Bird or something else

Bird flying across the screen. Notice the huge shadow it casts on the North Tower. Could this have been edited in to hide something else, like a spotter plane/jet? In both the Pentagon and the WTC 2 crash videos we see these huge black bird shaped things flying up and away from the fireballs. Too much of a coincidence?

From webfairy:

http ://thewebfairy(dot)com/911/bird/index(dot)htm