The black patch and light wings strongly suggest Forster's, but it's not conclusive and birders much more experienced than I are certain that this isn't a Forster's. (This is not at all where ia Forster's should be this early in the season). An Arctic has been suggested as has of course a Common but it's hard to get a sense of the legs. The bill is considered not right for Roseate. Unfortunately this and a couple of poor flight photos are all I have. Probability is a non-breeding Common tern, but that black eye patch and less dark crown.... hmmm...