Just cause I like this topic and it's what I deal with on a daily basis I'll beat this dead horse just a little more.
Food is only one part of the equation and it relationship with improved bird use is a very difficult one to understand because of all the factors involved. Waterfowl eat a variety of foods during their migration. Moist soil food plants (watergrass, smartweed, swamp timothy, etc) are all highly desirable to waterfowl (depending on species). Waterfowl also depend on a wide variety of agricultural food resources as well (rice, wheat, peas, corn, etc). The use of waterfowl to these agricultural resources depends on many factors (availability, weather, seasonal period, etc). Waterfowl also depend a great deal on submergent vegetation and invertebrates. By the second half of the season here in CA, pretty much all the ag waste grain and corn has been eaten up or destroyed by the elements. Birds switch to invertebrates to add the protein reserves they need for the upcoming egg laying.
As a private lands biologist, it kills me when I have a landowner who insists on planting peas (not grown in California) to hunt ducks over because he had a great mallard shoot in Canada over peas. Inevitably the ducks don't hit it and it's a waste of time and money.
Some theories that I've come to accept are 1) We're all farmers at heart and when in doubt we'd all rather plant something. 2)Waterfowlers are an impatient group always looking for the silver bullet. 3) Ducks are no different than people. I'd certainly choose eat hotdogs from a place where I won't get shot, rather than prime rib from a spot with a bunch of people who want me dead.
As a duck hunter, I'd go with good thermal cover and minimized disturbance over wall to wall food any day.
DD
