Description Some birds construct nests with their own saliva, while others use vomit as a defense! Sound strange? In Spit Nests, Puke Power, and Other Brilliant Bird Adaptations, curious kids ages 5 to 8 discover many of the unique adaptations of birds. Perfect as a read aloud or an early reader, layered text and back matter provide further information and encourage readers to dive deeper into the world of unique bird adaptations.