The Farmer and the Cranes
Some Cranes made their feeding grounds on some plowlands newly sown with wheat. For a long time the Farmer, brandishing an empty sling, chased them away by the terror he inspired; but when the birds found that the sling was only swung in the air, they ceased to take any notice of it and would not move. The Farmer, on seeing this, charged his sling with stones, and killed a great number. The remaining birds at once forsook his fields, crying to each other, "It is time for us to be off to Liliput: for this man is no longer
content to scare us, but begins to show us in earnest what he can do." If words suffice not, blows must follow."
(see Wilson - The Swallow and the Birds)