J.R. Forster, the biologist in Cook's second expedition, first discouvered paradise shelduck in 1773 in Dusky Sound, Fiordland. It was later found in the North Island by Dieffenbach, and the South Island by Earl in about 1840. They were uncommon before European settlement in the mid-1800s.
W.R.B. Oliver reported in 1930 that paradise shelduck were mainly found from Lake Rotomahana, Lake Waikaremoana and the East Cape south, but were not generally distributed in the North Island. Birds introduced to Lake Rotomahana were shot out in a short time.
Paradise shelduck formerly abundant throughout the South Island, are now more restricted owing to the advance of settlement [Oliver, 1930].
Throughout the remainder of the 20th century, the population grew as a result of intentional stocking of ponds by hunting groups, and the extensive availability of grassland following the clearing of native forest, despite the draining of their native wetland habitat.
Farmland is a favourite habitat for feeding on grass, clover and weeds, and their seeds, and insects and earthworms. Acquatic vegetation is also part of their diet.
In coastal locations crustacea are taken. Ducklings are at first fed insects or crustacea.
Paradise shelduck are listed as 'not threatened' on the 2008 New Zealand Threat Classification System, and 'least concern' on the 2009 IUCN Red List of Threatened Species.
The paradise shelduck is a freshwater and a coastal duck. All ducklings readily take to water, but young paradise shelduck are not afraid to venture out into small surf. They have been seen surfing in on tiny waves at Opunake Beach.
When sensing danger, parents have been observed sending their chicks out into the surf, while they stay on the shoreline in defense.
Paradise shelduck are good swimmers under water, using their wings. As with all ducks, chicks immediately take to paddling, but also start swimming underwater right away.
Crash landing into life .....
Paradise shelducks nest on the ground under tussock, and in open pasture. The nest of grass and down is most often in a ground depression or a hole in a fallen tree. Nests have also been found on mountain faces, and sometimes in tree holes six to eight metres above the ground.
New chicks normally leave the nest within a day of hatching. When it is time for them to leave a tree nest, the mother flies down to the ground and calls for the chicks to follow.
The little chicks jump one at a time, landing from the 8 metre free fall with a thump and a bounce, but appear to be unhurt, probably because the mother has made sure the landing is soft into the right depth of leaf litter.
The chicks seem to fearlessly respond to the mothers call, and follow her flight without realising they cannot fly. Even so, this must be a scary way to start life so soon after hatching.
Despite its' rapid decline and 'nationally critical' threatened status, the grey duck is still a game bird.
While the rapid decline of grey duck has been caused by the loss of wetlands, and hunting, another principle cause is interbreeding with the very large population of introduced mallard Anas platyrhynchos. Very few pure-bred grey duck remain.
Mallard plumage is predominant in most mallard/grey duck hybrids, suggesting that male mallards mate with grey duck females, as opposed to the other way around, however, the level of contribution to the hybrid's ancestry cannot be ascertained from plumage.
One of three New Zealand native ducks that is hunted .....
Paradise shelducks are widespread and common, however, periods of local decline sometimes occur because of over-hunting.
Paradise shelduck have always been the quarry of hunters. Maori took advantage when they were inable to fly during moulting. A one-day hunt at Lake Waihola in 1859 as described by Beattie, took up to 700 moulting adults and juveniles that were rounded up and clubbed.
Farmers have shot and poisoned "parries" because of damage flocks cause to pasture and crops.
Daily bag limits are as high as 20 birds per hunter over periods of two to three months.
According to the Wildlife Act 1953, paradise shelduck are "wildlife declared to be game".
In the North Canterbury Game Region during the 2010/2011 season, Fish & Game New Zealand paradise shelduck daily bag limits vary from 5 per hunter during a 3-month season in one area, to 20 per hunter during a 2-month and a 5-month season (in the same year) in two other areas.
Five game regions have daily bag limits of 10 during a two or three month season, with the exception that Waikato, and Eastern and Hawkes Bay also have limits of 20 over 2 to 2.5 months in some areas. Wellington has a limit of 15 during two months, and Otago allows 12 birds to be shot during four months.
Other native waterfowl that are hunted include nationally critical grey duck Anas superciliosa superciliosa, and non-threatened New Zealand shoveler Anas rhynchotis variegata, and pukeko Porphyrio melanotus.
Six protected native ducks include four Anas species of teal, New Zealand scaup Aythya novaeseelandiae, and blue duck Hymenolaimus malachorhynchos.