Figure 2. Geographic Distribution of Geographic Range Areas, Latitudinal Range Extent, and Species Richness for the Global Avifauna.

(A) Median geographic range area (km ²). (B) Minimum geographic range area (km ²). (C) Variance in geographic range area (km ²). (D) Median latitudinal range extent (degrees). (E) Minimum latitudinal range extent (degrees). (F) Total species richness. The map scales are based on quartiles of the underlying distributions; the scale bars show the quartile values for each map. Parallels are shown at 45° S, the Equator, and 45° N.