The paradise shelduck (Tadorna variegata), also known as the paradise duck, or in Māori, is a species of shelduck, a group of goose-like ducks, which is endemic to New Zealand. Johann Friedrich Gmelin placed it in the genus Anas with the ducks, geese, and swans. Both the male and female have striking plumages: the male has a black head and barred black body and the female has a white head with a chestnut body. They weigh between and are between in length.
Paradise shelducks mate for life and usually live as pairs, and moult their feathers from December to February. They are primarily herbivorous, and mostly graze on pasture grasses and clover, but have been observed eating a wide range of invertebrates. They are seasonally hunted as a game bird throughout New Zealand, and today the IUCN Red List classifies them as a species of least concern.
Taxonomy
thumb|This watercolour of a female is the [[holotype for the species, painted by Georg Forster on James Cook's second voyage to the Pacific Ocean. |left|236x236px]]
The paradise shelduck was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the other ducks, swans, and geese in the genus Anas and coined the binomial name Anas variegata. Gmelin based his description on the "Variegated goose" from New Zealand that had been described in 1785 by the English ornithologist John Latham in his A General Synopsis of Birds. The naturalist Joseph Banks had provided Latham with a water-colour drawing of the duck by Georg Forster who had accompanied James Cook on his second voyage to the Pacific Ocean. The picture of a female bird was drawn in April 1773 at Dusky Sound, a fiord on the southwest corner of New Zealand. This picture is now the holotype for the species and is held by the Natural History Museum in London.
The paradise shelduck is now placed with five other species in the genus Tadorna that was introduced by the German zoologist Friedrich Boie in 1822. The species is monotypic: no subspecies are recognised. Other common names include painted duck, pari, parry, parrie, and pūtangitangi in Māori.
Distribution and habitat
Paradise shelducks are the most widely distributed waterfowl in New Zealand. Kapiti Island, Great Barrier Island, and Stewart Island. They are common around the hilly farmland characterised by fertile riversides, farm dams, and natural pools of the North Island. On the South Island, they can commonly be found in the tussock river valleys and high-country lakes while a small number can be found in the mountain streams, coastal flats, and brackish inlets. Around water bodies are the preferred breeding habitat for which to use as a nursery area for young, the quality or depth of water does not influence the selection, but available vantage points with long views to or from water do influence the selection. Many chosen places have a grassland at the edge of the water and a cover for refuges which is dense, such as reedbeds and forest. This has the purpose of the birds being able to feed close to the water's safety, and lakes surrounded by dense vegetation might be chosen as well to feed at night. Both females and males have chestnut-colour undertails, primarily black wing feathers with green secondary wing feathers, and upper wing surface feathers that are white.
The adult male has a blue-black head and neck, with a black rump and tail; the back and flank are lightly flecked with a pale yellow colour. The wings of males have contrasting white upper-coverts and black remiges, metallic green speculum feathers, and rusty brown tertials feathers. The male also has a dark grey flecked with pale-yellow breast and abdomen, chestnut undertail and underwing, and black iris, bill, legs, and feet. The female, unlike the male, has an entirely white head and neck with a dark grey back heavily flecked with pale yellow. The rest is very similar to the male with the female's body being dark or light chestnut depending on age and stage of molting. The adults are primarily herbivorous preferring pasture grasses and clover while the young eat mostly aquatic insects for the first five weeks of life before grazing on land. They can feed on a variety of food including grazing or pasture crops, seed heads of grasses and weeds, earthworms, insects, and a variety of crustaceans. An extensive record of one bird's diet from the Canterbury district, South Island, New Zealand shows a wide range of leaves and seeds of terrestrial herbs, terrestrial and aquatic invertebrates, and some aquatic plants. Only periodic cases of avian botulism have been reported to affect populations.
Hunting
Hunting of the species happens throughout the islands where harvest numbers range from 5% to 48% depending on the region, with an average of just over 30%.
Conservation
Populations of the paradise shelduck used to be much smaller during pre-settlement times due to the increased forest cover but after the settlers began to inhabit the island and clear the land for pastures the populations eventually began to rise. But before the population could rise, it fluctuated dramatically because of overhunting and exploitation by the settlers. Only through protective measures between 1900 and 1920 and limited shooting in the South Island from 1923 to 1939, could the population rise to historical heights by 1935.