Pacific-slope Flycatcher

The Western Flycatcher, known scientifically as Empidonax difficilis, is a diminutive avian member of the Tyrannidae family. This insectivorous bird is adorned with olive-gray upperparts, which are darker across the wings and tail, and it boasts yellowish underparts. A distinctive teardrop-shaped white eye ring and white wing bars are notable, along with its small bill and abbreviated tail.

Identification Tips

Distinguishing this species from its congeners can be quite the challenge, as many Empidonax flycatchers bear a striking resemblance to one another. However, subtle differences do exist, particularly in the extent of buffy edging on the secondaries, a feature confirmed by DNA testing as a reliable field mark. The most reliable methods for identification are by voice, breeding habitat, and geographical range.

Habitat

The Western Flycatcher is a denizen of both coniferous and deciduous forests, with a preference for mixed woods, Douglas fir, redwood, and pine-oak forests, as well as riparian woodlands. It is often found in proximity to running water, which is a favored element in its breeding habitat.

Distribution

Breeding from the Rocky Mountains and Pacific Coast forests, this species' range extends from California to Alaska and down to central Mexico. During the winter months, the northern populations migrate southward to Mexico, where they join resident birds.

Behaviour

The Western Flycatcher is known for its hawking and gleaning feeding strategies, where it either captures flying insects mid-air or plucks them from foliage while hovering. It also partakes in the consumption of insects within swarms, such as gnats or mosquitoes. The species plays a vital role in controlling insect populations, including mosquitoes, caterpillars, and spiders.

Song & Calls

The vocal repertoire of the Western Flycatcher includes a series of notes often transcribed as pseet, ptsick, and seet, typically delivered in rapid succession. The male's position call is a loud and distinctive pit pete or tse-seet, with variations including a "rising tsweep" or a "slurred tseeweep."

Breeding

Nesting occurs near running water, where the female constructs a cup nest on a fork in a tree, usually situated low on a horizontal branch. The clutch typically consists of two to five eggs.

Similar Species

Previously, the Western Flycatcher was considered a single species with the Cordilleran Flycatcher, but they were split based on breeding habitats and vocal differences. However, due to extensive hybridization and lack of consistent differences, they have been re-lumped as one species.

Diet and Feeding

The Western Flycatcher's diet is primarily composed of flying insects, which it adeptly captures in flight. It also gleans insects from foliage and partakes in swarms of gnats or mosquitoes.

Conservation status

The IUCN Red List classifies the Western Flycatcher as Least Concern, indicating that the species does not currently face any significant threats to its survival.