Make Way for Ducklings!

One day I was sitting on my porch, and looking across the street, I saw a bunch of ducklings following their mom! They were walking right across a neighbor's yard.
We live about a block and half from a park with a pond, and the ducks were obviously heading in that direction. But to get there, they had to cross a high-traffic yellow line road! Others who were following the ducks with me actually stopped traffic to let them cross. Make way for ducklings, indeed!
I wonder how they cross the street when they don't have human crossing guards?