This field by the pines, is it short growth like a pasture or hay?
If it is, I love field edge set-ups, and putting decoys out. Just a thought.
Set-up close to those pines, that could be the roost... one way to find out,
roost those birds the night before. If you were above the birds and they didn't come your way, sounds like they pitched down the hill off the roost. That's if I'm pictureing your
area correctly.