Hooded Mergansers have a distinctive look that is indicated by their name. The male has a distinctive black and white head that bulges out in the back and the wings on its back have the same sharp contrast. They have chestnut sides.
Female Mergansers have their own look with a cinnamon-colored, fan-like hood on the back of their heads. Both have rather thin beaks with which they grab fish and crayfish by diving. Crayfish were once a plentiful food source in the Tualatin River. Pollution and farming have reduced their number, but one goal of the refuge is to bring them back. The Mergansers will be happy.
Mergansers like smaller bodies of water like ponds. They live in holes in trees. (See this one on the refuge.)