red-eyed Vireo.
The Florida race V. a. barbatulus is shorter-billed by 15% than the northern Caribbean subspecies V. a. bonairensis. The latter form has occurred in the USA as a vagrant to Florida and Louisiana.
The Black-whiskered Vireo gleans insects from tree foliage, sometimes hovering while foraging. It will also eat small quantities of berries
This bird suffers from nest parasitism by the Brown-headed Cowbird in its US range, and Shiny Cowbird further south.