The black-capped chickadee hides seeds and other food items to eat later. Each item is placed in a different spot and the chickadee can remember thousands of hiding places. Every autumn black-capped chickadees allow brain neurons containing old information to die, replacing them with new neurons so they can adapt to changes in their social flocks and environment even with their tiny brains. Even when temperatures are far below zero, chickadees virtually always sleep in their own individual cavities. In rotten wood, they can excavate nesting and roosting holes entirely on their own.