The Bodhisatta was once a bird. He lived on an isolated island and was the leader of a large flock. One time a ship sank near the island, and a crow from the ship flew there to safety. The crow wanted to eat eggs and chicks, so he flew to the other birds and stood amidst them on just one foot with his mouth open. They asked the crow what he was doing, and he told them he was a holy being who ate nothing but the wind; and if he put his other foot down, the earth could not bear his weight. He then gave them a short sermon about the importance of practicing virtue and greatly impressed the birds.
As the crow had predicted, the birds asked him to watch over their nests when they went out to feed. While they were away, the crow ate his fill, and then went back to his perch. When the birds returned, they were distraught and wondered who the killer was, but did not suspect the crow. After a few more days of this same thing happening, the Bodhisatta realized the problem only began after the crow had arrived on the island. The next day, he went off to a hiding place instead of going to their feeding grounds, and he saw the crow eating their young. When his flock returned, the Bodhisatta told them the truth about the crow and ordered him killed, striking the first blow himself.
In the Lifetime of the Buddha
The crow was an earlier birth of a deceitful disciple of the Buddha. He told this story so others knew that this disciple had also been deceitful in the past.