Bird migration within the Neotropics

Although the migration ecology of birds breeding in the Neotropics is still poorly studied relative to that of their counterparts breeding at north-temperate latitudes, studies conducted over the last 2 decades have revealed that migration in the Neotropics is much more common and diverse than previously thought. These studies have identified dozens of species that migrate latitudinally within South America, altitudinally within various mountain ranges, to and between Caribbean islands, and longitudinally across diverse ecosystems such as the Amazon rainforest. Advances in miniaturized tracking technologies, enormous citizen science databases, and powerful analytical approaches provide an unprecedented ability to detect and evaluate temporally and spatially fine-scale patterns, greatly facilitating the study of migratory patterns across tropical regions. We argue that a renewed effort in research on short- and long-distance bird migration within the Neotropics will allow (1) comparative studies that identify the emergent properties of migratory behavior, (2) identification of the convergent or unique mechanistic drivers of migration across diverse ecological settings, (3) formulation of effective conservation and management plans for migratory Neotropical birds, and (4) predictions about how migratory birds will respond to large-scale climatic changes within the Neotropics. Here, we review the current state of knowledge on Neotropical bird migration, with a focus on South America. We specifically examine similarities and differences in the observed migratory patterns of birds that breed in the Nearctic compared to the Neotropics and highlight key future research questions.