Do you wish you were better identifying different duck species? Then look at this "Ducks at a Distance" from the Dept of the Interior.
https://www.ncwildlife.gov/ducks-distance-ocr/download?attachment
From wigeon to shoveller to cinnamon teal to blue winged teal to gadwall to wood duck & more. I will need to study this a lot to pass any test.

Happy bird watching or hunting
Kirk