African Black Duck (Anas sparsa)

African Black Duck

Subspecies

Monotypic species

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

The African Black Duck is an entirely black duck with white marks on its back. It lives in central and southern Africa.It is also known as the black river duck, or (A. s. leucostigma) West African black duck or Ethiopian black duck. Sometimes all blick; female a little smaller. Juvenile white abomen with thin buff barring.

Listen to the sound of African Black Duck

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/African Black Duck.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by unknown

wingspan min.:	0	cm	wingspan max.:	0	cm
size min.:	45	cm	size max.:	48	cm
incubation min.:	26	days	incubation max.:	30	days
fledging min.:	84	days	fledging max.:	88	days
broods:	1		eggs min.:	4
			eggs max.:	8

Range

Africa : widespread. West equatorial Africa; East Africa South to Zimbabwe

Habitat

This species prefers fast-flowing shallow rivers and streams with rocky substrates, particularly in wooded and mountainous country up to 4250 m. It can also be found in open, arid habitats and on lakes, reservoirs, lagoons, sandy-bottomed estuaries, stagnant or slow-flowing water, and sewage ponds. During this species’ flightless moult period it requires cover near its foraging areas (e.g. lodged branches or undercut banks.

Reproduction

Ground cavity nests and elevated tree-nesting sites have been reported for this species, but usually nests are sited close to running water on islands, grassy river banks, in reedbeds or amongst driftwood. Important criteria for suitable nest sites are close proximity to water and near invisibility from above. Duck makes its cup shaped nest of driftwood and matted grass. Though it builds its nest near running water it is always above flood level and on the ground. Incubation lasts about 30 days and is done by the mother. The fledgling period is 86 days, only the mother takes care of the young. Clutch size ranges from 4 to 8 eggs.

Feeding habits

It has an omnivorous diet consisting of waterweeds and other aquatic vegetation, agricultural grain, fruits from terrestrial plants overhanging the water, mulberries (Morus), firethorn (Pryacantha) berries, fallen acorns, aquatic insects and their larvae, crustaceans, larval amphibians and fish spawn.

Video African Black Duck

httpv://www.youtube.com/watch?v=cMyqEtRdNaE

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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to 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.
This species breeds irregularly, the timing of breeding varying with locality, and throughout both breeding and non-breeding seasons the species remains dispersed as individuals or single pairs. It does not form large aggregations, although roosting flocks may be large. Adults undergo a flightless moulting period lasting around 25-30 days; males moulting between October and February (numbers peaking in November), females between November and February (numbers peaking in December). The species is diurnal, usually resting at night and spending daylight hours feeding, sleeping and preening.

Migration

It is not a migrant, being territorial and sedentary within a permanent range, although in South Africa some birds move from rivers to large local open waters to roost, returning to the rivers in the early morning.

Distribution map

African Black Duck distribution range map

Planet of Birds