Most modern day wilderness survival situations tend to be less than 48 hrs. In these cases berries and bugs tend to be your best source of food for sustaining your energy level and moral to buy time and get rescued. They’re easy to gather, don’t need other equipment, and fairly abundant when spotted. When leveraging berries as a food source keep in mind this simple berry rule which is easy to remember.
Aggregate berries that have segments like strawberries, raspberries, and blackberries are almost all edible, about 99%. I say 99% because there are few exceptions to the aggregate berries being edible idea, at least in eastern North America. The most well known one is the berry of goldenseal, Hydrastis canadensis. However, this berry is born, usually singly, atop an herbaceous single stem (in the buttercup family, Ranunculaceae). Clearly bushes and tree don't qualify here.
About 90% of blue and purple color berries are edible, good edible examples are blue berries, huckleberries, Oregon grape, service berries, and salal berries. Pokeweed berries are a poisonous example of a blueish berry.
About 50% of Red Berries are edible. Kinnikinnick also known as bearberry is an edible red berry.
Others that come to mind are cranberries and red chokeberry.
Poisonous red berry examples are soap berries which I’ve seen birds eat before (just because animals consume a plant doesn’t mean a human can or should). Unless I can positively identify and know a plant with red berries is edible I avoid them.
Most (about 90%) of white berries are poisonous. As a general rule you should avoid them.
Lastly if unsure or on the fence we recommend using the plant edibility test.