Common Merganser
Mergus merganser

There is no single easy ID on the common merganser; there are three or four, and you learn them one trip at a time.
Behavior tells the story: watch for twenty minutes and the bird tells you what it is in three or four actions.
My images for this species are all made with available light. I don’t use fill flash in the field.
A local patch has produced this species on roughly one in three visits, which is probably more than I deserve.
Some of my worst photographs are of this species. I keep trying anyway.