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. 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.
|wingspan min.:||45||cm||wingspan max.:||56||cm|
|size min.:||45||cm||size max.:||56||cm|
|incubation min.:||26||days||incubation max.:||28||days|
|fledging min.:||0||days||fledging max.:||0||days|
It was considered relatively common at Lake Alaotra in the 1930s, but declined dramatically through the 1940s and 1950s. Until the 1990s, the last certain record was at Lake Alaotra in 1960, with one unconfirmed sighting near Antananarivo in 1970 and several other possible records. Then a single male was captured alive in August 1991. Intensive searches (including major publicity campaigns) at Alaotra during 1989-1990 and 1993-1994 failed to discover more birds. However, in 2006 the species was rediscovered when nine adults and four juveniles were observed at a volcanic lake situated 330 km north of the last known site, Lake Alaotra. Reports from local people that the lake was not suitable for rice cultivation round the edge, it contained no fish and that the water was cold suggest that the species may have persisted at this new location because human disturbance has been minimal. Follow-up surveys in 2006 located c.20 mature individuals with up to nine ducklings observed at the same site. Five birds were seen at a second lake c.3-4 km from the site but these may be part of the 20 individuals counted previously. A total of 25 mature individuals were counted in 2008, with six pairs nesting in the 2007/08 season. However, no chicks fledged in 2008, and only 19 adults were recorded in July 2009, including six females.