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Radjah Shelduck (Radjah radjah) Fact Sheet
Radjah Shelduck (Radjah radjah)
Image credit: © San Diego Zoo Global. All rights reserved.
Order: Anseriformes — ducks, geese, swans, screamers, waterfowl
Family: Anatidae — ducks, geese, swans
Species: Radjah radjah — Radjah Shelduck
Subspecies: R. r. radjah — Moluccas Islands, New Guinea, Indonesia, and nearby islands
Subspecies: R. r. rufitergum — northern and eastern tropical Australia
590-1130 g (1.3-2.49 lb)
485-610 mm (19.0-24 in)
246-298 mm (9.68-11.7 in)
900-1000 mm (30-40 in)
Head, neck, and underbody white; sometimes rust-stained. Breast band narrow and reddish-brown. Upperwing dark (reddish-brown in R. r. rufitergum; more black in R. r. radjah). Wing patch iridescent green. Sexes similar.
|Distribution & Status
||Behavior & Ecology
Northern and north-eastern Australia, New Guinea, Indonesia, and adjacent islands
Many coastal habitats. Marshes, mangroves, tidal mudflats. Freshwater lagoons only used during dry season. Common near shallow water of river margins, creeks, floodplains, and lagoons.
Least Concern (2016 assessment)
Protected in Australia
Populations in the Wild
R. r. radjah: about 10,000-100,000 individuals
R. r. rufitergum: tentatively estimated at 150,000 individuals
Runs quickly. Slow but agile flier. Swims well but infrequently.
Roost during the day (nonbreeding season). Leave roost in late afternoon or at dusk. Feed in the early morning, evening, and at night.
Typically found in pairs or small family groups. Strong pair bonds. May gather in flocks of 20-60 individuals (maximum flock size not known).
Limited study. Appears to vary with geography. Molluscs, worms, insects, algae, and possibly seeds.
Reports of crocodiles and dingoes.
Not reported, but also very likely: foxes and feral cats.
|Reproduction & Development
Likely similar to other shelducks—about 2 years of age. Needs confirmation.
Dependent on seasonal rainfall. Typically, February to July. Coincides with end of wet season/early dry season, when more food available.
Thought to be monogamous. Probably form life-long pair bonds.
About 9 eggs, on average. Precise range unclear; likely 5-12 eggs.
About 30 days
In the wild: not reported
Managed care: up to 12 to 15 years
- Large duck with a distinctive white head, narrow chestnut breast band, and a pale cream iris
- Scientific name Radjah radjah comes from Hindi, meaning “king” or “ruler”
- Rarely on water; prefers wading and shallow edges of marshes
- Maneuverable flier—flies low through trees rather than over canopy
- Runs swiftly
- Usually found in pairs or small family groups
- Often described as “pugnacious”
- Very vocal, especially when roosting
- Feeds almost entirely on land and in very shallow water (about 1-2 inches deep)
- Breeding pair aggressively defends a breeding territory
About This Fact Sheet
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© 2019 San Diego Zoo Global
How to cite: Radjah Shelduck (Radjah radjah) Fact Sheet. c2019. San Diego (CA): San Diego Zoo Global; [accessed YYYY Mmm dd]. http://ielc.libguides.com/sdzg/factsheets/ radjah-shelduck.
(note: replace YYYY Mmm dd with date accessed, e.g., 2018 Dec 31)
Disclaimer: Although San Diego Zoo Global makes every attempt to provide accurate information, some of the facts provided may become outdated or replaced by new research findings. Questions and comments may be addressed to email@example.com.
Many thanks to Dr. John McEvoy for providing expert content review of this fact sheet.
Dr. McEvoy, postdoctoral fellow at the Smithsonian Conservation Biology Institute’s Conservation Ecology Center, conducts research on the behavioral ecology of animals. In particular, his work focuses on using knowledge of animal movements to inform the conservation of wide-ranging and nomadic species.
His Ph.D. research at Deakin University (Australia) investigated the spatial ecology of nomadic waterfowl in inland Australia. Some of Dr. McEvoy’s recent postdoctoral work includes the monitoring of water bird populations at continental scales and using new conservation technologies to improve approaches to counting waterfowl.
In addition to studying water birds, Dr. McEvoy also collaborates with many research groups and NGOs around the world on taxa as diverse as parrots, foxes, waterfowl, fish and elephants.
To learn more about Dr. McEvoy, view his research website and SCBI profile.