Sighting Record for Utah

Common name:	Long-tailed Jaeger
Scientific name:	Stercorarius longicaudus
Date:	8-29-2020
Time:	11:00 AM
Length of time observed:	Approx 3 minutes
Number:	1
Age:	Juvenile
Sex:	Unknown
Location:	"Jennifer's Phone Booth", Colorado River
County:	Grand County
Latilong:	38.8513637,-109.2851686
Elevation:	1256m
Distance to bird:	Minimim distance approx 150 meters
Optical equipment:	Canon 10x stabilized binoculars, Sony RX10 (IV) super zoom camera
Weather:	86f, partly cloudy, moderate breeze
Light Conditions:	Bright sun
Description: Size of bird:	Gull sized
(Description:) Basic Shape:	Gull-shape with long narrow wings
(Description:) Overall Pattern:	Darker gray with mottling. Light belly, underwing patches.
(Description:) Bill Type:	Gull-shaped, but smaller than average gull.
(Description:) Field Marks and Identifying Characteristics:	Upon first sighting, the bird showed a basic gull shape. Coloration and relatively long-narrow wings indicated some type of Jaeger. While flying low over the river/riverbank the flight style was less direct than gull, more reminiscent of a tern (though flying into stiff breeze may have some bearing on this). Bird had relatively small bill with dark tip. Overall coloration gray, with whiter belly and light underwing patches. Distance from bird did not reveal finer barring patterns. Relatively long dark tail tail with longer rounded central retrices. Upper and undertail coverts obviously barred. (see photos)
Song or call & method of delivery:	no vocalization
Behavior:	Flew in from upstream low over river/riverbank. Landed in water, bathed. Flew out, soared towards Northeast.
Habitat:	River
Similar species and how were they eliminated:	Similar species would be Parasitic or Pomarine Jaeger. Either of these would typically show some more brown/warmth in juvenile coloration. In all views this bird did not show any warm or brownish tones. This bird shows only two bright white primary shafts on upper wing, both Pomarine and Parasitic would show more. The tips of the central tail rectrices (especially in top-view photo, which is the closest photo) appear rounded and blunt. Parasitic would be pointed, Pomarine would be squared. The bill, though not overly clearly shown in the photos, appears quite short and not overly stout. (This is a rather subtle ID point given the quality of the photos)
Previous experience with this & similar species:	Seen Jaegers numerous times on pelagic trips, Long-tailed once previously in Grand County.
References consulted:	National Geographic Field Guide to the Birds of North America (6th Edition). Sibley Field Guide to Birds of Western North America (2nd edition). Kaufman Field Guide to Advanced Birding. Communication from Tim Avery and Paul Lehman.
Description from:	From memory From photo(s) taken at the time of the sighting
Observer:	Glenn Kincaid
Observer's address:	HC64 Box 2404 Castle Valley Utah 84532
Observer's e-mail address:	**
Other observers who independently identified this bird:	Stephen Heinrich
Date prepared:	8-30-20
Additional material:
Additional comments:	ebird checklist S72987974