The Stymphalian birds (ancient Greek Στυμφαλίδες ὄρνιθες Stymphalídes órnithes), also called stymphalids, were crane-sized birds of Greek mythology. They lived at Lake Stymphalos in Arcadia and were a nuisance because they shot their brazen (iron) feathers like arrows at people and destroyed crops. The hero Heracles drove them out or killed most of them.
The Stymphalian birds had their nesting places in the reeds of the lake Stymphalos. This stagnant body of water (lake without surface drainage and with varying water surface), known since time immemorial, is also today a nesting and resting place of endemic birds and of migratory birds. The lake is located in sparsely populated mountainous terrain at an altitude of about 600 m, which was counted as Arcadia.
The Stymphalian birds possessed iron beaks, talons, and wings and could even penetrate the armor of warriors with them. In addition, they could shoot their metal feathers like arrows specifically at their victims. The stymphalids raged among the people and animals of Arcadia.
Heracles was given the task of driving the birds away as part of the Twelve Labors of Eurystheus. However, since their number was extraordinarily large, he received from Athena large metal rattles that Hephaestus had made. Through the noise that the hero made by constantly banging the rattles together, he was able to scare away the apparently frightened birds.
According to another variant of the myth, he only scared them away by the noise of the rattles and then killed them with his arrows. To protect himself from their iron feather arrows, he used the two rattles as shields. After he killed most of the birds, the rest fled.
According to the Argonaut saga, after their expulsion by Heracles, the surviving birds dwelt on the island of Aretias or Ares Island in the Black Sea.
When the Argonauts were on their voyage to Colchis, Phineus prophesied to them that after passing the Mossynoics they would come to a lonely island long inhabited by numerous vicious birds and would chase these birds away with much cunning.
After the Argonauts came near Ares Island, one such bird appeared first and shot a sharp feather at their ship, wounding Oileus in the left shoulder so that his oar slipped away. Erybotes removed the feather and dressed the wound. But a second bird already appeared, which Klytios killed with an arrow before he could shoot pointed feathers at it.
Amphidamas pointed out that there were so many of these birds on the island that they did not have enough arrows to shoot them. He himself had observed that Heracles likewise did not control the birds at Lake Stymphal by this method, but drove them away by the noise of an iron rattle struck against a rock.
Amphidamas therefore subsequently advised the Argonauts to put on helmets with bushes; then one part of them should row and the other hold lances and shields over them to withstand the attack of the birds. They were also to frighten the birds by roaring loudly.
As soon as they reached the island, they were to make a great noise with their shields. The plan of Amphidamas was put into action, and the Argonauts succeeded in driving the birds, whose launched feathers bounced off the shields, away from the island.
According to Mnaseas, the Stymphalids were not birds, but daughters of Stymphalos and Ornis. Heracles killed them because they had not received him, but had entertained the Molions who were hostile to him.
However, on the pediment of the temple of Artemis at Stymphalos they were depicted as birds, and behind the temple were statues of maidens with birds' feet. The classical philologist Otto Gruppe considered the Stymphalides to be storm demons.
In Greek pictorial art, Athena's rattlers are never depicted. Instead, Heracles is always shown at the moment when he shoots the startled birds with a slingshot or a bow and arrow.
The constellations Swan, Vulture (today Lyra) and Eagle are thought to represent the Stymphalids and together belong to the Heracles family.