Jumping.
Not an activity always associated with waterfowl, but some are adept at hopping up steps and branches. Jumping from a height though is seen in many species which nest in high places, such as Barnacle Geese, Wood Ducks or Hooded Mergansers. https://youtu.be/bDJw43BJtCE
When making a nest box it will help the ducklings get out if you use a little mesh under the entrance hole.
