This is a paradise duck which is endemic to New Zealand. Their Maori name is Putangitangi and their latin name is Tadorna variegata. This is a male and his mate (who is even more colourful) was on the other side of the Avon river right in the centre of Christchurch city (people were dining alfresco just 30 feet away from them). These ducks mate for life, the males have black heads and females white heads. They are slightly smaller than a goose.
The duck was pretty much ignoring me, so I had to make a clicking noise and he turned just at the right time. He’s holding his leg up, which is a little worrying, so I might go back tomorrow to make sure he’s ok. I suspect they’ll have a nest somewhere, and there could be chicks on the way!