Populations of Neotropical migratory birds are declining throughout much of North America and continue to be at risk because they depend on a diversity of habitats spread over huge geographic and political areas. While extensive effort has focused on summer productivity and over winter survival, little attention has been paid to the role of migration in the population dynamics of Neotropical migrants. Only recently have conservation biologists begun to understand the importance of migration pathways, stopover behaviors, and stopover habitat quality in the long-term viability of migrant populations. This despite the fact that during migration, birds are physiologically taxed, have increased exposure to weather and predation, and therefore suffer extensive mortality. The research that has examined the dynamics of Neotropical migration is primarily focused on migration systems in Eastern North America. Critical differences in habitat between Eastern and Western flyways make the applicability these findings to Western systems difficult. In addition, increasing habitat alterations and loss of critical stopover habitat in the Southwest make understanding migratory patterns critical to maintaining viable populations of migrants.

 As a first step to increasing our understanding of Western Neotropical Migration we are beginning to identify critical migratory habitats and corridors along the Arizona-Mexico border. Within these habitats we are furthering our understanding of migration patterns by investigating how of invasive plants, hydrology, food availability, competition and predation risk influence migratory behaviors as well as migrant population dynamics.