The female bluebird is feeding the little ones in her nest, which she has been doing for almost two weeks now. If you look very closely at the beginning, you can see an open beak in the hole crying for food. When she leaves, she has something white in her beak. Can't tell for sure but it looks like feathers but it could be she is just taking out the trash, which there must be a lot of with 5 little ones in that small box...