Managed to spend a few minutes at lunchtime near a local hibernaculum in a park. They have the den areas protected & fenced off from human traffic but the inhabitants are of course tend to disperse as the season goes along. Got a couple of shots of what the local parietalis population usually looks like, they tend to be darker than what is seen in the hobby:





They do some counting of the snakes here & the green mark on the back would make it one of those that has been counted previously.