Heracles killed the Stymphalian birds using a bronze rattle or clappers supplied by Athena. The birds were man-eating creatures that terrorized the area around Lake Stymphalia in northern Arcadia. Their metallic feathers and dangerous flocks made them difficult for an ordinary fighter to confront.
The episode was the sixth of Heracles’ Twelve Labours, assigned by King Eurystheus. Heracles could not easily reach or shoot the birds while they remained hidden in the dense marshland. Athena therefore gave him a noise-making device, often described as a rattle or bronze clappers. The sound startled the birds into the air, where Heracles could attack them with his bow and arrows.
Ancient versions differ over the exact number of birds and whether Heracles killed all of them or drove many away. The central story remains consistent: Athena’s bronze instrument created the opening, while Heracles supplied the combat skill. The birds are sometimes confused with the Harpies, but they are a separate group of creatures in Greek mythology.