The purpose of this section is to work on a 3-note cadence. Cadences refer to rhythmic sequences or flows. This is a term used in music and poetry to describe how things are said, repeated, timed, etc. In our case, cadence refers to how we use the basic quack, its rhythm, and its sequence.
Before landing, flying ducks will often fire off a 4-5 note cadence as they approach swimming ducks on the water.