T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Duck (Brown teal) Anas chlorotis

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Anatinae
Genus: Anas
Species: A. chlorotis
Binomial name: Anas chlorotis
Synonyms: Anas aucklandica chlorotis, Elasmonetta chlorotisCommon names: Brown teal, pāteke.

Anas chlorotis is a New Zealand species of dabbling duck of the genus Anas. Common in the early years of European colonisation was heavily harvested as a food source. Its numbers quickly fell, especially in the South Island, & in 1921 they became fully protected. Captive breeding & releasing into predator-controlled areas has seen good localised populations re-introduced around the country in recent years. This endangered species occurs predominantly on offshore islands but also in predator-proof sanctuaries on the mainland such as Tawharanui Regional Park (a peninsula west of Warkworth). Formerly, it was widespread on the New Zealand mainland, but it disappeared there due to introduced predators. Brown teal have no defence against introduced cats, dogs, stoats & ferrets, which can kill adults & ducklings, or against rats which eat eggs.  According to the IUCN categorization as VU D1, fewer than 1000 adult birds remain. The species has recently been upgraded to endangered by Birdlife International (Birdlife 2007), and the change will be reflected in the next update of the IUCN red list.

The brown teal has a length of 48 cm with the males weighing 650 g and the females 580 g. Both sexes are a darkish brown and both have dark brown eyes, white eye rings, black and grey bill, legs and feet, and green speculum on the secondary wing feathers. The males in breeding plumage have green iridescence on the head, a narrow white neck ring, dark chestnut breast, and a whitish patch at the base of the tail feathers.

Anas chlorotisare largely nocturnal in habit and at night they will forage on land some distance from the streams used as a refuge during the day.  When on water they feed by dabbling and upending. Its diet consists mainly of aquatic invertebrates like insects and their larvae, or crustaceans. It appears quite fond of molluscs. Small species such as pipi (Paphies australis) and large wedge shell (Macomona liliana) are eaten whole and crushed in the gizzard. 

They build a nest of dry grass and line it with down. It is usually near water or under the shelter of large Carex (grassy plants called sedges). A clutch of four to eight creamy-brown eggs is laid. Incubation by the female alone takes 27–30 days. The male stays in his territory as a guard, aggressive to all other waterfowl. 



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