Types of birds hunting decoys
Decoying is not just a technique but an art, and that's the reason behind the success of some birds hunters and the catastrophic fail of many others.
No matters if you are out for ducks or geese, if your decoys are not properly set, you won't get good results, no matter how many of them you deploy out there.
In order to know how set your decoys, it's mandatory to know what kinds are available, on this regard first thing to do is to choose decoy species. As in nature, decoys come with all kind of sizes and colors, each one mimicking a particular bird specie; however rarely a single specie is moving around but on groups, and almost universally mallards are present, so mallard decoys may be mixed with all other kind such as pintails, teal and gadwalls.
Despite of the species, decoys come on three different sizes: regular, magnum and super magnum. The bigger the decoy is, better the visibility, however choosing the proper size is important as well mixing different decoy sizes, otherwise the result 
will be "unnatural".
Regarding materials, modern technology has lead to lightweight, realistic, thermoplastics built in decoys, which are most expensive but always available. Additionally it's possible to get old fashioned with wood decoys or use hard foam or cork decoys. Once again, proper mixing is the best guarantee of success.
Decoys may also be full bodies, shells or silhouettes. Experience says that not a single pattern works better alone, instead a mix of different decoy shapes is the best option.
Full body on sitting or standing position decoys are very realistic but also heavy weighted, so they must be mixed with shells and shapes in order to allow hunters to have more decoys while increasing visibility because of number, size and density.
Finally don't forget about floating decoys to add an extra touch or realisms. Floating decoys used wisely are able to catch birds attention better than stationary decoys, thus try to include always a bunch of floaters when deploying your decoys to attract birds towards your position.
At the end, everything depends of your personal experience and how good you know the birds behaviours. Remember, the key is not about expensive decoys or a huge decoys deployment, instead a natural looked, mixed, well balanced decoy spread will be the key for success. So next time out for birds, evaluate different decoys setting strategies in order to determine which one works better for you.
