This Purple Swamphen belongs to the Gallinules, large crakes with short bills and coloured frontal shield on the forehead. They love aquatic weeds, pulling them up to feed on bases and roots. They are quite common in Australia and can be found in many wetlands. I spotted this one at Warriewood Wetlands in Sydney. They have very wide feet, I assume they keep them stable when the surface is moist and yielding.