About Polioptila albiventris Lawrence, 1885
The Yucatan gnatcatcher (Polioptila albiventris Lawrence, 1885) measures 10 to 12 cm (3.9 to 4.7 inches) in length. Among measured specimens, six males weighed 5.4 to 6.2 g (0.19 to 0.22 oz), and three females weighed 5.0 to 5.7 g (0.18 to 0.20 oz). For female Yucatan gnatcatchers, upperparts from the crown to the rump are plumbeous gray. Underparts are white, sometimes with a pale grayish wash on the flanks. The central tail feathers are black, and each subsequent pair of feathers moving outward from the center is progressively more white, ending with a fully white outermost pair. Females also have a narrow white supercilium. Male basic (non-breeding) plumage is essentially identical to female plumage. Male alternate (breeding) plumage is also similar to female plumage, with the addition of a black cap that extends to the middle of the eye. The Yucatan gnatcatcher is found exclusively along the northern coast of Mexico's Yucatan Peninsula. Its primary habitat is arid coastal scrub, and it can also be found in low deciduous woodlands and coastal mangroves. Most observations of the species are within 50 km (31 mi) of the ocean, and the maximum elevation it is found at appears to be approximately 200 m (660 ft).
