Raptors in the City: Site Occupancy and Abundance of a Top Predator Inhabiting Urban Green Spaces Within a Megacity

Urban green spaces have the potential to harbor a rich biodiversity, including top predators, which maintain the structure and regulate the dynamic processes of these urban ecosystems. Conservation of top predators in cities requires quantitative knowledge of their populations. In this study, we provide critical information about population abundance and site occupancy rates of Harris's hawks (Parabuteo unicinctus) inhabiting urban green spaces in one of the largest cities in the world, Mexico City. We asked if this population permanently resides in the city or, alternatively, if individuals move into the city only during particular periods of the year. In addition, we tested the hypothesis that prey abundance in urban green spaces is the most important environmental trait that promotes the presence of this raptor in this megacity. We found that both population abundance and site occupancy rates differed between the dry and rainy seasons, increasing during the latter season. This seasonal change indicated that some individuals immigrated to the city and/or the presence of juveniles that were born just before the rainy season. Interestingly, their habitat preferences differed between seasons. During the dry season, when hawks are apparently nesting, they occupy parks surrounded by tall buildings and located relatively far from other green areas. In contrast, during the rainy season, hawks prefer parks with high abundance of large prey (doves and pigeons). Based on our findings, we propose specific management actions aimed at facilitating the presence of nesting individuals in the urban landscape.