This is the subspecies of the Great Horned Owl, b.v.subarcticus. Accoring to Hap Huber it is "sometimes called the taiga race" Like other birds from the Canadian north such as Snowy & Great Grey owls, they occasionaly move south in search of food. Other "irruptive" species like pine siskins, redpolls and crossbills also drop by here in southern Minnesota from the north country.
The picture was sent to me by Alex Watson, a young DNR ranger/birder, whom I met at Forestville State Park, a few years ago. He was leading a birding outing for campers at the park then. Later, I had joined him on a "tree" hunt." A possible state record black ash tree had been reported and he was assigned to locate and verify it. Of course, we did some birding along the way! Alex has since moved on to Lake Carlos State Park, one of the many beautiful sites here in the Land of Ten Thousand Lakes.