Verification of Unusual Sight Record
For Utah

Rec. # 2013-19a

Common name:

Western Gull

Scientific name: Larus occidentalis
Date: 12 Feb 2013
Time: 2:30 PM
Length of time observed:  ~1 hour
Number: 2
Age: One adult, one third-year
Sex: Unknown
Location: Farmington Bay
County: Davis
Distance to bird: down to about 10 feet
Optical equipment: Nikon 20x spotting scope, Nikon 10x42 binoculars
Weather: Overcast
Light Conditions: Overcast
Description:        Size of bird:  
(Description:)       Basic Shape:  
(Description:)  Overall Pattern:  
(Description:)            Bill Type:  
Field Marks and
Identifying Characteristics:
Please see photographs for details. Briefly, both were large, dark-mantled gulls with pure black wingtips and pink legs. Little to no streaking in the white head.
Song or call & method of delivery: Heard giving a call that sounded hoarser than the Herring Gulls.
Behavior: Feeding on dead carp among mostly Herring Gulls. A Nelson's Gull, a few Thayer's Gulls, and a few Ring-billed Gulls were also present for direct comparison.
Habitat: Farmington Bay. This time of year, mostly ice with some patches of open water.
Similar species and how
were they eliminated:
Larger and darker than most regular species: too large for California or Ring-billed Gull, too dark-mantled for Herring Gull. Pink legs eliminated Lesser Black-backed Gull, Yellow-footed Gull, Yellow-legged Gull, and Kelp Gull. Great Black-backed Gull eliminated by how dark pink the legs were, not pale pink; thicker bill with stronger gonydeal angle on these birds, and orange, not red, orbital ring. Slaty-backed Gull eliminated by lack of streaking on head given time of year, but also by shape of bill and orange (not pinkish-red) orbital ring. Hybrids, especially Western x Glaucous-winged, eliminated by pure stark black of primaries, darkness of mantle, and lack of streaking on the head.
Previous experience with
this & similar species:
I have seen this species and its hybrids many times in all the contiguous coastal states.
References consulted: None.
Description from: Photographs taken at the time of the observation
Observer: Ryan O'Donnell
Observer's address: 1098 Crescent Dr
Observer's e-mail address: **
Other observers who independently identified this bird:  
Date prepared: 19 Feb 2013
Additional material: Photos