| 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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