In many cases, this is exactly what birds will do. If the rain lasts several hours, though, or for a few days, then they won’t survive if they don’t eat. Most birds need to feed several times a day to keep their strength up. Missing a feed because it’s raining can be detrimental to their health. When it’s raining, they will only stop out as long as it takes to get the food they need before they return to shelter.