A really poor photo and heavily cropped! However, it does show the red tail and the underwing markings of this Red-tailed Hawk. Seen at Carburn Park on Tuesday.

"Red-tailed Hawks are the most commonly seen hawks in Alberta, especially in the aspen parkland." It's piercing call is a "powerful, descending scream." From Birds of Alberta by Fisher and Acorn. Very common from April to October.