Australian White Ibis
Encyclopedia
The Australian White Ibis (Threskiornis molucca), is a wading bird
of the ibis
family Threskiornithidae
. It is widespread across much of Australia
. It has a predominantly white plumage with a bare, black head, long downcurved bill and black legs.
Historically rare in urban areas, the Australian White Ibis has immigrated to urban areas of the east coast in increasing numbers since the late 1970s; it is now commonly seen in Wollongong, Sydney
, the Gold Coast
, Brisbane
and Townsville. Debate continues on whether to consider it a pest or vulnerable species. Populations have disappeared from natural breeding areas such as the Macquarie Marshes
in northwestern New South Wales. Despite this, the species has been culled in parts of Sydney due to their smell and at times obtrusive nature. Its sister species is the Sacred Ibis
.
in 1829 as Ibis molucca. It is considered part of a superspecies complex
with the Sacred Ibis
(T. aethiopicus) of Africa, and the Black-headed Ibis
(T. melanocephalus) of Asia. Its status in the complex has vacillated over the years. Many older guidebooks referred to the bird as a species T. molucca, until a comprehensive review of plumage patterns by Holyoak in 1970. Holyoak noted the three species' similarities and that the Australian taxon resembled T. aethiopicus in adult plumage and T. melanocephalus in juvenile plumage. He proposed they all be considered part of a single species T. aethiopicus. This was generally accepted by the scientific community until Lowe and Richards's assessment of plumage in 1991. They again recommended the recognition of molucca at species level. This was followed by chromosome
study which highlighted each of the three species having a different karyotype
. The Australian White Ibis has been considered a full species by most authorities since then.
Alternate colloquial names include "Dump Chook" or "Tip Turkey", from its habit of rummaging in garbage, and "Sheep-bird". It was known as Mardungurra among the Yindjibarndi people of the central and western Pilbara.
in size, as the slightly heavier male weighs 1.7–2.5 kg (3.7-5.5 lb) compared to the 1.4–1.9 kg (3.1–4.2 lb) 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.
. 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.
, frog
s and other water creatures, and also insect
s and garbage.
, that is, they are naked and helpless at birth, and take 48 days to fledge.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of the ibis
Ibis
The ibises are a group of long-legged wading birds in the family Threskiornithidae....
family Threskiornithidae
Threskiornithidae
The family Threskiornithidae includes 34 species of large terrestrial and wading birds, falling into two subfamilies, the ibises and the spoonbills. It was formerly known as Plataleidae. The spoonbills and ibises were once thought to be related to other groups of long-legged wading birds in the...
. It is widespread across much of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It has a predominantly white plumage with a bare, black head, long downcurved bill and black legs.
Historically rare in urban areas, the Australian White Ibis has immigrated to urban areas of the east coast in increasing numbers since the late 1970s; it is now commonly seen in Wollongong, Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
, the Gold Coast
Gold Coast, Queensland
Gold Coast is a coastal city of Australia located in South East Queensland, 94km south of the state capital Brisbane. With a population approximately 540,000 in 2010, it is the second most populous city in the state, the sixth most populous city in the country, and also the most populous...
, Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
and Townsville. Debate continues on whether to consider it a pest or vulnerable species. Populations have disappeared from natural breeding areas such as the Macquarie Marshes
Macquarie Marshes Nature Reserve
The Macquarie Marshes Nature Reserve is located in the Macquarie Marshes, a region along the lower Macquarie River in northwestern New South Wales, Australia, about 600 km northwest of Sydney. The marshes are created by irregular flooding of the flat lands along the river...
in northwestern New South Wales. Despite this, the species has been culled in parts of Sydney due to their smell and at times obtrusive nature. Its sister species is the Sacred Ibis
Sacred Ibis
The African Sacred Ibis is a species of ibis.-Description:An adult individual is 68 cm long with all-white body plumage apart from dark plumes on the rump. The bald head and neck, thick curved bill and legs are black. The white wings show a black rear border in flight...
.
Taxonomy
It was initially described by Georges CuvierGeorges Cuvier
Georges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
in 1829 as Ibis molucca. It is considered part of a superspecies complex
Cryptic species complex
In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
with the Sacred Ibis
Sacred Ibis
The African Sacred Ibis is a species of ibis.-Description:An adult individual is 68 cm long with all-white body plumage apart from dark plumes on the rump. The bald head and neck, thick curved bill and legs are black. The white wings show a black rear border in flight...
(T. aethiopicus) of Africa, and the Black-headed Ibis
Black-headed Ibis
The Black-headed Ibis or Oriental White Ibis is a species of wading bird of the ibis family Threskiornithidae which breeds in South Asia and Southeast Asia from Pakistan to India, Sri Lanka east up to Japan...
(T. melanocephalus) of Asia. Its status in the complex has vacillated over the years. Many older guidebooks referred to the bird as a species T. molucca, until a comprehensive review of plumage patterns by Holyoak in 1970. Holyoak noted the three species' similarities and that the Australian taxon resembled T. aethiopicus in adult plumage and T. melanocephalus in juvenile plumage. He proposed they all be considered part of a single species T. aethiopicus. This was generally accepted by the scientific community until Lowe and Richards's assessment of plumage in 1991. They again recommended the recognition of molucca at species level. This was followed by chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
study which highlighted each of the three species having a different karyotype
Karyotype
A karyotype is the number and appearance of chromosomes in the nucleus of an eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.p28...
. The Australian White Ibis has been considered a full species by most authorities since then.
Alternate colloquial names include "Dump Chook" or "Tip Turkey", from its habit of rummaging in garbage, and "Sheep-bird". It was known as Mardungurra among the Yindjibarndi people of the central and western Pilbara.
Subspecies
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.
Description
The Australian White Ibis is around 65–75 cm (25–30 in) long and has a bald black head and neck and a long black downcurved beak, measuring over 16.7 cm (6.6 in) in the male, and under in the female. There is some sexual dimorphismSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in size, as the slightly heavier male weighs 1.7–2.5 kg (3.7-5.5 lb) compared to the 1.4–1.9 kg (3.1–4.2 lb) female. The body plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
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.
Distribution and habitat
The Australian White Ibis is widespread in eastern, northern and southwestern AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. 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
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
, Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....
, the Gold Coast
Gold Coast, Queensland
Gold Coast is a coastal city of Australia located in South East Queensland, 94km south of the state capital Brisbane. With a population approximately 540,000 in 2010, it is the second most populous city in the state, the sixth most populous city in the country, and also the most populous...
, Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
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
Royal Botanic Gardens, Sydney
The Royal Botanic Gardens in Sydney, Australia, are the most central of the three major botanical gardens open to the public in Sydney....
, or Centennial Park
Centennial Park, New South Wales
Centennial Park is a large public, urban park that occupies 220 hectares in the Eastern Suburbs of Sydney in the state of New South Wales, Australia. Centennial Park is located 4 kilometres south-east of the Sydney central business district, in the City of Randwick...
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
Healesville Sanctuary
Healesville Sanctuary, or the Sir Colin MacKenzie Fauna Park, is a zoo specializing in native Australian animals. It is located at Healesville in rural Victoria, Australia, and has a history of breeding native animals. It is one of only two places to have successfully bred a platypus, the other...
to Sale
Sale, Victoria
Sale is a city in the Gippsland region of the Australian state of Victoria. It is the seat of the Shire of Wellington as well as the Roman Catholic Diocese of Sale and the Anglican Diocese of Gippsland. It has a population of around 13,336, and is expected to reach a population of 14,000 soon...
. However, the birds returned in a few days.
The Macquarie Marshes
Macquarie Marshes Nature Reserve
The Macquarie Marshes Nature Reserve is located in the Macquarie Marshes, a region along the lower Macquarie River in northwestern New South Wales, Australia, about 600 km northwest of Sydney. The marshes are created by irregular flooding of the flat lands along the river...
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.
Behaviour
Feeding
This ibis feeds on various fishFish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s and other water creatures, and also insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and garbage.
Breeding
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 altricialAltricial
Altricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
, that is, they are naked and helpless at birth, and take 48 days to fledge.