Plumage evolution in parrots

Abstract

Why is the natural world so colourful and what can it tell us about evolution? Bird plumage is the perfect system to explore these questions because of the wide gamut of colours it presents. Parrots are synonymous with diverse colouration but their plumage colouration is relatively understudied. I use three studies of parrots at different taxonomic scales the explore the role of signalling and non-signalling functions as drivers of plumage diversity. At the scale of the genus, in Amazon parrots (genus Amazona), I use avian visual modelling and and computer vision to show that the ambient light environment, and not species recognition, plays an important role in the evolution of face plumage colouration. In the Crimson Rosella (Platycercus elegans), a putative ring species, I comprehensively characterise geographic subspecific variation and show that this variation is correlated with climatic variables. Finally, I use lab experiments to show that psittacofulvin-containing (red, orange, yellow, green) parrot feathers are more susceptible to bacterial degradation than feathers of other colours (black, blue, grey)