We have several families of ducks nearby.
We have been told that these are Australian Wood Ducks. Australian Wood Ducks nest in hollows of trees, often some distance from water. Shortly after they hatch, the ducklings are jettisoned over the side of the nest, and fall to the ground. The proud parents then escort the ducklings to water green pastures.
Further, Australian Wood Ducks are actually a species of goose.
To add to the confusion, the Australian Tree Duck is more commonly called the Whistling Duck because it only occasionally roosts in trees, but whistles incessantly.
The things you learn!