I haven’t seen anything big enough to consider “migrating flocks” in ND/SD yet.
If the combines, carts, and Semi’s keep up their current pace you might only see waterfowl concentrated on big water with feeding flocks spreading out all over.
The kids and I would always go up to Moffit over Teacher Conversations for Cranes. It seems like that was the best time. As we always got into them. And the Upland hunting was great up there with lots of School and PLOTS land. This year it's the 15th and 16th of October.