Variant mallard drake

Left a bit early today; even so I was there for eight hours. After having the blood test done I headed toward Woodlands Park Road, and then stopped at Manawa Reserve in New Lynn for a walk and photo op. 

When I first spotted this bird I was the full length of the small lake away from it. Despite the distance I picked that its colour was slightly atypical. As I watched it got into the water from the boardwalk, and gradually moved to only a few metres away. It seemed very interested in the mallard ducks, despite the presence of a number of normally coloured drakes. This one seemed very confident.