How can I distinguish between rock pile types cairn, duck, and natural?

Question

I've seen cairns while hiking in mountains and they are usually easy to distinguish from natural rock piles. However, I am a bit confused by what makes a duck and what distinguishes it from a cairn or a natural rock pile. The Wikipedia entry for cairns indicates that ducks are cairns that have "beaks" pointing in the direction of the trail.

On the other hand, this survivallife.com webpage says that ducks are smaller than cairns and can be made from as few as three stones. This would seem to make ducks much more difficult to distinguish from natural rocks piles. So, what is the best way to distinguish between a cairn, a duck, and a natural rock pile?

Answer 1

In short,

• Cairn -> many rocks piled up
• Duck -> 3-4 rocks stacked on top of each other.
• Natural -> Small rocks don't stack directly on top of each other, gravity tends to spread them out.

In any case, they usually aren't necessary, except in places with lots of fog such as the White Mountains of New England, and their construction is usually frowned upon.

See here for an example of people putting up way too many of the things.