These are found throughout eastern and northern mainland Australia and are also found in New Zealand, Indonesia, Papua New Guinea and on some south-western Pacific islands. Their habitats are shallow freshwater and saltwater wetlands, intertidal mud flats and wet grasslands.
They feed in water that is less than 40 cm deep over sand, mud or clay, where they can sweep the water with their bill, eating mainly fish in freshwater and shrimps in tidal flats: they will also eat other crustaceans and aquatic insects. On the inside of the spoon shaped bill there are many vibration detectors, called papillae, with these the bird feels for prey.
The sexes are similar and when breeding long white plumes grow from the back of their heads, coloured patches also appear on the face. They form monogamous pairs for the duration of the breeding season and nest in colonies, building a solid bowl-shaped nest of sticks and twigs lined with leaves and water plants, the nest is usually placed in the crown of a tree over water or among high reeds and rushes and may be reused annually, both sexes incubate the eggs and feed the young.