The Arizona Breeding Bird Atlas is the capstone of the first comprehensive statewide survey of Arizona's breeding birds. More than 700 surveyors, mainly volunteers, reported a total of 376 bird species during the 1993-2000 field seasons. Of those species, 283 were confirmed as breeding and 18 additional species were suspected of potentially nesting in the state during the atlas survey period. This atlas provides a breeding distribution snapshot for each of Arizona's nesting bird species at the end of the twentieth century. Bird populations change constantly due to environmental factors and human activities. The data compiled in this book will serve as a baseline against which to judge future changes. It also provides a wealth of natural history information. Each of the 270 two-page species accounts contains a color photo of the species and a range map summarizing the breeding distribution records collected during the atlas survey period. The accompanying descriptive text and graphs provide nesting habitat information and a timeline chronicling each bird's breeding phenology and migratory status in Arizona. Another 47 species are briefly discussed. Additional chapters describe atlas methods, results, and Arizona ornithological history, as well as topography, climate, and habitat diversity, which ultimately govern bird species distribution in the state. Useful to land managers and biologists, the atlas will also be a resource for birders and educators and will increase public awareness of Arizona's vast avian life.