Well, it's hard to tell what gender they may be from the photos.
A good way to tell the gender of a nearly grown to full grown duck is to look at their tails.
Drakes, which are male ducks, normally have a curled feather on their tail while females do not.
And from what I can see from the photos, they are both probably female.
Keep an eye out to see if any of them lay an egg! (: Edited by ParkerK - 5/20/16 at 10:37am