The red breasted mergansers breeding habitat is freshwater lakes and rivers across northern North America, Greenland, Europe, and the Palearctic. They feed mostly on small fish, but also consume aquatic insects, worms, crustaceans, and amphibians which are caught by diving and swimming underwater. The red (orangie) breast that gives the species its common name is only displayed by males in breeding plumage. The species is considered a "game bird" under the Migratory Bird Treaty between the United States and Canada. This means that the species gets some protection, though hunting it is legal in North America in certain seasons and places determined by local hunting regulations. However, few hunters are interested in the species and relatively few birds are harvested.