I went to ND last fall. Long drive from upstate Ny. Although it was in the early season I shot quite a few bluebills. I mainly hunted Lake Alice (Public hunting) near Cando. Lots of birds.
Here in upstate NY there are a lot of Buffies. Heck we pass on them most of the time in order to shoot the bigger Goldeneyes, Redheads, and Canvasbacks. The best past of NY is the split season (Dec.27th to Jan.9th) . I have shot everything from Oldsquaws to white wing scoters. LakeOntario can be a tough hunt, but the ending result may make for a memorable hunt. Good luck with the Buffies.
Matt