Bird Brains VI

We have previously reported on incredible crow intelligence in several editions of News to Note: “Bird-Brained Toolmakers,” “Crows and Their Tools,” “Birds Able to Cooperate and Solve Problems,” “Crows May Outsmart Chimpanzees and Dolphins,” and "April 11, 2009, “And Don’t Miss” item .

In this case, scientists studied four captive rooks named Cook, Fry, Connelly, and Monroe. Although rooks are a type of crow, they have not been observed using tools in the wild, as have known tool-using New Caledonian crows. Nonetheless, the four-rook team used the tools as well as even wild chimpanzees.

For one experiment, the rooks were shown a vertical tube that extended to a trap door holding a worm—just out of reach. There were also several different-sized stones nearby. The rooks were smart enough to drop the largest stone onto the trap door, thus allowing them to get to the worm. They also were able to determine which shape of stone would fit through the tube.

In another experiment, the rooks were able to rival the sophistication of other captive crows and succeed at “meta-tool” use: employing one tool to enable the use of another tool. Presented with two vertical tubes of differing sizes, the rooks figured out how to use a large stone in the large tube to obtain access to a small stone, which they could then use to open the trap door in the small tube and obtain the worm. Besides the rooks, only New Caledonian crows and chimpanzees have demonstrated meta-tool capability.

The most complicated of the experiments presented the rooks with a piece of straight wire and a vertical well. At the bottom of the well (out of reach) was a bucket of food. Motivated by the reward, the rooks bent the straight wire into a hook shape, dangling the hook down to retrieve the bucket. What’s more, three out of the four rooks knew to create the hook on their very first try. This demonstrates that rooks can not only use tools cleverly, but also fashion them for specific purposes.

“The study shows the creativity and insight that rooks have when they solve problems,” explained the University of London’s Nathan Emery, one of the researchers. Another, Christopher Bird of Cambridge University, added, “We have found that they can select the appropriate tools out of a choice of tools and they show flexibility in the types of tools they use.”

One of the questions now is whether crows have broad general intelligence, or whether they have a more specific intellectual capability when it comes to tool use. And while the researchers chalk these “bird brains’” abilities up to evolution, we can see it as a mark of design. Not only that, but these birds’ mental abilities remind us that it’s not only chimps that have incredible animal intelligence.