Quivering trees

Interesting concept, I've seen both adders and grass snakes enter low bushes when foraging, and they certainly can make a small shrub sway about a bit. I have been drawn to observe snakes because of the movement/sound of dry leaves as they caused a low bush to sway. I would say the idea that it is to frighten predators may be far fetched, suggesting more awareness of the surroundings than I would credit a snake. Though I could easily see that a snake foraging in a bush could be perceived as purposely shaking it by an observer!