- Written by Nadia O’Carroll
There are two species of duck commonly seen on the Mountain:
The Pacific Black Duck (Anas superciliosa) is 47-50cm in length. Brown body, dark crown, pale face with two black stripes, purplish green upper wing. Beak and legs are greyish. Harsh quacking voice. Nest may be domed and made of dry grass located on ground, tree limb or tree stump. Breeds July to December. The Pacific Black Duck is presently a common species, but potentially may be threatened by the introduced Mallard. The Mallard has the same food and habitat needs and may also interbreed with the Pacific Black Duck and produce offspring, which resemble the more dominant Mallard strain.
Australian Wood Duck (Chenononetta jubata) is a goose-like duck 44-50cm in length. Stands erect, perches and more often walks than swims. The male has a dark head and mane, grey body with speckled brown breast. Female has pale stripe above and below eye and grey brown body plumage and mottled underparts. Call is a drawn out mournful, nasal waaa. Nest in tree hollow which may be high and far from water. The male stands guard while the female incubates the eggs. When ready the ducklings have to follow their mother and make a brave leap to the ground. They form monogamous pairs who remain together all year and may breed at any time depending on rainfall.
Many species of birds prefer to shelter from driving rain but ducks revel in wet conditions because their feathers are specially adapted to repel water. Feathers are composed of keratin, which is capable of absorbing water, however the microstructure of duck plumage is arranged to form an interlocking shield. Ducks also have a preening gland near their tail, the bird picks up the oil with its head and beak and smears it over its body, and the oil produced by this gland is rich in lipids, has antibacterial properties and keeps the feathers healthy and elastic. The combination of interlocking feather barbs covered with a coating of preening oil creates surface tension, which resists the infiltration of water into the plumage. Underneath the outer feathers is a layer of soft downy feathers, which trap pockets of air close to the duck’s skin to keep it warm. By ruffling and shaking their feathers ducks are able to adjust the amount of air trapped close to their body thus adjusting the thermal insulation of their feathers.
Pollution such as oil pollution kills and injures birds by upsetting the surface tension of their plumage. Water then infiltrates into the plumage, thermal insulation is disrupted with a consequent dramatic drop in body temperature.
We can help our native ducks by retaining tree hollows, controlling pets, watching waterway health and resisting the temptation to feed them bread and food scraps.