Fig. 2

Still-frame sequence from a video showing Aigaios using a natural stick to move a large wooden ball (Observation 2; time stamps in parentheses). a He attempts to pick up the ball but fails (0:58); b he picks up an experimental stick (see Fig. 1d), fails to insert it into the hole in the ball, tries to pick up the ball with his beak but fails again, and then leaves the experimental area (1:48); c he returns with a thin non-experimental stick and inserts it into the ball (6:44); d the stick-and-ball combination allows him to lift the ball off the table (6:53); e he moves the combined object (6:57); f he puts tool and object on the table and leaves the experimental room (6:59); g he returns and looks down the tool into the hole in the ball (7:29); h he grasps the stick and leaves the experimental room, simultaneously transporting tool and target object (7:33)