Rook

　The crow that breeds in northeastern China and migrates to Japan for the winter. Once rarely seen outside Kyushu, it is now observed nationwide, including Hokkaido.

　They often move in large flocks, sometimes numbering several hundred. In the Izumi Plain, they forage in farmland, and by evening, one can see them clustered like bells on power lines near residential areas.

    In Aesop’s fable “The Crow and the Pitcher”, a crow appears that uses tools. The story describes a crow dropping pebbles one by one into a jug containing only a little water, raising the water level so it could drink. Experimental results show that captive rooks also exhibit this behaviour: to reach earthworms floating in water inside a tube, they stack pebbles to raise the water level to the worms’ position. This proves that crows possess the ability to use tools flexibly.