I can't help you with specifics but you might want to look at the websites of some of the local Audubon chapters in Minnesota:

http://www.audubon.org/states/index.php?state=MN

Also, my friend helps organize the folllowing Upper Mississippi birding festival which will be happening just as you arrive:
http://www.mississippi-river.org/birding/festival_events.html

Have fun, and let us know if you see anything!

Margaret