Changes in version 3.1 of the Partners in Flight Population Estimates Database are detailed in the Handbook to the Partners in Flight Population Estimates Database, Version 3.1.
This version replaces previous versions of the Handbook and updates and integrates all relevant material from the Handbook to the Partners in Flight Population Estimates Database, Version 3.0, the Handbook to the Partners in Flight Population Estimates Database, Version 2.0 and the original Guide to the PIF Population Estimates Database. Version 3.1 describes in full the contents of the database and provides an overview of the process used to generate the estimates using data from the North American Breeding Bird Survey, including potential uses of the data, caveats, and future directions for revising these estimates.