If there are living things around you, there is food. Plain and simple. You may not like what you have available, but you will have a chance to survive. Just remember that not all of the plants and animals out there are edible and you will be fine.
Stay away from things you do not know. If it is brightly colored, smells bad or just doesn't look right, skip it. Mushrooms are the prime example of such things. Puffballs, which can be anywhere from 2 cm across up to almost soccer ball sized, are the safest bet, though there are some of the poseurs out there that can make you sick that look like the Puffball. Stay away from amphibians, no matter what those toad-molesters say. Toads and frogs can make a good meal, but some types, even in temperate climates, have either a tainted mucus or outright poison in them. In general, if it doesn't taste good, skip it.
Make
A Fire AND
Always try to cook whatever you have to eat. Our bodily systems are not used to the bacteria and other contaminants that our ancestors had to deal with. We also live longer, but only if we can keep our common sense straight. Boil water. Clean Fish and fry or char it, especially if it is from fresh water. Even the greens we use, such as fiddle head ferns, should at least be rinsed in hot water before eating. It may change the nutrient content and the mouth-feel, but it will keep you from contracting parasites that live on and in them.
When you are done eating, boil water in the pan that you used to help clean it, then BURY the remains of whatever you have. Dig a pit and put the fish guts, the cooking water, and other things in the hole and cover it up again. It will not only keep from stinking up the place as it decomposes, animals are less likely to be attracted by the food scraps. At one of my favorite camping spots, I have done a 'permanent' dump hole. I made it about 10 inches deep to begin with, put gravel and rocks in it to about the 7 inch mark and found a flat rock to put over it when I am not there. It is also a good hole to use for personal use(euphemism for peeing), but not for anything more solid, if you get my drift.
There are places where you will want to pack out anything you pack in. This can get messy, but that is what zippy bags were made for.
Whenever you can, pack out what you packed in.
Food to look for, Apples and Honeysuckle
Food to look for #2, Mushrooms and Sumac
Food to look for #3, Wild carrots, Queen Anne's Lace, Grapes, Wild Spinach
Food to look for #4, Pine cones
Food to look for #5, Strawberries, Chives, Onions, Rose Hips and Parsley
Food to look for #6, Dandelions, Mints, May Apples
Food to look for#7, daisies, tomato, nightshade, nettle, false strawberries
Food to look for #8, Elderberries
Food to look for #9, oak leaves, ants, burdock, thistle
Food to look for #10, Golden Rod, birds nest
Food to look for #11, Cattails
Food to look for #12, Wild Grapes
Finding Food #13, Mulberries
Finding Food, #14, Strawberries
Finding Food, #15 Grubs, larvae and ants
Finding Food, #16 Lichen
Finding Food #17 Ramson, Wild Garlic Parsnips
Medical Plants, Mullein
Medical Plants #2, Tansy, Raspberry, Plantain
Medical Plants #3, Bee Balm, Bergamot and Bees
Medical Plants #4, Yarrow
Medical Plants #5, Plantain
Medical Plants #6, Comfrey
Catnip, another medical plant
NEW - Plants to avoid.
How about Fishing?
Vicky's Pictures, including mushrooms, Jewel Weed and Solomon Seal
Now that you have it, how do you cook it?
Links to the USDA Forestry Service