Eurystheus sent Hercules to kill the Stymphalian birds for his sixth labor. They were some seriously nasty birds – man-eating, beaks of bronze, sharp metallic feathers they could launch at their victims, and their dung was highly toxic. And if that wasn’t enough to keep someone away, they were also sacred to Ares, the god of war.
The birds had settled in Arcadia to escape a pack of wolves, breeding quickly around Lake Stymphalia and destroying both crops and townspeople. Hercules couldn’t reach them because of the swamp around the lake.
Athena noticed Hercules’ dilemma and supplied him with a rattle to scare the birds into flight. Hercules shook it, then shot many of them with his arrows. The rest flew off and never returned.
Hercules took some of the dead birds back to Eurystheus. No doubt, the King was sorely disappointed to see the hero return and sent him quickly on to his next task.