
Distribution
This species is endangered and occurs predominantly on offshore islands but also in predator-proof sanctuaries on the mainland such as Tawharanui Regional Park. Formerly, it was widespread on the New Zealand mainland, but it disappeared there due to introduced predators like cats, dogs and rats, which easily preyed on this unwary, weakly flying bird. 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 , and the change will be reflected in the next update of the IUCN red list.Status
This species is endangered and occurs predominantly on offshore islands but also in predator-proof sanctuaries on the mainland such as Tawharanui Regional Park. Formerly, it was widespread on the New Zealand mainland, but it disappeared there due to introduced predators like cats, dogs and rats, which easily preyed on this unwary, weakly flying bird. 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 , and the change will be reflected in the next update of the IUCN red list.Behavior
The brown teal is largely nocturnal in habit by dabbling duck standards. This is an evolutionary response to natural diurnal predators such as the New Zealand falcon, Eyles' harrier, or skuas further south in their range. Brown teal have no defense against introduced cats, dogs, stoats & ferrets, which can kill adults & ducklings, or against rats which eat eggs.Reproduction
Nest of dry grass near water or under shelter of large ''Carex'', heavily lined with down. 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.Food
It feeds by dabbling and upending, like its relatives. Its diet consists mainly of aquatic invertebrates like insects and their larvae, or crustaceans. It appears quite fond of mollusks. Small species such as pipi and large wedge shell are eaten whole and crushed in the gizzard. For feeding on larger cockles such as ''Austrovenus stutchburyi'' , at least some New Zealand teals have developed a peculiar technique, as of now undocumented in other birds, to force their rather soft bills between the cockle shells and tear out the flesh with a jackhammer-like pumping motion. At night brown teal will forage on land some distance from the streams used as a refuge during the day .References:
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