[Rob_D]

Adders are superbly camouflaged when in long grass and seemingly invisible if they don't move. Last year I was out searching for them and "being stealthy". I heard a rustle and froze when I saw a common lizard a few feet away. I stayed still for a couple of minutes looking ahead before moving very slightly. At that point, the adder that I had not seen and which was right next to my foot began to move away. I was so surprised I had not seen a snake that was right next to me when I was paying very close attention to my surroundings.

So I have no doubt they can be trodden upon by accident, and no doubt they would not take kindly to it. Still, I'd love to see them more often, and such a shame there are none around here.