Individual-specific associations between behavioral events and song notes shape budgerigar vocal sequences

Abstract

Complex behavioral sequences such as courtship displays are often multimodal, and coordination between modalities is critically important. However, in learned and variable behavioral sequences such as songs, individual variability may extend to multimodal coordination. However, individual variability in complex multimodal sequences and in coordination between distinct behaviors remains underexplored. Here, we report that budgerigars, which continuously learn and modify their complex warble songs, exhibit associations between behavioral events during courtship and song notes. Some associations are unique to individuals, and others are universal across individuals. Additionally, some individuals exhibit more unique associations than others. We also find that birds warbling without courtship emit all notes with broadly similar odds ratios. The presence of individual variability opens up the possibility that social learning may modify the associations between complex sequences of behaviors, and this results in both individual variability and hierarchical differences in the links between courtship or copulatory behaviors and song.