I'll take a crack at it...... I would guess that you would want to be down wind from the setup... also have the owl and the dead crow on the down wind side of the tree.
Reasons: As the crows fly in they are concentrating on the owl and dead crow in the tree which would mean they would be hovering/flying into the wind... a bird has more control with the wind in their face.
Plus the birds are in the air working to stay on location looking in the opposite direction from where you are and will not see you moving when you blast their [beeep].
