Mediterranean Gulls have been on the increase in the UK for several years, presumably as a result of global warming. However, they are still only present in small numbers and generally associated with the coast. A few birds do stray inland and single birds have been recorded occasionally at Amwell over the years. Most of the records are from late afternoon towards dusk when the gull numbers increase as they fly in to roost, but recently one bird has been present during the day.
When I arrived at the viewpoint the gull, a 1st Winter, was on the water out on the spit with a handful of Black-headed, Common and Lesser Black-backed Gulls. I was hoping that it would eventually stand on one of the "goal posts" for some photos, but no such luck. Light conditions were good, but at a range of 40-50 yards, I was only able to get some record shots. Note the heavy black bill and the mask giving the bird an aggressive look.