Indian Spot-billed Duck (Anas poecilorhyncha)

Indian Spot-billed Duck

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas poecilorhyncha | [authority] Forster, 1781 | [UK] Indian Spot-billed Duck | [FR] Canard a bec tachete | [DE] Fleckschnabel-Ente | [ES] anade Picopinto | [NL] Vlekbekeend | [copyright picture] Jan Harteman

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

Head and neck pale buff-grey, lightly streaked with black, crown and broad line through eyes black. Lower neck and breast buff-grey with black spotting, graduating to flanks and abdomen dark feathers with buff-grey edging, ventral region, rump, tail and tail-coverts, almost plain black-brown. Upperparts blackish with fine buff-grey borders to mantle feathers and scapulars. Wing grey-black, with white inner tertials, white tips to greater coverts, green secondaries with black base and subterminal band and white tips (speculum green between black and white bands).

Listen to the sound of Indian Spot-billed Duck

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Indian Spot-billed Duck.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 83 cm wingspan max.: 95 cm
size min.: 55 cm size max.: 63 cm
incubation min.: 24 days incubation max.: 28 days
fledging min.: 50 days fledging max.: 55 days
broods: 1   eggs min.: 6  
      eggs max.: 12  

Range

Oriental Region : South, Southeast Asia from Pakistan, South to Sri Lanka, East to Laos and North to Southwest Yunnan

Habitat

It is a bird of freshwater lakes and marshes in fairly open country and feeds by dabbling for plant food mainly in the evening or at night.

Reproduction

Onset of breeding varies over the geographical range and with water levels, e.g. July-October in northern India, November-December in south India. Nest is concealed in vegetation on the ground near water. It is a grass and weed pad with down lining, built by female only. Occasionally in trees. Clutch size is 6-12 which are incubated for about 4 weeks by the female. Young fledge after about 6-7 weeks; the female tends top the ducklings, sometimes assisted by the male.

Feeding habits

Forages by dabbling, head-dip and up-ends in shallow, also feeds while walking and grubbing on marshland. Mainly vegetarian, seeds and vegetative parts grasses, sedges, aquatic vegetation, grain including cultivated rice. Also aquatic insects and their larvae, molluscs (e.g. water snails), worms.

Video Indian Spot-billed Duck

httpv://www.youtube.com/watch?v=xulwT4I6gwM

copyright: Suraj


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 has not been quantified but is believed to be very large, and hence does not 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 population is suspected to be decreasing at an unquantified rate, but the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion
Indian Spot-billed Duck status Least Concern

Migration

mainly sedentary, local movements depending on rains and water availability.

Distribution map

Indian Spot-billed Duck distribution range map

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