They do? I can’t see reference to geocaching in either, only letterboxing?
In any case, it would be hard to argue any activity that puts people next to wildlife isn’t going to disturb them in some way.
Incidentally, I used the Ring Ouzel as an arguement in a written objection to the Teignbridge development plan extending Buckland Estate into green fields along the Teign Estuary – on land specifically known to be a nesting ground to them. Somewhat more disturbing to a rare breed to have houses built on them, at least on Dartmoor this risk is far less!