We have two straight run mallards and one of them is displaying a clear bright blue sheen to the new feathers sprouting on their wings. Does that mean it's a boy? The other mallard has a black hue to the same feathers. Also, the bill on both ducks are different. The possible boy has one sort of a stripe going up the center of his bill, while the possible girl has an allover darker beak with no stripes. I will take pics later today. But wanted to ask. These ducks are only about six weeks old, so I didn't think that the gender of mallards would be apparent this early. oh, also, the possible boy mallard is a bit larger than the other mallard. Does this mean anything? thanks!