Bay duck

Aythya is a genus of diving ducks. It has twelve described species.

Aythya shihuibas was described from the Late Miocene of China. An undescribed prehistoric species is known only from Early Pleistocene fossil remains found at Dursunlu, Turkey ; it might however be referrable to a paleosubspecies of an extant species considering its age (see also Greater Scaup).

The Miocene "Aythya" arvernensis is now placed in Mionetta, while "Aythya" chauvirae seems to contain the remains of 2 species, at least one of which does not seem to be a diving duck.

Species
Listed alphabetically.
 * Aythya affinis Lesser Scaup
 * Aythya americana Redhead
 * Aythya australis Hardhead
 * Aythya baeri Baer's Pochard
 * Aythya collaris Ring-necked Duck
 * Aythya ferina Common Pochard
 * Aythya fuligula Tufted Duck
 * Aythya innotata Madagascar Pochard
 * Aythya marila Greater Scaup
 * Aythya novaeseelandiae New Zealand Scaup
 * Aythya nyroca Ferruginous Duck
 * Aythya valisineria Canvasback
 * Aythya valisineria Canvasback