|Species: Willow Flycatcher
Flycatcher is the most peweelike Empidonax flycatcher.
This species is usually indistinguishable from Alder Flycatcher
except by voice. The typical song is a snappy FITZ-bew.
Formerly considered conspecific with the Alder, the 2 together were
referred to as Traill’s Flycatcher until 1973, when they were
recognized as separate species. Like most members of the genus
Empidonax, this flycatcher is difficult to identify in the field
without vocal, habitat and geographical reference.
The Willow breeds from Maine to British Columbia and as far south as
southern Arizona and southern California. It winters from southern
Mexico to northern South America.
General: One of the
largest Empidonax, with relatively flat forehead and distinct peak
on rear crown; long, broad bill; moderate primary projection; and
broad, straight-sided tail. 13.3-17.0 cm length. 11.3-16.4 g weight.
Adult Male: White
throat contrasts with diffuse, dull olive to brownish breast band;
bill wide and moderately long for Empidonax, entirely dull
yellow-orange or pinkish on lower mandible and blackish on upper
mandible; whitish-gray wing-bars with anterior wing-bars often
darker and duller than posterior. Upper parts drab olive, becoming
brownish gray with wear; crown often darker. Underparts light gray,
washed with yellowish on the belly; indistinct (sometimes lacking),
Sexes alike in appearance.
Wood-pewees generally similar in plumage colour and pattern but
slightly larger, with longer wings that extend farther down tail,
longer primary extension, more notice-ably peaked nape and crest,
and different behaviour of habitually returning to prominent perch
(more so than Empidonax) and quivering wings but not flicking tail,
unlike Willow Flycatcher.
The Willow Flycatcher is primarily an aerial forager, capturing most
of its insect diet on the wing, but it may hover-glean extensively
from leaf surfaces or occasionally take insects from the ground.
Found in brushy habitats in wet areas; also in pastures; also edges
of mountain meadows. Shrubbery along watercourses and willow covered
Flycatcher is a common migratory species and the most widely
distributed North American Empidonax. This species was given its
name in 1831 by J.J Audubon for his friend Dr. Thomas Stewart Traill
The nest is a firm thick-walled cup of plant fibers lined with plant
down and cottony fibers, placed in an upright crotch of a shrub
2-6ft high. 3-4, whitish with darker marked eggs.
Because the Willow
Flycatcher is restricted to river corridors (at least in the arid
parts of the West), it is vulnerable to a variety of human
activities that may alter or degrade such habitats, activities
including river dewatering, channelization, overgrazing, dam
construction, and urbanization. Breeding Bird Survey data show this
species decreasing in number in the North American continent during
the period 1966-1996.
Common in high numbers and a breeding bird at Colony Farm,
Willow Flycatchers are present in the park from May through
October. Capture rates (2010-2012; standardized as birds
captured per 100 net hours) peak however in August
corresponding to juvenile dispersal. This flycatcher
migrates south for the winter as indicated by zero capture
rates from November through April.