Black rat snake

This beautiful black snake appeared to have been attempting to cross the road in my suburban neighborhood, but was reared up and preparing to do battle with a robin which looked like it'd just landed in the street to frighten it! I pulled up just as the confrontation was about to begin and the bird took off! A neighbor came out and we discussed possible species and we believe it's a black ratsnake. It had a beautiful dark black coloration, not very mottled, if at all. White flecks between scales. We estimate between 5-6' long. Snake was docile and calm as we photographed it. Didn't seem threatened or in any hurry to escape back to the treeline.