Cockatoos make the hook test

V gel bend their tools to the Angel at least some

Done: With the self-bent hook this Goffini cockatoo fishes the basket with the delicious nut. © Bene Croy
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Clever birds: After the crows, Goffin's cockatoos have now passed the "hook test": with a little trial and error, the birds learn to bend a wire so that they can fish a food basket from a pipe with it. However, only a minority of the test cockatoos mastered this complex process - possibly because, unlike crows, these birds do not naturally know and use tools, the researchers speculate.

Fifteen years ago, Betty astounded the scientific community: biologists watched as the animal bent a hook from a wire to fish a small basket of food from a tube. Meanwhile, other birds are known to use and make tools. The Goffin cockatoos, in particular, have turned out to be astonishingly clever: They crack safes, conclude logically and weigh very carefully whether it's worth making a bet.

A wire, a nut and a tube

Whether the clever cockatoos can also compete with the crow Betty, Isabelle Laumer from the University of Vienna and her colleagues have now examined. "We confronted our cockatoos with the same problem as Betty: The birds were given a basket filled with a cashew nut at the bottom of a vertical Plexiglas tube and the only aid was a straight piece of wire, " says Laumer.

In order to access the contents of the basket, the birds had to bend the wire into a hook, insert the tool in the correct direction, hook the hook into the handle and pull up the basket - a complex sequence of steps. In another experiment, the cashew nut was in the middle of a horizontal tube. In order to eject the food, the animals had to bend a piece of wire bent by 90 degrees.

The cockatoo bends the piece of wire with its beak. © Bene Croy

Hakentest passed ...

Would the cockatoos master these tasks? The experiments showed that, in principle, Goffini cockatoos, after some trial and error, also understand how they reach their food with the help of the hook. "The cockatoos showed different techniques to bend the hooks, " reports Laumer. "Mostly, however, the hook was bent directly with the beak and then immediately introduced the self-made tool." Display

This is particularly exciting because the Goffin's cockatoos, unlike Kr hen are not accustomed by nature to use tools. "The innovative ability of the birds surprised us: unlike Kr hen they had no prior experience with hook tools, " explains senior author Alice Auersperg. "They are not specialized in building or using tools, nor do they bother building nests."

But: not a good success rate

This could also explain why not all cockatoos have coped with the task: of the 13 cockatoos, only three managed the hook test. The straightening of the wire understood at least four of them. "The fact that only some cockatoos have come to the solution and that the technique of bending the hook differs from animal to animal suggests that the cockatoos have solved the problem quite individually and did not resort to innate stereotypical behaviors, "explains Auersperg.

In contrast to the crutches, the cockatoos have to work their solutions completely new and learn unusual behaviors for them. "The general intelligence of the Goffin's cockatoos apparently allows them to solve unusual problems that they usually do not encounter in the wild, " concludes Auersperg. (Proceedings of the Royal Society B, 2017; doi: 10.1098 / rspb.2017.1026)

(University of Vienna, 06.09.2017 - NPO)