There is an interloper among these Scaups. Can you spot him?

In winter, or during the non-breeding seasons, ducks, like songbirds, often form loose social groups composed of other birds of similar kinds. Songbirds with songbirds, ducks with other ducks. The interloper here is a male Ring-necked Duck. Don't bother looking for the ring on his neck. It is not obvious at all. But he also sports rings around his bill.

Location: A man-made stormwater management pond, Bristow, VA