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Researchers have reported observing crow-relatives called rooks use the same rock technique to get to a worm floating on the water in a narrow container. Three of the birds were used in the experiment. In previous experiments, crows and rooks have been shown to have used other tools like sticks (left). According to the scientists, the rooks appeared to get the idea that larger stones will do the trick faster.
Christopher Bird of Cambridge University and fellow researchers used a six-inch tall plastic tube filled with water with a worm floating on top. Bird (the researcher, not the rook) noted that the rooks appeared to estimate how many stones were needed. It's something to think about and one reason why the term "bird-brained" shouldn't really mean "stupid" anymore.
In Aesop's time, rooks were also called crows. Ever wonder why they were eventually called rooks? Perhaps they like to use rocks?