Actually, this cute little critter is not exactly a duck... its a swan! Most specifically, a coscoroba swan. I'm guessing you found this cutie wading along in a zoo?

Admittedly, they look very much like over-large ducks, and honestly, despite being an anthro swan (in character of course), I have no idea what the identifying factor is that makes a duck a duck, a goose a goose, and a swan a swan. The bird is apparently a sort of ancestral "missing link" between swans and ducks, so... I suppose you aren't all that off at all;)

Its an adorable photo... thanks for sharing!