Australian White Ibis

Appearance

The Australian White Ibis is around 65–75 cm long and has a bald black head and neck and a long black downcurved beak, measuring over 16.7 cm in the male, and under in the female. There is some sexual dimorphism in size, as the slightly heavier male weighs 1.7–2.5 kg compared to the 1.4–1.9 kg female. The body plumage is white although it may become brown-stained. Inner secondary plumes are displayed as lacy black 'tail' feathers. The upper tail becomes yellow when the bird is breeding. The legs and feet are dark and red skin is visible on the underside of the wing. Immature birds have shorter bills. The head and neck are feathered in juveniles.

The White Ibis usually gives off a foul stench. This smell is not described as rotten, but an odd smell that is rather unpleasant and distinct.

The call is a long croak.

The Australian White Ibis reaches sexual maturity in 3 years, and can reach 28 years of age.

Naming

Two subspecies are recognised:
⤷  "T. m. molucca" of mainland Australia, is the nominate subspecies.
⤷  "T. m. pygmaeus" is a dwarf form found on the Solomon Islands that has been considered a separate species at times.

Distribution

The Australian White Ibis is widespread in eastern, northern and southwestern Australia. It occurs in marshy wetlands, often near open grasslands and has become common in Australian east-coast city parks and rubbish dumps in the urban areas of Wollongong, Sydney, Perth, the Gold Coast, Brisbane and Townsville. Historically it was rare in urban areas; the first influx was noted after drought drove birds eastwards in the late 1970s. The urban population further increased after a further period of drought in 1998.

There has been debate in recent years over whether to consider them a pest or a possibly endangered species. Birds in tourist areas of Sydney such as Darling Harbour, the Royal Botanic Gardens, or Centennial Park have been a problem due to their strong smell. Populations in the latter two areas have been culled.
The birds have also come to be regarded as a problem species in Victoria as a result of their scavenging activities, scattering rubbish from tips and bins in the process. They are even known to snatch sandwiches from picknickers. Such behaviour, together with their propensity to build nests in "inappropriate" places, and competition with captive animals, led to surplus birds being relocated from Healesville Sanctuary to Sale. However, the birds returned in a few days.

The Macquarie Marshes in northwestern New South Wales was one of the main areas for breeding, but none has been reported breeding there since 2000, from 11000 pairs in 1998.

Reproduction

Breeding season varies with the location within Australia, generally August to November in the south, and February to May, after the Wet Season, in the north. The nest is a shallow dish-shaped platform of sticks, grasses or reeds, located in trees and generally near a body of water such as river, swamp or lake. Ibis commonly nest near other waterbirds such as egrets, herons, spoonbills or cormorants. Two to three dull white eggs are laid measuring 65 mm × 44 mm. The clutch is then incubated for 21–23 days. Hatchlings are altricial, that is, they are naked and helpless at birth, and take 48 days to fledge.

Food

This ibis feeds on various fish, frogs and other water creatures, and also insects and garbage.