Cape Shoveler (Anas smithii)

Cape Shoveler

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas smithii | [authority] Hartert, 1891 | [UK] Cape Shoveler | [FR] Canard de Smith | [DE] Kap-Loffelente | [ES] Cuchara de El Cabo | [NL] Kaapse Slobeend

Subspecies

Genus Species subspecies Region Range
Anas smithii AF s

Genus

Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank.[1] Indeed, as the moa-nalos are very close to this clade and may have evolved later than some of these lineages, it is rather the absence of a thorough review than lack of necessity that this genus is rather over-lumped. The phylogeny of this genus is one of the most confounded ones of all living birds. Research is hampered by the fact the radiation of the two major groups of Anas ? the teals and mallard groups ? took place in a very short time and fairly recently, roughly in the mid-late Pleistocene. Furthermore, hybridization may have long played a major role in Anas evolution, with within-subgenus hybrids regularly and between-subgenus hybrids not infrequently being fully fertile.[1] The relationships between species are much obscured by this fact, and mtDNA sequence data is of dubious value in resolving their relationships; on the other hand, nuclear DNA sequences evolve too slowly to resolve the phylogeny of the subgenus Anas for example. Some major clades can be discerned. For example, that the traditional subgenus Anas, the mallard group, forms a monophyletic (in the loose sense, i.e. non-holophyletic) group has never been seriously questioned by modern science and is as good as confirmed (but see below). On the other hand, the phylogeny of the teals is very confusing. For these reasons, the dabbling duck lineages more distantly related to mallard group (which includes the type species of Anas) than the wigeons should arguably be separated in their own genera. These would include the Baikal Teal, the Garganey, the spotted black-capped Punanetta group, and the shovelers and other blue-winged species. Whether the wigeons, which are very distinct in morphology and behavior, but much less so in mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequences, should also be considered a distinct genus Mareca (including the Gadwall and Falcated Duck) is essentially the one remaining point of dispute as regards the question which taxa should remain in this genus and which ones should not.

Physical charateristics

This species has a large spatulate bill. Adults have speckled grey-brown plumage and dull orange legs. As with many southern hemisphere ducks, the sexes appear similar, but the male has a paler head than the female, a pale blue forewing separated from the green speculum by a white border, and yellow eyes. The female’s forewing is grey.

Listen to the sound of Cape Shoveler

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Cape Shoveler.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 73 cm wingspan max.: 79 cm
size min.: 51 cm size max.: 53 cm
incubation min.: 27 days incubation max.: 28 days
fledging min.: 52 days fledging max.: 60 days
broods: 1   eggs min.: 5  
      eggs max.: 12  

Range

Africa : South. It is resident in South Africa, and uncommon further north in Namibia, Botswana, Zimbabwe, southern Angola, Lesotho, Mozambique, and Zambia

Habitat

Adult birds undergo a period of moulting after breeding during which they are flightless for around 30 days; during this time they seek the refuge of large open waters, rich in natural foods. It is both a diurnal and nocturnal feeder. This species shows a preference for shallow freshwater and brackish habitats, such as lakes, marshes and temporary floodwaters. 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. It generally avoids deep lakes, fast-flowing rivers, farm dams and reservoirs except as temporary refuges.

Reproduction

The preferred nesting sites of this species are close to highly fertile shallow-water areas that have abundant sources of invertebrate food2, 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

Feeding habits

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 matter.

Video Cape Shoveler

httpv://www.youtube.com/watch?v=6_yxYZw7A0I

copyright: Francesc Capdevila i Torrell


Conservation

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.
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
Cape Shoveler status Least Concern

Migration

This species is largely sedentary, but can be somewhat nomadic and dispersive within its southern African range. 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). Its movements are poorly understood, although migration appears to be between winter- and summer-rainfall areas and is dependent on water availability, whereas nomadic movements are believed to be responses to food availability. 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).

Distribution map

Cape Shoveler distribution range map

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