A second duckling walks by, again, covered in shit. The man feels bad and again takes a tissue and wipes this duckling clean, and lets it walk again.
Now, a third duckling walks by. Again, covered in shit. The man starts to wonder where the hell are all these ducklings coming from, but he takes another tissue, wipes it clean and lets it continue walking.
After a minute or so the man hears a deep voice behind him, saying:
“Hey, you got a tissue for me too? I ran outta ducklings.”