Some people have great stories about finding birds, I'm afraid this isn't one of them! We were driving along the road, I saw something in a tree, and stopped for photos! When processing the photos when we got home, I initially assumed this was a Merlin. Left the images in a folder for Hawks with no ID. Then I saw a Merlin, at home. And looked at a few photos. Prairie Falcons aren't very common in Manitoba, so this was a lucky sighting!
Why is this a Prairie Falcon, and not a Merlin? The mustache mark is much more pronounced than on a Merlin. The streaking is much finer, especially along the belly, which, along with the underside of the tail, is much whiter - almost unmarked. This bird was also larger than a Merlin, with different proportions (longer body and tail)
Why is this not a Peregrine Falcon? The mustache mark is much *less* pronounced than on a Peregrine. This bird is very much brown-and-white, and the breast is streaked, not barred. The breast of a juvenile Peregrine may be streaked, but it is usually dark brown on tan, not brown on white.
Here are some excellent Peregrine Falcon photos
Here are some great Prairie Falcon photos