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

Distribution

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)

Habitat

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

Radjah Shelduck Distribution

Distribution of the Radjah Shelduck, Radjah radjah

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).

At Home in Wetlands

Two Radjah Shelducks standing on bank, facing opposite directions

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.

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