Verification of Unusual Sight Record
For Utah

Rec. # 2011-69

Common name:

Western Gull

Scientific name: Larus occidentalis
Date: 12-28-2011
Time: 11:00AM
Length of time observed: 30 minutes
Number: 1
Age: 3rd winter
Sex: ?
Location: Farmington Bay
County: Davis
Elevation: 4,200
Distance to bird: 50 yards
Optical equipment: 20-60X Alpen spotting scope,10X50 Brushnell binoculars,Canon SX20is digital camera
Weather: overcast
Light Conditions: no direct sunlight,which would have mad everything backlite, but not a ton of light
Description:        Size of bird: Large gull
(Description:)       Basic Shape: gull like
(Description:)  Overall Pattern: pale head and breast,with a very dark mantle
(Description:)            Bill Type: huge spade shaped bill
Field Marks and
Identifying Characteristics:
This bird stood out prominently among the pale backed Heering, California, Ring-billed and Thayer's Gulls with its large size, dark charcoal gray mantle and very pale head with a huge bill. It was very close and tame and we watched it for nearly half an hour as it fed on dead fish
(see photos)
Song or call & method of delivery: no heard
Behavior: Feeding on dead fish on the ice bank with shallow open water nearby. A couple times it spoked and flew around, but landed back in the same spot.
Habitat: frozen over fresh water pond in a large marsh on the eastern edge of the great salt lake
Similar species and how
were they eliminated:
Only other dark mantled gull likely in Utah is a Lesser-black Backed Gull, which was also present giving direct comparisons, most notably the dirty brownish head and smaller size. Great Black-backed Gull should have a different shaped bill, and there are no Utah records I am aware.
Previous experience with
this & similar species:
Yes. I saw the 2nd winter bird at Farmington bay last february.also I saw an adult Western Gull at Farmington bay in february of 2009
References consulted: Sibley guide to Birds 2000
Description from: From memory
Observer: Bryant Olsen
Observer's address: 688 East 700 South SLC,UT 84102
Observer's e-mail address:
Other observers who independently identified this bird: Norman Jensen,Gail Jensen,Mark Jensen,Ned Bixler,Tanner Poe, Jerry Poe,Mark Thai,Karen Kirchhoff,others
Date prepared: 12-29-2011
Additional material: Photos
Additional_Comments: There has been some suggestion,by Tim Avery, that this gull may have some introgression of Glaucous-winged Gull, based on some brown markings on the nape. I am no expert on gull hybrids,but this was a very dark mantled bird,and if some hybridisation was involved,it is not a first generation hybrid,or an "Olympic Gull". I will let the committee decide on the exact ancestry of this bird,based on the photos submitted,as it is beyond me,but no doubt it has mostly Western Gull linage.