Table 1.
Mean (±s.e.) call features and postural begging intensity for tree swallows in Noise and Quiet playback treatments. (Noise treatment was 65 dB white noise; Quiet was 50 dB ambient laboratory noise. F, d.f. and p values for treatment effect from mixed model ANOVA.)
| variable | noise | quiet | F | d.f. | p |
|---|---|---|---|---|---|
| length (ms) | 33.0±3.61 | 32.5±9.94 | 0.62 | 1, 5 | 0.62 |
| amplitude (dB) | 67.1±1.36 | 53.2±1.89 | 26.64 | 1, 5 | 0.0002 |
| peak frequency (kHz) | 5.63±0.66 | 5.24±0.59 | 1.39 | 1, 5 | 0.26 |
| frequency range (kHz) | 1.67±0.15 | 1.81±0.19 | 0.42 | 1, 5 | 0.55 |
| rate (calls min−1) | 112.0±9.80 | 99.0±22.60 | 0.41 | 1, 5 | 0.55 |
| postural intensity | 2.06±0.05 | 2.20±0.35 | 0.24 | 1, 6 | 0.64 |