Gaze direction - A cue for hidden food in rooks (Corvus frugilegus)?

► We tested six rooks (Corvus frugilegus) in an object choice task. ► A human experimenter indicated hidden food with gaze cues in two experiments. ► In each experiment, one subject learned to find the food. ► When we increased the effort for the birds, they tended to rely on gaze cues.