Verification of Unusual Sight Record
For Utah

Rec. # 2015-18

Common name:

Pacific-slope Flycatcher

Scientific name: Empidonax difficilis
Date: 5/24/15
Time: 10:24 am
Length of time observed: 10 minutes
Number: 1
Location: Lytle Ranch
County: Washington
Latilong:  (37.0933, -113.9493)
Elevation: 1100 m
Distance to bird: 10 feet
Optical equipment: Pentax ED 8x43
Weather: Partially Cloudy
Light Conditions: Decent, not too harsh light.
Description:        Size of bird: Typical empid sized
(Description:)       Basic Shape: Flycatcher
(Description:)  Overall Pattern: Yellowish with darker olive back
(Description:)            Bill Type: Broad and flat
Field Marks and
Identifying Characteristics:
It has been long suspected that the Western Flycatchers migrating through southwestern Utah are Pacific-slope rather than the regular Utah breeder, Cordilleran Flycatcher. Migrants in lowland desert migrant traps in nearby Arizona and Nevada are considered to be Pacific-slope which seem to prefer to migrate in lowlands. Cordilleran Flycatchers on the other hand seem to favor migration routes through the mountains.

Nate Brown and I found this bird south of the first pond north of the ranch. It looked like a typical Western with a yellowish overall coloration with a yellowish throat, all yellow under the bill, pointed eyering and a raggedy crest.

The bird was initially silent so we tried to get it to call to record the voice as this is the best way to tell apart these species. Upon playing a Pacific-slope Flycatcher song, the bird responded for the first of two times. I got a recording of this call and uploaded it to xeno-canto:

The call from the bird is the upward slurred whistle. The other call note, the explosive ptik, is the 3rd part of the Pacific-slope Flycatcher song. The whistle matches the slurred up call of a Pacific-slope Flycatcher rather than the two parted Cordilleran call note. The sonogram image also better matches the sonogram of Pacific-slope which dips down in pitch before continuing rising rather than Cordilleran which tends to be two parted.

Here are a look at the sonograms:

My bird:

Western Washington PSFL 1:
Western Washington PSFL 2:
Vancouver PSFL:

Prescott, AZ COFL:
Colorado COFL 1:
Colorado COFL 2:
Song or call & method of delivery: Slurred upward one note whistle characteristic of Pacific-slope Flycatcher
Behavior: Typical flycatching. Excited responded to Pacific-slope Flycatcher song and called upon hearing it.
Habitat: Desert Riparian.
Similar species and how
were they eliminated:
The only other species to consider is Cordilleran Flycatcher which looks almost exactly the same. The best way to identify Western Flycatchers to species is through their songs and calls and this call matches a Pacific-slope call as shown in the sonograms above.
Previous experience with
this & similar species:
I have heard Pacific-slope Flycatchers in Seattle and have a decent amount of experience with Cordilleran flycatchers on breeding habitat in Nevada and Utah.
References consulted: Xeno-canto, Sibleys.
Description from: From photo(s) taken at the time of the sighting
Observer: Kenny Frisch
Observer's address: 4609 S Wallace Ln Holladay, UT
Observer's e-mail address: **
Other observers who independently identified this bird: Nate Brown
Date prepared: 5/28/15
Additional material: Photos   Audio recording.  Sonogram