This is the first in a forthcoming series of habitat management guidelines produced by the Cornell Lab of Ornithology as a tool to help those interested in managing and protecting habitat for birds. These guidelines offer a set of "management prescriptions"descriptions of the kinds and amounts of habitat that are required to sustain healthy bird populations. This guide is for the Scarlet Tanager (Piranga olivacea), a brilliant denizen of many mature eastern forests. Providing well-managed habitat for this Neotropical migrant songbird also will benefit a wide variety of other birds that use mature forest. We first offer a series of general management guidelines that are applicable throughout the eastern forest region. These include preventing the fragmentation of large forest tracts, minimizing the creation of edge habitats, establishing forested corridors to reduce isolation of small patches, and maintaining structural and plant-species diversity within existing forests. Because habitat requirements for the Scarlet Tanager vary geographically, our specific recommendations are tailored to conditions in four regions within this species' range. Two of these regions, the Midwest and Atlantic Coastal Plain, are sparsely forested, whereas the Appalachian and Northern Forest regions are more extensively and continuously forested. In all regions, tanagers show no area sensitivity in landscape blocks that are more than 70% forested; as regional forest cover is reduced, the minimum area required by tanagers increases. For example, in 2,500-acre (1,000-ha) landscape blocks that are approximately 50% forested, tanagers require 175300 acres (70120 ha) of habitat in the sparsely forested Midwest and Atlantic coastal plain, whereas they require only 70 acres (28 ha) or less in the extensively forested Appalachian and Northern Forest regions. The tables we provide help landowners and managers determine the minimum-sized habitat area required to support breeding Scarlet Tanagers in their region and determine the relative suitability of existing forest patches in a variety of landscape conditions.