Daphne Duck, according to Don Rosa's story "The Sign of The Triple Distelfink", is the daughter of Humperdink Duck and Elvira Coot. On the day of her birth, a traveling worker painted a giant sign of The Triple Distelfink on her parents' stable. The symbol was supposed to bring the baby luck, and it did: Daphne was always incredibly lucky.
She worked in her parents' farm until at least 1902. Later, she stopped working and started living on the things she won in contests.