Vernon Jones (1912)
236. THE SWAN
The Swan is said to sing but once in its life—when it knows that it is about to die. A certain man, who had heard of the song of the Swan, one day saw one of these birds for sale in the market, and bought it and took it home with him. A few days later he had some friends to dinner, and produced the Swan, and bade it sing for their entertainment: but the Swan remained silent. In course of time, when it was growing old, it became aware of its approaching end and broke into a sweet, sad song. When its owner heard it, he said angrily, "If the creature only sings when it is about to die, what a fool I was that day I wanted to hear its song! I ought to have wrung its neck instead of merely inviting it to sing."
Aesop's Fables: A New Translation by V.S. Vernon Jones with illustrations by Arthur Rackham (1912). This book is available online at Project Gutenberg.