During the period between 1949 and 1958, the Department of the Interior issued ten 2-dollar denomination Federal Duck Stamps. It was during this period that the first Duck Stamp Contest was held (1950, won by Walter A. Weber for his Trumpeter Swans). Within a few years, contest guidelines stipulated design measurement specifications and also that only images in black and white could be submitted. Further, the design must feature "wild American waterfowl." After sixteen years of stamps featuring only ducks and geese, the 1950 issue featured the image of swans. During this period, the public purchased 22,009,338 Duck Stamps, raising $44,018,676 for migratory bird refuges.