LC
Pacific Black Duck Anas superciliosa



Justification

Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence under 20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (over 30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.

Population justification
The global population size is estimated at 180,001-1,175,000 individuals (Wetlands International 2023), which equates to 120,000-783,000 mature individuals. The overall population trend is suspected to be decreasing over three generations (16.92 years) (Wetlands International 2023).

Trend justification
  .

Distribution and population

This species breeds in Indonesia from south Sumatra, Java and Sulawesi, through to Irian Jaya, Papua New Guinea (including New Britain and New Ireland), Solomon Islands, Vanuatu, New Caledonia (to France), Australia, Caroline Islands (Federated States of Micronesia), Palau, Fiji, Tonga, Samoa and American Samoa, Cook Islands (New Zealand), Society Islands (French Polynesia) and New Zealand. It occurs as three subspecies, with pelewensis found in the south-west Pacific Islands and north New Guinea, rogersi found in the Indonesian region, south New Guinea and Australia, and the nominate superciliosa occurring in New Zealand and associated larger offshore islands (del Hoyo et al. 1992).

Ecology

The species has a broad habitat tolerance, breeding and feeding in a wide range of terrestrial and marine wetlands and estuaries. It also utilises artificial habitats such as farm dams and drains. In New Zealand, however, agricultural regions are now largely dominated by the introduced Mallard A. platyrhynchos, and A. superciliosa has become increasingly restricted to undeveloped areas. Nests tend to be built away from water, and are often in tree holes. Ten to 12 eggs are usually laid. Young are capable of breeding in the first year, but about 65% of young die before starting to breed. Adults live 21 months on average in New Zealand, but the oldest bird in the wild was at least 20 years of age.

Threats

The species is believed to be declining throughout its range due to a combination of competition and hybridisation with A. platyrhynchos (Heather and Robertson 1997). This introduced species is most common in developed areas and, in New Zealand at least, numbers are still increasing (Marchant and Higgins 1990). Also in New Zealand, loss of wild habitats is considered to be a leading cause in declines (Heather and Robertson 1997), and there is a slow decline through Melanesia due to hunting and habitat degradation (G. Dutson in litt. 1999). Such habitat destruction is also occuring in Australia, but birds there have proved to be more able to utilise artificial habitats (Marchant and Higgins 1990).

Identification

55 cm. Large brown and buff duck. Whole body streaked and spotted dark brown and buff; head pale with distinctive dark stripes; green speculum; sexes alike; interbreeds with Mallard A. platyrhynchos which produces paler birds with lkess distinct facial stripes and blue speculum. Similar species: . Hints: . Voice: Male high-pitched 'quek'; female 'quack, quack'.

Acknowledgements

Text account compilers
Rutherford, C.A.


Recommended citation
BirdLife International (2024) Species factsheet: Pacific Black Duck Anas superciliosa. Downloaded from https://datazone.birdlife.org/species/factsheet/pacific-black-duck-anas-superciliosa on 18/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 18/12/2024.