Sighting Record for Utah

Common name:	Long-tailed Jaeger
Scientific name:	Stercorarius longicaudus
Date:	11 August 2023
Time:	0730
Length of time observed:	3 hours
Number:	1
Age:	Adult
Sex:	Unknown
Location:	Quichapa Lake, North end
County:	Iron
Latilong:	37.652161, -113.198734
Elevation:	5453 ft
Distance to bird:	150-200 yards
Optical equipment:	Vortex Viper 12x50 binoculars, Pentax PF-65 ED spotting scope with BST 1.25" eyepiece
Weather:	Mostly sunny, 65 deg F
Light Conditions:	Direct, low-angle sunlight
Description: Size of bird:	Similar to small gull (noticeably smaller than nearby Ring-billed Gulls)
(Description:) Basic Shape:	Shape and size were similar to a Bonaparte's Gull but with significantly longer wings (especially noticeable when sitting on water)
(Description:) Overall Pattern:	Gray back, whitish breast and neck, black cap
(Description:) Bill Type:	Gull-like
(Description:) Field Marks and Identifying Characteristics:	While scanning the lake with my scope, I noticed a very long winged bird swimming on the lake and it was immediately obvious that it was different than anything I expected to see at this location. The bird had medium gray back, white breast and neck with yellowish tinge, and very dark (black?) cap which angled upward toward the back of its head. Short, blunt-tipped bill. Faint gray wash on sides of breast visible when flying. During flight the tail seems long-ish. The central tail plumes were very pointy but only a couple inches longer than rest of the tail. Underside of wings was nearly uniform dark brownish gray. Pale shafts of leading primaries visible in flight. Character of flight was similar to a Bonaparte's Gull; I would not describe it as a powerful flight. (see photos)
Song or call & method of delivery:	N/A
Behavior:	The bird spent the bulk of the time swimming and appeared to feed on insects at the water's surface. It would often turn/pivot while swimming buoyantly on the surface of the water. I was able to watch it for about 3 hours and it seemed content, occasionally flying around and feeding on the surface of the lake at the North end. It never chased or attacked any other bird, as is typical for larger jaegers, despite many Ring-billed Gulls and a few Foster's Terns also flying around. It remained very solitary and did not interact with other birds.
Habitat:	Large freshwater inland lake in arid foothills
Similar species and how were they eliminated:	The dark/crisp cap, white neck/breast with yellow tinge, dark back/wings, and tail with elongated central tail feathers ruled out everything except a jaeger. The task remaining was to determine which jaeger species it was. Comparison of size with nearby Ring-billed Gulls made it clear that this bird noticeably smaller, definitively ruling out Pomarine Jaeger. Parasitic Jaeger was ruled out by multiple factors including this bird's paler gray back, very light/buoyant appearance on water's surface, and complete lack of any pursuit/aggression or even interest in any of the abundant other birds on the lake. Furthermore, there was no pale crescent at the base of the upper mandible, and there was minimal pale "window" at the base of the primaries, as are characteristic of Parasitic Jaeger. Also the bill was quite short and dainty or "stubby," more consistent with Long-billed.
Previous experience with this & similar species:	I've seen Parasitic Jaeger once (Alaska, 2018). This reported sighting was my first observation of a Long-tailed Jaeger. However, I have been an avid birder since for 34 years (since age 8), over 500 submitted complete eBird lists, and have been on several pelagic birding trips and observed countless gulls and terns.
References consulted:	Merlin & Sibley field guide apps
Description from:	Notes taken at the time of the sighting From photo(s) taken at the time of the sighting
Observer:	Nathaniel Nye
Observer's address:	3894 W 1225 N, Cedar City, UT 84721
Observer's e-mail address:	**
Other observers who independently identified this bird:	Steve Hedges, Rebecca Bonebrake, Stephen Nye
Date prepared:	20 August 2023
Additional material:	Photos
Additional comments:	Will email photos.