So say scientists writing this week in the journal Proceedings of the Royal Society B.
Christopher Bird from the Department of Zoology at the University of Cambridge and colleague used simple experiments on adult rooks to test whether they could understand that certain situations are impossible.
Using a concept called the 'Expectancy Violation paradigm' - where subjects in an experiment look for longer at an image that they think is strange or unexpected - the researchers were able to show that the birds don't expect objects to be floating in mid air, and therefore understand that due to gravity, still objects need to be supported.
Seven rooks were each shown four sets of images during the experiment. Because rooks naturally like to peep through holes, the research team set up an LCD screen behind a wooden board with a small hole in it for the rooks to look through. They then displayed the images on the screen.
In each experiment, the birds were shown two images of a possible situation - a Kinder Egg resting on a wooden platform, and two 'impossible images' where the egg was in a gravity-defying position such as floating in thin air above the platform.
The rooks spent significantly longer looking at the impossible images than those that were viable, suggesting that rooks don't expect objects to be hovering in mid air. Not only did the birds understand that contact between the egg and the platform were necessary in order for the object to be supported, but they also had an understanding of the type of contact needed and the amount of contact a concept which is lost on babies until they are over 6 and a half months old, and which chimpanzees never manage to grasp, even as adults.
This research provides evidence that rooks can solve complex problems through comprehension rather than through trial and error learning, and might cause us to question just how smart the animals really are.