Sighting Record for Utah

Common name:	Lesser Black-backed Gull
Scientific name:	Larus fuscus
Date:	3/30/12
Time:	7:30 AM
Length of time observed:	45 minutes
Number:	1
Age:	Adult
Sex:	Unknown
Location:	Alfalfa field approximately 4000 N and 1450 W in Pleasant Grove (South of Deerfield Elementary in Cedar Hills)
County:	Utah
Latilong:
Elevation:	4500'
Distance to bird:	Approximately 30 yards at times
Optical equipment:	Cabela's XT 8x42 Binoculars, Nikon D5000 Camera with 300mm f4 AFS lens with 1.4x teleconverter (420mm)
Weather:	Clear skies
Light Conditions:	Very good for photography
Description: Size of bird:	Appeared slightly longer (more slender) than the California Gulls around it
(Description:) Basic Shape:	See photos
(Description:) Overall Pattern:	Mantle slightly darker than California Gulls next to it, slight streaking/spotting on crown and the back and sides of neck. Dark primaries had a single white spot at tip when flying. See photos
(Description:) Bill Type:	deep yellow for the most part with bright red on the lower mandible and some black on top mandible and bording the red on lower mandible. See photos
(Description:) Field Marks and Identifying Characteristics:	In addition to comments above: Yellow iris and yellow legs
Song or call & method of delivery:
Behavior:	Was feeding with about 300 California Gulls yet it did not really interact with the other gulls. It moved about independently. It was much more skittish than the California Gulls when I approached.
Habitat:	Alfalfa field
Similar species and how were they eliminated:	Black-tailed Gull would be way out of range. My adult bird did not have a black band on the tail. Black-tailed also has red on upper and lower mandibles. LBBG does not have red on upper mandible. California Gull would have dark iris, not yellow. This gull also had a darker mantle than all the California Gulls around it. This gull also had a single white spot in the wing tip when flying not multiple white tips seen in California Gulls. Kelp Gull would be way out of range and show very dark mantle. Ring-billed Gull also has yellow legs and pale iris, but it is smaller than a California Gull and does not have red on its bill. Western Gull would have pink legs, not yellow. Yellow-footed Gull would be way out of range, would dwarf the California Gulls where the LBBG seemed only slightly larger, would have brighter yellow in the legs, and have a bulkier bill. Yellow-legged Gull would be way out of range, would dwarf the California Gulls and have a mantle color more similar to the California Gulls, not the darker gray of the LBBG.
Previous experience with this & similar species:	Recall seeing LBBG at Farmington Bay during a Utah County Birders field trip.
References consulted:	Sibley Guide and sent photos to Kris Purdy and Erich Huish for review.
Description from:	Notes made later
Observer:	Jeff Cooper
Observer's address:	3499 N 1270 W, Pleasant Grove, Utah 84062
Observer's e-mail address:	jeffcooper7@gmail.com
Other observers who independently identified this bird:
Date prepared:	3/30/12
Additional material:	Photos
Additional_Comments:	A link to photos has been submitted to Milt Moody.