South African Shelduck Tadorna cana Scientific name definitions

The rich russet and chestnut hues of the South African Shelduck render it a particularly handsome waterfowl. This impression is enhanced by its appreciable size. The species is certainly distinctive but can easily be overlooked amongst flocks of the ubiquitous Egyptian Goose (Alopochen aegyptiaca) that share its habitat. Females can also be confused with the White-faced Whistling-Duck (Dendrocygna viduata) by the inexperienced observer. Novice birders will also be surprised to learn that it is the females that are the most striking in appearance, with their startling, if variable, white faces. This striking partial sexual reversal, also characteristic of the Paradise Shelduck (Tadorna variegata), is similarly reflected in a female-biased sex ratio. It is further manifest in a decidedly assertive role adopted by females in territory defense and, especially, courtship. Juveniles resemble adult males in having dull gray heads. In flight, both sexes reveal conspicuous white coverts on both the upper- and underwings. As in all shelducks, the upper surface of the secondaries is glossy green.

The South African Shelduck is found primarily in South Africa (which likely supports more than 80% of the global population), Namibia, and southeastern Botswana. Small numbers also occur in Lesotho, and the species is an occasional vagrant to Swaziland and Zimbabwe. It has doubled its range and numbers in the region since historical times, benefiting primarily from the construction of artificial wetlands within its largely arid to semi-arid range, as well as from leftovers that the birds take advantage of in harvested crop fields. The species’ diet shifts dramatically, from largely plant-based, to mainly invertebrates as the breeding season approaches.

Nest sites used by this shelduck are unique among southern African waterfowl, being mainly underground burrows, particularly those dug by aardvark (Orycteropus afer). Nests can be as deep as 9 m in these dens, and up to 2 km from water. After breeding, the birds congregate at selected large dams to molt, sometimes in flocks numbering many thousands. This shelduck is unusual among most of the region’s waterfowl in breeding during the dry winter and molting during the wet summer.

The far-carrying and evocative honking calls of this often wary bird are emblematic of the vast open dry-country plains inhabited by this characterful member of the waterfowl family.