The Stymphalian Birds were a flock of monstrous, man-eating birds with beaks, claws and feathers of bronze, which infested the marshes of Lake Stymphalia in Arcadia — the quarry of the sixth Labour of Heracles. They darkened the sky in their multitudes, fed on human flesh, and loosed their metal feathers like arrows; driving them off required not strength but cleverness and the help of a goddess.
The Birds of Bronze
The Stymphalian Birds were sacred to Ares, the god of war, and were said to have bronze beaks, sharp metallic feathers that they could shoot like darts, and toxic dung that poisoned the crops. They had bred to a vast and uncontrollable number in the dense marshes around Lake Stymphalia, where they fed on the local people, and their sheer multitude — a whole sky-darkening swarm — made them impossible to fight by ordinary means. They were a plague with wings, a living storm of metal and hunger.
The Sixth Labour
King Eurystheus sent Heracles to clear the birds from the marsh — but the ground was too swampy to walk on and too watery to support a boat, and the birds too numerous to shoot down one by one. The solution came from the goddess Athena, who gave Heracles a great rattle or pair of bronze castanets (the krotala), forged by the smith-god Hephaestus. Standing on a height, Heracles shook the rattle, and its tremendous clashing din so terrified the birds that they burst into the air in a panicked cloud — whereupon the hero shot down great numbers of them with his arrows as they fled, and the rest scattered far away, never to return.
The Survivors and the Argonauts
The birds that escaped Heracles were said to have flown to an island in the Black Sea, where they were later encountered by Jason and the Argonauts, who drove them off in turn by clashing their shields and spears — borrowing Heracles's trick of frightening the metal birds with noise. Thus the creatures linked two of the great hero-cycles of Greek myth, a plague passed from one band of heroes to the next.
The Cleverness of the Labour
The Stymphalian Birds endure as a reminder that not all of Heracles's Labours were won by raw might. Against an enemy too numerous and too elusive for strength, the answer was ingenuity and a god's gift — noise to break their nerve, arrows to thin their ranks. They embody the Greek delight in the clever solution, the labour that defeated a sky full of bronze not with muscle but with a rattle.
An entire sky of man-eating bronze birds was defeated not by a sword but by a clatter loud enough to break their courage.