Dryad Exp 2 Zhou et al

Data for Experiment 2, examining the effect of noise of different frequencies, but constant amplitude (58 dB at 10 m), on the response to aerial alarm calls (52 dB at 10 m). Alarm calls have a mean peak frequency of c 9.1 kHz. Noise was of a frequency that either overlapped with the alarm calls (6–10 kHz) or did not overlap the alarm calls (2–6 kHz). The data also include the proportion of time the focal bird had its head up in the 10 s of noise immediately before the alarm call. Each location received a unique set of every playback type. Playbacks included alarm calls mixed with noise, and control playbacks of noise alone or alarm calls alone. The amplitude of ambient noise was recorded after each playback.