The emergence of multi-level combinatoriality in a life-long vocal learner: ontogenetic and structural evidence of socially learned call sequences in the Western Australian magpie

I present the first longitudinal ontogenetic study of combinatoriality in any non-human species. Utilising a whole-repertoire approach, I describe the ontogenetic emergence of call sequences in the Western Australian magpie—a life-long vocal production learner. Specifically, I investigate how the repertoire is shaped by social experience, and what this reveals about the developmental foundations—and potential evolutionary origins—of combinatorial vocal communication. I show that call sequences are formed through usage learning from seemingly innate building blocks and that structured, hierarchical ordering rules develop slowly through development. Ultimately I challenge the view that syntax evolved solely as a workaround to repertoire constraints.