As nature, landscape, and wildlife photographers we often place ourselves in locations and situations that are a bit off the beaten path. When we do go out to make photographs it is worth thinking a little about possible contingencies and how we will handle them should something occur. As the most basic precaution, I consider one of the least expensive pieces of gear a photography essential, the simple whistle.
In our modern society, we tend to take our safety or our ability to rapidly communicate for granted. Sometimes that is the case. For example, if you are out with me you know you are with an instructor who is certified in CPR and first aid, has had extensive survival training, and handles high stress situations well. More often though, most photographers think if they have their cell phone they are ready and help is just a call away. But it is amazing how often we find little to no cell coverage, a dead battery, or a situation where the phone is just out of reach.
As a pilot, I learned to plan for contingencies and to prioritize redundancy in safety or communication systems. To back up your phone one of the simplest preparations you can make is to carry a whistle when you go out to make photographs. Survival situation after survival situation has proven that a whistle is a "must have" piece of gear. Look at any list of items you should have in the field or wilderness and a whistle will be on it. Oh by the way, it is not enough to have the whistle with you, have it on your person and easily accessible with either hand.
Photographers in the field are just like hikers, campers, and other outdoor enthusiasts. Interestingly, they tend not to think of themselves as such because our hobby, passion, or profession is so dependent on high tech gear. But in most cases there is no difference. As an example, Hal has a friend in Alaska who recently almost lost his life while out in the wild. Overcoming incredible odds he was rescued and recovered, but only because of his whistle. He was in a bad position and the only way he could try and find help was to blow his whistle. He blew for over an hour and finally someone heard and investigated. They joked afterwards that his whistle was the $2 accessory that saved his life. Pretty amazing considering the guy had thousands of dollars of other gear with him. It is also worth mentioning that Hal's friend broke one of the cardinal rules, he went out alone without using the buddy system (the topic of another post.)
So when you are packing up the camera, lenses, and tripod, make sure to put a simple whistle in your pocket. If you ever run across him in the field, ask Hal to see the four essential pieces of shooting gear: Hoodman HoodLoupe, cell phone for DOF calculations/comms, a good knife, and a whistle.
Always remember making the photograph is optional but making it home is mandatory. (Paraphrased from my mountaineering buddies.)