Hooded Mergansers are small ducks with a thin bill and a fan-shaped, collapsible crest that makes the head look oversized and oblong. In flight, the wings are thin and the tail is relatively long and rounded. Adult male Hooded Mergansers are black above, with a white breast and rich chestnut flanks. The black head has a large white patch that varies in size when the crest is raised or lowered, but is always prominent. Females and immatures are gray and brown, with warm tawny-cinnamon tones on the head. https://www.allaboutbirds.org/guide/Hooded_Merganser/id