Summary: Realism is one of the most crucial elements of waterfowl hunting but it is also one of the most overlooked areas as well.
For example, many years ago on a spring scouting trip, I had the opportunity to watch and listen to thousands of ducks and geese that were sharing the same small pothole. There were mallards, pintails, gadwall, widgeon, teal, shovelers and Canada geese. I spent over an hour watching the birds on the water interact with each other as well as watching new flocks of ducks and geese join in.
What amazed me the most were the sounds that came from all of the birds on the water and in the air. Quacks, whistles, peeps, chuckles, clucks and honks were only some of the sounds I heard and I realized then and there that when hunting with multiple species of waterfowl in a spread, to become as realistic as possible, you need to produce more than one sound.
For instance, if you were duck hunting and your spread consisted of mallard, pintail, widgeon and Canada goose decoys, how do you think it sounds and appears to ducks when all they hear is a mallard call and nothing else? It doesn't sound or appear real.
To increase your realism, use a pintail and widgeon whistle, your mallard call and a goose call while working the birds. This is especially effective technique if you have 3-4 hunters calling and one or two of the hunters use different calls. By creating the various sounds that each species produces, you have, in effect, made your decoy spread come alive.
Although you may get some stares and laughs from the hunters around you, they certainly won't be laughing when you're the group that is taking home a limit of birds.
For duck calling instruction be sure to check out these Duck Calling DVDs.