Collectively, these birds need an array of habitats, including marshes, lakes, rivers, forests, and prairies. Diving ducks, swans, pelicans, and cormorants use the open waters of lakes and riverine pools. Dabbling ducks, herons, terns, bitterns, and many song birds use wetland marshes.
Forests support migrating and nesting songbirds, bald eagles, hawks, owls, herons, and wood ducks.
Habitat is the key requirement of all migratory birds. The landscape has been altered greatly by our expanding human population for agriculture, industry, and urban settlements, and it contains far fewer wetlands, forests, and prairies than did the presettlement landscape. The long-term viability of many bird populations is adversely affected by sedimentation, human development, urban and agricultural runoff, recreation, habitat loss, and habitat degradation. Many migratory birds that once flourished are now absent in altered or degraded areas. Center investigations of migratory birds provide essential information to management agencies within the Department of Interior, especially the U.S. Fish and Wildlife Service, which is charged with conserving migratory birds and their habitats for the American public.