Arthur W. Allen 1984 This report is part of the Habitat Suitability Index model series which provides habitat information useful for impact assessment and habitat management. The Habitat Use Information section is largely constrained to those data that can be used to derive quantitative relationships between key environmental variables and habitat suitability. The habitat use information provides the foundation for the HSI model that follows. In addition, this same information may be useful in the development of other models more appropriate to specific assessment or evaluation needs for the gray partridge (Perdix perdix). The HSI model section documents a habitat model and information pertinent to its application. The model synthesizes the habitat use information into a framework appropriate for field application and is scaled to produce an index value between 0.0 (unsuitable habitat) and 1.0 (optimum habitat). application/pdf en U.S. Fish and Wildlife Service Habitat Suitability Index Models: Gray partridge reports