Radjah shelduck

Radjah shelduck
Conservation status
Least Concern(IUCN 3.1)
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

Theradjah shelduck(Radjah radjah), is aspeciesofshelduckfound mostly inNew GuineaandAustralia,and also on some of theMoluccas.It is known alternatively as theraja shelduck,black-backed shelduck,or in Australia as theBurdekin duck.

Taxonomy

The specific nameradjahis from theMoluccannameRadjafor the radjah shelduck on the island ofBuruin Indonesia.

Formerly placed in thegenusTadorna,it differs markedly from other members in externalmorphologyandmtDNAcytochromebsequencedata, suggesting itsstatusshould be reinvestigated.Current classification places it in its own monotypic genusRadjah.

Description

Radjah shelduck at the London Wetland Centre

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.

Distribution and habitat

The radjah shelduck inhabits the mangrove forests and coastline ofNew Guinea(West PapuaandPapua New Guinea) and Australia, and some of theMoluccasin easternIndonesia.In Australia, its primaryrangeis coastal, tropical northern Australia, extending as far south as centralQueensland,west through the upper regions of theNorthern Territory(includingKakadu National Park) to theKimberleyinWestern 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 ofmangroveflats andpaperbarktree swamps, but will visit all manner ofbrackishand freshwaterswamps,lagoons,lakes,estuaries,river deltas,andbillabongsfurther inland during the wet season.

Behaviour

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 ofmollusks,aquatic or other insects, worms, aquatic weeds,sedgematerials andalgae.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 makeshabitat destructiona 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 thewet season.The clutches range from 6 to 12 eggs. Incubation time is about 30 days.

External links

• Radjah Shelduckarticle on theHonolulu Zoowebsite