So far as I know we don't have the Virginia opossum (Didelphis virginiana) in this part of Ontario yet, but it is now well established in Toronto, and all points to the southwest.
From a 2002 article in Now Magazine on-line:
Opossums One of the clearest indications that global warming has taken hold in southern Ontario is the rapid increase in the opossum population, particularly in the western part of the GTA.My brother had never seen one alive in the city before (though he had seen road-killed specimens). After this visit he discovered in conversation with friends and neighbours that sightings and visitations of this strange looking creature (North America's only marsupial) are becoming commonplace in the urban scene.
From ASSESSMENT OF SPECIES DIVERSITY IN THE MIXEDWOOD PLAINS ECOZONE:
Didelphis virginiana southern distribution
The Virginia Opossum is a southern species with a range that has recently expanded into the Mixedwood Plains Ecozone of Canada. The clearing of forests and maintenance of agricultural land in southwestern Ontario has benefited this species. Before the widespread destruction of the forests of this ecozone the Virginia Opossum did not occur in eastern Canada.
There are a couple of things I find very interesting about this. First, I have a general interest in the phenomenon of the southern species moving north, as I have alluded to in a couple of posts about bird species turning up around here. Opossums sometimes turn up in very out-of-the-way places, and it is suspected (or sometimes even established) that they accomplish this by stowing away on trucks coming north. The greater the number of trucks, the greater the number of opossums. But now it is understood that there is a more natural movement explaining the gradual build-up of the opossum population across southwestern Ontario, and now into the GTA.
But the other thing is the nature of urban wildlife. As a former city girl (born and bred in Toronto) turned rural nature watcher I often reflect on the differences between the experience of wildlife in the two habitats. This is best illustrated, I think, by experiences with raccoons. Toronto has a huge raccoon population--there is nothing unusual about seeing one there, in fact, there is nothing unusual about seeing one in your kitchen, eating your cat's food out of the bowl, and only leaving slowly and reluctantly after much shouting and stamping of feet on the part of the householder. When I lived in Toronto I often saw them, had to chase them out of attics, had them burst out from under my feet as I walked out the back door, etc. Now that I live in Thomasburg I see them rarely (although I know there are lots here too), and it's almost always a treat, not just another nuisance of life.
There is a wonderful book, Wild Nights by Anne Matthews, about the wildlife in New York City. Cities, the living is tough, but the food is plentiful!!