Yucatan gnatcatcher

The Yucatan gnatcatcher (Polioptila albiventris) is a species of bird in the family Polioptilidae. It is endemic to the Yucatán Peninsula in Mexico.

The Yucatan gnatcatcher is 10 to 12 cm (3.9 to 4.7 in) long. Six males weighed 5.4 to 6.2 g (0.19 to 0.22 oz) and three females 5.0 to 5.7 g (0.18 to 0.20 oz). The female's upperparts are plumbeous gray from the crown to the rump. Its underparts are white with sometimes a pale grayish wash on the flanks. The tail's central feathers are black and each pair out from them are progressively more white until the all white outermost pair. It has a narrow white supercilium. The male's basic (non-breeding) plumage is essentially the same. Its alternate (breeding) plumage is also similar with the addition of a black cap that extends to the middle of its eye.