Macroevolutionary dynamics of honeyeater diversification

Speciation is the process responsible for the formation of species and all biodiversity. This thesis examines the causes of speciation using honeyeaters, a monophyletic group of birds ranging throughout Australasia, focussing on geographic range size and acoustic signalling. Overall, range size and dispersal to islands have significantly contributed to speciation in honeyeaters. For birdsong, findings demonstrate that despite theoretical expectations, song evolution does not influence speciation on broad scales. This is likely due to song evolution being constrained by body size and environmental factors. These research outcomes enhance understanding of trait evolution and speciation across the Tree of Life.