The Bufflehead is a compact diving duck with a disproportionately prominent head and a distinctive contrast between male and female plumages. Males can look strikingly black and white at distance, while females are darker and show a smaller pale cheek patch. Cornell describes an important ecological connection to woodpeckers: nesting cavities are commonly old Northern Flicker holes, small enough to exclude larger cavity-nesting ducks. The registered river associations are Umatilla National Wildlife Refuge and the John Day pool on the Columbia, and the Upper Mississippi River refuge corridor from Wabasha to Rock Island. These are separate local evidence problems. The Upper Mississippi refuge explicitly mentions Bufflehead among mixed diving ducks, while the Columbia registry association requires its own seasonal verification. Neither should be treated as proof of local breeding, and neither allows a national migration map to substitute for reach-specific viewing advice.

Columbia
Umatilla NWR / John Day pool, Boardman–Irrigon; sheltered refuge waters and sloughs.


American Coot
American White Pelican