Corvids like this rook are clever animals - especially when it comes to foraging.
Reading Crows Crows can also solve complex tasks in a new context and thereby recognize abstract causal relationships. New Zealand researchers have found this out by means of experiments with Gerbil beak crows. The ravens used an auxiliary tool to get another tool, with which they finally reached a piece of meat. The crows show the ability to use a tool as a means to an end, which in a previous experiment has proved to be useless for direct food procurement. The scientists see this as a sign of cognitive skills that go beyond simple learning by trial and error. Rather, the crows could translate the abstract rule "an inaccessible object can be achieved with a tool" into various situations, say Alex Taylor of the University of Auckland and his colleagues. The scientists caught seven wild Gerbera crow crows (Corvus moneduloides) and presented them with a task that could only be accomplished in several steps: To get to a piece of meat in a box with hole, the crows had to use a long stick. This was but in a grid box and could be outmaneuvered only with a second smaller floor. In turn, the birds had to release this small stick from a string dangling from the ceiling. Four crows were already familiar from previous tasks with using a stick connected to a string to get food. The second group was even further? In addition, these crows had already used string or stick individually to reach a second tool. These advanced students had to connect only the individual actions. The "beginners" from the first group, however, had to learn new behaviors.

All three advanced crows were able to solve the problem easily in the first attempt. This also succeeded two crows from the group of four? the other two had to practice three or four times until they finally made it. Similar experiments had previously demonstrated the birds' amazing cognitive abilities. However, some researchers believed that the crows did not make any causal considerations, such as "a first tool is needed to acquire a second, which is then the key to food." On the contrary, the corvids would be attracted to unattainable things like a long stick in a box, and then fished it out with another shorter stick and only then realize that the food could be reached with the long stick.

However, in the current study, the crows' actions could not be explained with such a learning model: the scientists had made the short stick for the crows an unattractive object before the experiment. they let the crows try several times unsuccessfully to reach the piece of meat with this tool. According to Taylor and his colleagues, the crows thereby created the mental link "short stick equal to improper tool". Only a conscious realization that the short stick is needed as a means to get the coveted food, then could delete this association again and thus help to solve the problem successfully.

Alex Taylor (University of Auckland) et al.: Proceedings of the Royal Society B, online pre-publication, doi: 10.1098 / rspb.2010.0285 ddp / Thomas Neuenschwander advertisement


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