It was great to catch up with this beauty again at Denton res. I have seen and photographed this bird (sure it’s the same one), since 2012. Search archives Nov2012 and Dec2014 to see previous pics.
It is a leucistic black-headed gull. It is pure white all over apart from the wing wedges. This feature is baffling as this wedge area is normally darkish, not jet black. It’s a cracker!
Where it gets to in summer is anyones guess.
Also on the res were a female pintail and a female goldeneye.