Brown Teal (Anas chlorotis)

Brown Teal

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas chlorotis | [authority] Gray, 1845 | [UK] Brown Teal | [FR] Sarcelle de Nouvelle-Zelande | [DE] Braunente | [ES] Cerceta de Auckland | [NL] Auckland-Taling

Subspecies

Genus Species subspecies Region Range
Anas chlorotis AU New Zealand

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

In breeding plumage the male will display a chestnut coloured breast, a greenish coloured head, and invariably display a distinctive, mallard-like, white stripe on each side of their flank. Some will display a white clerical neck band and some males tend to be more colourful than others, with a few occasionally resembling the spectacular colours of a Chestnut teal (Anas castanea) male. Both sexes have a black iris, a green tending to black speculum, with a thin white wing-bar, and both have grey slate coloured legs and feet.

Listen to the sound of Brown Teal

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

Copyright remark: Most sounds derived from xeno-canto

recorded by brownteal.com


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 36 cm size max.: 48 cm
incubation min.: 27 days incubation max.: 30 days
fledging min.: 53 days fledging max.: 57 days
broods: 1   eggs min.: 5  
      eggs max.: 6  

Range

Australasia : New Zealand. Anas chlorotis is endemic to New Zealand, where it was once widespread in the North, South, Stewart and Chatham Islands, but its range is now much reduced. The current strongholds are on Great Barrier Island, where there were 1,300-1,500 birds in the early 1990s, declining to little over 500 in the early 2000s and increasing to over 600 in 2004, and at Mimiwhangata and Teal Bay on the east coast of Northland

Habitat

It formerly inhabited a wide range of freshwater wetlands and swamp-forests, especially in the lowlands. It is now restricted to coastal streams, wetlands and dams in predominantly agricultural environments

Reproduction

It nests in bowls of grass, always under dense, low vegetation, only the female incubates the eggs.The main breeding season for wild Brown Teal is from July to November, but in certain circumstances, that is, if the conditions are suitable, Brown Teal have been known to breed in every month of the year; a truly unique phenomenon. The eggs of Brown Teal are cream-tan in colour and for a bird weighing only 500g a Brown Teal egg is by far the largest of all teal eggs, equivalent to a massive eleven percent of the female’s weight and measuring a unique teal sized egg of 58 x 43mm. The clutch size rarely exceeds five to six eggs and the incubation period is 27-30 days. Juveniles fledge at 55 days. In the wild two clutches in a breeding season have been regularly recorded from one pair of teal and this is undoubtedly one of the reasons for moult irregularities. There is also considerable inconsistency with the moulting period for both wild and captive Brown Teal; many pairs will moult immediately after rearing a brood, but others are much slower.

Feeding habits

It feeds on aquatic or marine invertebrates and plant detritus. Wild Brown Teal are incredibly active at night and spend hours searching in paddocks (fields) for worms and insects, or in estuaries for small shellfish. They also seem to mostly enjoy themselves dissecting patches of cow dung and also sieving endlessly in muddy pools.

Video Brown Teal

httpv://www.youtube.com/watch?v=8BT_I4Hgeek

copyright: Brooke Clibbon


Conservation

This species has a very small range and only three significant remaining subpopulations. Until recently its overall range, area of occupancy, area and quality of habitat, number of locations and subpopulations, and number of individuals were undergoing a very rapid decline; however intensive management has halted the decline and populations are now increasing, with several new populations being established. Despite this recent change in fortunes, it is remains classified as Endangered until these trends are consolidated.
Between the 1890s and 1930s, wetland drainage and severe hunting pressure (which continued in several areas despite legal protection in 1921) caused widespread local extinctions. Predation by the introduced mammalian predators, primarily cats, dogs, mustelids Mustela spp. and possums Trichosurus pulpecula, as well as the native Purple Gallinule Porphyrio porphyrio (locally known as Pukeko), were the primary cause of the modern decline. Research has shown that captive bred birds have shorter digestive tracts than wild birds, this may reduce the re-introduced birds’ chance of efficiently digesting a wild diet and account for some of the deaths of re-introduced birds which were found with very little body fat. Habitat modification, drought-induced habitat change and traffic-caused road deaths and especially predation continue to endanger remnant mainland populations
Brown Teal status Endangered

Migration

Sedentary

Distribution map

Brown Teal distribution range map

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