Number of freshwater bird species, by freshwater ecoregion.
Freshwater obligate birds include those species that need freshwater habitats for breeding (e.g., ducks, herons) or feeding (i.e., birds that depend almost exclusively on food found in freshwater habitats, such as freshwater fish, mollusks, and crustaceans). In all, 815 bird species were found to meet this criterion, with almost all bird families represented. We mapped freshwater bird species to freshwater ecoregions with the following procedures: for North and South America, NatureServe GIS data were summarized by freshwater ecoregion; for Africa, distribution maps presented in Birds of Africa (Brown et al. 1982–1997) were used to assign species to freshwater ecoregion by hand; for Asia and Australia, data were summarized using a grid system of bird species derived from the terrestrial ecoregion WildFinder data set. Literature sources were used to determine whether a species was considered a freshwater bird.
These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.