Australian White Ibis

The Australian white ibis (Threskiornis molucca) is a member of the ibis family, Threskiornithidae, and is a native bird of Australia. It is characterized by its predominantly white plumage, bare black head, long downcurved bill, and black legs. This species is not an introduced feral species, but rather an integral part of the Australian avifauna.

Identification Tips

Adult Australian white ibises are distinguished by their white body plumage, which may become stained brown. They have a bald black head and neck, and a long black downcurved beak, which is longer in males than in females. The inner secondary plumes appear as lacy black "tail" feathers, and the upper tail turns yellow during the breeding season. The legs and feet are dark, and red skin is visible on the underside of the wing. Juveniles have feathered heads and necks and shorter bills.

Habitat

The Australian white ibis frequents marshy wetlands and is often found near open grasslands. It has adapted to urban environments, commonly seen in city parks and rubbish dumps.

Distribution

This species is widespread in eastern, northern, and south-western Australia. It has historically been rare in urban areas but has established increasing urban populations since the late 1970s. Notably absent from Tasmania, the Australian white ibis has experienced a decline in natural breeding areas such as the Macquarie Marshes in New South Wales.

Behaviour

The Australian white ibis has adapted to urban life by reducing its fear response to humans and expanding its diet to include human refuse. It has been observed in groups of up to 30 birds and is known to forage alongside domestic chickens in villages.

Song & Calls

The vocalization of the Australian white ibis is described as a long croak.

Breeding

Breeding seasons vary by location, with nests made in trees near water. The nest is a shallow dish-shaped platform made of sticks, grasses, or reeds. The species lays two to three dull white eggs, with an incubation period of 21-23 days. Hatchlings are altricial and take 48 days to fledge.

Similar Species

The Australian white ibis is closely related to the African sacred ibis and the black-headed ibis but is distinct in its native Australian habitat.

Diet and Feeding

The diet includes terrestrial and aquatic invertebrates and human scraps, with crayfish and mussels being favored foods. The ibis has also been observed to eat cane toads by employing a unique "stress and wash" technique to avoid the toad's defensive toxin.

Conservation status

The IUCN Red List classifies the Australian white ibis as Least Concern, although urban populations have prompted discussions about whether the species should be considered a pest or protected. Management plans have been introduced in some urban areas to control problematic populations.