Fig. 2. Previous epizootics of HPAI in Australia (open circles) in relation to Wallace’s Line (solid line), poultry density (heads km-2: squares, color gradation from fawn to black in steps 17–10, 10–50, 50–100, 100–200, 200–500, 500–1000, 1000–2500), and important wetlands for Charadriiformes (solid triangles). Source: Poultry density modified from Wetlands International (2006) and FAO (2007).