Verification of Unusual Sight Record
For Utah

Rec. # 2013-39

Common name:

Lesser Black-backed Gull

Scientific name: Larus fuscus
Date: 2 May 2013
Time: 1:45 PM
Length of time observed:  ~15 minutes
Number: 1
Age: Immature, probably first-cycle
Sex: Unknown
Location: "Sue's Ponds" (Logan River Wetlands and Shorebird Playa), immediately west of the Logan Landfill
County: Cache
Distance to bird: ~50 feet
Optical equipment: Nikon 20x spotting scope, Nikon 80-400mm lens on SLR
Weather: Sunny
Light Conditions: Lit from the side but at a longer distance, then I moved closer to the gull along the road but it became backlit from this angle.
Description:        Size of bird:  
(Description:)       Basic Shape:  
(Description:)  Overall Pattern:  
(Description:)            Bill Type:  
Field Marks and
Identifying Characteristics:
Medium-sized gull immature gull with a relatively dark mantle. Appeared slightly larger than the California Gulls nearby, and significantly larger than the Ring-billed Gulls and Franklin's Gulls. Leg color not seen because the bird was seen swimming and then in flight (never perched on the ground). Bill appeared solidly black, which is unusual for any Larus gull in May; flight shots may show a slight amount of pink on the lower mandible in the chin area, but this was not readily visible from a side view. Streaking on the head was concentrated in the eye area, giving a "black eye" look that is typical of this species. No pale window in the inner primaries: inner primaries were very slightly lighter than outer primaries, but both were very dark and this difference in shade was not readily apparent, much less so than expected for a Herring Gull. Head shape varied with posture and angle of view, but overall appeared more aggressive than California Gull and less so than Herring Gull.
(see photos)
Song or call & method of delivery: None noted for sure to come from this individual.
Habitat: Shallow freshwater pond adjacent to a landfill.
Similar species and how
were they eliminated:
Herring Gull eliminated by solidly black bill of this bird in early May, smaller size (about the same size as California Gull, or slightly larger), and lack of obvious pale panel in inner primaries. Great Black-backed Gull eliminated by smaller size of this bird compared to adjacent California Gulls; relatively thin, parallel-sided bill; and less checkering in wing coverts. California Gull eliminated in direct comparison by solidly black bill of this bird, lack of checkering in wing coverts, and darker mantle color of this bird. Western and Yellow-footed Gull eliminated by smaller size of this bird; thinner, parallel-sided bill, and long primary projection. Slaty-backed Gull eliminated by size and long structure of this bird and relatively dark, unbleached mantle color of this bird in May. Thayer's Gull eliminated by solidly dark outer primaries of this bird, solidly dark bill given time of year, and relatively dark mantle.
Previous experience with
this & similar species:
This is my tenth observation of Lesser Black-backed Gull, all of which have been in Utah (and some of which were repeated observations of the same individual). See records 2008-32, 2008-33, 2009-22, 2012-48, and 2013-28.

References consulted: Howell and Dunn 2007.
Description from: Photos 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: 10 May 2013
Additional material: Photographs
Additional_Comments: Note: eBird checklist: