X Black-headed Gull
Thanks to Steve Arlow who sent these images from Pitsea, Essex, of an occasionally seen type of hybrid. Can’t remember ever seeing one myself, though they were more regular when Med Gulls were first colonising Britain I think.
Thought you may be interested in this hybrid Black-headed X Mediterranean Gull that was at Pitsea Landfill today [Thursday 17th Feb. 2011]. This may be the same bird that was seen at this site last February and in nearby Hole Haven Creek February 2008″