for canvasbacks just call like a mallard (not feed call) and they seem to come in better than if you use the brrrrrp brrrrrp for bluebills. Can hens actually quack like a mallard only not as loud or raspy. As for ringnecks being in the right place seems to me works better than any calling. I will wave my hat at the ducks when they are a long way off and I think that gets them to turn to the decoys and then let the decoys do the work for you.