The musk duck (Biziura lobata) is a highly aquatic, stiff-tailed duck native to southern Australia. It is the only living member of the genus Biziura. An extinct relative, the New Zealand musk duck or de Lautour's duck (B. delautouri), once occurred on New Zealand, but is only known from prehistoric subfossil bones. It was about 8% longer than the living species, with a particularly large head. Musk ducks float very low in the water, almost like a cormorant, and the large, webbed feet are well back on the body. The ducklings are covered in dark brown down.
In its native range, the fanned tail is distinctive, allowing to distinguish this species from the freckled duck (Stictonetta naevosa) which has similar size, colouration, and habits. The blue-billed duck (Oxyura australis) has a similarly shaped tail, but the main colour of its males in breeding plumage is a much richer chestnut brown. Females and males in nonbreeding plumage are very similar, however, and if one is not intimately familiar with the slight differences in behaviour, they cannot be told apart from female musk ducks at a distance. Male musk ducks in the breeding season are usually unmistakable due to the large bill lobe.
Systematics
The relationships of this peculiar species are quite enigmatic. It is traditionally included with the stiff-tailed duck subfamily Oxyurinae, but appears to be only distantly related to the genus Oxyura, and its peculiar apomorphies make it difficult to place. Its relationship with the equally strange pink-eared ducks (Malacorhynchus) is unresolved, but seems to be quite close, and it seems to be part of an ancient Gondwanan radiation of Anatidae. As such, it is fairly closely related to the stiff-tailed ducks proper, but it seems not quite as closely related as formerly believed, with many similarities due to convergent evolution. Reportedly, the recording demonstrates the duck saying "you bloody fool", possibly repeating a catchphrase from one of the caretakers of the reserve. Although other bird species are capable of mimicking human speech, no other duck species is reported to have that capability.
Subspecies
The musk duck has two recognized subspecies. Biziura lobata menziesi, commonly referred to as the eastern musk duck, has a range from South Australia extending to the southern reaches of Queensland, through most of New South Wales and Victoria, and finally reaching as far south as Tasmania. The other subspecies is Biziura lobata lobata, commonly referred to as the western musk duck. Its range is the south-west of Western Australia.