Visible crew/equipment: When the O'Hara family does their prayer, you see two boom mic shadows on the ceiling. (00:14:15)
Visible crew/equipment: When Mammy catches Scarlett trying on a pretty bonnet when she is supposed to be in mourning, when the camera pans wide to show the room, in the mirror on the wall behind Scarlett you can see the shadow of the grip holding the mic above Scarlett.
Chosen answer: It looks to me like a bird flying from the tree to the ground. Nothing controversial there and no reason to edit it out.
ChiChi