Each year I am amazed at how clean the nest is. The females carry out all of the young's waste and eggshell remnants so all that is left is a soft and cozy little moss mattress!
The females also do all the work in collecting the moss and hair to build the nest. The males' only responsibility is to bring food to the female while she incubates her 6 eggs for about 12 days.
There are about 4 different sub-species of these birds, but here on the west coast we have Chestnut-backed chickadees. They are bold little birds which often flock with kinglets, nutchatches, and Downy woodpeckers.