Straw-necked Ibis

The Straw-necked Ibis is one of Australia's most recognizable wading birds, named for the stiff, straw-like feather plumes that project from its lower neck and breast. Unlike its close relative the Australian White Ibis, it favors dry grassland and pasture as much as wetlands, moving in huge, loosely coordinated flocks that track rainfall and insect outbreaks across the continent. Its bold black-and-white pattern and glossy sheen make it easy to pick out even at a distance.

• Back and wing feathers are deep black with a strong green-to-bronze iridescent sheen that flashes in direct sun, similar in structure to other ibis contour feathers but darker overall.
• Underparts, neck, and thigh feathers are clean white, creating a strong two-tone contrast with the dark upperparts.
• The bird's namesake straw plumes are narrow, stiff-shafted feathers on the lower foreneck and upper breast that stick out at odd angles rather than lying flat like normal contour feathers - a texture not seen in other ibises.
• Flight feathers are glossy black with little pattern variation, so a found flight feather will look plain and dark rather than barred.
• Distinguish from the Australian White Ibis (mostly white body, bare black head/neck, no iridescent black back) and from glossy ibis (smaller, uniformly chestnut-and-green, no white underparts).

Adults have a bare, dark grey-black head and upper neck, glossy black-green upperparts, and white underparts, with the diagnostic straw-colored breast plumes most developed in breeding adults. Both sexes look alike, though males average slightly larger. Juveniles are duller, with a browner cast to the upperparts and reduced or absent straw plumes, gradually acquiring full adult feathering over one to two years. Molt is not tightly seasonal since breeding is triggered by favorable water levels rather than a fixed calendar, so worn and fresh feathers can be seen in the same population at different times.

Straw-necked Ibis are found throughout mainland Australia and into New Guinea, favoring open grasslands, pastures, floodplains, and shallow wetlands rather than deep water. They are highly nomadic, moving in large flocks in response to rainfall, flooding, and insect abundance, and can appear suddenly in numbers far from their usual range during wet periods. Most populations are considered resident but locally irruptive rather than strictly migratory.

This ibis forages mainly on the ground, walking through grass and shallow water to take insects such as grasshoppers and crickets, along with other small invertebrates. It nests colonially, often alongside other waterbirds, building stick platforms in trees, reedbeds, or low shrubs over water. Its call is a low, harsh grunting croak, given mostly at breeding colonies rather than in flight. Large foraging and roosting flocks are a hallmark of the species, and its close association with insect outbreaks in farmland has made it a familiar sight in rural Australia.