I'm sure that a mallard spread is all you need, but a few different species mixed in your spread definitely will not hurt. For example, from what I've seen teal tend to hangout with their own kind and pair off, so some tealdecoys in the spread will probably make them more likely to light into your spread. Also, it would just make your spread look more realistic. Greenhead Gear has some puddler packs if you didn't already know, that have 6 decoys, like drake/hen pintail, teal, and gadwall decoys. Like I said, i dont thinkits a necessity, but it would hurt at all.