Verification of Unusual
Sight Record
For Utah
Rec. # 2020-70
| Common name: |
Pomarine Jaeger |
| Scientific name: | Stercorarius pomarinus |
| Date: | 11-18-2020 |
| Time: | 3:15pm |
| Length of time observed: | 1.5 hours |
| Number: | 1 |
| Age: | juvenile |
| Sex: | ? |
| Location: | Lee Kay Ponds |
| County: | Salt Lake |
| Latilong: | 40.739012, -112.038901 |
| Elevation: | 4250 |
| Distance to bird: | 50m at closest |
| Optical equipment: | Nikon 10 X 42 Binoculars, Brushnell 20-50X Spotting Scope |
| Weather: | Overcast, windy and 57F |
| Light Conditions: | OK to poor |
| Description: Size of bird: | Slightly smaller than California Gulls |
| (Description:) Basic Shape: | gull like |
| (Description:) Overall Pattern: | mostly dark brown |
| (Description:) Bill Type: | |
|
(Description:)
Field Marks and Identifying Characteristics: |
As I was scoping through the gulls on the Pavilion pond, I noticed an all dark
brown bird all by itself near the bank in the back, when I got the scope on it,
it became apparent it was a dark morph Jaeger. Knowing Jaeger ID can be tricky,
I quickly got as close to the bird as I could to get photos, but as I approached
it got up and started harassing gulls, only to land back down again even closer
to shore where I was able to walk down to the bank and get great looks at it. It
repeated this pattern several times over the next 1 1/2 hours, getting up
periodically chasing gulls, then landing by itself on the water. It was a
Juvenile intermediate dark morph, not black but a dark chocolate brown, paler
brown on the belly, finely barred under wing coverts, bill looked long with a
prominent hook on the tip, it had a double flash in the under wings in flight,
bold black and white barring on the undertail coverts, short blunt R1 tail
feathers, white on shafts of P5,6,7,8,9 on upper side of wing, size was slightly
smaller than California Gulls and had a bulky pot bellied look, which all led me
to lean towards a Pomarine. I posted photos of the Jaeger online for ID and it
was confirmed by multiple sources as a Pomerine, some comments on the facebook 'Skuas
and Jaegers of the world' group are "A perfect juvenile (1st cycle) Pomarine.
Classic, textbook bird","100% Pom. Alone the almost unmarked head, darkening in
loral area is diagnostic.", "Pom. Darkening in the loral area plus double white
crescent on the underwing." Unanimous consensus online (see photos) |
| Song or call & method of delivery: | None heard |
| Behavior: | Spent most of its time loafing on the water, but would get up and fly directly into the gull flocks, seemed to target individual gulls with food, which would usually quickly drop their food. None of the gull chases lasted more than a couple minutes. At about 4:45 it got up and flew over us then went west to the other pond where I lost it among the large flocks of gulls. |
| Habitat: | Freshwater ponds near a garbage dump which attract many thousands of gulls |
| Similar
species and
how were they eliminated: |
Long-tailed Jaeger juvenile-generally smaller and more tern like in flight and
behavior. Shorter bill with the nail being about half the length. Longer tail
with longer but blunt R1 tail feathers. Small head with a big eyed look. White
limited to base of P9 and P8 primaries on the upper side Parasitic Jaeger juvenile-slightly smaller and faster and more agile in flight, often going on long intense aerial pursuit of prey, unlike this Jaeger. Bill narrower with a smaller nail on the tip, weakly barred low contrast undertail coverts, usually only shows a single "flash" in the underwing from the white base of the primaries, underwing coverts usually uniformly dark. Doesn't have the dark lored look. R1 tail feathers longer and coming to a point |
| Previous
experience with this & similar species: |
Yes, I saw several adults on a pelagic trip in September of this year. None with juveniles. |
| References consulted: | Sibley Guide to Birds, Macaulay Library photos |
| Description from: | From photo(s) 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: | Mike and Max Malquist, Matthew Pendleton, Pomera Fronce, Joanna Kane, Kendall Watkins, Lauri Taylor, Vivian Schneggenburger joined me after I found it, others also found and reported it on eBird later that day and the next. |
| Date prepared: | 1-19-2020 |
| Additional material: | Photos |
| Additional comments: | eBird checklist: https://ebird.org/checklist/S76374673 |