When I bought my 3 ducks, my breeder had thought that the two black and white ones (called Snowy Call Ducks) were females and the brown one a male. Sounded good to me. However, not knowing anything about keeping ducks, I hit the library and took out books on raising ducks. There was a section on how to determine the gender of your duck. So following these directions I went out and studied my ducks.
Linking up to Farmgirl and Farm Friend Blog Hop.