Reproductive Effort and Success in Birds

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Organisms live in an uncertain and challenging world where the critical measure of success (fitness) is the number of progeny they produce that subsequently also reproduce. Processes operating during the breeding cycle can especially influence fitness. In birds, for example, choice of an appropriate mate, allocation of energy and nutrients to offspring, and external factors such as parasitism are all critical. To better understand why fitness varies among individual birds, my research focuses on four major areas of study:***(1) Resource Acquisition and Allocation: A key objective in evolutionary ecology is to understand how organisms allocate limited resources between reproduction and self-maintenance, but a lack of knowledge of the resources available to individuals has impeded progress in this area. By measuring food abundance on spatially appropriate scales (territories), and manipulating work rates of parents, we will provide much needed insight into how environmental factors such as resource availability drive parental investment strategies.***(2) Indicators of Quality: Indicators of quality such as elaborate plumage colours in birds are thought to be costly to produce, but demonstrating that production of non-pigment based colour is costly has been elusive. I will test how nutrient limitation during feather growth influences the ability to produce elaborate plumage colour. Further, it is now recognized that conditions experienced early in life can impact performance during adulthood, and experiments and long-term data sets will be used to explore how natal conditions influence ability to produce colourful plumage as adults.***(3) Patterns of Paternity: In socially monogamous birds, females often mate outside the pair bond but the benefits of this are unclear. By manipulating perceived hatching failure in nests and then measuring rates of extra-pair paternity in subsequent breeding attempts, I will test whether this is a strategy that females use for ensuring fertility of their eggs.***(4) Host-Parasite Interactions: Nest-dwelling ectoparasites have detrimental effects on offspring growth and survival, and so can have important consequences for fitness, yet we know little about what drives variation in infestation rates among nests. Genetic diversity of hosts, both in terms of specific genes involved with immunity and more generally throughout the genome, can be an important determinant of resistance to parasites. I will test how genetic diversity of hosts influences the ability of parasites to exploit them, which in turn can influence size of parasite populations.***My research will provide significant insights into the reproductive ecology of birds, which is vital to understand as environmental conditions continue to change, and will provide rich opportunities for students to solve critically important questions in evolutionary ecology and basic biology.