Paradise Shelduck (Tadorna variegata)

Paradise Shelduck

[order] ANSERIFORMES | [family] Anatidae | [latin] Tadorna variegata | [authority] Gmelin, 1789 | [UK] Paradise Shelduck | [FR] Tadorne de paradis | [DE] Paradieskasarka | [ES] Tarro Maori | [NL] Paradijscasarca

Subspecies

Monotypic species

Genus

The shelducks, genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans. The namesake genus of the Tadorninae, Tadorna is very close to the Egyptian Goose and its extinct relatives from the Madagascar region, Alopochen. While the classical shelducks form a group that is obviously monophyletic, the interrelationships of these, the aberrant Common and especially Raja Shelducks, and the Egyptian Goose were found to be poorly resolved. Fossil bones from Dorkovo (Bulgaria) described as Balcanas pliocaenica may actually belong to this genus. They have even been proposed to be referable to the Common Shelduck, but their Early Pliocene age makes this rather unlikely.

Physical charateristics

The paradise shelduck is New Zealand?s only shelduck, a worldwide group of large, often semi-terrestrial waterfowl that have goose-like features. Unusually for ducks, the female paradise shelduck is more eye-catching than the male; females have a pure white head and chestnut-coloured body, while males have a dark grey body and black head.

Listen to the sound of Paradise Shelduck

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Paradise Shelduck.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by Daniel Lane


wingspan min.: 60 cm wingspan max.: 70 cm
size min.: 63 cm size max.: 71 cm
incubation min.: 32 days incubation max.: 33 days
fledging min.: 70 days fledging max.: 85 days
broods: 1   eggs min.: 8  
      eggs max.: 10  

Range

Australasia : New Zealand. Paradise shelducks are endemic to New Zealand

Habitat

Paradise shelducks are generally found in two different habitats, hill-country farmland, which is typical of the North Island and the tussock grasslands of the South Island.

Reproduction

From April breeding pairs will defend their territories against neighboring pairs and newly paired birds who are attempting to establish a territory. Additionally, males will tenaciously guard their mates against any rival males. Meanwhile, the flock of young birds and failed breeders remaining at each moulting site, slowly break off into smaller groups and migrate to better nearby feeding areas, where they remain throughout the rest of the year. Although, from September through to November, some juvenile pairs will leave the flock temporarily and visit areas which are prospective breeding sites and some will even migrate more than 100km away found that paradise shelducks, banded near Taihape in North Island and several South Island sites in New Zealand, migrated within 20 km of the banding site 50% of the time, and within 60 km 90% of the time. Some individuals traveled over 200 km. Starting in July, breeding pairs will begin to search for potential nesting sites typically in trees, hollow logs or holes in the ground. Pairs will spend a lot of their day away from their territories looking for a place to nest, which can be from 100m to 1km away from their territories. The first eggs are generally laid in August with a mean clutch size of 9.4 eggs. Ducklings first appear towards the end of September. During the first week, ducklings will feed frequently on aquatic insects but will subsequently change their diet to plant material (Williams 1979b). After fledging, the family group remains on the territory while the adults undergo most of their body moult. By December, breeding territories are abandoned and all birds start to return to their moulting sites to start the annual cycle once more.
They lay one clutch of up to 10 eggs per year in August or September. The female incubates eggs for about one month, during which time she leaves the nest two or three times each day for about an hour at a time to get food. After the eggs hatch, the male and female share the parenting. Ducklings are covered in brown and white down when they are born, but by the time they fledge at eight weeks, they resemble adult males. The female fledglings have white patches around their eyes and bill, which will expand to their entire head after a few months.

Feeding habits

Shelducks combine grazing and dabbling feeding methods, and their diet usually consists mainly of plants, such as grasses, as well as small shore invertebrates, like crustaceans and insects.

Video Paradise Shelduck

httpv://www.youtube.com/watch?v=CYFm1w18oYk

copyright: Brooke Clibbon


Conservation

This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
While paradise shelducks are widespread and common, periods of local decline sometimes occur because of over-hunting. Introduced predators and the draining of wetlands are also threats to paradise ducks, although these dangers are, in most cases, outweighed by the large amount of pasture and grassland habitat available to them.
Paradise Shelduck status Least Concern

Migration

Adults are generally sedentary but leave their territories and flock together each year to moult
(December ? February). Moulting birds were important food for early Maori.

Distribution map

Paradise Shelduck distribution range map

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