Threatened bird species density

BirdLife
International has developed digital range maps of all threatened bird species.
This map is based on distribution data for the 1186 species assessed as threatened
in 2000. The data are plotted as a global density surface, representing the
number of species potentially present in each location. The map is the first
such treatment of any large group of threatened species.
Source: density surface provided by BirdLife International, further information
on threatened birds in BirdLife International.
BirdLife International. 2000. Threatened birds of the world. Lynx Edicions
and BirdLife International: Barcelona and Cambridge, UK.