blackheaded gull

[beeeater67]

I saw a blackheaded gull on the Thames in Marlow in mid-December which had almost a complete black cap. Two other individuals had substantially black caps. Is this normal at that time of year?

[Cristian Mihai]

It isn't normal for December. Usually BH Gulls change the plumage during February. But I have to say that the color of the head it isn't black, it is dark brown. Black-headed Gulls have dark brown heads in the breeding plumage...There is another medim size gull which has a black head - the Mediterranean Gull.