Habitat

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 Herrmann, E., M. D. Anderson, and M. Seaman (2004). Occurrence and abundance of waterbirds at an ephemeral pan in the Northern Cape Province, South Africa. Ostrich 75(4):275–284. Close ), river pools (22 Taylor, J. S. (1944). Notes on the South African Shelduck. Ostrich 15:188–193. Close , 3 Maclean, G. L., and G. Darroll (1986). Ducks of Sub-Saharan Africa. Acorn Books, Johannesburg, South Africa. Close ), and estuaries (84 Velasquez, C. R., B. Kalejta, and P. A. R. Hockey (1991). Seasonal abundance, habitat selection and energy consumption of waterbirds at the Berg River Estuary, South Africa. Ostrich 62(3/4):109–123. Close ). 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 Dean, W. R. J., S. J. Milton, H. P. Forsyth, and D. R. Tissiman (2015). Fluctuations in bird numbers on sewage treatment ponds in an arid environment, South Africa. Ostrich 86:145–153. Close , 49 Tyler, S. J. (2020). Changing status of South African Shelduck (Cape Shelduck) Tadorna cana in Botswana. Babbler 66:4–10. Close ), commercial saltpans (86 Martin, A. P., and R. M. Randall (1987). Numbers of waterbirds at a commercial saltpan, and suggestions for management. South African Journal of Wildlife Research 17:75–81. Close ), mine dams (87 Maritz, L. (2020). Ecological role of mining ponds in southern coastal mines, Namibia. M.S. thesis, University of Cape Town, Cape Town, South Africa. Close ), quarries (88 Sherley, R. B., B. M. Dyer, L. G. Underhill, and T. M. Leshoro (2011). Birds occurring or breeding at Robben Island, South Africa, since 2000. Ornithological Observations 2:69–100. Close ), and evaporation ponds at solar-power facilities (89 Jeal, C. (2017). The impact of a ‘trough’ concentrated solar power facility on birds and other animals in the Northern Cape, South Africa. M.S. thesis, University of Cape Town, Cape Town, South Africa. Close , 90 Jeal, C., V. Perold, S. Ralston-Paton, and P. G. Ryan (2019). Impacts of a concentrated solar power trough facility on birds and other wildlife in South Africa. Ostrich, 90(2):129–137. Close ). The nearby proximity of crop fields enhances the attractiveness of waterbodies to the species (1 Geldenhuys, J. N. (1980). Breeding ecology of the South African shelduck in the southern Orange Free State. South African Journal of Wildlife Research 10:94–111. Close ). At a biome level, it largely occurs in the Karoo, fynbos, and drier grassland regions (43 Harrison, J. A., D. G. Allan, L. G. Underhill, M. Herremans, and A. J. Tree, Editors (1997). The Atlas of Southern African Birds. Volume 1. Non-passerines. BirdLife South Africa, Johannesburg, South Africa. Close ).

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 Taylor, J. S. (1944). Notes on the South African Shelduck. Ostrich 15:188–193. Close , 91 Geldenhuys, J. N. (1976). Physiognomic characteristics of wetland vegetation in South African Shelduck habitat. South African Journal of Wildlife Research 6:75–78. Close ). The preference for poorly vegetated wetlands may at least partially explain its restriction to semi-arid regions (44 Geldenhuys, J. N. (1981). Effect of temperature and rainfall on the distribution of the South African Shelduck Tadorna cana. South African Journal of Zoology 16:167–171. Close ).

Despite being found at coastal lakes , estuaries, and lagoons (92 Taylor, J. S. (1957). Notes on the birds of inland waters in the eastern Cape Province with special reference to the Karoo. Ostrich 28(1):1–80. Close , 93 Hockey, P. A. R., L. G. Underhill, and M. Neatherway (1989). Atlas of the Birds of the Southwestern Cape. Cape Bird Club, Cape Town, South Africa. Close , 84 Velasquez, C. R., B. Kalejta, and P. A. R. Hockey (1991). Seasonal abundance, habitat selection and energy consumption of waterbirds at the Berg River Estuary, South Africa. Ostrich 62(3/4):109–123. Close , 31 Maclean, G. L. (1993). Roberts’ Birds of Southern Africa. Sixth edition. John Voelcker Bird Book Fund & New Holland, Cape Town, South Africa. Close ), the species is only very rarely recorded in marine environments (94 Baron, S. (1977). South African Shelduck at sea. Cormorant 3:19. Close , 1 Geldenhuys, J. N. (1980). Breeding ecology of the South African shelduck in the southern Orange Free State. South African Journal of Wildlife Research 10:94–111. Close , 95 Ryan, P. (1980). South African Shelduck Tadorna cana feeding at sea in South Africa. Cormorant 8:27. Close , 31 Maclean, G. L. (1993). Roberts’ Birds of Southern Africa. Sixth edition. John Voelcker Bird Book Fund & New Holland, Cape Town, South Africa. Close ). 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 Velasquez, C. R., B. Kalejta, and P. A. R. Hockey (1991). Seasonal abundance, habitat selection and energy consumption of waterbirds at the Berg River Estuary, South Africa. Ostrich 62(3/4):109–123. Close ).

Breeding is typically associated with freshwater and man-made, rather than brackish and natural, wetlands (1 Geldenhuys, J. N. (1980). Breeding ecology of the South African shelduck in the southern Orange Free State. South African Journal of Wildlife Research 10:94–111. Close ).

For breeding, the South African Shelduck requires suitable holes. There is a record of nesting on a large offshore island (Robben Island) (88 Sherley, R. B., B. M. Dyer, L. G. Underhill, and T. M. Leshoro (2011). Birds occurring or breeding at Robben Island, South Africa, since 2000. Ornithological Observations 2:69–100. Close ).

Expansive, deep state-controlled freshwater impoundments are the favored molting sites of the South African Shelduck during the non-breeding season (96 Geldenhuys JN 1981 Moults and moult localities of the South African Shelduck. Ostrich 52:129-134 Close ). At other times non-breeding birds apparently prefer brackish, natural, wetlands over freshwater sites (1 Geldenhuys, J. N. (1980). Breeding ecology of the South African shelduck in the southern Orange Free State. South African Journal of Wildlife Research 10:94–111. Close ).