Sighting Record for Utah

Common name:	Long-tailed Jaeger
Scientific name:	Stercorarius longicaudus
Date:	9/4/2023
Time:	12:15pm, again at 3pm
Length of time observed:	20 Minutes, later 15
Number:	1
Age:	immature
Sex:	?
Location:	Antelope Island Causeway
County:	Davis
Latilong:	41.076524, -112.197968
Elevation:	4,200ft~
Distance to bird:	300-500m
Optical equipment:	Kowa 66mm Spotting Scope
Weather:	Overcast, 60F, 10mph northwest wind.
Light Conditions:	Good, flat light and no heat shimmer
Description: Size of bird:	smaller than gulls nearby
(Description:) Basic Shape:	gull like
(Description:) Overall Pattern:	uniform medium brown
(Description:) Bill Type:	small
(Description:) Field Marks and Identifying Characteristics:	"Immature intermediate morph, uniform medium cold brown, no rufous tones, darker cap & paler nape, short small bill paler at base(nail not seen due to distance), big headed cute look, paler belly, barred black and white undertail coverts, underwing mottled brown with white barring, longish tail with short R1 & R2 tail plumes(shape not seen due to distance), white primary bases only on P8 & P9 in flight on upperside in flight, short primary projection past tail when perched, very small and petite, smaller than surroundings ducks and stilts. Observed flying 3 times, got up and fluttered on wind like a tern and would drop back on the water. Flight buoyant, once flew 100m, did not chase birds and only a few ducks got up and flew around. Observed in scope for 20 minutes initially, then on the way out relocated and watched again for 15 minutes. Very distant, 400m to south initially on mudflat with gulls, flew into water and started preening a bit closer. Observed in flight in the scope as well. farther out on return view. Overall GISS of Long-tailed." From notes taken during sighting. Due to distance of the bird I knew photos wouldn't necessarily clinch the ID, so I studied it extensively in the field through the scope looking for the defining characteristics to make the ID. (see photos)
Song or call & method of delivery:	None heard
Behavior:	mostly seen loafing and preening on water and mudflats, briefly flew short distances on 3 occasions
Habitat:	Shallow water and mudflats of Farmington Bay, brackish to fresh water
Similar species and how were they eliminated:	Pomarine Jaeger juvenile-Larger and bulkier with pot belly, broad wings and short tail, long primary projection past tail when perched, "double flash" in underwings, longer bill with large hooked tip, mean and manacling looking. Often harass nearby birds in flight. Typically shows at least 5 white primary shafts on upper wing making a white crescent at the base of the primaries that was lacking on this Jaeger Parasitic juvenile-usually much warmer rusty brown lacking white edging on underwing and barred black and white undertail coverts. . Generally bulkier and a more direct less buoyant flight, often harassing other birds. Long primary projection past tail when perched Typically shows at least 4 white primary shafts on upper wing making a white crescent at the base of the primaries that was lacking on this Jaeger
Previous experience with this & similar species:	My 5th Long-tailed in Utah, I've also seen many in Alaska and 1 at sea. I've also seen many Parasitic and Pomarine both in Utah, at sea and in the Arctic, adults and immatures
References consulted:	Memory
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:	None that I know of
Date prepared:	9/4/23
Additional material:	Photos
Additional comments:	eBird checklist: https://ebird.org/checklist/S149015768