Verification of Unusual Sight Record
For Utah

Rec. # 2006-30

Common name:

Parasitic Jaeger

Scientific name: Stercararus parasiticus
Date: 10 Sept. 2005
Time: 5pm
Length of time observed: 2 1/2 hours
Number: 1
Age: Juvenile, older than hatch year?
Sex: unknown
Location: West of Willard Bay west dike, 4 miles north of Harold Crane WMA
County: Box Elder
Latilong:  (2) N41* 23, 474' W112* 06.787
Elevation: 4194
Distance to bird: Highly variable; 20-100 feet
Optical equipment: Brunton Epochs 10.5 x 42 and Leica APO Televid 77
Weather: Cloudy, windy 55 degrees
Light Conditions: Overcast; no glare
Description:        Size of bird: 15-16 inches
(Description:)       Basic Shape: Stocky, gull shape
(Description:)  Overall Pattern: Dark chocolate gray brown; more grayish in earlier light, underparts paler with dark barring
(Description:)            Bill Type: Slender gull - like bill; not very angular
Field Marks and
Identifying Characteristics:
Bill - Approx 1 1/2 inch long, slender bill with slight gonydeal angle about 1/4 way back from the tip of the bill. The tip was dark for approx 1/4 of bill. Base color of bill was light bluish-gray. Did not have a significant hook at the end of the bill. At base of upper mandible, narrow white crescent formed a border between bill and forehead.
Head Color - Dusky chocolate grayish. Eye was dark and surrounded by darker plumage as if it had black (bruised) eyes. When alert, bird appeared to have two low points on it's crown, one over the eye and one at the back of the head. Between the two points the crown was flat. Very
faint, slightly paler plumage extended from lower breast upward and back across the neck, under the eye, and formed an upward hook behind eye.
Nape was a lighter color than top of head. From below the nape to the tail tip, the base color was a dark, sooty gray brown. Every row of wing coverts had a thin, pale reddish - buffy edge, giving the coverts a scalloped appearance. Primaries and secondaries had a very small, pale
In flight, upper wing showed a distinct pale, streaked crescent at base of primaries: contrasted strongly with base color of upper parts. When extended, wing appeared crooked backward from wrist area.
Wingtips were pointed.
Uppertail coverts were barred the sooty base color and orangy-buffy color.
Tail shape - Short, narrow fan-shaped tail with two central tail pointed feathers and projecting beyond other tail feathers.
Underparts - Throat: Slightly lighter than sooty, chololate gray-brown of head. Upper 1/3 of breast gradually became darker than throat and showed a faint rufous barring. Pattern and color continued through undertail coverts. Coverts were irregularly barred, pale colored and had a
faint buffy cast.
Legs - grayish-blue
Feet - webbed, very small, black
(see photos)
Song or call & method of delivery: None heard
Behavior: Bird was sitting on a dirt road within dry furrows, out of the wind and preening. Bird appeared to be injured as if it had sore feet. It would take a few halting steps before it settled back down
again, breast first. Bird took several short, low flights and returned to the road. During two of the flights, bird flew out over the water and harassed gulls and terns. During one of these flights, bird ws only 100 feet away. Bird circled around and above gulls before it dove down at them.
Habitat: Muddy/sandy road lined with tamarisk between freshwater reservoir and brackish Willard Bay.
Similar species and how
were they eliminated:
Skuas - Larger bulkier birds without barring on breast and tail coverts.
Juvenille Gulls - None have the rufous colored barring on dark back-ground on breast and tail coverts.
LongTailed Jaeger - Bill is heavier with the nail much longer in proportion to the bill length. Barring on tail coverts is not rufous and is a more even pattern. The two protruding central tail feathers are rounded.
Pomerine Jaeger - Much heavier bill with very prominent gonydeal angle. Two central tail feathers are not pointed.
Previous experience with
this & similar species:
Have seen LongTailed and Paracitic Jeagers (adults) briefly on pelagic trip.
References consulted: Sibley, Kaufman's Advanced Birding, National Geographic
Description from: Notes taken at time of sighting
Observer: Steve and Cindy Sommerfeld
Observer's address: 462 E. Willow Ave. SLC, UT 84107
Observer's e-mail address:
Other observers who independently identified this bird: Kristin Purdy, Glenn Barlow, Jack Binch and Bob Huntington
Date prepared: September 10, 2005
Additional material: Photo's on
Additional comments: