 The Important Bird Area (IBA) boundary is defined by patches of habitat suitable for endangered regent honeyeaters and swift parrots, centred on the woodlands between the Agnes Banks, Windsor Downs and Castlereagh Nature Reserves, and extending south to Penrith and north-east to encompass Scheyville National Park.It is adjacent to the forested hills of the Greater Blue Mountains IBA.The woodlands are dominated by an overstorey of coastal grey box, narrow-leaved ironbark and forest red gum.