So I was given these two Call mallard ducks a month or so ago. I was told they were two males. The first picture you can see the green head of the duck while the other one has much more of a gray head. Also, it's tough to see but the duck with the green head has a white ring on its neck. It also has more colorful feathers, but not by much. The other ducks is more gray overall. As far as I know they are about 4-5 month old. I can't really tell a difference in their quacking sounds however they are very binder and stay close together and like to stay away from me so it's tough to tell who makes what noise. No eggs yet (because that would be an obvious give away). Any thoughts? Because I have mine.