The Fan-tailed Warbler, Euthlypis lachrymosa , is an New World Warbler in the monotypic genus Euthlypis that lives along the Pacific slope from northern Mexico to Nicaragua. There are a few unconfirmed reports of it occurring within the USA: one was reported in Big Bend National Park, Texas in August 2007. It is yellow on its throat and underparts with a tawny wash on its chest. The head is gray with a black-framed yellow crown and white around the eyes. The undertail coverlets are white. They are 5.8-6.3 in (14.5-16 cm) long and have pleasant, upslurred song. Fan-tailed Warblers live in and at the edge of evergreen and semideciduous forest, especially near ravines. They eat ants, especially army ants, and are seen hopping around on either the forest floor or close to it. They are found alone or in pairs.
The Fan-tailed Warbler is sometimes placed in the genus Basileuterus, since its nest, eggs, voice, and juvenile plumage are similar. However, no Basileuterus warbler has a tail or a tawny breast like the Fan-tailed's, so it is generally kept in the monotypic genus Euthlypis.