Sighting Record for Utah

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
Latilong:
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
(Description:) 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 http://www.birdpop.org/docs/pubs/Heindel_and_Pyle_1999_Identifcation_of_YBFL_and_WEFL.pdf 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:	.