Mallard or Black Duck or X (or one of each)??

[CaraRose]

At the rock fountain outside the nature center today there were six ducks. Three male mallards, and at first I thought three females as well. They I noticed the color, beak, and size differences. The first three shots are of each one individually.

Shot 1- here I'm positive is just a female mallard. Much lighter brown than the other two. Very clear white border around the speculum, and an orange bill.

Shot 2- is darker than the bird in shot 1, smaller white border on the speculum. Bill was yellow with dark discoloration.

Shot 3- is larger than either the other two, much darker. Does not appear to have a border on the speculum. Yellow bill.

Shot 4 & 5- These are the bird in shot 2 with the bird in shot 3.

I'm thinking the bird in shot three may be a black duck and the bird in shot 2 may be a mallard X black duck hybrid.

Or maybe they're all mallards and I'm just not aware of the color variations :P Anyway, any birders here could give me a hand with the ID, I'd appreciate it.

[Singletracklovr]

I'm going to guess the black billed hens are Teal.
Beautiful shots...

[paulnj]

most if not all are mallards in my opinion. I have trouble IDing images of black ducks mixed in with wild and domestic mallards