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. == Taxonomy and systematics == The Yucatan gnatcatcher is monotypic. "The continually changing species to which albiventris has been allied gives testament to the general confusion that has afflicted the classification of most Central American Polioptila taxa." It was originally described as a full species. It was later variously considered a subspecies of tropical gnatcatcher (P. plumbea), black-capped gnatcatcher (P. nigriceps), and "white-browed" gnatcatcher (P. plumbea bilieata) during its time as a separate species. It was most recently considered a subspecies of the white-lored gnatcatcher (P. albiloris) until a 2018 molecular study showed significant differences from all other gnatcatchers. == Description == 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…