The wide, expansive sky is a highway for many beautiful, flying creatures. Though they have wings to help them escape danger, they're not safe from the invasive species in the air that try to take over their territory. Age-appropriate text explains the important concept of ecosystems and the delicate balance species rely on for survival, and how one unwelcome invasion can have consequences for an entire animal community. Colorful photographs help readers visualize invasive species in the air, and helpful information on how to protect native species concludes the text.