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 environmental conditions are all critical. To better understand why fitness varies among individual birds, my research will focus on three major areas of study: (1) Sensitivity of Avian Life-History Strategies to Environmental Change and Stochasticity: A key objective in evolutionary ecology is to understand how organisms allocate limited resources between reproduction and self-maintenance, but the strategies that result in the highest individual fitness are dynamic and depend on the environmental context in which they occur. Using tree swallows and mountain bluebirds, we will test how variable conditions and demands influence parental decisions regarding investment in offspring versus self-maintenance, how the sexes resolve conflicts over optimal levels of parental care, and the consequences of these decisions for offspring performance. (2) Effects of Natal Conditions on Adult Phenotype and Fitness: An organism's phenotype is a complex interaction between genotype and environment, and early life conditions can have important and lasting effects on adult phenotype and performance. Moreover, evidence is growing that early life conditions can also affect subsequent generations, but the prevalence of these effects in nature is largely unknown. Using long-term data on tree swallows and mountain bluebirds, we will test how natal conditions of individuals influence lifetime reproductive success and adult phenotype, and whether they are transgenerational and carry over to influence performance of subsequent generations. (3) Microplastic Pollution: Microplastics are small fragments of weathered polymers, as well as microbeads from personal care products and synthetic fibres from clothes washing released to the environment in sewage, and are a potential global threat to many ecosystems. We will assess whether microplastics are transferred within food webs, and their effects on higher trophic level organisms such as insectivorous birds. This research will clarify the degree to which insectivorous birds are exposed to microplastics, and may help identify possible causes of population declines in this group of birds. My research will provide significant insights into the reproductive ecology of birds, which is vital to understand as environmental conditions continue to change and become increasingly variable, and will provide rich opportunities for students to solve critically important questions in evolutionary ecology and basic biology.