Birdstone of banded claystone

From Ohio, North America
Late Archaic Period, 1500-1000 BC

A counterweight to help launch a projectile

A birdstone was used as a weight in an atlatl, or throwing stick. This was a tool in use in much of Meso- and North America, for 'flick-levering' a projectile or dart over the shoulder. The earliest evidence for the use of a throwing stick comes from the Upper Palaeolithic, in the Mahgreb, 40,000 years ago. It was still in use among Inuit until well into the twentieth century.
The technique of using the forefinger to launch a projectile is still used by the Iroquois in the winter game of snowsnakes, in which weighted projectiles are flicked along a channel in the snow. Players compete for the distance achieved.

The bow is a more recent introduction into North America, perhaps arriving from Asia between one and two thousand years ago.

J.C.H. King, First peoples, first contacts: (London, The British Museum Press, 1999)