The structure and function of vocalisations in female superb lyrebirds Menura novaehollandiae

Abstract

In this thesis, I provide the first in-depth examination of the structure and function of vocalisations in female superb lyrebirds. I demonstrate the current state of knowledge in research on female vocalisations and the problematic nature of a male-biased approach to bird vocalisation research. I have demonstrated, both through observations and with an experiment, that around the nest female lyrebirds use mimicry almost exclusively in the context of defence from predators and that they adjust the amount and type of mimicry they use in response to different threats. This raises exciting questions about vocal learning and cognitive capacity. I have also revealed age-related effects on the mimetic and conspecific vocalisations of females and shown that age does not provide a compelling explanation for inter-female variation in mimetic repertoire size. Further, I have provided the first detailed quantitative description and comparison of female and male lyrebird whistle song, and in so doing, have provided valuable new information into what may account for sexual difference in vocal behaviour in this species. Finally, I was able to confirm previously anecdotal reports of high intrasexual competition between female lyrebirds, and so provide insight into female-specific social conditions that potentially drive female vocalisations. My research has demonstrated the importance of examining female-specific vocalisations in the context of female-specific behaviours. While challenging, such research can help reveal drivers of difference between the sexes and highlights the importance of examining females and males independently and in relation to each other. My thesis expands our understanding of the behavioural ecology of female superb lyrebirds and reveals them to be a fascinating and important study species for understanding female avian vocalisations more broadly.

Date of Thesis submission	2021
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Justin Welbergen (Supervisor), Anastasia Dalziell (Supervisor) & Naomi E. Langmore (Supervisor)