Table 2. Acoustic features of drums produced during courtship by males of Pomatoschistus pictus and P. minutus.
| P. pictus | P. minutus | |||||||
| Acoustic parameters | Mean | SD | Range | Rangeabs | Mean | SD | Range | Rangeabs |
| Drum duration (ms) | 628.8 | 171.8 | 358.0–1118.8 | 29–4288 | 797.2 | 395.4 | 387.4–1914.1 | 108–8044 |
| No. of pulses | 23.3 | 6.5 | 11.2–38.0 | 2–139 | 24.8 | 12.1 | 12.2–62.7 | 3–229 |
| Pulse repetition rate (Hz) | 38.4 | 6.7 | 27.2–52.1 | 19.5–64.7 | 31.5 | 3.8 | 25.0–39.3 | 15.2–47.6 |
| Dominant frequency (Hz) | 229.8 | 18.0 | 194.2–255.0 | 144–266 | 151.9 | 19.6 | 126.7–187.9 | 94.7–236 |
| Drum interval (s) | 2.27 | 0.74 | 1.24–3.29 | – | 0.95 | 0.69 | 0.16–2.90 | 0.06–0.63 |
| Number of sounds in a burst | – | – | – | – | 3.5 | 1.58 | 1.1–7.0 | 1–12 |
| Drum burst duration (s) | – | – | – | – | 2.5 | 0.98 | 0.98–4.85 | 0.14–9.75 |
| Burst interval (s) | – | – | – | – | 81.3 | 71.14 | 5.8–289.4 | 0.5–867.3 |
| Drum calling rate(drum min−1) | – | – | – | – | 1.7 | 1.36 | 0.2–4.3 | – |
| Active calling rate(drum min−1) | – | – | – | – | 7.4 | 3.64 | 1.9–15.5 | – |
| Calling effort | – | – | – | – | 16.2 | 10.12 | 6.9–42.9 | – |
| Sound pressure level(dB re 1 µPa) | – | – | – | – | 90.7 | 5.11 | 83.8–98.1 | 78.5–137.3 |
| Sound production fatigue | – | – | – | – | 1.1 | 0.09 | 0.9–1.3 | 0.8–1.9 |
Descriptive statistics is based on male means except for absolute range values (rangeabs) that concern all data (P. pictus: 1073 drums and 884 sound intervals from 16 males; P. minutus: 580 drums and 594 sound intervals from 21 males). Sound intervals only concern interval up to 10 s.