There's no greater thrill than spotting one of these tiny birds in the garden, and young readers will be fascinated by how this avian machine works. Hummingbirds are the smallest birds in the world, but they exploit every advantage that comes with their modest size. Exploring the World of Hummingbirds is a fully illustrated introduction to the hummingbird's high-performance lifestyle. Built for efficiency and fueled with high-energy nectar, this bird runs at a high temperature during the daytime, its heart beating 650 beats a minute, and its dense feathers keep it warm at night as it rests. Most impressive, however, are its skills as an aerial acrobat. Like a helicopter, it can move forward, backward and sideways. When feeding from a blossom, it can hover in midair and then turn and whir away at full speed -- all in two-tenths of a second. Readers will find out how hummingbirds and flowers have evolved for their mutual success. They'll also discover intriguing facts about hummingbird biology, flight, mating and nesting behaviors, family life, migration, and just how a hummingbird achieves and maintains its dazzling, shimmering colors. The Exploring the World of... nature series was created for young readers who are eager to learn more about the wild creatures of the world. Each title contains beautiful photographs of the animals in their natural habitats and the highly readable text explores their daily lives and physical characteristics, how they make their homes, how they raise their young and what they eat. AGES: 8 to 12 AUTHOR: Tracy C. Read is an editor and writer with a special interest in nature and the environment.