I used to work in Downsview Park. Lots of mockingbirds and most days I'd see the big female red-tail or one of the kestrels that nest every year in one of the hangars, and hear the meadowlarks. I found turkey tracks and a spotted sandpiper pair that tried to raise a brood in the crummy little 'marsh' one time, nesting savannah sparrows, willow flycatchers... It's quiet nowadays but in the spring you can pick up some good migrants... sparrows, buntings, orioles, many kinds of warbler. My best bird was probably the short-eared owl I accidentally flushed on Christmas morning before work two years back.