Blue Duck (Hymenolaimus malacorhynchos)
- Dutch name:
- Nieuw-zeelandse blauwe eend
- English name:
- Blue Duck
- German name:
- French name:
- Hyménolaime bleu
- Scientific name:
- Hymenolaimus malacorhynchos
Virtually whole plumage is slaty grey with bluish sheen. Head a little darker and crown brown grey, though brownish tinge often slight or even absent. Breast paler grey heavily mottled with reddish brown elongated blotches, which often arranged, at least in center of breast, into ill-defined streaks running down onto upper belly, mottling petering out onto anterior flanks; undertail converts dull chestnut. Smudgy black mottling on mantle and scapulars. Upper wings same uniform blue-grey color, but inner secondaries have black edges and outer six secondaries have narrow white tips; under wings uniform paler grey, with white tips to secondaries showing. Bill pale pinkish white with black nail, and black pendent lobes of skin on each sides of tip; nostrils blackish. Legs and feet light brown with darker brown patches.
Identical to male but, mottling on breast less extensive and rarely reaching flanks or belly. Wings, tail and bare parts as male.
Lacks bluish sheen; mottling on breast absent at first and then brown, lacking reddish color, and more limited in extent then female. Upper wing converts with brownish tinge. Bill very pale flesh grey, with black nail, skin lopes and stripe down center of upper mandible almost to tip.
Adult plumage acquired after first year.
Blue ducks are monogamous and fiercely territorial; the territory and pair bond are maintained throughout the year.
- Body Length (cm):
- The male (drake) of the Blue Duck measures approximately 53-56 centimeters. The female measures approximately 53-56 centimeters.
- Body Weight (grams):
- The male will weight about 880-920 gram. The female will weight about 750-790 gram.
The weight is notoriously variable and can only be used as indication!
There are two subspecies:
- H. m. malacorhynchos - western South Island, New Zealand
- H. m. hymenolaimus - central North Island, New Zealand
Blue ducks are not commonly kept in captivity. They may be fed a diet of mixed ordinary waterfowl pellets (80%) and seaduck pellets (20%), with a little wheat, and they greatly appreciate access to natural food such as aquatic invertebrates.
These ducks should be kept in a seperate enclosure, with flowing water. Pairs are normally formed in the first year of life, soon after fledging, and considerable problems have been encountered with aggression within pairs. There have also been fertility problems in captivity, with generally low fertility. Work has now started on the use of artificial insemination to overcome this problem.
Parent incubation has been successful. However, ducklings left with their parents died after only a few days from Acanthocephala Infection (Thorny-headed worms) ingested in freshwater shrimps Gammarus spp.. Artificial incubation and rearing has been successful, with ducklings reared without swimming water initially, being given access to trays of water in outside pens from ten days old.
- The female Blue Duck usually lays from 5-6 creamy-white to pale buff eggs and incubates them for 33-35 days.
- Bird banding:
- Recommended leg band size for the Blue Duck is 0 mm.The leg band can only be applied on a young duck at around 0 days old.
- It doesn't matter what leg that you band, but it is good to have a consistent system. Suggested: Left leg = Female, Right leg = Male
- Preferred food:
Floating full food for all sea ducks, green ducks, eider ducks and geese, especially in the moulting and breeding phase ideally suited. Packed with wholesome raw materials, natural vitamins and trace elements, this performance food with a protein content of 30% forms the basis for lifelong vitality.
Floatable special complete food for sea birds with the highest nutritional requirements. Each chunk contains the complete nutrient spectrum. The high protein content of 35% ensures a healthy and species-appropriate diet. Spiral algae give a more magnificent coloration of plumage and sea salt promotes the salt gland.