Alfred Newton

“ GADWALL, a word of obscure origin, [1] the common English name of the duck, called by Linnaeus Anas strepera, but considered by many modern ornithologists to require removal from the genus Anas to that of Chaulelasmus or Ctenorhynchus, of either of which it is almost the sole species. Its geographical distribution is almost identical with that of the common wild duck or mallard (see Duck) , since it is found over the greater part of the northern hemisphere ”

“ She closely resembles the female of the mallard in colour, but has, like her own male, some of the secondary quills of a pure white, presenting a patch of that colour which forms one of the most readily perceived distinctive characters of the species. ”