Common Mergansers are streamlined ducks that float gracefully down small rivers or shallow shorelines.
The males are striking with clean white bodies, dark green heads, and a slender, serrated red bill.
The elegant gray-bodied females have rich, cinnamon heads with a short crest.
In summer, look for them leading ducklings from eddy to eddy along streams or standing on a flat rock in the middle of the current. These large ducks nest in hollow trees; in winter they form flocks on larger bodies of water.

Yellowstone NP
Wyoming