Pacific Black Duck
Encyclopedia
The Pacific Black Duck is a dabbling duck found in much of Indonesia
, New Guinea
, Australia
, New Zealand
, and many islands in the southwestern Pacific, reaching to the Caroline Islands
in the north and French Polynesia
in the east. It is usually called the Grey Duck in New Zealand. It is also known in New Zealand by its Maori name, Pārera.
is found in a variety of wetland habitats, and its nesting habits are much like those of the Mallard
, which is encroaching on its range in New Zealand. It feeds by upending, like other Anas ducks.
It has a dark body, and a paler head with a dark crown and facial stripes. In flight, it shows a green speculum
and pale underwing. All plumages are similar. The size range is 54–61 cm; males tend to be larger than females, and some island forms are smaller and darker than the main populations. It is not resident on the Marianas islands, but sometimes occurs there during migration. The now extinct Mariana Mallard
was probably originally derived from hybrids between this species and the mallard
, which came to the islands during migration and settled down there.
There are three subspecies of Anas superciliosa:
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The New Zealand subspecies has declined sharply in numbers, at least in its pure form, due to competition from and hybridisation with the introduced mallard. Rhymer et al. (1994) say their data "points to the eventual loss of identity of the Grey Duck as a separate species in New Zealand, and the subsequent dominance of a hybrid swarm akin to the Mariana Mallard."
It was assumed that far more mallard drakes mate with Grey Duck females than vice versa based on the fact that most hybrids show a mallard-type plumage, but this is not correct; it appears that the mallard phenotype is dominant, and that the degree to which species contributed to a hybrid's ancestry cannot be determined from the plumage. The main reasons for displacement of the Pārera seem to be physical dominance of the larger mallards, combined with a marked population decline of the Pārera due to overhunting in the mid-20th century.
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, 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...
, and many islands in the southwestern Pacific, reaching to the Caroline Islands
Caroline Islands
The Caroline Islands are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically they are divided between the Federated States of Micronesia in the eastern part of the group, and Palau at the extreme western end...
in the north and French Polynesia
French Polynesia
French Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
in the east. It is usually called the Grey Duck in New Zealand. It is also known in New Zealand by its Maori name, Pārera.
Description
This sociable duckDuck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
is found in a variety of wetland habitats, and its nesting habits are much like those of the Mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
, which is encroaching on its range in New Zealand. It feeds by upending, like other Anas ducks.
It has a dark body, and a paler head with a dark crown and facial stripes. In flight, it shows a green speculum
Speculum feathers
The speculum is a patch, often distinctly coloured, on the inner remiges of some birds.Examples of the colour of the speculum in a number of ducks are:* Common Teal and Green-winged Teal: Iridescent green edged with buff....
and pale underwing. All plumages are similar. The size range is 54–61 cm; males tend to be larger than females, and some island forms are smaller and darker than the main populations. It is not resident on the Marianas islands, but sometimes occurs there during migration. The now extinct Mariana Mallard
Mariana Mallard
The Mariana Mallard or Oustalet's Duck is an extinct type of duck of the genus Anas that was endemic to the Mariana Islands...
was probably originally derived from hybrids between this species and the mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
, which came to the islands during migration and settled down there.
There are three subspecies of Anas superciliosa:
- rogersi − MathewsGregory MathewsGregory Macalister Mathews CBE was an Australian amateur ornithologist.Mathews made his fortune in mining shares, and moved to England around 1900....
, 1912 Australasian Duck, breeds in IndonesiaIndonesiaIndonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, southern New GuineaNew GuineaNew Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... - pelewensis − HartlaubGustav HartlaubKarel Johan Gustav Hartlaub was a German physician and ornithologist.Hartlaub was born in Bremen, and studied at Bonn and Berlin before graduating in medicine at Göttingen. In 1840, he began to study and collect exotic birds, which he donated to the Bremen Natural History Museum. He described some...
& FinschOtto FinschFriedrich Hermann Otto Finsch was a German ethnographer, naturalist and colonial explorer.-Biography:...
, 1872 - Island Black Duck, breeds on the southwest Pacific islands and northern New GuineaNew GuineaNew Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago... - superciliosa Gmelin, 1789 − New Zealand Grey Duck, breeds in New ZealandNew ZealandNew 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 was assumed that far more mallard drakes mate with Grey Duck females than vice versa based on the fact that most hybrids show a mallard-type plumage, but this is not correct; it appears that the mallard phenotype is dominant, and that the degree to which species contributed to a hybrid's ancestry cannot be determined from the plumage. The main reasons for displacement of the Pārera seem to be physical dominance of the larger mallards, combined with a marked population decline of the Pārera due to overhunting in the mid-20th century.