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 |
| Latilong: | |
| Elevation: | |
| 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: | |
|
(Description:)
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 |
| Additional_Comments: |