King Brahmadatta was very talkative, and his minister, the Bodhisatta, sought an opportunity of admonishing him. This opportunity occurred while they were watching a crow’s nest in which a cuckoo had laid an egg. The crow watched over it and fed the young cuckoo after its birth. One day the cuckoo cried before it was grown up, and the crow killed it and threw it away. The king inquired of the Bodhisatta the reason for this, and he explained that the garrulous who talk in and out of season meet with a similar fate. The king was cured of his evil habit.
The story was told in reference to Kokālika, who is identified with the young cuckoo. J.iii.102 f