Duck ID needed (New Zealand)

[Rosie Perera]

I saw this duck at Hamilton Gardens in New Zealand. I thought it was simply a run-of-the-mill mallard at first, but upon looking more closely, I see that it does not have the characteristic shiny green head coloring of the male mallard, nor the speckled brown coloring of the female either. So does anyone know what this is? Is it perhaps a juvenile mallard or some other species?

http://farm6.static.flickr.com/5292/5535822451_c57527a349.jpg

Thanks!

[John Chardine]

Hi Rosie- Mallards freely hybridise with other species of duck and with domestic ducks. They also have varying plumage depending on their age and time of year, and of course the sexes look different. It is hard to say what this bird is other than you are correct in saying it's a Mallard. I think it could be a male in "eclipse" plumage which they moult into in the summer, once breeding has commenced.

[Paul Guris]

I'd probably go with male Mallard in molt, but as much as they freely hybridize it can be tough to say in this will definitely come into a pure plumage.