This is garbage, I haven't hunted SD but I have a friend who has gone there a long time and hunts just public he usually gets his birds but not without hunting very hard with a good dog, the last few years have been hard hunting with the flooding and last year the crops were still in.
I have hunted ND maybe 6 times and other than the SW which is commercial and heavily hunted the state bird numbers are not any higher than KS, I hunt by myself, and until this year with one ESS and it is far from a gimme, many all day hunts, and not always limits. If you go to a ranch that hardly no one hunts and pay it might be a gimme at times.
Last year went to NC KS first time in Jan,and took my SIL for his first hunt, we were told the numbers aren't great, we didn't limit, but shot plenty, I let my SIL do most of the shooting so we could have done allot better, it was after some of the big snow had melted, allot of the roads were not drivable so we couldn't travel as much as planned. I had never hunted in Milo before and most CRP was still smashed down but I certainly don't think it was any harder than late season ND, or less productive. I will say because of the blizzard no one had probably hunted those area's recently.
I think the main differeace is hunter numbers, making KS tougher in spots.