So there is Humber River Trail that starts from the park that is at Finch and Islington intersection. And it goes south. On the way close to sundown it is possible to see a beaver (but it gets scared of any noise), and there are also deer there on the trail (if you get lucky).
There is a beautiful trail that starts in Marie Curtis Park and goes north.
There is Colonel Samuel Smith Park, where we saw a turtle laying eggs and a family of beavers near a marina
Edwards gardens and than south trail has groundhogs living there
Now, if you take Hamilton into consideration than you got a tons of trails with waterfalls there.