Table 3.
Temporal structure measurements taken for complete duets at the pair level of analysis
| Temporal structure measurements | Code | Description |
|---|---|---|
| Interval starts (s) | INS | Absolute difference between the starts of female and male songs |
| Interval ends (s) | INE | Absolute difference between the ends of female and male songs |
| Coordination score | COR | (Observed amount of overlap between female and male syllables—mean overlap expected by chance)/ mean overlap expected by chance |
| Number of syllables | SYL | Number of syllables in a duet |
| Syllable length (s) | SLE | Mean duration of syllables in a duet |
| Syllable rate | SRT | Number of syllables divided by the duration of complete duet or overlapping duet section |
| Duet sound density | DSD | Proportion of duration of complete duet or overlapping duet section composed by syllables and excluding gaps |
| Song overlap degree | SOD | Proportion of duration of complete duet in which female and male songs were overlapped in time |
Temporal structure measurements were extracted from acoustic signals using the functions gaps, song_analysis, and test_coordination from warbleR package in R (Araya-Salas and Smith-Vidaurre 2017). In addition, measurements COR, SRT, and DSD were obtained for overlapping duet sections.