Hmm not good. Another try:
Set 1:
1) Shoveler
2) Long-tailed Duck
3) Pochard (not sure it really looks like one though)
Set 2:
1) Eider
2) Teal
3) Shoveler
Set 4:
1) Is difficult - Tufted Duck?
2) Pintail
Set 1:
1) Shoveler
2) Long-tailed Duck
3) Pochard (not sure it really looks like one though)
Set 2:
1) Eider
2) Teal
3) Shoveler
Set 4:
1) Is difficult - Tufted Duck?
2) Pintail