This book is an authorized updated and expanded edition of Helen Downing's Birds of North-Central Wyoming and the Bighorn National Forest (1990). The Bighorn Mountains in Wyoming are more than 100 miles in length with a maximum elevation of 13,167 feet. Flanked to the west by the Bighorn River basin and to the east by the Powder River basin, they have produced a wide variation of vegetation types and ecosystems, including native grasslands and coniferous forest. At least 327 bird species have been reported from the region, and breeding has been confirmed for 190 species. Species descriptions indicate relative abundance, breeding status by latilong, and locality/date records. Regional birding areas are described and mapped, and results of recent regional breeding bird surveys and seasonal bird counts are summarized. Line drawings illustrate representatives of each of the 53 avian families documented for the region, and there are 7 maps and more than 60 literature citations.