A Mongrel Gull

I had a few hours off work today, and surprisingly I was back at Shawell. I soon spotted the very distinctive third-winter Caspian Gull that I saw yesterday, but it was a bit too foggy to get any decent images. 

Yellow-legged Gulls seem to have moved back north with at least 11, of various ages, seen at the lagoons today. Whilst trying to count the YLG's I came across a gull with yellowish legs, but something about it made me discount it and make a mental note to go back to it once I'd finished my sweep. 

Its bill was perfect in colour for a Caspian Gull, but maybe it was a little short. Its body shape was more Herring Gull like and its legs were also short, but maybe not so short as to rule out Caspian Gull. Its eyes were quite pale and its wing length appeared a tad short. Its longest primary feather (P10) has a long white tip, which is a pro-Caspian feature, but the black on the feather didn't look quite right. In one of the photos P10 looks reasonable, but in others not quite right.

Its jizz was generally more Herring Gull like than Caspian Gull.

Gulls like this are a challenge to in-experienced observers, especially those who think that all you need to do is look for a gull with a clean white head at this time of year.

Presumed Hybrid Caspian Gull

Presumed Herring x Caspian Gull

Underside of the Primary Feathers

Shortly after the hybrid flew off, I found another third-winter Caspian Gull roosting on the bank betweens the lagoons. It's progress towards adulthood was further advanced compared to the other third-winter. Quite a lot of black was left in its tail feathers and the black on the primaries was more of a match for third-winter than fourth-winter.

Third-winter Caspian Gull