It has orange-brown body plumage with a paler head, while the tail and the flight feathers in the wings are black, contrasting with the white wing-coverts.
It is a migratory bird, wintering in the Indian subcontinent and breeding in southeastern Europe and central Asia, though there are small resident populations in North Africa.
The male and female form a lasting pair bond and the nest may be well away from water, in a crevice or hole in a cliff, tree or similar site.
The bird was first described in 1764 by the German zoologist and botanist Peter Simon Pallas who named it Anas ferruginea, but later it was transferred to the genus Tadorna with the other shelducks.
[5] The generic name Tadorna comes from the French tadorne, the common shelduck,[6] and may originally derive from a Celtic word meaning "pied waterfowl".
The female is similar but has a rather pale, whitish head and neck and lacks the black collar, and in both sexes, the colouring is variable and fades as the feathers age.
[9] The call is a series of loud, nasal honking notes, it being possible to discern the difference between those produced by the male and the female.
[9] There are very small resident populations of this species in Northwest Africa and Ethiopia, but the main breeding area of the bird is from southeast Europe across the Palearctic to Lake Baikal, Mongolia, and western China.
[11] Outside the breeding season it prefers lowland streams, sluggish rivers, ponds, flooded grassland, marshes and brackish lagoons.
[14] A stable population exists in Moscow, settling the city parks' ponds alongside the endemic mallards.
Unlike the wild population, these ducks are non-migratory, wintering instead in the non-freezing parts of the city's bodies of water.
Though more common in the lowlands, it also inhabits higher altitudes and in central Asia is one of the few waterbirds, along with the bar-headed goose (Anser indicus), to be found on lakes at 5,000 m (16,400 ft).
[9] Mating takes place on the water after a brief courtship ritual involving neck stretching, head dipping and tail raising.
[7] The nesting site is often far away from water in a hole in a tree or ruined building, a crevice in a cliff, among sand-dunes or in an animal burrow.
[7] Buddhists regard the ruddy shelduck as sacred and this gives the birds some protection in central and eastern Asia, where the population is thought to be steady or even rising.
The Pembo Black-necked Crane Reserve in Tibet is an important wintering area for ruddy shelducks, and here they receive protection.