Buffleheads and mergansers are both diving ducks that are commonly found in North America. Buffleheads are smaller than mergansers and have a more rounded head. Mergansers have a long, narrow bill that is serrated on the edges. Both buffleheads and mergansers are fish-eaters, but buffleheads also eat insects and crustaceans.
Buffleheads and mergansers are both important members of the aquatic ecosystem. They help to control the population of fish and other aquatic organisms. Buffleheads and mergansers are also a valuable food source for other animals, such as eagles and hawks.