Over two-thirds of all land birds and over half of the migratory species in North America move long distances to areas in Mexico, Central and South America, and the Caribbean islands. For birds crossing the Gulf of Mexico, habitats along the northern coast provide the last possible stopover before autumn migrants make a nonstop flight. In spring, this area provides the first possible landfall for birds returning north after a 1,000-kilometer flight. Many migratory bird populations are declining in association with losses in quantity and quality of critical migration stopover habitats. Effective conservation strategies for declining migrants require a better understanding of how the birds respond to habitat they encounter en route. Toward this goal, this project established six landbird migration monitoring stations in southern Alabama and Louisiana in forested habitats that differ in their patch size, distance from the coast, and surrounding landscape composition. Scientists measured bird abundance and changes in bird physiological condition during stopover, as well as food availability and habitat structure and composition. On-the-ground data were paired with remotely collected data, such as land cover maps and weather surveillance radar, which can be used to predict migrant use for the entire northern Gulf region. Integrating field and remotely collected data provides the parameters needed to establish a bioenergetics model for migrants in the northern Gulf region. Fine-scale field data are used to populate energetic demands of birds and resource availability within habitat types, while large-scale remote data allow findings to be extrapolated across a large spatiotemporal area to meet regional, State, and local land management needs. Results will provide critical information on how migratory birds are using stopover habitat along the northern Gulf of Mexico coast to assist natural resource managers in addressing declines in migratory bird populations linked to quantity and quality of stopover habitat.
Predicted biomass of birds for the northern Gulf of Mexico based on weather surveillance radar data.