|Second-winter Kumlien's Gull (left) with adult Lesser Black-backed Gull of the subspecies graellsii.|
|The dark pigmentation in the primaries tips was not always obvious when the bird was perched, even at close range.|
Good move, however ... within five minutes of arriving I picked up a white-looking gull loafing among the Herrings and Lesser Black-backeds. Despite numerous visits to the Thames this winter I hadn't scored any large white-winged gulls, and had resorted to twitching Beddington on the other side of town to get a fix of its Icelands. I therefore almost expected this stand-out individual to be the famous leucistic Herring Gull that bears the ring number SH1T - an occasional visitor to Rainham (and also Beddington). Instead, when I got the bins on it alarm bells rang immediately - this was clearly an Iceland-type, but looking at it rear on there was obvious dark pigmentation on the white-edged outer primary tips: it surely had to be a Kumlien's Gull.
|Note the 'airbrushed' dark outer webs to the four outermost primaries in particular, and the contrast to the whiter inner primaries, as well as the strong tail band.|
|At range, the darkest area of the wing was actually the greater coverts, in contrast to its appearance at rest.|
I put a call in to David Callahan at the Birdwatch office to run through the features with references to the article and fully confirm my ID before putting the news out. As we were speaking, a white gull flew through the throng and I paused the conversation to eyeball it - second-winter Iceland Gull! Apologies to David for the abrupt end to the call, but the result is a few more images to enjoy:
After a lull in proceedings, I twice got distant and very brief views of a more adult-like white-winger. From the poor record shots below it looks like a third-winter, but what, exactly? There is a hint of darkness in the outer primaries and Andy Tweed told me today that there was a sub-adult Kumlien's briefly at Rainham this week which, like this bird, had a slight dark mark on the bill. Steve Arlow apparently had a similar bird over at Pitsea, only 13 miles or so downriver. I put the news out as Iceland or Kumlien's, pending better views or photos by others, but two comments so far have also suggested leucistic Herring. What do you think?
|Third-winter gull over the stone barges today. Could this be the bird reported as a Kumlien's Gull, or is it even just a leucistic Herring Gull, as suggested by others?|
|In this shot the outer primaries appear slightly darker, but tinged brownish - shame it was so distant.|
|Adult Iceland Gull - the fourth and final white-winger of this morning's unprecedented session.|
My final gull list for the morning: 2w Kumlien's Gull, 2w and ad Iceland Gulls, 3w Iceland or Kumlien's Gull, 1w Caspian Gull, ad and 1+ 2w Yellow-legged Gulls, and good numbers of Herring Gull, Lesser Black-backed Gull, Great Black-backed Gull, Common Gull and Black-headed Gull. That's an acceptable haul for one morning. Let's sign off with that Caspian (the last of the winter?):
|A first-winter Caspian Gull makes a brief appearance in the crowd.|