A little taste of the Florida everglades during the freezing depths of horrid Toronto winter? No! A taste of Toronto in the summertime!!
Yes, there are lots of Great Blue Herons in Toronto, many right in the centre of the city. In fact, herons are so common if you go to most any sort of wetland area (even a small one) there's probably a blue heron hanging around for at least part of the day, most likely the early morning or late evening. The difficulty lies in the fact that they are very skittish, so if you walk up to a marshland like an approaching army, or even just walk up casually, most herons will fly away as soon as they see you. More crucially, they'll fly away before you see them. They're also surprisingly difficult to see when they're wading in the water, because their camo is good and because they stay very still. All the better to lure in the fishies.
