Nearly stood on one this year at Jura whilst descending from checkpoint 2 towards Keils after doing a recce. Although it gave me quite a fright I did feel quite privilaged to have seen one. April/May and in warm weather is when they are most active due to it being their mating time. Although they would sooner retreat from danger they can be quite confrontational if they feel threatened, so always be on the cautious side when you come across one.