Sighting Record for Utah

Common name:	Lesser Black-backed Gull
Scientific name:	Larus fuscus
Date:	Feb 25, 2009
Time:	between 1:30 and 4:30 p.m.
Length of time observed:	about 40 min total
Number:	1
Age:	Adult
Sex:	?
Location:	River Lane
County:	Utah County
Latilong:
Elevation:	4500 ft
Distance to bird:	200 ft
Optical equipment:	8x42 bins and kowa spotting scope
Weather:	wind
Light Conditions:	grey
Description: Size of bird:	Between California and Herring Gull
(Description:) Basic Shape:	Gull
(Description:) Overall Pattern:	Grey and white
(Description:) Bill Type:	Gull
(Description:) Field Marks and Identifying Characteristics:	I first noticed this gull after an eagle scared all the birds off the field. While scanning the flock in flight I saw a bird who's mantel didn't contrast with the black wingtips nearly as much as all the other birds in the flock. This birds wings also appeared long and narrow compared to the other birds in flight. I followed the bird until it landed then put the scope on it. The mantle was darker than all the other gulls in the group, just a little darker than the California Gulls. The bird was larger than the Ring-billed Gulls. Close in size to the California Gulls (never had a direct side-by-side comparison with a California). It had light brownish streaking on head and nape but white on the front of the head around the bill. The bill was yellow with a large bright red spot near tip of the lower mandible bordered on the top of the lower mandible by a darker blackish area. I am not sure whether this dark spot was the bill color or just dirt. The legs where yellow. The iris was yellow. The gape and orbital ring were reddish. Tail, breast and belly clean white. Tips of primaries were black. (See photos)
Song or call & method of delivery:	None that I could pick out of all the noise.
Behavior:	The bird was actively feeding with a large flock of gulls on dead carp. Several times the bird flew up with the other gulls whenever a Bald Eagle flew over. Sometimes it would land where the carp were so deep you couldn't see the bird. At one point it landed past the field out of sight at which point Matt Mills and I went down to the lake to look for other birds. On our way back out it was again feeding on carp this time near the west fence line.
Habitat:	Agricultural field near Utah Lake with thousands of dead carp spread and piled up across the field.
Similar species and how were they eliminated:	California Gull has a dark iris. This bird looked darker mantled than the California Gulls. It did not have any black in front of the red spot on the lower mandible or black crossing onto the upper mandible. Herring Gull has pink legs and much lighter mantle. This gull also looked less bulky (a little smaller and thinner) than the nearby Herring Gulls. Great Black-backed Gull is much larger with pink legs and darker mantle. Western and Slaty-backed Gulls are larger with pink legs and broader wings. Yellow-legged Gull has paler mantle. Yellow-footed Gull is larger with a heavier bill.
Previous experience with this & similar species:	I have seen a couple different Lesser Black-backed Gull at the Bountiful Landfill. I have no other experience with this gull. I have seen many Herring, Ring-billed and California Gulls. I've seen a few Western Gulls in Washington and one in Utah. I've seen a few Greater Black-backed Gulls in Main, Mass, and Ontario. I have no experience with Yellow-legged, Yellow-footed, or Slaty-backed Gulls.
References consulted:	Sibley Guide to Birds at the time of the sighting.
Description from:	From memory
Observer:	Eric Huish
Observer's address:	850 E 100 N Pleasant Grove Ut
Observer's e-mail address:	poorwill_@hotmail.com
Other observers who independently identified this bird:	Matt Mills was with me and Bryan Shirley joined us later and saw the bird. Pat Jividen reported seeing it the next day.
Date prepared:	8/19/09
Additional material:	Photos
Additional_Comments: