Apes, crows and dolphins have been seen to make and use tools. Now, captive rooks have joined the band of animals who are “tool users.”
Rooks have not been seen to use tools in the wild. But not only can they use tools, they can use two in succession and they can make new ones. This BBC article reports research in which the rooks worked out how to get a food treat from a apparatus consisting of a tube and a small trap door. They needed to choose a suitable stone and drop it into a tube to release the trap door and get their treat. They chose the heaviest stone as the most likely to be weighty enough to make the trap door open. They also had to choose from different-shaped stones, not all of which would fit into the tube. They chose the best-shaped stone! Here’s the film of the clever rooks with rocks.
Rooks are even more clever than we thought. Photo: foxypar4
The birds also quickly learnt how to bend a straight piece of wire to make a hook, so they could pull up a small container with food in it from the bottom of a test tube. It is amazing to see! Watch the film clip.
Betty, a captive New Caledonian crow, was the only captive bird who had previously been seen to do this. Crows in the wild do use tools, such as twigs and leaves. They use their beaks to make these tools into a satisfactory shape and then pick up ants and other insects. They also use grass stems. The rooks showed they can use and make tools too; three out of four made a hook in their first trial. One of the researchers pointed out: “The study shows the creativity and insight that rooks have when they solve problems.”
Rooks also understand that they can work in pairs to get a good food source. In this experiment, also reported by the BBC, researchers put two hooks on a small tray which had treats for the rooks, and then put a length of string through the hooks. The rooks were in an enclosure and the tray was just out of their reach. To pull the tray to them and get the food, each rook needed to pull on the strings at either side of the tray. The rooks all worked this out – some immediately and others took a bit longer. The rooks’ understanding of this “need for team work” is said to be as good as that of chimpanzees. Here’s the film clip of the dexterous rooks.
Rooks and crows are both in the corvid family, along with jackdaws, jays, magpies and ravens. These birds have long had a reputation for being clever and researcher Nathan Bird at the University of Cambridge said: “I would rate corvids as being as intelligent as primates in many ways.”
Tags: captive, corvid, crow, Intelligence, jackdaw, magpie, raven, rook, sentience, tool use, wild
[...] such advanced abilities, but we are increasingly learning that we are not so unique after all (see Rooks, [...]