How organisms persist under extreme conditions has received a lot attention in ecology. Some extreme environments are natural and pristine (e.g., open lands and wilderness), while others are highly impacted (e.g., large cities). Unfortunately, we know little about the ecology of species that live in urban environments relative to those in pristine environments. My research focuses on population ecology of birds in Mexico City, one of the largest urban landscapes in the world. Specifically, I study how birds utilize green spaces across Mexico City. Previous work suggests that parks are occupied by dozens of different species, including top-predator raptors. I will spend two months in Mexico City surveying birds at 101 parks to determine how native and exotic species interact to shape population dynamics of these species. I use occupancy models to determine how birds utilize urban habitats, how they interact with each other, and if some species facilitate or limit the persistence of other species.