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Pennsylvania Breeding Bird Atlas
Pennsylvania Game Commission
Part of the Pennsylvania Gap Analysis Project the Breeding Bird Atlas database indicates bird species and nesting behavior of known birds species in Pennsylvania. The database is organized into two primary segments; the block and the species lists (data). Blocks are defined by a code for the USGS topographic map, and the block number. All records are organized by the Atlas region. Various attributes of the Atlas block are incorporated, including geographic features (physiographic locations), effort (hours of fieldwork). The species segment, being replicated the full 320,000 times, was kept to a minimal size, and lists only the species and breeding code, the year and comment. Evidence of birds nesting within an Atlas block was recorded with a set of codes that describe behavior and physical evidence of nesting. These codes are divided into four hierarchical categories, three of which indicate breeding. "Observed," "Possible," "Probable," and "Confirmed" breeding codes represent increasing evidence that nesting occurred within the block a species was recorded. "Probable" and "Confirmed" categories were further segregated into hierarchical codes that represent individual breeding behaviors or physical evidence of nesting. A description of breeding codes may be provided upon request. All of Pennsylvania's 4,928 atlas "blocks" were surveyed, with an average of 65 species per block recorded. A total of 188 breeding species were documented statewide. Data catalogued geographically by atlas "block," USGS 7.5 minute quadrangle, county, and physiographic province. Species files include political status designation and a number of life-history characteristics.