The only half-decent shot I managed of one half of a pair of Northern Mockingbirds (Mimus polyglottos) that summers in the Markham/Steeles area. (Click on the picture above and it doesn't look too bad) The range of these animals have been creeping North with our warming summers until, at the moment, there are 400 pairs living in the GTA (according to a representative of the Toronto Ornithological Club).
Here they look like a nondescript grayish thingy, but with wings spread (see below, picture from web) they become quite a bit more notable. According to some, by displaying the white stripes as they fly low over fields, they frighten insects into flight.

If you want to try attracting Mimus polyglottos to your feeder, try chopped apples or raisins, or plant multiflora rose (another invader). Although, if their GTA numbers continue to increase, they will probably come to be seen as an annoyance. They are very noisy and aggressive birds, especially when defending a nest (the one above buzzed my head not long after the shot was taken.)