Mosquero occidental

Identificación

Adults have olive-gray upperparts, darker on the wings and tail, with yellowish underparts; they have a conspicuous teardrop-shaped white eye ring, white wing bars, a small bill and a short tail. It differs only subtly from most Empidonax flycatchers in North America, but its breeding habitat and call are different. Many species of this genus look closely alike. The best ways to distinguish species are by voice, by breeding habitat, and by range.<p>DNA testing in 2014 confirmed a new field mark, involving the extent of buffy edging on the secondaries, to reliably distinguish this species from the yellow-bellied flycatchers.<p>The song includes notes represented as pseet, ptsick, seet usually sung rapidly together. In Pacific birds, the ptsick or ptik note has the first syllable higher-pitched than the second—this was previously seen as the only difference between their calls and those of the "Cordilleran" flycatcher (Sibley 2000). The male's typical position call is a loud and distinctive pit pete[citation needed] or tse-seet, but some give a "rising tsweep" or a "slurred tseeweep".

Taxonomía

The western flycatcher was recognized as a single species until 1989, when the American Ornithologists’ Union split it into two different species: the Pacific-slope flycatcher (E. difficilis) of coastal western North America and parts of the western Rocky Mountains, and the Cordilleran flycatcher (E. occidentalis) of the interior Rocky Mountains, with both species wintering in Mexico. Both species looked virtually identical to one another, with the split being based on differing breeding habitats and apparent differences in songs and calls. The split was recognized until 2023, when the American Ornithologists’ Union and International Ornithological Congress again lumped both species due to a lack of consistent vocal, genetic, morphological differences and extensive hybridization across much of their range.<p>There are five subspecies recognized:<p>The latter two subspecies were previously thought to comprise the "Cordilleran flycatcher".

Nombre científico

Empidonax difficilis

Autoridad

Baird, SF, 1858

Orden

Passeriformes

Familia

Tyrannidae

Género

Empidonax

Distribución y hábitat

These birds migrate to Mexico for the winter, where the Mexican central-southern birds are resident. The non-resident birds are on the western coast from Jalisco northwards, and then to inland regions, in a corridor strip on the western flank of the Sierra Madre Occidental. The western flycatcher inhabits either coniferous or deciduous forests. In its range it enters mixed woods, Douglas fir forests, redwood forests, pine-oak forests, and many other wooded environments including riparian woodlands. As of November 2019, there has been one case of these West Coast birds showing up on the East Coast, in Palmyra, New Jersey. The preferred breeding habitat is usually near running water. They make a cup nest on a fork in a tree, usually low in a horizontal branch. Females usually lay two to five eggs.

Área de cría

NA, MA : w Canada and w USA to s Mexico

Área no reproductiva

w Mexico

Migración

Complete migrants

Conservación

Tendencia poblacional

stable