[2][3] The male crested shelduck has a greenish-black crown, breast, primaries, and tail, while the rest of its face, chin, and throat are brownish black.

It apparently breeds in Korea and eastern Russia and is probably a relict species that had a wider distribution in prehistoric times.

[5] However, it was not described until 1890 when the English zoologist Philip Lutley Sclater decided that the specimen was a possible hybrid between the ruddy shelduck (Tadorna ferruginea) and falcated duck (Mareca falcata).

[7] Kuroda noted that the plumage of the specimens was not definitively intermediate between Sclater's suggested parents of the alleged hybrid.

[10] The genus name Tadorna comes from the Celtic word tadorne and means "pied waterfowl", essentially the same as the English "shelduck".

[10] The crested shelduck is sexually dimorphic, with the male possessing a greenish-black crown, breast, primaries, and tail, while the rest of its face, chin, and throat are brownish black.

[13] While all collected individuals are from the coast, especially near river mouths, recently there have been a number of reports from interior wetlands in northeastern China.

[4][14] Though not much is known about this shelduck, it is believed to be migratory, traveling from Siberia in the breeding season to Korea, southern Russia, and Japan for the winter.

[13] The crested shelduck is believed to eat aquatic vegetation, agricultural crops, algae, invertebrates, mollusks, crustaceans, carrion, and garbage.

[17] The crested shelduck has never been numerous in modern times, though it is thought to have been more widespread historically due to its presence in Japanese aviculture.

[5] The species is known from only a handful of sightings and some retroactively declared it extinct in 1916 after a female was shot at Busan, South Korea.

[13] A group of three birds, two females and a male, was sighted by two Russian students in 1964 in the Rimsky-Korsakov Archipelago near Vladivostok with a small flock of harlequin ducks.

[17] The Tumangan Development Project is threatening to destroy potential habitat in the area of several of the historic records.

[7] The female specimen described by Philip Lutley Sclater, collected by Lieutenant F. Irmininger near Vladivostok in April 1877, was displayed in 1894 by the Zoological Society of London and today is kept in the National Museum of Denmark in Copenhagen.