How do birds find their way?

The Let's-Read-and-Find-Out Science Books series, originally published by Crowell, now HarperCollins, is an American children's book series designed to educate preschoolers and young elementary school students about basic science concepts. Many Let's Read and Find Out titles have either been reillustrated (sometimes more than once) or reissued under different titles. Some of these titles may be duplicates because of the renaming. Since the 1990s, the series has been divided into two levels.