Traill's Complex

Willow Flycatcher
Alder Flycatcher
Song analysis of Alder/Willow Flycatchers
This is the empid most likely to be confused with Western Wood Pewee and
can be separated by its shorter, less pointed wing. Willow Flycatcher has
little or no eyering and this easily separates it from all other likely
Empidonax species except the controversial Alder Flycatcher.
Definitive Willow Flycatchers say "fitz-spew" or "ritz-beyew" or some
variation on this bi-syllabic theme. Birds making a distinct three
syllable "ritz-bee-oh" have been observed in several eastern localities in
our region (most notably Malheur NWR.) These birds have been variously
identified as Alder Flycatchers, a subspecies or variant of Willow
Flycatcher, hybrids and (God forbid) a distinct species. Alder
Flycatchers in the eastern U.S. say "Fee-bee-oh" (it's less sneezy
sounding).
Statistics presented in Pyle (1987) separate Alder and Willow Flycatchers
with about 95% certainty using a combination of wing and culmen
measurements. Willows have a shorter more rounded wing and a longer bill.
These characters are probably not reliably used in the field.
Willow Flycatcher in hand

Western Complex

Pacific-slope Flycatcher
Cordilleran Flycatcher
The split that created these two species is still hotly debated. Many in
the Pacific Northwest will tell you that the criteria used to justify this
split is equivocal, that there is overlap in habitat and call note, the
two primary characters used to separate these siblings. There are no
consistent characters (other than calls on territory) that can be used to
sort these two out. Cordilleran Flycatchers are said to to do both PSFL-
like and COFL-like position notes.  While Pacific-slope Flycatchers are
said to only do the "sweewheet" position note.  There are also subtle
differences in the song, which probably require in-field recording and
analysis to be useful for most observers.  They are effectively "Western"
Flycatchers outside their respective breeding ranges.
"Western" Flycatcher is actually pretty easy. They are yellow and green.
The eyering is elongated behind the eye forming a distinctive sideways
teardrop. This eyering is often yellowish. Presumed (by virtue of being
west of the Cascades) Pacific-slope Flycatchers in fresh plumage seem
darker and brighter. Presumed Cordilleran Flycatchers (seen east of the
Cascades) seem washed out and paler overall. This character has not been
quantitatively measured nor would it be expected to hold for individuals
in worn or basic plumage.
Pacific-slope Flycatcher in hand

Least Flycatcher
Least Flycatcher is the smallest flycatcher in our region (and you thought
it meant least likely to find.) It has a large head for its size, a short broad
bill, a short primary extension and a short tail. Its upper parts are
greenish-olive and its underparts are whitish to pale yellow. In coloration
it most closely resembles a "Western" Flycatcher and in size and shape it
resembles a Hammond's Flycatcher.
The song is an oft repeated "Che-bek." Caution should be taken here,
however, as variations on the Dusky Flycatcher call confused a large
gathering of birders (this author included) at Indian Ford Campground,
Deschutes County, OR.
Least Flycatchers have become established in small populations east of the
Cascades. The most famous of these at Clyde-Holiday State Park near John
Day, OR. Least Flycatchers have turned up intermittently in the Willamette
Valley and a winter record (in hand identification) exists for Tillamook
County, OR.

Hammond's Flycatcher
Dark gray to olive upper parts, throat pale gray, breast dusky green to
dusky yellow, often with a smudgy breast band. Small with noticeably
short tail and short, narrow bill.
Hammond's has a lower, burrier call than most other Empidonax Flycatchers.
This species is found in mature coniferous or mixed forests. It would be
more expected at high elevations, but has been recorded in appropriate
habitat to about 200ft.

Dusky Flycatcher
Dark gray to olive upper parts, throat and breast are dirty white usually
with a distinct breast band. Duskies have a long, narrow bill and a long
tail with distinctly pale outer web margins. Dusky Flycatchers are one of
the noisiest Empidonax Flycatcher (only rivaled by Pacific-slope
Flycatcher.) They always seem to be making some kind of noise, either
their song or any of several sub-songs or calls.
Dusky Flycatcher breeds east of the Cascade range in open pine or mix
pine- deciduous forests. It is a regular migrant west of the Cascades in
migration.