Sighting Record for Utah

Common name:	White-rumped Sandpiper
Scientific name:	Calidris fuscicollis
Date:	5/27/2025
Time:	7:30am~
Length of time observed:	15 minutes
Number:	1
Age:	adult-alternate plumage
Sex:	?
Location:	Antelope Island Causeway
County:	Davis
Latilong:	41.088512, -112.145123
Elevation:	4200ft~
Distance to bird:	5m at closest
Optical equipment:	Nikon 10x42 Binoculars, Kowa 66mm and 88mm spotting scopes
Weather:	Sunny, clear, calm, 60F
Light Conditions:	Good, sun has just rose giving low angled golden light
Description: Size of bird:	small shorebird
(Description:) Basic Shape:	peep
(Description:) Overall Pattern:	grayish overall with pale belly
(Description:) Bill Type:	long and thin
(Description:) Field Marks and Identifying Characteristics:	We had stopped to scan for Snowy Plovers as they commonly nest in this area. Recent rains had created several new shallow ponds and puddles, which attracted several Wilson's Phalarope to the spot. We quickly found a Snowy Plover, some Phalarope and a Spotted Sandpiper then I spotted a peep nearby. Due to the gray streaking on the breast I initially thought it looked like a White-rumped, but I second guessed myself and though it was more likely a alternate plumage Western Sandpiper, but I was unsure so I got it in my window mount scope and watched it for some time. Then it passed next to a Snowy Plover and Spotted Sandpiper giving a size comparison and was larger than the Snowy and similar to the Spotted, which favored WRSA. Then I alerted the group of the possibility it was a WRSA, so we got out and got 2 larger scopes on it. I then walked down to the edge of the water within 30m of it to get better looks and photos. It alerted and called, so I played the WRSA call on the Sibley app to compare, it was a perfect match, high thin weak and sputtery. When the bird heard me play the call, it called more then flew at me and around me and landed just few feet away (unintended but fortuitous) and I was able to see the white rump and wing bars confirming White-rumped Sandpiper. Overall a larger peep (but initially alone so nothing to compare to), with a long primary projection and long but stout bill. The color was a cold gray, with some rust in the cheek, crown and back, fine streaking on the breast and flanks, a pale supercilium, black legs, the bill was long and stout with a prominent decurved on the tip, the base of the lower mandible was pinkish, belly was white. When it flew the rump was white with notable white wingbars as well, which was very distinctive (Photos)
Song or call & method of delivery:	I did hear it call several times-a weak, high thin sputtery twitter unlike most Calidris shorebirds
Behavior:	Foraging in rocky playa on the south side of the causeway near some Snowy Plovers and Wilson's Phalarope
Habitat:	Gravely playa with some short pickleweed and shallow puddles from recent rains
Similar species and how were they eliminated:	Western Sandpiper-very similar in alternate plumage with the same cold gray color with some rust in the face and back and fine streaking, but they usually have a longer, thinner bill that's all black and lack the long primary projection and are smaller, similar in size to a Snowy Plover. Always have a dark rump Baird's Sandpiper-very similar is size and structure, but are usually a warm buffy brown without the streaking on the flanks and always have a dark rump Wilson's Phalarope-probably the shorebird most often misIDed as a White-rumped Sandpiper, especially in basic plumage, because they also have a white rump, but they are larger with a longer thinner bill, and do not have a wingbar in flight. There were several nearby for direct comparison, however alternate plumage WIPH are very different in plumage and distinctive
Previous experience with this & similar species:	My 4th
References consulted:	Sibley app
Description from:	Notes taken at the time of the sighting From photo(s) taken at the time of the sighting
Observer:	Bryant Olsen
Observer's address:	84102
Observer's e-mail address:	**
Other observers who independently identified this bird:	I was leading a Great Salt Lake Audubon field trip with 7 other participants. Several others also refound and reported it later that day, see eBird
Date prepared:	5/27/25
Additional material:	Photos
Additional comments:	eBird checklist:https://ebird.org/checklist/S243602930