- Title
- Finding the keys to spread: behavioural, morphological, and nutritional consequences of urbanisation on one of the world’s most successful avian ecological invaders, the Common Myna
- Creator
- Peneaux, Chloe Juliette Fanny Yvonne
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2021
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Relative to natural habitats, avian species richness is drastically reduced in cities despite an increase in population densities, mainly due to thriving alien bird populations. Over recent decades, researchers have been interested in understanding how ecological conditions in urban environments affect native as well as alien bird populations. However, while advances have been made in relation to the morphological and behavioural characteristics that make a species likely to succeed in urban environments, less attention has been given to nutritional factors in cities and how they might drive dispersal in alien birds. This thesis aimed to study the diet and phenotype of common (Indian) myna Acridotheres tristis) and their association with urban environments in New South Wales, Australia. Mynas are currently still spreading in Australia and, while they are more abundant in cities, they can be found across an array of suburban and more rural/natural habitats, providing the opportunity to study how an ecologically successful alien bird respond to urban ecological and nutritional conditions relative to other habitat types. I first examined how environmental and nutritional parameters can modify the expression of a type of coloured signal used by conspecifics as an indicator of individual quality and showed that urban environments can alter the expression of carotenoid-based colouration (Chapter 2). I then demonstrated that mynas display such signal in the form of yellow-orange skin around their eye (Chapter 3). When examining food preference in mynas, I highlighted that birds willingly ingested novel foods and did so in order to fulfil their specific nutritional requirements (Chapter 4). I also found associations between specific nutritional preferences and behavioural traits (e.g. exploration tendency). Moreover, I found that male and female mynas adopted different nutritional strategies, with males ingesting combination of nutrients that enhanced their signal colouration and females prioritizing intake of nutrients that improved reproductive functions (Chapter 5). Finally, I showed that the isotopic niche of birds in highly urbanized habitats was different from the niche of less urban birds (Chapter 6). Health and signal colouration also decreased with increasing urbanisation levels, suggesting that mynas in cities could suffer from detrimental environmental conditions and nutritional deficiencies generated by overcrowding. I propose that suboptimal living condition in overpopulated cities could become a driver for dispersal to less densely populated habitats in mynas and raise concern about the potential increase in competitive interaction with native bird species in more natural environments as a consequence.
- Subject
- acridotheres tristis; invasive species; spread; nutrition; colouration; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1468449
- Identifier
- uon:48052
- Rights
- Copyright 2021 Chloe Juliette Fanny Yvonne Peneaux
- Language
- eng
- Full Text
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