Everyone loves ducklings, and this female Mallard had ten in tow. Along with them was this odd specimen below, which I first thought must be the father and had me wondering what rare breed I had discovered. However wiser heads prevailed (thanks Sheila) and surmised that it is in fact a juvenile from the last brood that has stuck with it's mother. It is a funny coloured mongrel Mallard, the result of cross-breeding and genetic mutation, but a mallard nonetheless. This web page coins the term "manky mallard" and has a massive rundown of the varieties of Mallard that are out there, including endless pictures from around the world. I had no idea before today!

You can see in the picture below (and the one at the top) that one of the ducklings has inherited this colouration, presumably it being from the same father as that of the juvenile.