From the mysterious starling murmurations to the frenzy of a seabird colony on a vertical cliff, large gatherings of birds offer among the most spectacular wonders of nature. In this book, the nature writer Marianne Taylor explains why some bird species are social and live together, while others choose a solitary lifestyle. Her book is divided into ten chapters describing different colony types (e.g., on cliffs, in trees, on islands) and social strategies. Each chapter includes an introduction, the articulation of a few key concepts and two examples called “colony profile” and “species profile”. The reader will find numerous interesting anecdotes, such as the sneaky liaisons that are parts of the colony life, which cleverly illustrate the complexity of bird social structures. The book features some of the most spectacular bird colonies on earth, from the “supercolonies” of the Everglades in Florida, seabird colonies on Scottish cliffs and in Antarctica, to massive Social Weavers’ nests in the Kalahari Desert. My favorite part is the species profile of the Passenger Pigeon (Ectopistes migratorius), which narrates how and why the once most abundant bird species in the world went extinct because of hunting pressure. It is a good reminder of our direct impact on biodiversity: even what seems like an exhaustible resource can quickly vanish, past an invisible tipping point. Beautiful pictures and illustrations accompany the text and make the book very lively. The book is characterized by an elegant and clear style, sometimes poetic or with a touch of humor, so that any passionate ornithologist with or without a scientific background can enjoy it. Apart from a few imprecisions (e.g., some species distribution maps), a little abrupt ending and the lack of some useful references that would allow dedicated readers to dig further, I strongly recommend reading Why Birds Live Together. Although this is not a scientific textbook, it will be an informative and pleasing read for whoever wants to learn about birds’ different forms of social life.