In Greek mythology, the Stymphalian Birds were birds with claws of brass and sharp metallic feathers they could launch at their victims, and also they were Ares' pets. Furthermore, their dung was highly toxic. They had migrated to Lake Stymphalus in Arcadia to escape a pack of wolves, and bred quickly and took over the countryside, destroying local crops and fruit trees. Ridding the land of these birds was one of Heracles' Twelve Labors, and some sources claim the Stymphalian birds were the same avians that attacked the Argonauts.
The forest around Lake Stymphalus was very dense, making it so dark as to impair vision. Athena and Hephaestus aided Heracles by forging for him huge bronze clappers, which scared the birds into flight. Heracles shot them down with his arrows, or according to other versions, a catapult. The birds that survived never returned to Greece.