Fig. 11.13.

Referential alarm call playback. Playback was conducted over a two minute period. The number and type of responses were recorded for four different calls (including one control) and then tabulated. For the innocuous control calls, little interest was shown and brief visual checks were conducted. The generic alarm call led to more sustained interest but exclusively of looking around. However, when the ‘eagle’ alarm call was played highly vigilant behaviour followed. The chief difference to other, and even mixed, calls was the strenuous effort in scanning overhead and the sky (last, white column). The grey column indicates movement of head starting with looking around but then also shifting the attention towards the sky. Note that the sound source is on the ground while the magpie scans the sky.