Verification of Unusual
Rec. # 2008-31a
Iceland Gull (Kumlien's)
|Scientific name:||Larus glaucoides kumlieni|
|Time:||10:00 AM both days|
|Length of time observed:||5 minutes first day, 1.5 hours second day|
|Location:||Logan River Wetlands and Shorebird Playa (locally known as Sue's Ponds)|
|Distance to bird:||Less than 15 meters|
|Optical equipment:||10x Binos and ~20x Camera Lens|
|Light Conditions:||Good to Fair|
|Description: Size of bird:||22 inches (slightly larger than nearby California Gulls)|
|(Description:) Basic Shape:||Gull shape|
|(Description:) Overall Pattern:||Light beige to white overall|
|(Description:) Bill Type:||Thin bill for a gull, black at tip gradiating to pinkish.|
Field Marks and
On the most basic level, this gull was only slightly larger than nearby
California Gulls. Color was very light overall with light-brown detail/etching
in wings and very light buff neck and belly.
Head was small and round with short and thin bill. Bill color was dirty-pinkish with dark tip. Neck appeared short and stout.
Legs were bright pink.
In flight, tail and wing tips were both very light color both above and below and there was no dark terminal band on the tail.
|Song or call & method of delivery:||none|
|Behavior:||Calm; less skittish than other gulls (California and Ring-billed). Gull mainly stayed among other gulls and showed no aggressive behavior towards others - didn't seem to mind close proximity.|
|Habitat:||Shallow wetland area near landfill|
were they eliminated:
The two most similar species would be the Glaucous Gull and Thayer's Gull.
The Glaucous Gull possibility can be ruled out for a few reasons. First, Glaucous is substantially larger than this specimen overall. The Glaucous bill is also heavier and longer than this gull's. Structurally speaking, this bird has longer primary projection than Glaucous and its legs are more forward-of-center than Glaucous. The Glaucous head should also be flatter than this bird.
Thayer's Gull is much closer in appearance to this bird, but the tail and tips of the primaries are both too light to be Thayer's. Also, at this time of year, Thayer's bill would be completely black. Tertials on a Thayer's are dark-centered, but this gull had finely patterned tertials.
Last possibility would be that of a Iceland x Thayer's hybrid, but this gull has several features which rule that out: First, the bill on this gull has nearly enough pink on it to pass for the nominate subspecies of Iceland Gull (Larus glaucoides glaucoides). If this were a hybrid, the bill would need to be much darker at this time of year.
Second, the wingtips and tail are too light even for a hybrid. The wingtips of Thayer's typically range from dark to medium brown whereas this individual's wingtips were completely light. The tail of a Thayer's has a dark terminal band, but this individual has no terminal band at all. Both of these factors strongly suggest Kumlien's subspecies of Iceland Gull whereas a hybrid would show some sign of an intermediately dark terminal band and darker wingtips.
Third, the tertials of Thayer's have dark centers whereas the tertials of Kumlien's and nominate Iceland Gulls are both intricately patterned. A hybrid should show an intermediate pattern, but this bird does not.
this & similar species:
|No experience with this particular gull, moderate experience with other gulls in the area. Since discovering this bird, I've spent a great deal of time researching on the subject and poring over endless photos of similar gulls.|
|References consulted:||Sibley Field Guides, Pete Dunne's Field Guide Companion, Dunn and Howell's Gulls of the Americas|
|Description from:||Notes made later|
|Observer's address:||308 E 1270 N Logan, Utah 84341|
|Observer's e-mail address:||firstname.lastname@example.org|
|Other observers who independently identified this bird:||Ryan O'Donnel, Craig Fosdick|
|Additional Comments:||This is the first Rare Bird Report I have filled out in any state so I hope I have filled it in clearly and thoroughly enough. Please let me know if there is anything I can or should do to clarify anything at all or if there is any other way I can be helpful in the processing of this report. Regards - Jason Pietrzak|