I have found that a lot of it depends on where you are hunting them. In Western Kansas where a average wind is 20+mph, I can burn up a whole lot of ammo sitting over a pond. Here in Eastern Kansas, my shot to kill ratio is much better cause they aint flying near so fast! When you have 4 or 5 of them coming in at a time with a 20 or 30 mph tailwind, those buggers are flat crankin when they come over the pond!!
Still isnt much better than going out opening day and shooting several boxes of shells. Woke up many mornings after opening day with a black and blue shoulder!