Ring-billed gull and a posssible hybrid, Preston Dock

I was in the Preston area today so called in at the Riversway docklands on the off chance that the ring-billed gull might still be around, it last appeared on Birdguides on 26th September. It was still there and showing as well as ever near the Green Frog takeaway van.

The adult gull in the center is interesting, it was obviously darker than the adult herring gulls (e.g. the bird on the left) but paler than the lesser black backs (e.g. the bird on the right). It also looked bigger, had a heavier bill and a very red patch on the gonys. My initial reaction was adult yellow-legged gull, though I was concerned about the amount of streaking on the head and the amount of white in the primaries. I'm also told that it might be too dark for yellow-legged gull and that the head shape doesn't look quite right either. It may in fact be a herring x lesser black back hybrid! Don't think I'm ever going to get to grips with gulls......

Then again in this photo it looks considerably paler than the lesser black back.

Center bird again, behind the herring gull.

Second bird from the left.