Verification of Unusual Sight Record
For Utah

Rec. # 2021-54

Common name:

Parasitic Jaeger

Scientific name: Stercorarius parasiticus
Date: 9/26/2021
Time: 8:30amish
Length of time observed: 4 minutes
Number: 3
Age: all adults
Sex: ?
Location: Antelope Island Causeway
County: Davis
Latilong: 41.087711, -112.193387
Elevation: 4200ft
Distance to bird: 500m
Optical equipment: Kowa spotting scope
Weather: Sunny, clear, calm, 60F
Light Conditions: Excellent
Description:        Size of bird: large, flying so no frame of reference
(Description:)       Basic Shape: gull like
(Description:)  Overall Pattern: mostly dark brown with pale bellies
(Description:)            Bill Type: too far to make out any detail
Field Marks and
Identifying Characteristics:
Max initially spotted 3 Jaegers flying together heading west, north of 3.5 mile marker, I watched them in the scope for about 3 minutes. All adult light morphs, smooth dark chocolate brown wings and back, contrasting pale buffy white belly, light brown low contrast collars, smallish head with pale nape and small medium brown cap(paler than back). White crescent seen at the base of the primaries. Smooth, even fast and direct falcon like flight, 2 together about 20ft above mudflats, 1 in the lead and much Lower, just a foot or 2 above the mudflats. No long tail plumes seen, but many Jaegers drop their tail plumes this time of year, but tail fairly short. All 3 the same size, shape, color, speed and flight style. Eventually lost them as they headed west out onto Gilbert Bay north of Antelope Island.
(see photo)
Song or call & method of delivery: none heard
Behavior: flying throughout the observation, generally heading west across the playa/mudflats
Habitat: mostly over dry lake bed of Great Salt Lake between causeway and Fremont Island, but some shallow mudflats with an inch or two of fresh water coming from Howard Slough WMA. Eventually headed out over the salt water of Gilbert Bay.
Similar species and how
were they eliminated:
Long-Tailed Jaeger-adults do not have a white crescent at the base of the primaries and usually no collar or a faint indistinct hint of a collar. Totally different flight style with buoyant wing beats, generally longer and lengthier looking and long tailed (even if tail plumes dropped)

Pomarine Jaeger-adult light morphs should be darker overall, wings and back more a blackish brown, more extensive and darker cap often with darker nape, usually bolder darker high contrast collar, often show extensive barring on flanks making the pale belly look dirty and lower contrast. Have a bigger headed and pot bellied look, tail looks disproportionately short (if plumes dropped). Generally a big bold powerful flight style unlike these birds.
Previous experience with
this & similar species:
Yes, I saw a juvenile Parasitic Jaeger at Decker Lake just 2 days before, many adults in Alaska in August of this year, several adults in Washington State September of 2020, and 3 other Parasitic Jaegers on the AIC in 2014, 2 juvenile and one adult. I've also saw many several Long-tailed Jaegers this year, 2 juvenile in Utah and many adults and juveniles in Alaska. I saw several Pomarine Jaegers last year, adults at sea in Washington State and 1 juvenile in Utah
References consulted: Sibley app, Macaulay Library photos and video
Description from: Notes 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: Max and Mike Malmquist initially spotted them, plus 11 member of the 'Birds of Utah' class fieldtrip I was leading also saw them
Date prepared: 9/26/21
Additional material: Photo
Additional comments: Photo taken by Max Malmquist, extremely poor but show 3 birds that do have the right color to be Jaegers. Photos used with reluctant consent. eBird checklist: