The authorization contained in the Act limits the availability of grain acquired through price support operations to the prevention of crop damage by migratory waterfowl (brant, wild ducks, geese, and swans) and such grain may not be made available for the feeding of any other species of migratory birds, whether or not such other species of migratory birds are committing or threatening to commit crop damage. Further, the Act does not authorize the use of such grain to conduct a migratory waterfowl feeding program for the purpose of augmenting natural sources of food available to migratory waterfowl, nor for any purpose incident to migratory waterfowl management not related to the prevention of crop damage. Accordingly, such grain shall not be made available pursuant to the Act to augment or to substitute for natural sources of migratory waterfowl food except as may be determined by the Secretary to be necessary to aid in the prevention of crop damage by such birds.