This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2025. The fellowship supports research and training of the fellow that will contribute to biology in innovative ways. A fundamental goal of evolutionary biology is to understand how organisms adapt and change in response to their environments. But this is challenging to study in nature because most organisms we observe today have been evolving gradually in concert with their environmental conditions for thousands to millions of years. To work around this challenge the fellow will use the wild population of parrots (genus Amazona) in southern California, which descend from pet birds released within the last 70 years, as a natural experiment. This natural experiment will reveal how quickly bird populations are able to adapt to new environments and reveal the physical and genetic changes that help them to survive and thrive alongside humans in urban areas. Members of the local southern California community can play an active role in the project by contributing their photos and observations of parrots to community science databases. Additionally, the fellow will work with education specialists from the Natural History Museum of Los Angeles County to develop public presentations and table displays informing visitors about ongoing study of the well-known southern California parrots. Because urbanization and human development continue to modify environments at a global scale, we need to understand the capacity of organisms to adapt to these increasingly urbanized landscapes. This project will treat the independent introduction and establishment of four species of Amazona parrots from the pet trade into southern California as a replicated experimental framework for studying the ability of birds to rapidly adapt to a highly urbanized environment. Undergraduate and graduate researchers will be trained in using museum specimens to quantify the physical and genetic characteristics of each species. Th