Sighting Record for Utah

Common name:	White-rumped Sandpiper
Scientific name:	Calidris fuscicollis
Date:	5/18/24
Time:	9:15 AM
Length of time observed:	10-15 minutes
Number:	1
Age:	Adult
Sex:	Unknown
Location:	Pelican Lake
County:	Uintah
Latilong:	Right about here: 40.203395, -109.679064
Elevation:	4800'
Distance to bird:	About 30'
Optical equipment:	Vortex Viper HD 10x50 binos, Nikon Z8 cameral with 180-600mm lens
Weather:	sunny
Light Conditions:	Sunny with the bird often somewhat backlit
Description: Size of bird:	Seemed a little long and slender for a peep
(Description:) Basic Shape:	Same as Baird's due to long primary projection
(Description:) Overall Pattern:	Light brown and black with some soft rufous tones
(Description:) Bill Type:	Sandpiper
(Description:) Field Marks and Identifying Characteristics:	I saw this sandpiper with a long, slender appearance and noticed that its wingtips extended beyond the tip of the tail. My initial impression was Baird's based on previous observations of that species. I had no experience with White-rumped prior to this observation. It was backlit at the time, but when I later examined images I noticed that, unlike Baird's, this one had streaking into the flanks, some fine streaking in the undertail, and lighter coloring at the base of the lower mandible. (see photos)
Song or call & method of delivery:	The bird never vocalized during my observation
Behavior:	Foraging, mostly with head down
Habitat:	Grassy edge of marsh
Similar species and how were they eliminated:	Baird's is similar. In fact, I initially considered this to be a Baird's Sandpiper. I didn't initially consider White-rumped since I had never seen one before. However, I recognized the White-rumped traits when I was able to review my images and see streaking in the flanks and undertail. A closer look revealed that the base of the lower mandible was slightly orange in appearance as well, a trait indicative of White-rumped.
Previous experience with this & similar species:	I've seen Baird's previously during migration. I've never seen a White-rumped Sandpiper.
References consulted:	Sibley Birds v2 app, AllAboutBirds.org, and UBRC archives for White-rumped Sandpiper, and finally birders having experience with the species.
Description from:	Notes taken at the time of the sighting From photo(s) taken at the time of the sighting
Observer:	Jeff Cooper
Observer's address:	Utah County
Observer's e-mail address:	**
Other observers who independently identified this bird:	I was alone and am not aware of anyone else observing this bird.
Date prepared:	5/26/24
Additional material:	Photos
Additional comments:	eBird Checklist: https://ebird.org/checklist/S175361082 nnina