Aesop tale more than just a fable.

A FAMOUS Aesop's fable about a canny crow with a knowledge of physics is more than just folklore, scientists have shown.

Researchers found that rooks, members of the crow family, can use stones to raise the level of water in a container - just like the bird in the tale The Crow And The Pitcher.

In the story, written thousands of years ago by the Ethiopian slave Aesop, a thirsty crow finds a pitcher containing too little water for his beak to reach.

He solves the problem by throwing pebbles into the pitcher one by one, until the water level rises high enough for him to drink.

A similar challenge faced the rooks studied by the appropriately named Cambridge University zoologist Christopher Bird.

In a series of tests, the four rooks named Cook, Fry, Connelly and Monroe were offered a tempting treat - a juicy worm floating on the surface of water in a vertical tube.

To start with, the worm was out of reach. Videos show the birds examining the tube from different angles, appearing to think the problem through.

Then the researchers provide a solution in the form of a handful of pebbles. The rooks can be seen picking up the stones and dropping them into the tube to raise the water level and bring the worm within reach.

Cook and Fry succeeded straight away; Connelly and Monroe took two attempts.