Building a bioenergetics model for landbird conservation in the northern Gulf of America (Gulf of Mexico) region: energy supply, bird energy demand, and surplus/deficit maps

The majority of landbirds breeding in eastern North America migrate through the Gulf of America (Gulf of Mexico; hereafter Gulf) region during spring and fall. Rarely do migratory landbirds make nonstop flights between breeding and non-breeding areas, rather they stopover in habitats (a.k.a. stopover sites) en route to rest and refuel. Forested habitats in the northern Gulf region provide the last possible stopover for fall migrants making a trans-Gulf flight south, and the first possible landfall for birds returning north in spring. Forested stopover sites also provide resources to millions of circum-Gulf migrants, yet the quality and quantity of these sites have both decreased over time. Thus, land managers and conservation planners have a critical need for data on the quality and quantity of available habitat in relation to where peak numbers of birds consistently stop to rest and forage.
We developed a spatially explicit bioenergetics model to determine whether sufficient food resources are available to landbirds during spring and fall migrations in the northern Gulf region. Using field and remotely sensed data, we predicted food energy supply, bird energy demand and their difference (i.e., energy surplus versus deficit) at a 240-m2 spatial resolution for hardwood forests (i.e., NOAA Coastal Change Analysis Program codes 9, 11, and 13) within 85 km of the Gulf from Brownsville, TX to Key West, FL. This data release is a subset that includes maps of food energy supply, bird energy demand, and energy surplus/deficit during periods of peak migration (late April and late September) for the region within the Gulf Coast Joint Venture planning boundary, an area that extends from Brownsville, TX to Mobile, AL.