Figure 1.

(a) Side and (b) plan views of experimental situation. In experiment 1, the predator faced directly towards the aviary unit (predator A) or directly away. In experiment 2, the predator faced directly towards the aviary (predator A) with eyes showing or eyes covered. In experiment 3, the predator faced directly towards the aviary with eye-gaze directed either laterally towards the food source (predator B) or laterally away from the food source (predator C). The experimenter (E), sitting behind the predator, recorded the starlings' responses to the human predator without providing face cues (head is obscured by a fine-mesh stocking hood). A starling was considered near to the food in zone N (forward and below the lowest perch) and within bird's reach of the food source in region F.