Alzavola marrone

Identificazione

There are no distinctive differences between a male, female and a juvenile brown teal during non-mating season. They all have a white ring around their eyes as well as a mottled brown color on their heads and throat. During breeding season the male will begin to change color, now having a green colored head, chestnut colored breast and a white stripe on each side of their body. They will sometimes also have a white clerical neck band. This does vary as some males do tend to be more colorful than others.

Tassonomia

Pateke is the progenitor of the flightless Auckland teal and Campbell teals but all are now recognised as separate species on account of their geographic isolation and their plumage, size and genetic distinctions. The insular A. aucklandica and A. nesiotis are recognised as distinct species, but are still sometimes referred to as being part of the "brown teal group". The use of the name 'pateke' is now common and is specific for this particular species.<p>Concerns have been raised about establishing genetically similar populations during re-introduction. The original captive pateke were sourced from Great Barrier Island, where only one haplotype was found in abundance, compared with eleven haplotypes found in the other remaining population at Mimiwhangata. The newly released flocks exclusively contain these birds of captive origin, and diversity is perhaps now not being fully represented in the National population.<p>The former population of Fiordland brown teal, which died out by 2013 has been replaced with captive-origin birds. Sequencing showed striking similarity to grey duck and mallard sequences, with which they group. It therefore seems extremely likely that the former Fiordland population of brown teal have at sometime in the past hybridised extensively with these invading species.

Nome scientifico

Anas chlorotis

Autorità

Gray, GR, 1845

Ordine

Anseriformi

Famiglia

Anatidae

Genere

Anas

Areale e habitat

Migrazione

Resident species

Comportamento

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 &amp; ferrets, which can kill adults &amp; ducklings, or against rats which eat eggs.

Conservazione

Tendenza della popolazione

rising