This is a rather big duck. We haven't photographed a Gadwall before, we're not sure whether this is because they're rarely in our area or that we simply haven't noticed them. This male was accompanied by a female that was difficult to differentiate from a female mallard. A picture of her is below.
Photography notes:
The original image has been cropped slightly to make this photograph. No other changes (other than resizing) were made, including no sharpening nor noise reduction.