South African shelduck

Taxonomy

The South African shelduck was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the other geese, ducks and swans in the genus Anas and coined the binomial name Anas cana. Gmelin based his description on the "Grey-headed goose" from the Cape of Good Hope that the English ornithologist John Latham had described in 1785 in his A General Synopsis of Birds. The South African shelduck is now placed with five other species in the genus Tadorna that was described by the German zoologist Friedrich Boie in 1822. The genus name comes from the French name Tadorne for the common shelduck. The specific epithet cana is from Latin canus meaning "grey". The species is monotypic; no subspecies are recognised.

Description

Adult South African shelducks have ruddy bodies and wings strikingly marked with black, white and green. The male has a grey head, and the female has a white face and black crown, nape and neck sides. . In flight they can be hard to distinguish from Egyptian geese. Juveniles are duller in appearance. Young females lack the white on the head, excluding white eye circles. The colour on the females head is highly variable, with the extent of white increasing with age, and can become almost fully white-headed. Males make a deep honk or hoogh call while the female tends to produce a louder, sharper hark.

South African shelduck is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

Gallery

File:Cape Shelduck Tadorna cana, Hopefield South Africa.jpg|Pair in flight showing the extensive white wing patches and iridescent green speculum; Hopefield, Western Cape, South Africa File:South African Shelduck (Tadorna cana), Kgalagadi, Northern Cape, South Africa (47081125551).jpg|Male, with grey head; Kgalagadi Transfrontier Park, Northern Cape, South Africa File:Tadorna cana, Etosha NP, Namibia 311071339.jpg|Female with extensive white on the head; Etosha National Park, Namibia File:Tadorna cana, Cannon Rocks, Eastern Cape, South Africa 318512728.jpg|Younger female with less extensive white on the head; Cannon Rocks, Eastern Cape, South Africa

Captivity

In common with the other orange-plumaged shelducks like ruddy shelduck, it is popular in zoos and duck collections; hybrids with these other species in captivity are frequent and are problematic to identify.

References

• Ian Sinclair, Phil Hockey and Warwick Tarboton, SASOL Birds of Southern Africa (Struik 2002)

References

1. BirdLife International. (2016). "''Tadorna cana''".
2. Newman, Vanessa. (2010). "Newman's Birds of Southern Africa". Pippa Parker.
3. Gmelin, Johann Friedrich. (1789). "Systema naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis". Georg. Emanuel. Beer.
4. Latham, John. (1785). "A General Synopsis of Birds". Printed for Leigh and Sotheby.
5. (1979). "Check-List of Birds of the World". Museum of Comparative Zoology.
6. Boie, Friedrich. (1822). "Tagebuch gehalten auf einer Reise durch Norwegen im Jahre 1817". Königl Taubstummen - Institut.
7. (January 2022). "Screamers, ducks, geese & swans". International Ornithologists' Union.
8. Jobling, James A.. (2010). "The Helm Dictionary of Scientific Bird Names". Christopher Helm.
9. (1992). "Wildfowl". Helm.
10. (2017-02-17). "Ruddy Shelduck x South African Shelduck hybrid".