Sighting Record for Utah

Common name:	Vega Gull
Scientific name:	Larus vegae
Date:	2/6/2022
Time:	12pm~
Length of time observed:	10 minutes
Number:	1
Age:	1st cycle
Sex:	?
Location:	Farmington Bay WMA
County:	Davis
Latilong:	40.926007, -111.946802
Elevation:	4200ft~
Distance to bird:	80m at closest
Optical equipment:	Nikon 10x42 Binoculars, Kowa 88mm spotting scope
Weather:	Sunny, cool
Light Conditions:	Good, bright sunny day but bird was in excellent light
Description: Size of bird:	large gull
(Description:) Basic Shape:	gull like
(Description:) Overall Pattern:	mostly pale gray
(Description:) Bill Type:	piscivore
(Description:) Field Marks and Identifying Characteristics:	Since the Herring Gull complex was split in the 66th AOS supplement, Vega Gull should now be a review species in Utah. Initially spotted a gull in flight and was struck by the rump and tail pattern, watched as it flew then landed on the mudflats. I pointed out the gull to Max and said, "get photos of that thing". A 1sts cycle immature gull, rather large, overall the body was quite pale, mostly whitish feather bases with darker gray feather tips, palest on the head. This contrasts with the black outer primaries and tertials. The rump and upper tail coverts were strikingly white, contrasting with a dark black terminal tail band. Bill was large and pink based, legs were pink. After observing the gull in the field and getting as many photos as possible, I began to ponder the ID. I know that Vega(which was considered a subspecies of Herring at that time) often show a distinctive band in the tail, and was why the gull drew my attention. But beyond that I wasn't sure of the full range of variation the Herring complex. I consulted many online resources, including image searches of the Macaulay Library, as well the "Gull Research Organization" website. I then sent photos to Cameron Cox, who is very experience with gulls and used to guide in Alaska, to get his take on it, and he agreed it look like a Vega. I then sent it to Amar Ayyash, author of 'The Gull Guide' and often considered the leading expert on North American Gulls. Here is his comment: "I have no doubt this bird wouldn't be called anything but Vega if it was in Asia. For me, it suffices to say that is what a Vega looks like. The paler underparts, thin anchors on the 2nd gen scaps, white uppertail coverts, checkered greater coverts panel, notched tertial tips, large broad-leaf centers to the lower juvenile scaps and pale/dark pattern to the subterminal tips of the inner primaries should all collectively point away from smithsonianus." (see photos)
Song or call & method of delivery:	Non-heard
Behavior:	Initially seen in flight, then landed in the mud flats and fed on dead fish
Habitat:	Freshwater marsh complex
Similar species and how were they eliminated:	American Herring Gull-1st cycle American Herring are highly variable and have a complex molt cycle but generally are darker in 1st cycle plumage, often very dark gray brown plumage, lacking the white feather bases. Should have a uniform dark rump and solid dark tail, lacking the white rump and tail band of Vega. Glaucous, Glaucous-Winged, Glaucous-Wing x Herring, Glaucous-Wing X Western & Iceland-should all have paler primaries and tertials Lesser Black-backed Gulls-smaller and usually have an all dark bill in 1st cycle. Have a similar tail pattern, but should have all black flight feathers lacking the pale window in the inner primaries. Great Black-backed Gull-also show a similar rump and tail pattern but should have solid dark flight feathers lacking the pale window in the inner primaries, much larger Slaty-Backed Gull-an enigma in 1st cycle, but generally look very pale and washed out looking, most show an all dark bill and uniform colored rump and tail. Western Gull-generally much darker, sooty brownish, bigger bill and solid dark tail California-have a solid dark tail and a boldly bi-colored bill, smaller Ring-billed Gull-much smaller and bold bicolored bill, more advanced plumage by that date.
Previous experience with this & similar species:	I had seen many Vega Gulls in Nome Alaska the previous year in Aug. 2021, of all age classes: many adults, 2nd and 3rd cycles, and at least 1 1st cycle.
References consulted:	Macaulay Library
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:	Address: 84102
Observer's e-mail address:	**
Other observers who independently identified this bird:	Max Malmquist was with me
Date prepared:	2/9/26
Additional material:	Photos
Additional comments:	eBird checklist: https://ebird.org/checklist/S102161066