Seeing as the object is extremely blurry, doesn't that suggest it's being videoed at a great distance - even though the full video is not what you would call 'sharp.' A bird - or a drone would not be visible at all, I would imagine? Especially as the rest of the video doesn't show any other Seagulls and the like.I think it travels too fast to be a helicopter. A bird is more likely. Smaller, and closer. A small drone is also a possibility.