Campbell Teal (Anas nesiotis)

Campbell Teal

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas nesiotis | [authority] Fleming, 1935 | [UK] Campbell Teal | [FR] Sarcelle de Campbell | [DE] Champbell-Insel-Ente | [ES] Cerceta de Campbell | [NL] Campbell-Taling

Subspecies

Genus Species subspecies Region Range
Anas nesiotis AU Campbell Islands

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, flightless, dark brown duck. Brown eclipse male, female and juvenile. Mottled dark brown breast. Prominent white eye-patch. Breeding male has glossy green head. Very narrow white collar, flank patch. Breeding males are a dark sepia colour, with strong green iridescence on their head, neck and back, dark chestnut tones on the breast, and lighter plumage on the abdomen, in addition to a conspicuous white ring around the eye and obvious white tail spot. During non-breeding plumage, the iridescence on the head and back becomes less intense, the tail spot becomes indistinct and the eye ring becomes pale fawn. Females are uniformly dark brown with a paler abdomen, and prominent white eye ring


wingspan min.: 130 cm wingspan max.: 140 cm
size min.: 46 cm size max.: 50 cm
incubation min.: 30 days incubation max.: 34 days
fledging min.: 0 days fledging max.: 0 days
broods: 1   eggs min.: 3  
      eggs max.: 4  

Range

Australasia : Campbell Islands. Anas nesiotis is endemic to New Zealand, where it had been confined to Dent Island, an offshore islet of Campbell Island, for many decades.

Habitat

It lives under thick, chest-high tussock (there are no pools or running water on Dent). It has been sighted over most of the island, but is probably more common below 100 m, and in damp areas.

Reproduction

There has been no biological study of the Campbell Island teal on Dent Island, with most knowledge of the bird coming from captive or post-release populations (8). Clutches are small compared to most ducks, consisting of one to five eggs, with a typical clutch size of three or four . In captivity, these are laid from October to January. The inubation period lasts for 30 to 34 days and both sexes can breed at one year.

Feeding habits

It has not been observed feeding on the island, but in captivity it feeds on amphipods, weevils, earthworms, seaweed and other insects. Birds released onto Codfish Island have been observed feeding on invertebrates in piles of rotting seaweed along the shore and foraging offshore at night.

Video Campbell Teal

httpv://www.youtube.com/watch?v=KsErlK4Tc48

copyright: Brooke Clibbon


Conservation

This species qualifies as Critically Endangered as it has had a tiny breeding population for many years. The one wild population on Dent Island off Campbell Island is assumed to have been stable. Recent reintroduction of birds to Campbell Island appears to have successfully established a second population, and overall numbers are now above the threshold for listing as Critically Endangered, and increasing. However, this classification will be retained for five years until the species is confirmed to be self-sustaining in larger numbers in the wild, at which time it will warrant downlisting.
Brown rats Rattus norvegicus on Campbell (one of the most dense field populations in the world) may have caused its disappearance from this island. The successful eradication of this invasive alien species in 2001 has allowed the reintroduction of teal from captive stock. However, accidental reintroduction of rats, severe weather events and the introduction of avian disease remain possible threats. Brown Skua Catharacta lonnbergi, Kelp Gull Larus dominicanus, and Northern Giant-petrel Macronectes halli are potential natural predators.
Campbell Teal status Critically Endangered

Migration

Sedentary

Distribution map

Campbell Teal distribution range map

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