American Dusky Flycatcher (Empidonax oberholseri)

American Dusky Flycatcher

American Dusky Flycatcher (Empidonax oberholseri)

[order] PASSERIFORMES | [family] Tyrannidae | [latin] Empidonax oberholseri | [UK] American Dusky Flycatcher | [FR] Moucherolle sombre | [DE] Buschtyrann | [ES] Mosquero Oscuro | [NL] Struikfeetiran

Subspecies

Monotypic species

Physical charateristics

Very similar to Hammond’s Flycatcher (gray throat, etc.), but identified by habitat, voice, white outer tail feathers.

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Range

North America : Westcentral

Habitat

Breeds in mountain chaparral (Canadian-zone brush) with scattering of trees. Favored habitat includes both trees and low bushes: varies
from open conifer forest with understory of deciduous shrubs to brushy slopes with a few taller trees. In migration, often in foothills. Winters in streamside woods in Southwest, or in a variety of semi-open habitats in Mexico.

Reproduction

Male defends nesting territory by singing from prominent perch; occasionally performs short flight-song display. In courtship, both sexes hop about in branches, fluttering wings.
Nest: Site is usually in deciduous shrub, less often in conifer; usually 3-6′ above ground, rarely up to 16′. Placed in vertical fork among den
se foliage. Nest (probably built by female only) is cup of grasses, weeds, shreds of bark, lined with plant down, feathers, animal hair, and other soft materials.
Eggs: 4, sometimes 2-3, rarely 5. Smaller clutches may be laid on second attempts if first nesting fails. Eggs dull white, rarely dotted with brown. Incubation is by female only, usually 15-16 days.
Young: Brooded by female, fed by both parents. Young leave the nest about 15-20 days after hatching, may be fed by parents for another 3 weeks. 1 brood per year.

Feeding habits

Insects.
Diet not known in detail, but so far as is known feeds entirely on insects, including moths, bees, wasps, grasshoppers, damselflies, caterpillars, butterflies, and undoubtedly others, probably all of rather small size.
Behavior: Forages by watching from an exposed perch (often on a dead branch), then flying out to capture insects, usually in the air. Sometimes drops to ground or hovers next to foliage or bark to capture insects there.

Conservation

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.
American Dusky Flycatcher status Least Concern

Migration

Western Canada, western United States. Winters in Mexico.
b Migration: Arrives on breeding grounds mostly in May, departs mostly in August. Evidently migrates at night.

Distribution map

American Dusky Flycatcher distribution range map

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