Glaucous Gull

After the gulls had deserted the restaurant many headed into the sand quarry. I altered my viewing spot to Gibbett Lane where I picked up what at first looked like a juvenile Glaucous Gull. However, as it moved closer I could see that its primaries were a greyey brown colour and the pattern on the underparts were a little odd and recalled a first-winter Herring Gull. My assumption is that it is a hybrid Glaucous x Herring Gull or a Viking Gull. It was quite a smart beast and structurally it was spot on for a Glaucous Gull. It's a shame it wasn't closer in better light.

I placed the bird on Facebook and an Icelandic birder commented that in his opinion it is a pure Glaucous Gull.

Yes, this one is imo pure glaucous. The primaries have all similar shading, apart from P7 and P10 which is whiter. This brown wash of the primaries is often much more variable (perhaps even the rule!) than for this individual. It does not appear to have darker tailband than the rump. Such brown wash over the primaries is also typical for many dark Iceland gulls.

Here's a bit of video of it (Don't forget to set the quality to HD)