You may never need it, until you do. I added the SOL Emergency Bivvy to my vest this season because I have learned over the years just how fast the weather can turn on you, especially in alpine environments. This bivvy has enough room for me and the dogs (or a hunting partner) and reflects 90% of your body heat.
The SOL Emergency Bivvy can save your life and it’s too light (5.8 oz), compact and inexpensive to go without. Add it to your bird hunting EDC — $23.