Aythyini

The diving ducks are placed in a distinct tribe in the subfamily Anatinae, the Aythyini. While morphologically close to the dabbling ducks, there are nonetheless some pronounced differences such as in the structure of the trachea. mtDNAcytochrome b and NADH dehydrogenasesubunit 2 sequence data indicate that the dabbling and diving ducks are fairly distant from each other, the outward similarities being due to convergent evolution. Alternatively, the diving ducks are placed as a subfamilyAythyinae in the family Anatidae which would encompass all duck-like birds except the whistling-ducks. The seaducks commonly found in coastal areas, such as the long-tailed duck (formerly known in the U.S. as oldsquaw), scoters, goldeneyes, mergansers, bufflehead and eiders, are also sometimes colloquially referred to in North America as diving ducks because they also feed by diving; their subfamily (Merginae) is a very distinct one however.