The Paradise Shelduck, also simply known as the Paradise Duck, is a species of shelduck endemic to New Zealand.
Description[]
The Paradise Shelduck is a large, goose-like duck endemic to New Zealand. It is about 63cm long and weighs 1.4-1.7kg. Both birds have a white and green speculum, but the male has completely black plumage while the female is chestnut-brown with a striking white head. They are often seen in pairs or large groups.
Behaviour[]
Populations are structured as territorial breeding pairs and flocks, the latter comprising mostly first-year and some second-year pre-breeders. Flocks mostly inhabit extensive river-side pastoral flats or expansive areas of young grass. The annual communal moult extends over January-March. Birds gather in large numbers around isolated or large ponds or lakes, or on expansive riverbeds, to shed all wing feathers.
Feeding[]
Paradise Shelducks are generally herbivorous, with a preference for pasture grasses and clover. An extensive diet has been recorded that embraces a broad range of leaves and seeds of terrestrial herbs, some aquatic plants, and terrestrial and aquatic invertebrates.
Breeding and Nesting[]
Paradise Shelducks disperse as territorial pairs for breeding, and pairs occupy their territories year-round except when at a communal moult site. Hence birds are invariably seen as single pairs. Pair bonds may persist for several years but are regularly challenged by unpaired individuals. Territories usually contain some water body on which the brood will seek refuge. However, broods can be raised in wet areas without access to open water.
Females prospect potential nest sites within or beyond the territory in tree holes or bases, rock crevices, under buildings or debris piles and will use almost any site that confers overhead cover and has just a single entrance. Egg-laying is usually in August and September but young birds and some repeat nesters will lay in October, but rarely later. Clutches of 5-15 are reported but most over 12 will have been contributed to by two females. Incubation is by the female only and takes 30-35 days. Both parents guard the ducklings for 55-65 days until able to fly. Parents will perform a broken-wing display to distract mammalian predators and sometimes people. Some broods may amalgamate. The family may remain together for several weeks thereafter, with the bond broken when the parents depart for the communal moulting sites.
Distribution and Habitat[]
The Paradise Shelduck is New Zealand’s most widely distributed waterfowl, when both geographic spread and habitat use are taken into account. It occurs on North, South and Stewart Islands, all large near-shore islands with grassland (e.g. Kapiti, Great Barrier, D’Urville) and has straggled to distant Raoul and Lord Howe Islands, and to the Chatham Islands from which an as-yet unnamed shelduck species was exterminated by the first Polynesian settlers.
Paradise Shelducks inhabit throughout the pastoral landscape, whether high country or lowlands, on river flats in mountain areas, at heads of protected bays or fiords, around the shorelines of all large lakes and hydro-dams, and increasingly on recreational grasslands and parks within urban areas.
Conservation and Threats[]
The Paradise Shelduck is so widespread and abundant as to be without conservation threat. Excessive hunting in the past severely impacted numbers, and 2-3 decades of cautious exploitation was required to restore their abundance and expand their distribution. 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 Shelducks, although these dangers are, in most cases, outweighed by the large amount of pasture and grassland habitat available to them.