As discussed in the post about the 2 Keys To Success While Duck Hunting, concealment is one of the two key tenets to successful duck hunting.  The key premise is that we are trying to keep our silhouettes hidden from the keen eye sight of incoming ducks.

A key way to keep your whereabouts unknown to oncoming ducks is to use any shadows available.  Shadows are a powerful way to blend into the surroundings.  The military has been using it for decades to keep themselves camoflaged from the enemy, why not use the same concept to your advantage in the duck blind.  When you get to your spot, look around and see if there are any shadows around that you can use.  Normal suspects to utilize are trees, but can also come from the bank of a river or a large rock.  If you can get hunkered down in behind these you can virtually disappear.  The other key thing to consider if hiding in the shadows is not possible is to keep a keen eye for the shadow that you cast.  The key concept being the further you protrude from the ground or water, the large shadow you will cast.  Try to get as close to the ground or water as possible.

Have you used shadows to conceal yourself while duck hunting?