In some localities the shelduck is so numerous that one might wonder why it requires to be protected by law. Fortunately it is so distinctive in appearance that there is never any excuse for mistaking it for any other bird. Both sexes have a black neck and head, a white body and a rich brown yoke at shoulder level. There is a dark stripe down the underparts and the wing primaries are black. The male may be distinguished by the knob at the base of its bright red bill. The shelduck has a strong goose-like flight. It is large in size and its contrasting markings are usually visible, even when flying in poor light. The male occasionally whistles and the female has a short, low "quack".

I am grateful to Eric Begbie who allowed us to use this information which is reprinted from 'Fowler in the Wild'.