[2] The populations of this species in Australia are known to be nomadic like most water birds in Australia, moving from one water source to another, often entering habitats they have not previously occupied, taking advantage of flooding and heavy rain where the surplus of food allows them to breed and raise their young.

Irruptive movements may occur when environmental conditions are right in places where the species has been rare or absent.

[4] It has an elongated neck and beak designed to reach out and catch fish, frogs, spiders and other food animals available in its habitat.

[2] In the downy young, the down is longer, especially on the crown, with the neck and head white and upperparts and upper wing light grey-brown.

Movements are still largely unknown due to irruptive habits, which are commonly attributed to genetic adaptions to erratic environmental conditions.

[2] The white-necked heron is a shy bird, keeping to areas where it has a clear view of its surrounds.

It will defend feeding territories against other species and has been seen harassing ibises (Threskiornis moluccus) and raptors, often stealing prey they have caught.

[2] Nests are commonly at a height of between 15m-30m above the ground on a tree structure associated with access to a close a food and water source.

[2] The diet includes freshwater mussels, fish, shrimp, freshwater crayfish, spiders, dragonfly nymphs, damselflies, praying mantis, grasshoppers, water beetles, lizards, young ducklings, young rodents and amphibians.