Many birds, including starlings, crows, and penguins, find strength in numbers. Some birds avoid predators by joining large flocks or colonies that nest and migrate together. Others work as a group to find food and protect their young. Bird Groups explores how and why different bird species form groups. Easy-to-read text, vivid images, and helpful back matter give readers a clear look at this subject. Features include a table of contents, infographics, a glossary, additional resources, and an index. Aligned to Common Core Standards and correlated to state standards. Core Library is an imprint of Abdo Publishing, a division of ABDO.