When is a mallard not a mallard? That may sound like a trick question but the indiscriminate breeding habits of mallard ducks can produce offspring that confuse people who are trying to identify their species.
As far as I understand it, the story goes like this. First came the mallard (Anas platyrhynchos). Then, humans decided they would domesticate the mallard to more easily obtain their eggs and meat to eat. Next, humans decided to ‘improve’ on the original mallard genes, using selective breeding to produce larger ducks with various colour variations (Chocolate magpie, Aylesbury, Welsh harlequin, Orphington, Swedish blue are just a few of these more specialised varieties and, if you’re interested in seeing more, there’s an excellent guide to domestic breeds of duck and the results of their various interbreeding here).
Sometimes, these domestic breeds escape from their captive situation or are illegally released into the wild and, when this happens, they can and do breed with pure mallards, thus producing a wonderfully varied and colourful array of offspring. These ‘mixed’ breeds are sometimes referred to as ‘manky mallards’, which is not meant as a derogatory term but rather as a way to differentiate them from pure-bred mallards. Manky they most certainly are not!