Justification This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Family/Sub-family Anatidae

Species name author (Hartert, 1891)

Taxonomic source(s) Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

20,000 - 50,000

unset

2,430,000 km²

No

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Behaviour This species is largely sedentary, but can be somewhat nomadic and dispersive within its southern African range⁸. There may also be some true seasonal north-south migrational movements through central South Africa (South African birds have been recovered in Namibia up to 1,650 km away)^{2, 8}. Its movements are poorly understood^{7, 8}, although migration appears to be between winter- and summer-rainfall areas⁷ and is dependent on water availability, whereas nomadic movements are believed to be responses to food availability⁷. In much of its range this species breeds throughout the year, although in some areas breeding is more seasonal (for example the breeding peak for birds in the south-west of Cape Province, South Africa is August-December)². The species breeds in single pairs or loose groups, but may crowd together where suitable nesting sites are scarce^{1, 6}. Outside the breeding season the species is usually found in small groups, or very rarely in numbers up to 600^{2, 6}. Adult birds undergo a period of moulting after breeding during which they are flightless for around 30 days¹; during this time they seek the refuge of large open waters^{1, 8} rich in natural foods¹. It is both a diurnal and nocturnal feeder¹. Habitat This species shows a preference for shallow freshwater and brackish habitats, such as lakes, marshes and temporary floodwaters^{1, 2, 4}. It will feed in fertile waters rich in planktonic organisms such as sewage disposal ponds, and will also tolerate highly alkaline lakes (pH 10), tidal estuaries, saline lagoons and salt-pans^{1, 2, 4, 7, 8}. It generally avoids deep lakes, fast-flowing rivers, farm dams and reservoirs except as temporary refuges^{1, 2, 4, 6}. Diet This species is omnivorous, commonly consuming the stems and seeds of water plants, snails, insects, molluscs, crustaceans and amphibian larvae¹. Animal matter makes up a significantly larger proportion of its diet than does plant matter¹. Breeding site The preferred nesting sites of this species are close to highly fertile shallow-water areas that have abundant sources of invertebrate food^{2, 4}. The nest itself is a shallow scrape in earth, often with sides and a canopy built up from vegetation, and it is generally positioned near the waters edge^{2, 4, 6}.

Threats The only known potential threats to this species are the reduction of suitable ephemeral wetland habitats², and hybridisation with invasive Mallard Anas platyrhynchos⁷. The species is also susceptible to avian botulism, so may be threatened by future outbreaks of the disease^{9, 10}. Utilisation This species is hunted, and although hunting is not currently a threat, it has the potential to become one if not managed sustainably^{2, 5}.

References 1. Brown (1982). 2. Kear (2005b). 3. del Hoyo, et al. (1992). 4. Johnsgard, (1978). 5. Little, et al. (1995). 6. Madge and Burn (1988). 7. Hockey, et al. (2005). 8. Scott and Rose (1996). 9. Blaker (1967). 10. van Heerden (1974).

Text account compilers Stuart Butchart (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Anas smithii. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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