Here's another photo, not sure if it will help. We actually have a few Red-shoulder's that apparently nest in the neighborhood, but I didn't think this was a Red-shoulder when I saw it. This hawk seemed larger than the usual Red-shoulder's I see, unfortunately it never made a sound while I was watching it. One of the other things about this hawk, the Red-shoulders are usually somewhat shy, as when I happen to get close to their perch, they fly off. This bird sat on this perch for 15-20 minutes and I walked under the tree, it didn't seem to care. I did see it in flight and it didn't look like a Red-shoulder to me.