According to a Guarani indigenous legend from southern Brazil, a young man named Jaebé fell in love with an indigenous woman and went to ask for her hand in marriage.
The girl's father asked Jaebé what proofs he could provide to marry his daughter, and the young man replied that it would be proofs of his love. The girl's father told him that the last suitor promised to fast for five days but died on the fourth day.
Jaebé challenged him by saying that he would fast for nine days. Jaebé was wrapped in a heavy tapir hide and remained under constant surveillance day and night to ensure he was not fed. The girl cried and pleaded to the goddess Moon, Jacy, to keep him alive. Time passed, and one morning the daughter asked her father not to let him die, but her request was not granted. When the trial ended, they opened the hide, and Jaebé jumped out swiftly, his eyes were shining, and his smile had a magical light; he no longer belonged to the physical spaces of this world.
Touched by his capacity to love, Tupã (God) transformed him into the joyful and singing João-de-Barro.
In love, upon seeing her beloved transformed into a bird, she asked Jacy to also enchant her as a little bird. And that is how João-de-Barro always has a lifelong companion, to whom he is faithful.