Figure 3.

Nestling cuckoo responses to playback of host alarm calls and a control call, measured as: (i) time(s) spent gaping per second and (ii) number of begging calls per second, during a pre-test stimulation period (to measure baseline begging) and then three successive periods of the playback experiment; PBS (playback during stimulation to beg), PB (playback alone) and S (stimulation alone). Mean±1 s.e. are shown for: (a) reed warbler-cuckoos raised by reed warblers (n=9); (b) reed warbler-cuckoos raised by robins or dunnocks (n=7); and (c) redstart-cuckoos raised by redstarts (n=6). The different symbols refer to the different playback calls. In (b), the heterospecific alarm is robin for dunnock-raised cuckoos and dunnock for robin-raised cuckoos.