Do conservation translocations influence song diversity: Saddleback, a model system?

One of the most intriguing features of songbirds is in the formation of distinct, geographical song dialects – or cultures. Song learning from conspecifics is a crucial aspect of songbird ecology as song cultures can have important consequences on the survival and reproduction of individuals, and potentially contribute to speciation through their influence on mate choice. Conservation translocation procedures commonly measure their success on the preservation of genetic diversity and consequently the impacts of these practices on cultural processes goes largely overlooked. With growing evidence emphasising the importance of preserving socially transmitted song cultures, the varied translocation strategies employed at different mainland and island sanctuaries to re-establish populations of saddleback / tīeke (Philesturnus rufusater) provides us with an excellent opportunity to examine the cultural consequences of conservation management policies. This is the basis of my master’s project, for which I ask three main questions: (1) how does cultural diversity differ between source and translocated populations?; (2) How does cultural diversity change and evolve within ten years?; and (3) How does cultural diversity change over one generation? I am addressing these questions by focusing on three populations: (1) Tāwharanui Regional Park, (2) and (3) Shakespear Regional Park, which have different translocation histories. At Tāwharanui Regional Park, North Island saddlebacks from three culturally distinct island populations were selected for translocation to maximise song diversity. I am examining how the cultural evolution of this population has been shaped by the simulatenous reintroduction of three cultural divergent populations by comparing the song diversity of the source populations with the Tāwharanui population. On Motuihe Island, a population of tīeke was successfully established in 2005 from a single sourced translocation of 20 birds from Tiritiri Matangi Island. In 2010, the population’s song repertoire was recorded and analysed by Dr Kevin Parker. For my project, I am re-recording the population’s song repertoire to examine how this population’s song diversity has changed over ten years. At Shakespear Regional Park, North Island Saddlebacks were re- introduced in 2018 from Tiritiri Matangi Island (40 birds) and Tāwharanui Regional Park (10 birds) and all translocated birds were banded. The timing of this recent translocation presents us with a unique opportunity to examine how song types change over one generation because we can compare the song types of the banded, translocated birds with the song types of the unbanded, first generation progeny of the translocated birds. Central to this project is obtaining high quality recordings of tīeke songs within and across these three populations. Receiving The Project Assistance Fund has been integral to the project because it has enabled us to purchase state of the art recording equipment. We would like to thank Birds New Zealand for awarding this grant and supporting our research. Kyle Sutherland July 2019