Foresters and recreation managers are now more aware of the esthetic and economic values of nongame wildlife, including cavity-nesting birds. In summer of 1977 the U.S. Forest Service established a national snag policy requiring all Regions and Forests to develop guidelines to “provide habitat needed to maintain viable, self-sustaining populations of cavity-nesting and snag-dependent wildlife species.” These guidelines are also to include “retention of selected trees, snags, and other flora, to meet future habitat requirements” (USDA Forest Service 1977). Some Forest Service Regions had already established policies for snag management. For example, in 1976 the Arizona-New Mexico Region (USDA Forest Service 1976) recommended that three good quality snags be retained per acre within 500 feet of forest openings and water, with two per acre over the remaining forest. The policy also requires that provisions be made for continued recruitment of future snags; spike-topped trees with cavities and obvious cull trees should be left for future cavity nesters. Some foresters are now using tags to protect the more suitable snags from fuelwood cutters in high-use areas. In this book, we have summarized both published data and personal observations on the cavity-nesting birds of North America in an attempt to provide land managers with an up-to-date, convenient source of information on the specific requirements of these birds. Bird nomenclature follows the American Ornithologists’ Union _Checklist of North American Birds_ (fifth edition, with supplements). Bird illustrations and distribution maps are reprinted with permission of Western Publishing Co. from _A Guide to Field Identification of Birds of North America_ by Robbins et al. (1966). The small range maps indicate where birds are likely to be found during different seasons. Summer or breeding range is identified in red, winter range in blue; purple indicates areas where the species may be found all year. Red cross-hatching identifies areas where migrating birds are likely to be seen only In spring and fall. Length measurements (L) are for birds in their natural position, while W indicates wingspan. Percentages of the diet under “Food” in species accounts refer to volume, unless otherwise indicated. Since nestlings of most species require insect protein, “Major Foods” refers largely to adult diets. Appendices list common names of plants and animals mentioned in the text, with scientific names when they could be determined. Table 1.—Cavity-nesting birds: tree use and major foods.