Sometimes they are more on the ball than i think.

[DukesDucks]

It is interesting to watch ducks stare at things going overhead. I had also heard about the sleeping with one eye open ability. When my ducks are out free ranging, I have noticed that they tend to sleep together close to something, and that one of them seems to be the watcher.

 

[Magnolia Ducks]

I always have a watcher. They take turns doing this.