Chickadees are cavity nesters, and if they can't find a suitable hole (cavity) in a tree, they will use a nest box. This chickadee, one of a pair at the Fletcher Wildlife Garden, is coming out of a standing dead birch tree, actually a broken off snag about 15 feet tall. The wood is very soft and as you can see, a beak full of it is being taken out. The chickadees made multiple visits over several days, excavating this hole. Every few minutes one or the other would fly out carrying a load of debris. Can you imagine the work this takes! Sadly, these dead birch trees are so weak that a puff of wind will blow them down. This is a poor shot, but I thought it interesting enough to post for now.