South African Shelduck Tadorna cana Scientific name definitions

David G. Allan
Version: 2.0 — Published February 23, 2023

Habitat

Introduction

The natural habitat of the South African Shelduck includes shallow, brackish ephemeral (endoreic) pans, where it can be among the most frequently recorded and abundant waterbirds (e.g., 83), river pools (22, 3), and estuaries (84). Currently, however, it is more likely to be found at artificial wetlands, especially dams, ranging from small farm reservoirs to extensive state-run impoundments (deeper expanses are preferred when the species is molting). Other favored artificial wetlands include sewage works (85, 49), commercial saltpans (86), mine dams (87), quarries (88), and evaporation ponds at solar-power facilities (89, 90). The nearby proximity of crop fields enhances the attractiveness of waterbodies to the species (1). At a biome level, it largely occurs in the Karoo, fynbos, and drier grassland regions (43).

The xeric regions inhabited by the species result in the brackish nature of most of the waterbodies it uses. South African Shelduck prefers areas with exposed muddy shorelines and extensive areas of open shallow water . It avoids deep water surrounded by tall emergent vegetation and wetlands with tall dense vegetation, but tolerates patchy, even continuous, short vegetation (mainly grasses, e.g., swamp grass Diplachne fusca, couch grass Cynodon dactylon, Transvaal quick grass Cynodon transvaalensis, and pankweek Sporobolus tenellus, plus herbs, and some sedges) provided visibility is not impaired (22, 91). The preference for poorly vegetated wetlands may at least partially explain its restriction to semi-arid regions (44).

Despite being found at coastal lakes , estuaries, and lagoons (92, 93, 84, 31), the species is only very rarely recorded in marine environments (94, 1, 95, 31). At the Berg River Estuary, Western Cape Province, where this is among the most abundant waterfowl species, it strongly preferred mudflats over saltmarshes and salt pans when foraging (84).

Habitat in Breeding Range

Breeding is typically associated with freshwater and man-made, rather than brackish and natural, wetlands (1).

For breeding, the South African Shelduck requires suitable holes. There is a record of nesting on a large offshore island (Robben Island) (88).

Habitat in Nonbreeding Range

Expansive, deep state-controlled freshwater impoundments are the favored molting sites of the South African Shelduck during the non-breeding season (96). At other times non-breeding birds apparently prefer brackish, natural, wetlands over freshwater sites (1).

Recommended Citation

Allan, D. G. (2023). South African Shelduck (Tadorna cana), version 2.0. In Birds of the World (G. D. Engelbrecht, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.soashe1.02
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