For his Sixth labour, King Eurystheus sent Herakles back to Arcadia where he had previously captured the Boar of Erymanthus.

He told Herakles to find a lake surrounded by a dark dense forest that was home to a large flock of birds. Herakles' task, this time, was to kill all the birds. When he asked the king why the birds had to be killed, King Eurystheus said that they were savage birds with claws that could pierce armour and tear a person to pieces. No one had ever faced them and lived.