My wife and I are amateur mushroom hunters (Colorado Mycological Society
). I find my Magellan Gold GPS receiver invaluable for this activity. For starters, whenever I plan to march off into the woods to hunt 'shrooms (which involves lots of "aimless" wandering with eyes focused on the ground), I always waypoint (mark) the starting point of our hunt (usually my truck). That way if I become disoriented during the hunt, I can use my GPS to find my way back to the starting point. My other use for the GPS in 'shrooming is to mark really good mushroom finds so that I can return there later. We also enjoy using our GPS receiver for geocaching, particularly during the off season for mushrooms or on bad hunting days.
Just an aside, but another set of tools that we use for safety in mushroom hunting is a pair of walkie talkies so that we can keep in touch and find each other when separated during the hunt. In the past we relied on whistles (mine a English bobby police whistle) to contact each other and we still carry them in addition to the walkie talkies.