Campbell Island Teal
Encyclopedia
The Campbell Teal or Campbell Island Teal (Anas nesiotis) is a small, flightless, nocturnal
species of dabbling duck of the genus Anas endemic
to the Campbell Island group
of New Zealand
. It is sometimes considered conspecific
with the Brown Teal
. The plumage
is similar to that of the Auckland Teal, dark sepia with the head and back tinged with green iridescence
, and a chestnut breast on the male, with the female dark brown all over. Its natural habitat is tussock grassland dominated by Poa
tussock grass, ferns and megaherb
s. The species also uses the burrows and pathways of petrel
species that nest on the islands. They are apparently territorial in the wild, and probably feed on amphipods and insects.
of Norway Rats (which ate their eggs and chicks), and was for a while presumed extinct. In 1975 it was rediscovered on Dent Island
, a small (23 hectare) islet near Campbell that had remained rat-free. The population was so small that a single event could have driven it to complete extinction; to prevent this from happening, 11 individuals were taken into captivity by the Department of Conservation
for captive breeding
at the Mt Bruce Wildlife Centre
in 1984 while the rest followed in 1990. They were also put on the list of critically endangered species in 1979.
Captive breeding was initially very difficult to achieve, as no studies on the behaviour of the species had been carried out in the wild and "staff [at Mount Bruce] thus had to experiment with a range of techniques to encourage breeding. Success came in 1994 when Daisy, the only wild origin female to ever lay eggs in captivity, finally accepted a mate. Subsequently, breeding has occurred every year – wild origin males contributed genes by pairing with captive raised females."
A small population of 25 captive-bred individuals was released on Codfish Island
in 1999 and 2000, already intensively managed and pest-free as an important habitat for the critically endangered Kakapo
. In the final phase of the ecological restoration of Campbell Island (cattle, sheep and cats had already been removed), the world's largest rat eradication campaign was undertaken by helicopter
drops of more than 120 tonnes of poisoned bait over the entirety of the island's 11,331 hectare
area in 2001; this operation successfully removed
what was estimated to be the world's densest population of Norway rats (200,000) from Campbell Island and it was officially declared rat free in 2003. Fifty Campbell Teal, a mix of captive-bred and wild-acclimatised animals (from Codfish), were reintroduced
to Campbell Island in mid 2004, after an absence of more than a century. Subsequent monitoring in 2005 has shown that the majority of these birds are now thriving in their ancestral homeland. By 2011 the species has firmly been returned to Campbell Island, resulting in a reclassification of its threat status to Endangered.
Nocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....
species of dabbling duck of the genus Anas endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to the Campbell Island group
Campbell Island group
The Campbell Island group is a group of subantarctic islands, belonging to New Zealand. The group has a total area of , consisting of one big island, Campbell Island , and several small islets, notably Dent Island , Isle de Jeanette Marie , Jacquemart Island , and Monowai Island 1...
of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. It is sometimes considered conspecific
Conspecificity
Conspecificity is a concept in biology. Two or more individual organisms, populations, or taxa are conspecific if they belong to the same species....
with the Brown Teal
Brown Teal
The Brown Teal or New Zealand Teal, is a species of dabbling duck of the genus Anas. The Māori name for it is Pāteke. It was considered to be conspecific with the flightless Auckland and Campbell Teals in Anas aucklandica; the name "Brown Teal" was applied to that entire taxon...
. The plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is similar to that of the Auckland Teal, dark sepia with the head and back tinged with green iridescence
Iridescence
Iridescence is generally known as the property of certain surfaces which appear to change color as the angle of view or the angle of illumination changes...
, and a chestnut breast on the male, with the female dark brown all over. Its natural habitat is tussock grassland dominated by Poa
Poa
Poa is a genus of about 500 species of grasses, native to the temperate regions of both hemispheres. Common names include meadow-grass , bluegrass , tussock , and speargrass. "Poa" is Greek for fodder...
tussock grass, ferns and megaherb
Megaherb
Megaherbs are a group of herbaceous perennial wildflowers growing in the New Zealand sub-antarctic islands. They are characterised by their great size, with huge leaves and very large and often unusually-coloured flowers, which have evolved as an adaptation to the harsh weather conditions on the...
s. The species also uses the burrows and pathways of petrel
Petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes. The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group...
species that nest on the islands. They are apparently territorial in the wild, and probably feed on amphipods and insects.
Conservation
The Campbell Teal was once found on Campbell Island, but was driven to extinction there by the introductionIntroduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
of Norway Rats (which ate their eggs and chicks), and was for a while presumed extinct. In 1975 it was rediscovered on Dent Island
Dent Island, New Zealand
Dent Island is a subantarctic rock stack, lying 3 km west of Campbell Island and belonging to the Campbell Island group. Dent Island is located at ....
, a small (23 hectare) islet near Campbell that had remained rat-free. The population was so small that a single event could have driven it to complete extinction; to prevent this from happening, 11 individuals were taken into captivity by the Department of Conservation
New Zealand Department of Conservation
The Department of Conservation , commonly known by its acronym, "DOC", is the state sector organisation which deals with the conservation of New Zealand’s natural and historic heritage...
for captive breeding
Captive breeding
Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...
at the Mt Bruce Wildlife Centre
Mt Bruce Wildlife Centre
Pukaha Mount Bruce Wildlife Centre is a wildlife restoration organisation based around a protected forest area in New Zealand's Wairarapa district.-History:...
in 1984 while the rest followed in 1990. They were also put on the list of critically endangered species in 1979.
Captive breeding was initially very difficult to achieve, as no studies on the behaviour of the species had been carried out in the wild and "staff [at Mount Bruce] thus had to experiment with a range of techniques to encourage breeding. Success came in 1994 when Daisy, the only wild origin female to ever lay eggs in captivity, finally accepted a mate. Subsequently, breeding has occurred every year – wild origin males contributed genes by pairing with captive raised females."
A small population of 25 captive-bred individuals was released on Codfish Island
Codfish Island
Codfish Island or Whenua Hou is a small island located to the west of Stewart Island/Rakiura in southern New Zealand. It reaches a height of close to the south coast. Following the eradication of possums and weka, it is a predator-free bird sanctuary and the focus of Kakapo recovery efforts...
in 1999 and 2000, already intensively managed and pest-free as an important habitat for the critically endangered Kakapo
Kakapo
The Kakapo , Strigops habroptila , also called owl parrot, is a species of large, flightless nocturnal parrot endemic to New Zealand...
. In the final phase of the ecological restoration of Campbell Island (cattle, sheep and cats had already been removed), the world's largest rat eradication campaign was undertaken by helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
drops of more than 120 tonnes of poisoned bait over the entirety of the island's 11,331 hectare
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
area in 2001; this operation successfully removed
Island restoration
The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as important breeding grounds for seabirds and some...
what was estimated to be the world's densest population of Norway rats (200,000) from Campbell Island and it was officially declared rat free in 2003. Fifty Campbell Teal, a mix of captive-bred and wild-acclimatised animals (from Codfish), were reintroduced
Reintroduction
Reintroduction is the deliberate release of a species into the wild in zones formerly inhabited by said species but where it has disappeared from for a number of reasons, from captivity or relocated from other areas where the species still survives in...
to Campbell Island in mid 2004, after an absence of more than a century. Subsequent monitoring in 2005 has shown that the majority of these birds are now thriving in their ancestral homeland. By 2011 the species has firmly been returned to Campbell Island, resulting in a reclassification of its threat status to Endangered.
External links
Database entry includes justification for why this species is critically endangered- BirdLife International - "Campbell island teal can go home"
- BirdLife International - Species Factsheet
- TerraNature - Campbell Island teal