Leucism is also known as dilute plumage. All the ducks I have seen and photographed exhibiting this coloration have been female until recently when I discovered a Mallard male in Shelby Co. TN. See photos in this album. The dilution is variable in depth of color and usually through the dusty to pale cream coloration the patterns seen on normal birds can be discerned. Unlike partial albinism it is an overall condition. Partial albinism can range from random pure white feathers to symetrical areas of white on both sides of the body that usually follow feather tracts.