Like many birds, it’s the males that steal the show, with gorgeous iridescent black/green/purple highlights around a wedge-shaped white spot behind the eye. Like Hooded Mergansers, they are diving ducks, but they only stay down for 15 seconds or so, bouncing to the surface and riding much higher in the water than the mergansers do. The thin black mark on the top doesn’t have stripes, and the sides of bright white are also ways to distinguish this duck from a merganser.