This layer represents a potential habitat model for birds in Pennsylvania at 30 meter resolution. The model associates occurrence of suitable habitat with key environmental factors that can be mapped over the entire region. These key factors include vegetative land cover, presence of human activity, elevation, topographic position, wetland characteristics and stream size and proximity. Areas of potential species presence were tabulated based on current and historical information and a series of conditional statements proceeded using layers derived to depict the key factors on a landscape scale.