It's a gull, I believe. "Larus ridibundus", judging by the relatively flat cut tail feathers. Terns have scissored tails and are slightly slimmer.
Interesting capture anyway. These are decorative and this particular fellow seems to have damaged a wing some time in the past.. or has a slight deformity. That's the kind of stuff I only notice on pictures.. never when I see them live. They move around too fast to study properly.
-k2
