Radjah Shelduck (Rajah rajah) Fact Sheet: Distribution & Habitat

Distribution

• Australia (Pizzey 2012; Carboneras and Kirwan 2018, except as noted)
  • Coastal and near-coastal tropical northern Australia
  • Northeastern Queensland
    • Not present south of Cape York Peninsula (Garnett and Crowley 2000)
  • Occasionally observed farther south
• Eastern Indonesia (Pizzey 2012)
• New Guinea
  • Widely distributed but local (Carboneras and Kirwan 2018)
  • Found only in coastal areas and on islands (Pratt and Beehler 2014)
• Torres Strait and Timor Sea Islands (Marchant and Higgins 1990; Pizzey 2012)
• Maluku (Moluccas) Islands (Pratt and Beehler 2014; Reeve et al. 2015; Carboneras and Kirwan 2018)
• Most commonly observed outside of typical range at end of dry season (Marchant and Higgins 1990)

Elevation range

• 0-200 m (0-650 ft) (Pratt and Beehler 2014)
• One source describes an observation of a large group on a pond at 1,280 m (4,200 ft) in east Timor (British Ornithologists’ Union 1986)

Historical distribution

• Until the late 1800s, widespread in Kimberley, Western Australia, and northeastern New South Wales (Frith 1967; Carboneras and Kirwan 2018)
  • Probably disappeared due to early unregulated hunting
• Once observed as far south as Narromine (New South Wales) (Phillips 1922)
  • Rare observations from southern areas of Australia (e.g., Melbourne, Adelaide) (Frith 1967; Royal Australasian Ornithologists Union 1984)

Coastal and near coastal regions

(Frith 1967, except as noted)

• Marshes near coasts
• Mangroves
  • Particularly those at mouth of tropical rivers (Royal Australasian Ornithologists Union 1984)
• Tidal mudflats
• Estuaries
• Sheltered bays
• Muddy pools
• Freshwater lagoons
  • Mainly during dry season and breeding
• Indonesia and New Guinea
  • Mangrove and sago marshes
  • Mud banks of large rivers
  • Shallow pools in gravel-lined riverbeds

Habitat preferences

• Prefer very shallow water (< 5 cm, or 2 in, deep) and adjacent marshland (Marchant and Higgins 1990)
  • Restricted to complexes of shallow pools and mud banks, or upper reaches of wetlands
• Rarely move more than 20 m (70 ft) from water (Marchant and Higgins 1990)
• Brackish water, mudflats, and mangroves near the coast (Frith 1967)
  • Brackish areas not used for nesting
• Move farther inland during dry season (Frith 1967)
• Use some human-constructed habitats (e.g., irrigation channels, sewage ponds (Royal Australasian Ornithologists Union 1984; Marchant and Higgins 1990)
• Also see "Breeding Habitat" in Reproduction

The Radjah Shelduck is found in coastal northern and northeastern Australia, and New Guinea and Indonesia, as well as nearby islands.

Adapted from www.d-maps.com according to IUCN fact sheet. Click here or on map for detailed distribution (IUCN).

Radjah Shelducks on mudflat.

This duck prefers very shallow water (1-2 inches deep, at most) and the muddy margins of wetlands.

Image credit: © Brian McCauley via Flickr. Some rights reserved. CC BY-NC-ND 2.0.