ID is always tough (for me anyway) with Buteos. After looking through Birds of North America Online and a couple of books I am still not absolutely sure what the bird is (not at all unusual for me btw) though I tend to agree with the OP that it is a juvenile Red Shouldered Hawk (first year) because of the way it's breast is marked.
Love the pose and detail in this capture. Great eye contact and composition. The angle is a bit steep but then that is not always something that we can control. Beautiful work !!!