See what an emperor penguin has in common with an Antarctic petrel. Learn what sets an emperor penguin apart from an osprey. Readers will compare key traits of emperor penguins—their appearance, behavior, habitat, and life cycle—to traits of other birds. Charts and sidebars support key ideas and provide details. Through gathering information about similarities and differences, readers will make connections and draw conclusions about what makes this animal a bird and how birds are alike and different from each other.