Some, like the Ruddy Shelduck, Tadorna ferruginea , have a large natural distribution. The male Kelp Goose, Chloephaga hybrida , is the only naturally pure white duck. The Eurasian Shelduck, Tadorna tadorna , has the unusual habit of the adults congregating together for the autumn moult, when as in all ducks they lose all their flight feathers and are flightless for several weeks. At the end of the breeding season, Eurasian Shelduck chicks are gathered together in cr ches and looked after by one or two 'aunt' ducks while the rest fly off to Bridgwater Bay in the UK or Knechtsand in Germany to moult. Shelducks are the most evolutionary primitive of the ducks.
Shelducks tend to feed on molluscs and crustaceans from shallow water.
The young are precocial and are cared for by both adults for 6-9 weeks after hatching. They are predominantly herbivores and have a world-wide distribution. These are land and flooded meadow ducks, they include the ancestor of the common and variable domestic duck, the Mallard, Anas platyrhynchos . Dabbling ducks are so-called because they feed in shallow water, putting only their heads and shoulders underwater. They do not dive.