Vancouver Avian Research Centre

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Species: Dusky Flycatcher Empidonax oberholseri

Description:

The Dusky Flycatcher, a common breeding species throughout much of mountainous western North America small but not as compact as Hammond’s: longer tail, shorter winged, longer-billed; rounded head.

Identification:

General: Small Empid with white eye-ring and short primary projection. 15cm long 10.3 g weight.

Adult Male: Adult sexes alike. Olive-gray under-parts with yellowish belly and undertail coverts, two pale white wing-bars on dark wings; lower mandible mostly dark; breast has olive wash; whitish throat, belly and undertail coverts sometimes with yellowish wash

Narrow, usually mostly dark bill; short wings; rather long, narrow, square or notched tail; rounded head.

Juvenile: July-February short primary projection; low-contrast edges on wing feathers

Similar Species: Hammond’s Flycatcher (Empidonax hammondii)

Behavior: Like most flycatchers perches on prominent dead branches and twigs where it forages by sallying back and forth after flying insects or occasionally pouncing on prey on the ground.

Nest: In crotch of juniper or sage, near base of thorny shrub, of weed stems, grass, lined with feathers, grass, hair. Female believed to build nest.

Eggs: Creamy white, unmarked. 0.7" (18 mm).

Chick Development: Female incubates. Incubation takes 12-15 days. Development is altricial (immobile, downless, eyes closed, fed). Young leave the nest after 18 days. Both sexes tend young.

Diet: Exclusively insects.

Habitat: Inhabits open coniferous forest, mountain chaparral, aspen groves, streamside willow thickets and brushy open areas. This species typically nests in deciduous trees and shrubs within a few meters of the ground, weaving its nest of plant fibers and animal hair into an upright crotch. Only females incubate, but they are often fed by their mates; both adults feed young, which fledge in about 18 days. Although little is known about the Dusky’s diet, its foraging tactics have been well-studied. Primarily an aerial forager—a sit-and-wait predator—it sallies forth after flying insects or occasionally pounces on prey on the ground.

Information:

Like other small temperate-zone flycatchers, the Dusky appears to be particularly vulnerable to bad weather. Severe spring rain and snow may kill entire local breeding populations. Likewise weather may account for a significant percentage of total nest failures, equal in many years to what is taken by predators. Nevertheless, survey data suggest that this species is at least holding its own, if not growing in numbers, in most regions where it nests. The Dusky may benefit from forestry practices that thin dense coniferous stands or leave small openings.

Conservation Status:

The Dusky Flycatcher is common and increasing and its conservation status is listed as least concern (LC).
 
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