Silk,
In any kind of calling, the fact that you are so close to the call often impairs your ability to hear yourself.
Recording your own calling, and listening to it, is one of the best ways to improve.
Likewise, some recordings of real ducks, to mimic while you practice, is a great way to get better. Cadence is usually what most intermediate callers lack, making a "quack" isn't that hard, it's getting seven of them with the right rhythm... three times in a row.
My Uncle always said, "Good sets kill more birds than good calling", and he was a really good caller.

Krusty
