Alberta Terminals, Edmonton, AB, Canada
Thanks everyone for confirming the ID of this bird! I guess my initial ID was correct. I only had a brief glimpse of this bird and it didn't return. I initially thought it was a Gyrfalcon then named it as Merlin when I posted on Flickr because when trying to confirm the ID of the bird, the slimmer body resembles the Merlin more than the Gyrfalcon (bulkier). The undertail coverts also looks more like the Merlin than the Gyr.
Below are some of the hunting shots of the Prairie Falcon. A Bald Eagle also flew by and was harassed by the Ravens.