I saw several great grey owls one winter a couple years ago when they came out of the boreal forest into the more open wooded areas in central Saskatchewan. That was on a nature society field trip.
I also saw a great grey perched on a fence pole with a small mammal in his mouth in late summer in Alberta. Completely by chance. What luck! I even happened to have my camera with me and I watched him swallow that mammal through the zoom lens, while also getting a couple photos. Amazing! The person who lived there said there was a family raising young on the property.
I came upon a great horned owl perched on a branch during the day one summer.
I saw a few northern saw whet owls when I visited a banding station in Saskatchewan. So adorable!