The radjah shelduck (''Radjah radjah''), is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

shelduck The shelducks, most species of which are found in the genus ''Tadorna'' (except for the Radjah shelduck, which is now found in its own monotypic genus ''Radjah''), are a group of large birds in the Tadorninae subfamily of the Anatidae, the biologi ...

found mostly in

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, and also on some of the

Moluccas The Maluku Islands (; Indonesian: ''Kepulauan Maluku'') or the Moluccas () are an archipelago in the east of Indonesia. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located eas ...

. It is known alternatively as the raja shelduck, black-backed shelduck, or in Australia as the Burdekin duck.

Taxonomy

The specific name ''radjah '' is from the

Moluccan Moluccans are the Austronesian-speaking and Papuan-speaking ethnic groups indigenous to the Maluku Islands (also called the Moluccas), Indonesia. The region was historically known as the Spice Islands, and today consists of two Indonesian prov ...

name ''Radja'' for the radjah shelduck on the island of

Buru Buru (formerly spelled Boeroe, Boro, or Bouru) is the third largest island within the Maluku Islands of Indonesia. It lies between the Banda Sea to the south and Seram Sea to the north, west of Ambon and Seram islands. The island belongs to Ma ...

in Indonesia. Formerly placed in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Tadorna'', it differs markedly from other members in external

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

and

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

cytochrome ''b''

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

data, suggesting its

status Status (Latin plural: ''statūs''), is a state, condition, or situation, and may refer to: * Status (law) ** City status ** Legal status, in law ** Political status, in international law ** Small entity status, in patent law ** Status conference ...

should be reinvestigated.Sraml, M.; Christidis, L.; Easteal, S.; Horn, P. & Collet, C. (1996): Molecular Relationships Within Australasian Waterfowl (Anseriformes). ''Australian Journal of Zoology'' 44(1): 47–58. Current classification places it in its own monotypic genus ''Radjah''.

Description

Tadorna radjah, London Wetlands Centre, UK - Diliff

Both the male and female of the species are mostly white, with dark wing-tips and a distinctive "collar" of dark feathers. Seen from above in flight the birds have green bands on the tops of their wings. The female has a harsh rattle and the male has a breathy, sore-throat whistle.

Distribution and habitat

The radjah shelduck inhabits the mangrove forests and coastline of

( West Papua and

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

) and Australia, and some of the

in eastern Indonesia. In Australia, its primary

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

is coastal tropical northern Australia, from central

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

through northern

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

(including

Kakadu National Park Kakadu National Park is a protected area in the Northern Territory of Australia, southeast of Darwin. It is a World Heritage Site. Kakadu is also gazetted as a locality, covering the same area as the national park, with 313 people recorded liv ...

) to the Kimberley in Western Australia. The radjah shelduck is listed as a protected bird in all states of Australia and penalties exist for harming or disturbing them. The species prefers the brackish waters of

mangrove A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...

flats and

paperbark ''Melaleuca'' () is a genus of nearly 300 species of plants in the myrtle family, Myrtaceae, commonly known as paperbarks, honey-myrtles or tea-trees (although the last name is also applied to species of ''Leptospermum''). They range in size f ...

tree swamps, but will visit freshwater swamps, lagoons, and

billabong Billabong ( ) is an Australian term for an oxbow lake, an isolated pond left behind after a river changes course. Billabongs are usually formed when the path of a creek or river changes, leaving the former branch with a dead end. As a result ...

s further inland during the wet season.

Behaviour

The radjah shelduck forms long-term pair-bonds, and is usually encountered in lone pairs or small flocks. During the wet season the males commonly become very irritable, and have been observed attacking their mates. The diet consists mainly of

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s, insects,

sedge The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...

materials and algae. Pairs start searching for nesting sites during the months of January and February. They nest close to their primary food source, often in the hollow limbs of trees, which makes

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

a particular issue. The radjah shelduck does not use nesting materials except for some self-supplied down feathers. Egg-laying is usually done by May or June, but depends on the extent of the

wet season The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...

. The clutches range from 6 to 12 eggs. Incubation time is about 30 days.

References

External links

Radjah Shelduck
article on the

Honolulu Zoo The Honolulu Zoo is a zoo in Queen Kapiʻolani Park in Honolulu, Hawaii. It is the only zoo in the United States to be established by grants made by a sovereign monarch and is built on part of the royal Queen Kapiʻolani Park. The Honolulu Z ...

website {{Taxonbar, from=Q28125248, from2=Q1051000

radjah shelduck The radjah shelduck (''Radjah radjah''), is a species of shelduck found mostly in New Guinea and Australia, and also on some of the Moluccas. It is known alternatively as the raja shelduck, black-backed shelduck, or in Australia as the Burdekin ...

Birds of the Maluku Islands Birds of New Guinea Birds of the Northern Territory Birds of Queensland

Taxa named by René Lesson