Verification of Unusual Sight Record
For Utah

Rec. # 2016-33

Common name:

Yellow-bellied Flycatcher

Scientific name: Empidonax flaviventris
Date: 09-13-2016
Time: 3:00pmish
Length of time observed: 5 minutes
Number: 1
Age: adult
Sex: ?
Location: [International Center, Salt Lake City]
County: Salt Lake
Elevation: 4250ft
Distance to bird: 3m
Optical equipment: Vortex 8.5 X 32 Binoculars, Canon SX50 hs Digital Camera
Weather: Sunny, breezy, 80F
Light Conditions: Good
Description:        Size of bird: 5.5in
(Description:)       Basic Shape: typical Empidonax
(Description:)  Overall Pattern: overall olive yellow
(Description:)            Bill Type: Short, bi-colored
Field Marks and
Identifying Characteristics:
 I got a call from Matt Pendleton that he had a weird Empid at the International Center that he couldn't figure out. So I went to check it out and see if I could relocate it. Sure enough, there was an empid in the exact location he described, and photos show it was the same bird as his. At first I could not figure this thing out (I will go over the process of elimination I went through in similar species). I sought the help of some other birders-Mark Stackhouse and David Wheeler, and 'Western' Flycatcher was suggested as a possibility, but it seemed off for that taxon to me, especially the white throat and eyering, so I then pulled up an article on telling Western's from Yellow-bellied, and bingo, I had a match (Western's and Yellow-bellied are each others closest relatives, and along with the Yellowish Flycatcher of Central America, form a clade within Empidonax, BNA). What was a particular match were:

The Primary Formula-tiny gap between P8 and P7, long gap between P7 and P6, another long gap between P6 and P5(double long gap unique to YBFL), unlike 'Western which has a longer, but still short gap between P8 and P7, and single long gap between P7 and P6, and a short gap between P6 and P5, see pg.#84 , compare with photos

The eyering was very round and complete, lacking the long extension of a 'Western'.

The tertials were very high contrast blackish with white edging, unlike the brownish tertials of a 'Western'.

The whitish throat, which is seen in worn YBFL, but lacking in 'Western'
(see photos)
Song or call & method of delivery: None heard
Behavior: Fly catching from low perches under pines
Habitat: Cultivated landscape of planted trees and lawn, known migrant trap
Similar species and how
were they eliminated:
Process of elimination which lead to YBFL:

Hammond's-has a short mostly dark bill and grayish throat

Dusky-has a gray throat, duller brownish color, shorter primary projection and dusky tip to lower mandible

Gray-Uniform dull gray, long bill with dusky tip to lower mandible, long tail that is pumped up and down

Willow-Duller brown color, less prominent of an eyering

Alder-originally considered as a candidate, but this bird has a crest, unlike Alder, and a more prominent eyering, and Alder are duller colored.

Least-Shorter primary projection, brighter white high contrast throat

Acadian-highly unlikely, duller colors, lack of crest, longer bill and primary projection

Pacific-slope/Cordilleran("Western")-Most difficult to eliminate, but usually have a darker yellowish throat, a longer eyering extension to the rear, duller brownish tertials, and a different primary formula. One thing that gave us trouble was the prominent crest in one of Matt's photos, which is better for 'Western' than YBFL, however a search of photos on Macaulay Library showed that YBFL can show a very prominent crest when excited, and it is within variation of YBFL.
Previous experience with
this & similar species:
Yes, I've seen a few of these things during fall migration, have yet to get one accepted, but they say 3rd times the charm!? What can I say, empids are difficult birds.
References consulted: Macaulay Library, Birds of North America online. 'Identification of Yellow-bellied and "Western" Flycatchers' Pyle and Heindel(online article)
Description from: From photo(s) taken at the time of the sighting
Observer: Bryant Olsen
Observer's address: 688 East 700 South #105, SLC, UT 84102
Observer's e-mail address: **
Other observers who independently identified this bird: Matt Pendleton
Date prepared: 09-20-2016
Additional material: Photos
Additional comments: .