It is exceptionally important that orphaned waterfowl are taken to licensed wildlife rehabilitator as soon as possible to prevent inappropriate imprinting on humans. Imprinting is a form of learning where a young bird learns to identify with their own species.
For young waterfowl, they imprint on their mother very quickly after hatching which allows them to follow their mother who will provide them with protection. If a young bird sees a human instead during this critical learning period, they will imprint on a human. Imprinting is a permanent, irreversible process, and if they are imprinted on a human, they will never relate to their own species, and can be dangerous to people once older if released into the wild.