Passage taken from Richard Adam's book, "Watership Down" page 136 (at least in my copy)

“The short June darkness slipped by in a few hours. The light returned early to the high down, but the rabbits did not stir. Well after dawn they were still sleeping, undisturbed in a silence deeper that they had ever known. Nowdays, among fields and woods, the noise level by day is high – too high for some kind of animals to tolerate. Few places are far from human noise – cars, buses, motorcycles, tractors, lorries. The sound….”