A version of the tale also appears in A Book of Ogres and Trolls, by Ruth Manning-Sanders.
He refused food to two beggars and threw stones at birds that looked for crumbs.
He found the same cave and realized from bones and scraps of cloth that it was an ogress's lair, but remained.
The next day, the ogress set him to spread the feathers from her pillows to dry them and put them all back.
These proved to be the princess, a chest filled with gold and jewels, and a magical ship that moved over land and sea.