The Blue-billed Duck, also known as the Oxyura australis, is a species of duck found only in Australia. It is a small to medium-sized bird that measures about 42cm in length, with a distinct bright blue bill which is unique to this species. The female Blue-billed Duck is slightly smaller than the male, but both sport striking plumage and a distinctive crest on the head. The males have a black head and neck, and the female has a brownish-grey color with white feathers around the eyes and cheeks.
Blue-billed Ducks are usually found in freshwater habitats, such as shallow lakes, lagoons, and freshwater wetlands. They are generally a solitary bird, preferring to live independently or in small groups rather than in large flocks. Although they are not migratory, they may move around during the breeding season to find suitable nesting sites.
The breeding season for Blue-billed Ducks starts in August and lasts until January. During this time, males perform a courtship display that involves head-swinging, bill-lowering, and swimming in circles around the female. Once they have found a mate, the pair builds a nest close to the water's edge, using reeds and grass. The female then lays around eight to ten eggs, which she incubates for about 28 days.
This species feeds on aquatic vegetation, insects, and small aquatic invertebrates, which they pick up using their uniquely shaped beak. They are also constantly diving to forage, and spend up to 80% of their time below the water's surface. The blue-billed duck has a broad, flat beak that allows them to effectively sieve and strain water to gather food.
The Blue-billed Duck is categorized as vulnerable by the International Union for Conservation of Nature (IUCN). Habitat loss, degradation, and fragmentation, along with altered water regimes have significantly impacted their population numbers. Conservation efforts to restore their habitat include the prevention of water re-cycling, spraying of herbicides and pesticides around their habitats, and managing invasive plant species. Hunting regulations also play an important role in their conservation. There is a need to raise awareness among the general public to conserve this species, which could lead to better conservation-mindedness and strategies.