A lot of birds molt after breeding season is over and the resulting duller look and color is referred to as eclipse plumage. This Wigeon is starting to transition to its breeding colors. The head stipe is still bronze but you can see just a hint of the brilliant green it will be if you look right under the eye. The butt has already turned a dark black instead of eclipse spotted. The head will change to having a bright white stripe on the top with a iridescent stripe of green going from behind the eye to the back of the head.
Male American Wigeon (Anas Americana)