Here are quoted comments I had received about the above gull:
1) "{on your bird} that rump and uppertail coverts look
surprisingly
blotchy and even spotted, overall brownish. The vast majority
of FW SBGs
show largely whiteish rump and uppertail coverts (at least ground
colour), barred or spotted with dark brown".... Do you
feel that the
rump on my bird is a negative point for SBGU?
Rump and uppertail coverts of SBGU show dark spots/bars in really various degree. I think your bird is safely within the normal range of SBGU.
2) "most FW SBG show rather more speckling on the outer
two pairs of
tails feathers than this bird"... Is this really true?
does the tail
pattern of my bird seem wrong to you?
I think the tail pattern is also quite normal for SBGU.
3) "the rather odd distribution of pale and brown on
the bird. Most FW
SBGs when worn show rather more obvious white or whitish on the
underparts than on the bird in your images (eg on the belly, which
looks
almost solid brown in your images"... Do the underparts
of my bird
trouble you for SBGU in Feb?
Far from that, uniformly brownish underparts of SBGU are normal even in Feb.
4) "{SBGU} do not usually look clearly streak-crowned
like the bird in
your images"... Do you agree?
The streaked crown of your bird is also quite normal for SBGU.
5) "the scapulars: usually, bleached looking birds
look more contrasting
here." - Other gullers have also wondered if the upperparts
lack enough
contrast for a SBGU in Feb - what do you think?
Does the 'contrast' mean distinct markings such as anchors?
Or, 'contrast between new scapulars and worn coverts'? I think
many SBGUs show more distinct markings on scapulars than in your
bird. However, many other SBGUs often show plain scapulars just
like your bird, though those are usually not as extremely uniform
as in GWGU.
In my experience, progress in molt/wear/bleaching of SBGU is very
variable. And I think the progress in your bird is normal for
SBGU in Feb.
6) Are there any other features that you feel are not good for SBGU?
Your bird looks like a normal female-type SBGU to me. I don't see any wrong features for that.
- of course, this does not address the possibilities
of this bird being a New World taxon (or hybrid thereof), but
it does at least establish that it looks perfectly fine for a
SBGU.