Abstract stone carving by the prehistoric cultures of North America.
They resemble birds and are about 6 in. (15 cm) long. Many were carved from black, brown, or dark green slate and polished with sand or other abrasive materials. All feature a pair of conical holes running diagonally through the base. They may have been used as weights or handles on a short rod (known as an atlatl) used to hurl spears or arrows.