|Australian Bush Birds|
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|Australian White Ibis - Threskiornis molucca|
|White Ibis foraging for food on low tide flats at Broome, WA.|
|In flight showing the white underside with red underwing bars and black tipped feathers.|
The Australian White Ibis - Threskiornis molucca - has white plumage overall with lacy black tail plumes. Head and extreme top of neck are bare black skin. Long, down-curved beak is also black. Legs are dark grey with red smudges. Males and females are similar; females are slightly smaller with a shorter bill. Breeding birds have sparse, stiff, yellow plumes hanging from the lower neck. Plumage and skin are often stained muddy grey from feeding activities. Grows 65 to 75 centimetres.
Immature birds are similar to adults but the upper neck is spotted black and white.
|Australian White Ibis - page 2|
In flight the feet trail behind the tail feathers. The neck is always extended in flight. An underwing patch of bare skin along the line of the wing bones is bare pink becoming scarlet in breeding birds.
Lives in shallow fresh and tidal wetlands and pastures and on tidal mud flats. Forages only in swampy or wet ground. In the water the ibis moves its head from side to side probing for crustaceans, water insects, fish, snails and frogs. Also eats crickets and earthworms. Mussels are a favourite food opened by hammering them on hard surface to break open the hard shell. Roosts in trees in or near water, bull-rush beds and mangroves, usually in large flocks. Has adapted to urban parks and is rapidly becoming a nuisance as a scavenger in cities. Distributed around Australian mainland, except for the arid centre, and Tasmania; common to abundant in the south-east, south-west and north. Usually found in flocks which fly in undulating lines or a rough "V" formation.
White Ibises do not begin breeding until the nesting area is flooded to a particular depth, usually at least a metre to ensure there will be sufficient water during the breeding period; dry and drying breeding grounds are deserted by the Ibis.
|Left. Immature adult with spotted black and white upper neck.|
Right. Breeding adult with red skin visible on the back of the head.
|White Ibis in full breeding plumage with neck plumes and red skin on the back of the head. (Casino, NSW)|
|Australian White Ibis - page 3|
Subject to sufficient water, breeding takes place in colonies between September and April. At breeding time a male secures a territory on a branch in a tall tree where he puts on a noisy display and shows aggression to other males.
When a female arrives the male bows from the branch and offers a twig. If she grasps the twig they begin mutual preening before flying off to build a nest elsewhere. They nest in large colonies, often with Straw-necked Ibis.
The nest is a platform of sticks, built on low plants, generally in secluded places. Two to five dull white eggs are laid; oval, tapered about 66 by 45 millimetres. Incubation takes 20 to 25 days with both parents incubating in shifts; they greet each other with deep bows when changing over. Both parents feed the young working as a team with one actually feeding by regurgitation while the other stands guard. Adults always establish voice contact with the young before feeding them. Young Ibis fledge in about four weeks and stay together after leaving the nest; still unable to fly (for another two weeks) they settle on nearby bushes; after beginning to fly they remain around the nest and the parents continue feeding them.
Similar Species/Identification. The long down-curved beak is a sure indication of an Ibis; colouring distinguishes the Australian White Ibis from the Glossy Ibis and the Straw-necked Ibis.
Formerly Threskiornis aethiopicus - the Sacred Ibis.