These maps represent current knowledge of range for all bird species occurring in the Western Hemisphere, based on available sources of distribution data and expert opinion.
These map images were generated from shapefiles retrieved from BirdLife International’s website (http://www.birdlife.org/datazone/info/spcdownload), where they are also freely available to the public for non-commercial purposes (see Acknowledgement below). Species' range maps were originally digitized by eye or from scanned images of source maps occurring in field guides or species accounts (such as the Birds of North America series), and then reviewed and corrected by the organizations listed in the Acknowledgements. A list of the references is available in the full project metadata document that accompanies the BirdLife International download.
Several BirdLife International/NatureServe maps have been updated using reviewed observation from the Northwest Territories/Nunavut Bird Checklist Survey Program, created by Environment Canada’s Canadian Wildlife Service. These maps were only created by Bird Studies Canada, for bird species known to breed in the Northwest Territories and Nunavut.
Data provided by BirdLife International and NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - Center for Applied Biodiversity Science, World Wildlife Fund – U.S., and Environment Canada - WILDSPACE. Craig Machtans provided the updated NatureServe Northwest Territories/Nunavut data, and Andrew Couturier of Bird Studies Canada provided the associated maps.