We saw plenty of American wigeons during the trip. The American wigeon is closely related and very similar to the [Eurasian] wigeon, but the male is much browner on the sides and has a large field of iridescent green from the eye and back, down to the neck. I was standing outside the harbor in San Diego and had this male in the lens for a long time, before it turned left, just enough for the shimmering green field on its head to be visible (otherwise that patch appears to be more dark grey).