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Nov 12 2011

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Berniers Teal (Anas bernieri)

Berniers Teal

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas bernieri | [authority] Hartlaub, 1860 | [UK] Berniers Teal | [FR] Sarcelle de Bernier | [DE] Bernierente | [ES] Cerceta Malgache | [NL] Madagaskartaling

Subspecies

Genus Species subspecies Region Range
Anas bernieri AF Madagascar

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

Small dabbling duck. Rather pale, warm greyish-brown all over, scalloped darker most conspicuously on flanks and breast, wing with black speculum. Head rather uniform, pale, pinkish-grey bill, slightly upturned. Told from all other ducks by lack of conspicuous head-pattern, bill colour, rather long neck, wide white borders to distinctive black speculum, and habit of feeding by wading in shallow muddy water.

Listen to the sound of Berniers Teal

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Berniers Teal.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 40 cm size max.: 42 cm
incubation min.: 28 days incubation max.: 30 days
fledging min.: 40 days fledging max.: 45 days
broods: 1   eggs min.: 4  
      eggs max.: 10  

Range

Africa : Madagascar. Endemic to Madagascar. Its range encompasses the whole of the west coast and the extreme
north-east. It is known to breed at two sites, Masoarivo on the central west coast, and
Ankazomborona on the far north-west coast. The largest numbers recorded in recent times have
been between Mahajanga and Morondava on the west coast: 100-500 were estimated present
between Antsalova and Morondava in July-August 1993 and a flock of 67 was seen near
Tambohorano in 1998; however, a new breeding population of 200-300 individuals was recently
discovered at Ankazomborona, north of Mahajanga and some 720 km north of the Masoarivo
breeding site.

Habitat

The species breeds only in seasonally flooded, non-tidal areas dominated by Black Mangrove, Avicennia marina, on the landward side of littoral forest. During its post-breeding moult, during which time it is flightless, the species seeks out lakes that are rich in aquatic vegetation, and in the subsequent dry season it is found in coastal wetland areas of shallow water and nutrient-rich mud, including saline and brackish areas. Here it prefers open rather than vegetated wetlands and is most often found in coastal mangrove forest, bays, estuaries and shallow saline wetlands just inland of mangroves (tannes), though it can also be found less frequently in marshes, dense deciduous forest, areas of open water and herbaceous savannah, especially where Hyparrhenia and Heteropogon grasses are present.

Reproduction

Pair formation and breeding occurs during the wet season (from December to March). Nesting occurs in cavities in tree trunks, particularly in black mangrove trees. Pairs are monogamous and very territorial, defending their nesting site aggressively against intruders. About six eggs are laid, which hatch after around four weeks. After a further six weeks the chicks will have developed adult plumage and will begin to fly.

Feeding habits

This species tends to occur in small groups, which feed during the day and night, but are most active at dawn and dusk. This duck feeds on invertebrates and plant matter whilst wading, sifting through the water with the bill.

Video Berniers Teal

httpv://www.youtube.com/watch?v=HVoh4Bm4v20

copyright: Josep del Hoyo


Conservation

This species is listed as Endangered because it has a very small population, in one subpopulation, that is undergoing a rapid and continuing decline owing to habitat loss and hunting.
The species is now extremely threatened throughout its breeding range, having suffered extensive
habitat loss and disturbance. Conversion of shallow, muddy water-bodies to rice cultivation has
been so widespread on the west coast that the species now appears to be confined to the few
suitable wetlands that are too saline for rice-growing, i.e. some inland lakes and coastal areas
such as mudflats. Its previous abundance at the freshwater lakes of Bemamba and Masama
would seem to confirm this. Mangroves are under considerable pressure from prawn-pond
construction and timber extraction, which also lead to massively increased hunting. However, the
newly discovered breeding site at Ankazomborona is not threatened by aquaculture; there is little
pressure from subsistence hunters but some pressure from sport hunters.
Berniers Teal status Endangered

Migration

This species is mostly sedentary. Birds breed during the wet season months of December to March and moult at the beginning of the dry season

Distribution map

Berniers Teal distribution range map

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