I first thought is it was a Pekin duck. A Domestic duck that is bred from the mallards in China. Then in the late 1800's it was brought to the United States. Here it became a popular commercial duck. The Pekin duck was used by Disney for the fashioning of Donald Duck. Today the company Aflac used the Pekin duck as their mascot.
There are so many types of Swans, searching for the right one was very informative. However this photo is of a Coscoroba Swan belonging to the family of Anatidae and the monotypic genus Cocoraba. It is the smallest of the swan species. The males and females look alike. These Swans look more like Geese due to their size, heads and wing span. As you can see this breed is lacking the Black mask that the Swans we are use to have.
They like to feed on Grasses along the water banks, algae and underwater plant life, as well as mussels and fish. There is approximately 100,000 of these Coscoroba Swan in the world. South America is the habitat of choice. In the winter they fly north to Central Chile, Uruguay and the south east tip of Brazil.
The Photo above was taken in Florida at SeaWorld, in May 2010.