When a bird flies into their window by accident, Callum and his sister, Emmy, learn that from the outside, the glass looks just like the sky. They also learn that the United States has lost a lot of birds in recent years--and that there are lots of things their family can do to help. First, they set out feeders and make the windows safe. Then, for the winter, they build a little shelter and put out a heated birdbath. By springtime, all kinds of birds are visiting their yard But with such a big problem, is there more they can do to make a difference?