Black Racer (Coluber constrictor) 2014-7-29 by David, Aberdeen, Harford County, MD - snake rescued from bird netting

The lack of keels on scales leads me to believe this is the Black Racer (C. constrictor).

The Eastern Ratsnake (Pantherophis alleghaniensis) is most likely to be confused with the Northern Black Racer (Coluber constrictor constrictor), however, P. alleghaniensis has keeled scales (weak, but keeled) and C. constrictor has smooth scales - no keels. The picture taken 4/24/2010 shows the keels on P. alleghaniensis.