Paradise Shelduck

Largest and conspicuous of endemic New Zealand waterflow Paradise Shelducks (Tadorna Variegata) are the most dimorphic of Shelducks, with female more brightly colored and boldly patterned than their mates. Heaviest of the Shelducks, the nearly completely black drakes are so dissimilar from the more attractive white-headed females that they appear to be a different species. The ducks are unique in that females rather than males assume the duller postnuptial eclipse plumage, possibly because they may be the dominant member of the pair. Their rich chestnut color is replaced with a much grayer plumage, but the white head is retained at all times. Atypical of ducks, juveniles more closely resemble drakes than females. They are noisy birds, pairs commonly call in loud duets whenever alarmed or excited. They feed on semi-aquatic vegetation, but invertebrates are not ignored, and the ducklings are essentially dependent on aquatic insects until about five weeks of age. They often graze in low pasture or crops, where flocks can cause damage. Usually encountered as pairs or family units, they frequent a diversity of habitats, ranging from mounting and forest creeks to coastal flats, inlets and lagoons. During the breeding season, the ducks are divided into two social classes. One consists of lifelong monogamous pairs holding territories, and the other of flocks of primarily immature non-breeders that usually remain at specific sites near water or feeding areas. Nets may be in tree hollows up to 65 feet above ground or in cliff cavities, rabbit burrows, culverts, under abandoned buildings and haystacks, or concealed beneath clumps of vegetation. Broods normally break up when parents desert territories to join flocks on molting waters. A small percentage of young accompany parents and remain with them on the molting grounds. Molting birds congregate on traditional communal sites on open water, where flocks can be large. Flightless for about a month, the Shelducks remain in flocks following the molt, though molting sites are usually abandoned by the end of April.