I am seeking opinions on the identification of this gull. It was originally identified as a
first-cycle Glaucous-winged Gull. However, the extremely pale primaries and, especially, the
pattern on the tertials, make that identification unlikely.
Suggestions have generally centered on "Kumlien's" Iceland Gull or some hybrid, perhaps "Nelson's Gull" (Glaucous X American Herring Gull) or Glaucous X Glaucous-winged Gull.
I have attempted to include some photos that will allow for an assessment of size, but photos can be very deceptive on that issue. In actual viewing, my own impression was that the gull was approximately the size of some of the Herring Gulls that were present, and was larger than a first-cycle Thayer's Gull present. Most gulls at Sparks Marina are California or Ring-billed Gulls, and there are photos with those. In actual viewing, the bird seemed significantly larger than California Gull.
As an aside, there are no confirmed records of Iceland Gull for Nevada.
Here are photos from the first day, 12/14/09. Lighting was poor, with fog and overcast. Photos
taken between 2:00 and 2:30 p.m. ("Official" sunset is approximately 4:30 p.m., although
mountains to the west cause sun to actually disappear considerably earlier.)
California Gull on right.
Mostly California Gulls, but the bird on the immediate right of our gull is a first-cycle Thayer's and the bird facing in from the left is, well, frankly, I am not sure now. There was a rather dark Glaucous-wing (type) Gull around -- perhaps that's it. Perhaps not. : < (
With Ring-billed Gulls (left) and California Gulls
The next photos were taken 12/15/09.
Lighting conditions when I first encountered the bird today at about 2:40 p.m. were excellent with sun low in the sky behind me and unobstructed by clouds.
The bird soon flew to the other end of the lake, and by the time I got there (around 3:15 p.m.),
the sun had gone behind a heavy cloudbank, where it remained for the rest of the day.
The remainder of the photos from 12/15/09 were attempts to show the size of the bird relative to
nearby gulls (and Common Mergansers).
Lighting deteriorated badly but the shapes are still evident.
In the next two photos, with California Gulls and Ring-billed Gulls.
There is one adult Herring Gull facing in from left. The rest are California and Ring-billed Gulls.
In the next four photos, there is a group of four gulls, one being the unidentified bird in question, one probably the first-cycle Thayer's that was around all afternoon, one bird I'm presuming to be the dark Glaucous-wing type, and one California. There are also Common Mergansers (and a few Tundra Swans in the background on some of the shots.) Sorry I can't be more certain on the Thayer's or Glaucous-wing, but these photos were taken from a long way away and it was getting pretty dark. (Nice to have an 18 megapixel camera.)
Gulls, from left: California, unidentified, Thayer's, GWGU.
Gulls in same order as previous photo.
From left, California, presumed Thayer's (front), unidenified, presumed Glaucous-wing
California, unidentified, Thayer's, Glaucous-wing
Herring Gull to left of the unidentified gull. Foreground mostly California Gulls (with a few Ring-bills in front.) Uh, yeah, Coot, too.