This large white-winged gull has been making frequent visits to Frampton Marsh RSPB for the past week or so and has caused some excitement by showing signs of being a Kumlien`s Gull. Myself and Chris Orders paid a visit on Sunday to see the gull for ourselves.
This type of gull is commonly regarded as a hybrid of an Iceland Gull and Thayer`s Gull, or a sub-species of Iceland Gull, indeed its latin name is Larus glaucoides kumlieni which basically means Iceland Kumlien`s Gull. Very confusing.
The major identification point of this gull is the darker parts of its plumage. A true Iceland Gull is very pale and in some lights this bird looks like this, but you can see in the second photo that the bird has dark primary feathers ( the longest ones on the wing ) and in flight the bird had a dark band on the tail, both signs of kumlieni. The jury is still out on this bird, is it Kumlien`s or `just` a plain old Iceland? I don`t think we will find out definitively.
The kumlieni form comes from North-West Quebec and winters on the North American East coast, whereas the glaucoides form (Iceland) is from Greenland, wintering in the North Atlantic.