Radjah shelduck
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Genus:	Radjah Reichenbach, 1853
Species:	R. radjah
Binomial name
Radjah radjah (Garnot & Lesson, RP, 1828)
Subspecies
R. r. radjah (Lesson, RP, 1828) R. r. rufitergum (Hartert, 1905)
Synonyms
Tadorna radjah

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 duck.

The specific name radjah is from the Moluccan name Radja for the radjah shelduck on the island of Buru in Indonesia.^[2]

Formerly placed in the genus Tadorna, it differs markedly from other members in external morphology and mtDNA cytochrome b sequence data, suggesting its status should be reinvestigated.^[3] Current classification places it in its own monotypic genus Radjah.

Both the male and female of the species are mostly white, with dark wing-tips and a distinctive "collar" of dark feathers. When viewed from above, during flight or with wings outstretched, green bands are visible on the tops of their wings. To communicate, the female utters a harsh rattle while the male emits a breathy, "sore-throat" whistle.

The radjah shelduck inhabits the mangrove forests and coastline of New Guinea (West Papua and Papua New Guinea) and Australia, and some of the Moluccas in eastern Indonesia. In Australia, its primary range is coastal, tropical northern Australia, extending as far south as central Queensland, west through the upper regions of the Northern Territory (including Kakadu National Park) to the Kimberley in Western Australia. The radjah shelduck is listed as a protected bird in all the states of Australia, and penalties are enforced for harming or disturbing them.

The species prefers the salty waters of mangrove flats and paperbark tree swamps, but will visit all manner of brackish and freshwater swamps, lagoons, lakes, estuaries, river deltas, and billabongs further inland during the wet season.

The radjah shelduck forms long-term, bonded pairs, and they are usually encountered in lone pairs or small flocks. During the rainy season, the males commonly become very irritable, and have been observed attacking their mates.

The ducks' preferred diet consists mainly of mollusks, aquatic or other insects, worms, aquatic weeds, sedge 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 dead or dehydrated trees, which makes habitat destruction a particular issue.

The radjah shelduck does not use nesting materials apart from some self-supplied down feathers. Egg-laying is usually completed by May or June, but depends on the extent of the wet season. The clutches range from 6 to 12 eggs. Incubation time is about 30 days.

Wikimedia Commons has media related to Radjah radjah.

Wikispecies has information related to Radjah radjah.

• Radjah Shelduck article on the Honolulu Zoo website

v t e Genera of waterfowl and their extinct allies
Kingdom: Animalia Phylum: Chordata Class: Aves Clade: Neognathae Superorder: Galloanserae Avemetatarsalia see Avemetatarsalia Theropoda see Theropoda Maniraptora see Maniraptora Anserimorphae see below↓
Anserimorphae Anserimorphae †Conflicto †Gastornis? †Dromornithidae? †Pelagornithidae? †Vegaviidae? †Presbyornithidae Bumbalavis Headonornis? Murgonornis Presbyornis Proherodius Telmabates Teviornis Wilaru †Anachronornithidae Anachronornis Danielsavis? Anseriformes sensu stricto †Agnopterus? †Eonessa †"Headonornis"? †Naranbulagornis †Paakniwatavis †Palaeopapia †Peioa †Petropluvialis? †Proherodius? †Wunketru Anhimae †Chaunoides Anhimidae Anhima †Chainkanas Chauna Anseres Anseranatoidea †Anatalavis? Anseranatidae Anseranas †Anserpica †Eoanseranas Anatoidea †Paranyrocidae Paranyroca Anatidae See below ↓
Anatidae Anatidae †Aldabranas? †Allgoviachen †Ankonetta? †Awengkere †Bambolinetta? †Caerulonettion †Cayaoa? †Chelychelynechen? †Cousteauvia †Eonerornis? †Eutelornis? †Garganornis? †Helonetta? †Heteroanser? †Lavanttalornis †Loxornis? †Mioquerquedula? †Nogusunna? †Notochen †Proanser? †Protomelanitta? †Ptaiochen? †Selenonetta †Sharganetta? †Sinanas? †Tagayanetta †Talpanas? †Teleornis? †Thambetochen? †Wasonaka? †Romainvillinae Paracygnopterus Romainvillia Saintandrea Dendrocygninae Dendrocygna Thalassornis †Dendrocheninae Dendrochen Manuherikia Mionetta Stictonettinae Stictonetta Anserinae †Afrocygnus †Annakacygna Anser †Anserobranta †Asiavis †Bonibernicla Branta Cereopsis †"Chenopis" †Cnemiornis Coscoroba †Cygnavus Cygnus †Cygnopterus †Eremochen †Megalodytes †Paracygnus †Presbychen Tadorninae Alopochen †Australotadorna †Brantadorna Cairina †Centrornis Chloephaga Cyanochen Hymenolaimus †Kaikenia Merganetta †Miotadorna †Nannonetta Neochen Plectropterus †Pleistoanser Radjah Sarkidiornis Tachyeres Tadorna †Tamtamia Anatinae Aix Amazonetta †Anabernicula Asarcornis Biziura Callonetta †Chenoanas? Chenonetta †Dunstanetta †Eoneornis? †Lavadytis Lophonetta Malacorhynchus Marmaronetta Netta Nettapus †Pinpanetta Pteronetta †?Rhodonessa Salvadorina Speculanas Oxyurini Heteronetta Nomonyx Oxyura †Tirarinetta Mergini Bucephala †Camptorhynchus †Chendytes Clangula Histrionicus Lophodytes Melanitta Mergellus Mergus Polysticta †Shiriyanetta Somateria Anatini Anas Mareca †Matanas Sibirionetta Spatula Aythyini Aythya