Long-bodied duck with a thin bill and shaggy crest. Breeding males have a dark green head, brown breast, and gray sides. Females and immature males have a brown head and gray body. Bill is dull red. Separated from Common Merganser by thinner bill, shaggier crest, and slimmer shape overall. Dives to catch fish on large bodies of water, including freshwater lakes and coastal regions. Favors saltwater more than Common Merganser.