I'm not going to claim that I know what this bird is, but here are some features that I notice: there appears to be a contrast between gray flanks and slightly rufous wings; the breast spots are fairly large and conspicuous; the eyering is fairly muted; and there appears to be a dark smudge between the eyering and the pale lore (or is this a shadow?). I don't know if these marks help in this case, but typically they would point us towards Hermit Thrush.
The pronounced buff bridge above the lores appears to be visible through the foliage. This is a strong Swainson's feature. In Hermits it is not noticeable. I'd also agree with Tim regarding the breast spotting.
Despite having no experience of either species, I would lean towards Swainson's based on the head pattern, and also I would expect slightly stronger breast spotting on a Hermit Thrush. It is difficult to say for sure based solely on this one pic, though.
I've done a little more research since seeing so many pro-Swainson's posters. I think my previous opinion of Hermit Thrush is wrong and based on regional bias, combined with a blind-spot in my birding skill. I am an easterner and we almost always see the "olive-backed" variety of the Swainson's Thrush. But you may have a "russet-backed" from Western N. America. They could easily become, or have been, 2 different species. Here are some photo links that illustrate that point.
This is the typical "olive-backed" we find in the east. It clearly looks nothing like your photo, rivaling vireos for the intensity of its "spectacles." The superloral and eye ring are extremely bold. There is no hint of red in the wing. The bill is noticeably thicker.
Here are some "russet-backed" in Colorado. They look much more like the bird you have with the same dark spotting and the narrow white eye ring. Some, according to Sibley (Western edition) are redder on the back and wing (your bird), some are browner, like these in Colorado.
So, you probably have a "russet-backed" Swainson's Thrush.
Do let us know where the picture was taken. Canada is a big place to be from. It's amazing what variety exists inside many species between East and West N. America.
Happy to learn something today.