NatureServe no longer serves digitized maps for the distributions of the birds of the Western Hemisphere. These maps, suitable for use in GIS mapping software, have been merged with a data set created by BirdLife International to create a complete global database of distribution maps of the world’s birds. You can access the digitized maps here.
These maps are suitable for use in analyses that employ GIS mapping software. For example, you could look at the relationship between various landscape features and the distribution of one or more bird species.