Magpies are common out west, and are definitely expanding their range into Minnesota, but would still be considered rare in NE Minnesota. I watched a family of seven Black-Billed Magpies up at Sax-Zim Bog this morning. The magpies were hanging around the intersection of Zim Road and Hwy #7. Use your ears, and you’ll likely find them. They were on both sides of the highway, and often foraging right next to the RR tracks (south of Zim Rd).
This is a repeat performance from my birding experience over on Northstar Lake two weeks back. It was delightful.