Sighting Record for Utah

Common name:	Vega or Siberian Gull
Scientific name:	Scientific_Name: Larus (argentatus) vagae
Date:	18 February 2011
Time:	11:30a
Length of time observed:	1-2 minutes
Number:	1
Age:	1st cycle
Sex:
Location:	Farmington Bay WMA, Unit 1
County:	[Davis]
Latilong:
Elevation:
Distance to bird:	see below
Optical equipment:	swarovski 65mm, 25-45x eyepiece
Weather:	high overcast to dappled sunlight; modest wind
Light Conditions:
Description: Size of bird:	similar to Herring Gull
(Description:) Basic Shape:	similar to Herring Gull
(Description:) Overall Pattern:
(Description:) Bill Type:	gull like
(Description:) Field Marks and Identifying Characteristics:	At approximately 11:30 am, I was watching a 2nd year Western Gull at Farmington Bay, a bird that I d been pursuing and photographing for a while. I noticed, nearby, an odd Herring-type Gull. Its highly patterned upperparts and paler overall coloration caught my eye. I studied it for 30 seconds or so, and remained intrigued. When it raised its wings, I saw a pale panel to the inner primaries, similar to a Herring Gull, but a bit more extensive and distinctly more contrasting with the outer primaries than usual. Nonetheless, this wing pattern eliminated most other first year gulls, including Thayer s, and I very much wanted to continue documenting the 2nd year Western Gull (not knowing that it had been found there some time before). The sun was largely behind or to side of me, there were no heat waves, and only modest wind. I was using a Swarovski 65mm 25-45x scope. Distance was about 200 feet, though I am bad enough at estimating even when I am actively tryi! ng at the time. Note that photos were taken with 500mm lens; that and size of photos should give idea of distance. I did, however, snap a number of photos of the bird, some intentional, and some the result of its proximity to the Western Gull. Most of my description comes from the photographs, though some were noted when I watched the bird in the field. The photos, taken at a moderate distance, tend to make fine markings look blurrier than when under direct observation, and thus more diffuse or faint. This will be included in my commentary. Overall, the bird s size and structure was similar to that of a Herring Gull, though the bill seemed heftier. The bill was mostly black or blackish, with a pink base coming in. The head and chest were largely white, except a faint smudgy dusky area near eye, and fine and faint streaking on crown. The crown streaking merged into broader and bolder streaks on the nape, hind-neck, and neck sides, yet this streaking was still not blurry and remained relatively well defined (shown best on 10a, 12a, and 16a). The throat, chest and uppermost belly were large white, excepting a few stray brownish spots on the sides of the chest. The mid to lower belly were medium brown and somewhat mottled in appearance. The vent and undertail coverts were largely white, with some blackish bars and spots. The back was gray with scattered brownish markings, apparently darker at upper back. The apparent consolidation of darker gray on back into a solid cowl on upper back is somewhat an illusion of the photographs, perhaps best hinted at in 7a. The back color was darker than that of an adult RB Gull, and was similar (or a bit paler) than the back color of an adult California Gull. The scapulars were gray with cross-bars. The blurry photos make the cross-barring on the scaps less apparent, in general, then in the field. Figure 7a hints at this the best. In figure 13b, one can best see that a couple of the rear lower scaps had rather distinct crossbars. The wing coverts were white with brown barring or speckling throughout, without any area of consolidation. The tail had a blackish-brown band that does not extend fully to the base. The outermost tail feathers were white, barred blackish-brown, to (or nearly to) the end of the feather. The uppertail coverts and distal rump were white with a couple bands of blackish-brown barring. The anterior rump was white with coarse spotting. The legs were rather bright pink, reminding me of a Thayer s Gull when the bird first landed. (see photos)
Song or call & method of delivery:
Behavior:
Habitat:
Similar species and how were they eliminated:	Identification Discussion I have seen a couple hundred Vega Gulls, but all during summer/early fall when they are ugly critters indeed. When I saw the photos on my camera, an hour or two after seeing the bird, I quickly scribbled notes of that which I remembered seeing, as conveyed above. What first struck me upon looking at the photos were the wing coverts. This pattern of whitish background and heavy brown speckling and barring throughout the coverts, lacking an area of consolidation in the greater coverts, is extremely unusual in an American Herring Gull. The blackish tail-band (tail not all dark) would also be unusual in American Herring Gull, especially when paired with the white tail-base, uppertail coverts, and rump all barred or freckled in blackish brown. I think these would be the primary marks for identification, and I ve not seen these marks together in any American Herring Gull. I later consulted Howell s gull guide, Sibley, and the NGS, as well as on-line photos on the Ujihara s website and the BirdKorea website. The pinker legs, larger bill, limited pink on bill (in mid-Feb), more prominent inner primary panel on opened wing, and lightly marked white vent/undertail coverts are all suggestive of Vega Gull over American Herring Gull. So is the ! white head and chest with brownish belly. Most Vega Gulls do have more obvious barring on their scapulars in 1st winter plumage. As noted earlier, I believe that some of this is due to the limits of resolution in the photographs. However, some barring can be seen (as noted above), including a couple lower scaps that seem particularly well marked. For examples of birds with somewhat similar scaps, from Feb or March: See 5th photo down at http://www23.tok2.com/home/jgull/070308/vegagull.htm Several birds at http://www23.tok2.com/home/jgull/050331/vegaeE.htm And several birds at http://www23.tok2.com/home/jgull/050224v/vegagull1w.htm Also, for a bird with similar back and scaps, fig 2 at- http://www.birdskorea.org/Birds/Identification/ID_Notes/BK-ID-Herring-Gull-Page1.shtml Finally, I found the following instructive: For the 3 December 2005 bird at http://www.birdsofchile.com/vega.htm- PHOTO3 This image shows the pale inner primary window well. Also you can see the pale rump and uppertail coverts, as well as a small amount of the white at the base of the tail. In fact it is interesting to note that this more boldly marked individual shows a wider tail band than thte 2005 bird. However, when spread, the tail of the 2003 individual was clearly pale based. The well banded coverts are also visible here. While the outer greater coverts are not crisply barred to the base, there is no dark base as expected on asmithsonianus. and photos of the Feb 2006 Vega at http://www.coastside.net/chucao/gulls/Vega.htm Conclusion Though there is overlap between American and Vega Herring Gulls in nearly all marks, all indicators in this bird point towards Vega except the suggestion of a cowl on upper back and the fact that the bird is into first-winter plumage, not in juvenile plumage. Though some guides suggest that most Vega Gulls retain their juv plumage through Feb, there are many photos on the Ujihara s website and in Howell s gull book that would argue otherwise. Based on this wide net of sources, I feel confident that this bird is not an American Herring Gull. The elimination of European Herring Gull relies nearly entirely on the tail band, which would be unusually extensive for that taxon.
Previous experience with this & similar species:	I've seen tens-of-thousands of Herring Gulls from North American interior, east coast, and west coast
References consulted:	see discussion above
Description from:	Notes made later
Observer:	Steven G Mlodinow
Observer's address:	1522 Venice Lane, Longmont, CO 80503
Observer's e-mail address:	sgmlod@aol.com
Other observers who independently identified this bird:	none present
Date prepared:	26 February 2011
Additional material:	Photos
Additional comments: