Nice pic and way more clear than my own pitiful underbrush phonecam attempt! I have been biking & hiking the Catoctin Trail regularly since 1997 and in all that time, I have only seen two and was rattled at by a third. One was flattened/dead from trying to cross Fishing Creek Rd, one was crossing the blue trail so I gently provoked him with a fallen branch just to hear him rattle and the third rattled at me after I disturbed him trying to be suave setting up a picnic lunch for my wife at the Rte 15 overlook. What's nuts is how some timbers have a very olivish tint to their banding that makes them near impossible to spot once Spring and Summer green the area back up. I don't know if it's an individual trait or a seasonal, dietary or environmental one but it sure makes me happy for their auditory alert.
I thought I saw on the Maryland DNR website that there were no poisonous snakes in Maryland?