Westmount Park’s Crows.  They are an interesting species of birds.  An interview with Kevin McGowan, an ornithologist from  Cornell University, provides a fascinating insight into their behaviour:

http://www.nwf.org/news-and-magazines/national-wildlife/birds/archives/2008/bird-watching.aspx

“What is a group of crows called?
The poetic term used in literature is a “murder.” Scientists would call them a flock.

Why do crows roost in cities?
Urban living offers crows several possible advantages. Cities are often 5 to 10 degrees F warmer than rural areas, an advantage in cold weather, and may offer protection from human hunters. Great horned owls, which frequently prey on crows, presumably number fewer in urban areas. Artificial light may assist crows in watching for owls at night, and cities may provide some of the largest roost trees in a given area.

How can you attract crows?
Crows have an endearing characteristic that apparently is not shared by other birds—they can identify people as individuals. While you can get chickadees to eat out of your hand, any old hand will do, and I suspect the chickadees do not know you as an individual. Crows will! If you toss them peanuts (preferably unsalted, in the shell) on a regular basis, they will wait and watch for you. Not just any person, but you. If you do this often enough, they will follow you down the street to get more, even if you’re in your car. “