Of Birds and Their Gizmos
Animal behavior: You can learn a lot from a featherhead.
Once upon a time, we humans believed that our use of tools separated us from other animals. But Jane Goodall knocked the stuffing out of that theory in 1960, when she discovered a group of chimpanzees who fished for termites with sticks. Tool use has since been observed in many animals, and scientists want to know how each species learns it. Does the information come hard-wired, or
do they pick it up by watching others?
Sabine Tebbich of Germany’s Max-Planck Institute for Behavioral Physiology investigated this question in the woodpecker finch (Camarhynchus pallidus) of the Galapagos Islands. The bird uses twigs or cactus spines to dig out its lunch — except when it resides in moist areas that are plentiful with bugs, where it doesn’t use tools at all. Scientists paired tool-users with non-tool users to see if the skill would rub off on the ignorant birds. It didn’t. Next, fledglings were paired with both tool-using and non-tool-using adults. All of the fledglings, regardless of mentor, learned to use twigs. Tebbich concludes that all of the finches are probably “born with the program to learn this behavior. But if they don’t have enough stimulus or opportunities to practice early, they may not be able to perform it as adults.”
Meanwhile, another tool-using bird, the New Caledonian crow (Corvus moneduloides), has exhibited a different characteristic that we humans once thought was ours alone: the so-called “right-hand bias.” Some 90 percent of humans are right-handed, and many scientists have long thought this was tied to our use of language. That’s because our language circuitry is centered in the part of the brain that controls the right side of our bodies. According to Gavin Hunt of the University of Auckland, New Zealand, the crow also favors its right side when fashioning tools from leaves, which, like the woodpecker finch, it uses to get at bugs. After studying bill marks left on leaf material, researchers determined that the crow uses its right eye and the right side of its beak to carefully taper the gadgets. Hunt therefore suspects that the right-hand bias must be linked not to something specific, like language, but to something general, like the ability to carry out complex sequential tasks. He’s also proven that you don’t need hands to have a right-hand bias.