Mallard cross-breeds

Hi all,

On the Thames near my place there are a fair number of cross-bred mallards. I can tell they are mallard crosses because of the main colours of the plumage and the males have the two curly feathers above the tail.

They all look suspiciously like they are cross-bred with pintails, with lots of white up the neck, and sometimes the neck looks longer and slimmer.

Does anyone know if the mallardXpintail is the only really common cross, or whether there are others to be seen?

Cheers,

Andy

Seriously thinking about trying harder!