9/11 UFO alternate camera angles

Would anybody who wishes to state categorically that it is a bird please ALSO post a reason for the "bird" coming from BEHIND the smoking tower. It comes from behind the building just below the level at which the smoke starts. Is it perhaps a Roc? You know, the giant bird that kept on nicking that bloke's liver. It is larger than the plane for pity's sake.

If you cannot be bothered to check the video more than once, then... oh post anyway, but please be aware that you are contributing a NEGATIVE amount to the discussion, thankyou.