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 |
|
(Description:)
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 tip. 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: | ssfeld@xmission.com |
| 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 utahbirds.org |
| Additional comments: |