@Helveticus that is very clever indeed. i suppose they probably do that to other food sources they can't reach.
@Helveticus yes, they're surprising. here's a good book on their intelligence. new investigations are bringing more to light every day.
@holon42 Thank you, that will help satisfy my curiosity😀
@holon42 I wish I knew more about birds and their intelligence. I already read about crows having the intelligence of a 7-year old, but ducks?