In the Twelve Labors of Hercules, what kind of feathers did the Stymphalian Birds have?

The Stymphalian Birds had bronze feathers that they could use as deadly projectiles.

These man-eating birds lived around Lake Stymphalus in Arcadia and formed the subject of Hercules’ sixth labor. Their feathers were described as hard and metallic, allowing the birds to attack people from the air. The birds also had poisonous or dangerous droppings in some versions of the myth.

Hercules struggled to make the birds leave their dense marshland habitat. Athena helped him by providing a loud clapper, sometimes described as a rattle made by Hephaestus. The noise startled the flock into the open, where Hercules could shoot many of them with his bow.

Ancient writers do not describe the episode in exactly the same way. Some accounts say Hercules killed the birds, while others say he drove them away permanently. The bronze-feather detail is the most distinctive physical feature of the creatures.