The female Chickadee (Paridae) has built her nest. I expect by now the eggs have hatched and both the male and the female are out searching for caterpillars, spiders and insects for their young.
A bit of a timeline: One to two days after the female builds the nest, her eggs are laid. She incubates the eggs for about twelve days before they hatch. All this time the male Chickadee takes care of his mate by bringing her food.
Upon hatching, these new birds are naked and blind but within a week, though still with eyes closed, they are growing feathers. The female now goes out searching for food as well.
At eleven days old they have grown their feathers and have opened their eyes. At two weeks, or just a couple days longer, the fledglings are able to fly short distances. After a couple weeks of guidance and feeding by their parents the juveniles are on their own to face the wide world.