Radjah Shelduck

Taxobox
name = Radjah Shelduck
status = LC
status_system = IUCN3.1


regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Anseriformes
familia = Anatidae
genus = "Tadorna"
species = "T. radjah"
binomial = "Tadorna radjah"
binomial_authority = Lesson, 1828
subdivision_ranks = Subspecies
subdivision =
* "T. r. radjah" (Black-backed Shelduck)
* "T. r. rufitergum" (Burdekin Duck)

The Radjah Shelduck, "Tadorna radjah", (in Australia also known as Burdekin Duck) is a species of shelduck. Placed in the genus "Tadorna", it differs markedly in external morphology, and mtDNA cytochrome "b" sequence data (Sraml "et al." 1996) suggests its status should be reinvestigated. The genus name "Tadorna" comes from Celtic roots and means "pied waterfowl", essentially the same as the English "shelduck".cite book| last =Kear| first =Janet| title =Ducks, Geese, and Swans| publisher =Oxford University Press| date =2005| pages =420| url =http://books.google.com/books?id=MfrdBcKd79wC&pg=RA1-PA439&lpg=RA1-PA439&dq=crested+shelduck&source=web&ots=RS734hgSmI&sig=006C0Hb6hpDK1aAEwu-ivfssJBk#PRA1-PA441,M1| isbn =0 19 861008 4 ]

Both the male and female of the species are mostly white, with dark wingtips 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.

The Radjah Shelduck inhabits the mangrove forests and coastline of New Guinea and Australia. In Australia, its primary range is coastal tropical northern Australia, from central Queensland through northern Northern Territory (including Kakadu National Park) to the Kimberley in Western Australia.

The species prefers the brackish waters of mangrove flats and paperbark tree swamps, but will visit freshwater swamps, lagoons, and billabongs further inland during the wet season.

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 mollusks, insects, 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 trees, which makes habitat destruction a particular issue.

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

The Radjah Shelduck is listed as a protected bird in all states of Australia and penalties exist for harming or disturbing them.

References

* Database entry includes justification for why this species is of least concern.

* 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. DOI|10.1071/ZO9960047 (HTML abstract)

External links

* [http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=403&m=0 BirdLife Species Factsheet] . Retrieved 2006-DEC-02.
* Honolulu Zoo: [http://www.honoluluzoo.org/radjah_shelduck.htm Radjah Shelduck] . Retrieved 2006-DEC-02.