Willow Flycatcher (Empidonax traillii)

Willow Flycatcher (Empidonax traillii)

[order] PASSERIFORMES | [family] Tyrannidae | [latin] Empidonax traillii | [UK] Willow Flycatcher | [FR] Moucherolle des saules | [DE] Weidentyrann | [ES] Mosquero Saucero | [NL] Wilgenfeetiran

Safely separated from the Alder Flycatcher (with which it was formerly lumped) only by voice and to some extent by breeding habitat. The eye-ring is very narrow or absent.

North America : East, Central, West

Bushes, willow thickets, brushy fields, upland copses. Breeds in thi
ckets of deciduous trees and shrubs, especially willows, or along woodland edges. Often near streams or marshes (especially in southern part of range), but may be found in drier habitats than Alder Flycatcher. Winters around clearings and second growth in
the tropics, especially near water.

Male defends nesting territory by singing (female may sing also). Courtship behavior is not well known, probably involves male actively chasing female through the trees. In some regions, Brown-headed Cowbirds often lay their eggs in nests of this species.

Nest: Site is in a deciduous shrub or tree, especially in willow, 4-
15′ above the ground. Placed in a vertical or diagonal fork of a branch, or on top of a horizontal branch. Nest (built by female alone) is an open cup of grass, strips of bark, plant fibers, l
ined with plant down and other soft materials. Nest often has strips of plant material dangling from the bottom.
Eggs: 3-4. Pale buff to whitish, with brown spots concentrated toward larger end. Incubation is by female, 12-15 days.
Young: Both parents bring food for nestlings. Age of young at first flight about 12-14 days.

Mostly insects.
Differences in diet, if any, between this species and Alder Flycatcher are not well known. Apparently eats mostly insects, including wasps, bees, winged ants, beetles, flies, caterpillars,
moths, true bugs, and others. Also eats some spiders, a few berries, and possibly some seeds.
Behavior: Forages by watching from a perch and then flying out to catch insects. Usually forages from perches within tall shrubs or low trees; catches insects in midair or takes them from foliage while hovering.

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Alaska, Canada to southwestern and east-central United States. Winters from southern Mexico to northern South America. Migration:
Migrates relatively late in spring and early in fall. In North America, migrants are seen moving north mostly during mid to late May, moving south in August and September.