Bachelor of Conservation Biology (Honours)(Dean’s Scholar)
School of Earth, Atmospheric and Life Sciences
Bradstock, Emily, The Song Culture of the Endangered Eastern Bristlebird, Dasyornis brachypterus, Bachelor of Conservation Biology (Honours)(Dean’s Scholar), School of Earth, Atmospheric and Life Sciences, University of Wollongong, 2022.
Conservation interventions are increasingly being used to manage populations of threatened species, but they require careful planning, tailored to the species’ requirements, to ensure positive conservation outcomes. The Eastern Bristlebird, Dasyornis brachypterus, is a highly cryptic, semi-flightless songbird confined to three isolated regions along Australia’s east coast. The species has received active conservation management since being listed as endangered nationally in 1999, and as of April 2022, has been subject to the first of three conservation translocations, with the goal of establishing a stable and genetically resilient second population of the species in Victoria. First, I present a literature review discussing how conservation translocations can lead to issues with animal behaviour and highlight the potential consequences this may have for species that rely on social learning to develop behavioural skills and maintain communication pathways. Mechanisms of social learning are particularly important for the oscine passerines, known as the songbirds, who possess unique song cultures that are critical for information sharing, conspecific recognition, and fitness. A systematic literature review conducted to quantify the impact of translocation on song culture produced only four studies, thereby identifying a considerable knowledge gap in the literature when it comes to understanding the impact of the translocation process on culture and sociality. Second, I help to address this knowledge gap by providing the first quantitative study of Eastern Bristlebird song, using a valuable source population located at Bherwerre Peninsula in Jervis Bay, Australia. An extensive database of recordings collected using autonomous acoustic recorders enabled the investigation of song characteristics, singing behaviours, and patterns of geographic variation in song sharing across the extent of the populations range. I found that song sharing was correlated with geographic distance, resulting in nearby individuals sharing a greater proportion of their song type repertoires with one another, than with those situated in distant territories. Consequently, three geographically distinct dialect groups were identified. Interestingly, a consistent species-specific song syntax was present in the population with the ‘introductory’ elements of the song being structurally invariant and culturally stable across sites, and the ‘body’ elements exhibiting greater variability in their acoustic features. Third, I conducted a pilot study to test the efficacy of playback for measuring changes in singing behaviour and song complexity following the removal of individuals for a 4 translocation. I found no detectable changes in either parameter, but difficulties with the experiment design inhibited my ability to make robust conclusions. Nevertheless, this study helped to identify alternative research avenues for which experimental playback may be suitable. In sum, this thesis presents the first study of song culture in the endangered Eastern Bristlebird, provisions new baseline data for future comparative research, and discusses the efficacy of experimental playback techniques in measuring song culture, so as to inform, refine and improve conservation management efforts. The in-depth discussion presented here advocates for the importance of gaining a wholistic overview of the target species acoustic ecology. Only then can species-appropriate methods be used to adequately monitor and manage cultural and acoustic diversity in this highly vocal species. For the Eastern Bristlebird, ongoing conservation management that takes into account the importance of song culture, will hopefully lead to favourable outcomes for this species into the future.
FoR codes (2020)
310301 Behavioural ecology, 310405 Evolutionary ecology, 410401 Conservation and biodiversity
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.