When little ducks swim two by two, they quack a bit, that's all they do. And when there's three of them or four, they sometimes quack a little more. But what is all this quacking for? Quack, quack, quack, quack, quack, quack, quack, quack, quack, quack, quack, quack. But if they could sing together, their song would soar like this. Yodel-le-hee-hoo, yodel-le-hee-hoo, yodel-le-hee-hoo.