|
The Anatinae are a subfamily of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalo, a young but highly apomorphic lineage derived from the dabbling ducks. There has been much debate about the dabbling ducks' systematical status and which ducks belong to the Anatinae. As understood here, the subfamily contains only the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively,〔 the Anatinae are considered to include most "ducks", and the dabbling ducks form a tribe Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of Anatidae (waterfowl).〔 ==Systematics== The dabbling duck group, of worldwide distribution, was delimited in a 1986 study〔 to include eight genera and some 50–60 living species. However, Salvadori's teal is almost certainly closely related to the pink-eared duck, and other genera are likewise of unresolved affiliation.〔〔 The peculiar marbled duck, formerly tentatively assigned to the dabbling ducks, is thought to be a diving duck or even a distinct subfamily.〔 This group of ducks has been so named because its members feed mainly on vegetable matter by upending on the water surface, or grazing, and only rarely diving. These are mostly gregarious ducks of freshwater or estuaries. These birds are strong fliers and northern species are highly migratory. Compared to other types of duck, their legs are placed more towards the centre of their bodies. They walk well on land, and some species feed terrestrially. "Puddle ducks", as they are also called, generally feed on the surface of the water or feed on very shallow bottoms. They are not equipped to dive down several feet like their diving counterparts. The most prominent difference between puddle ducks and divers are the size of the feet. A puddle duck's feet are generally smaller because they do not need the extra propulsion to dive for their forage. Another distinguishing characteristic of puddle ducks when compared to diving ducks is the way in which they take flight when spooked or are on the move. Puddle ducks spring straight up from the water, but diving ducks need to gain momentum to take off, so they must run across the water a short distance to gain flight. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Anatinae」の詳細全文を読む スポンサード リンク
|