The Fan-tailed Warbler (Euthlypis lachrymosa) is an New World Warbler

New World warbler

The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....

 in the monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Euthlypis that lives along the Pacific slope from northern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 to Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

. Vagrant records exist for Arizona, New Mexico and Texas. 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

Evergreen forest

An temperate evergreen forest is a forest consisting entirely or mainly of evergreen trees that retain green foliage all year round. Such forests exist in the tropics primarily as broadleaf evergreens, and in temperate and boreal latitudes primarily as coniferous evergreens.-Tropical evergreen...

 and semideciduous forest, especially near ravine

Ravine

A ravine is a landform narrower than a canyon and is often the product of streamcutting erosion. Ravines are typically classified as larger in scale than gullies, although smaller than valleys. A ravine is generally a fluvial slope landform of relatively steep sides, on the order of twenty to...

s. They eat ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s, especially army ants

Army Ants

Army Ants are a discontinued fantasy toy soldier line from Hasbro in much the same venue as the M.U.S.C.L.E. and Monster in My Pocket lines. It featured an army of humanoid 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

Basileuterus

Basileuterus is a genus of New World warblers, best represented in Central and South America. This is one of only two warbler genera that are well represented in the latter continent...

, 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.