Birds coped with the difficult test the first time.
In the experiment, the crows had to use a short stick to drag a stone from a narrow tube. Then use another long stick, the crow had placed the stone in another tube, which allowed them to release the platform with a piece of meat. Each stage of the task were isolated from the other a wooden shield, so that crow could see only one part at a time. To further complicate the test, the scientists randomly changed the positions of the two tubes to crow focused on memory and found the right tool.
In order to successfully cope with the test, the ravens had to keep in mind the location of the long sticks, stone and meat, and then use this knowledge to plan. Many crows successfully coped with the task from the first attempt.