Hi, I'm new here and I've been trying to find out what kind of duck I saw while vacationing in Ruidoso, NM. It was a rather large duck, brown in color with a greenish tint on the head. The only green-headed ducks I could find pictures of were mallards. This duck doesn't have a white ring around it's neck so I assume it's not a mallard. Any help would be greatly appreciated. Thanks!