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Description |
Geographic Range [top]
Range Description: 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).
Countries occurrence:
Native:
American Samoa; Australia; Cook Islands; Fiji; French Polynesia; Indonesia; Marshall Islands; Micronesia, Federated States of ; New Caledonia; New Zealand; Palau; Papua New Guinea; Samoa; Solomon Islands; Timor-Leste; Tonga; Vanuatu
Additional data:
? Continuing decline in area of occupancy (AOO): Unknown
? Extreme fluctuations in area of occupancy (AOO): No ? Estimated extent of occurrence (EOO) - km2: 49800000
? Continuing decline in extent of occurrence (EOO): Unknown ? Extreme fluctuations in extent of occurrence (EOO): No
? Continuing decline in number of locations: Unknown
? Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.
Population [top]
Population: The species currently has a large global population estimated to be 180,000-1,200,000 individuals (Wetlands International 2006). Both superciliosa and rogersi have undergone significant declines in the last 20 years (Marchant and Higgins 1990). In New Zealand, the superciliosa population was estimated at 1.5 million birds in 1970, decreasing to 1.2 million by 1981, and less than 500,000 in the 1990s (Heather and Robertson 1997). A second estimate placed numbers at between 80,000 and 150,000 in 1993 (Rose and Scott 1997). Subspecies pelewensis was estimated at 10,000-25,000 birds and is considered stable (Rose and Scott 1997).
Trend Justification: The overall trend is uncertain, as some populations are decreasing, while others are stable or fluctuating (Wetlands International 2006).
Current Population Trend: Unknown
Additional data:
? Continuing decline of mature individuals: Unknown
? Extreme fluctuations: No ? Population severely fragmented: No
? Continuing decline in subpopulations: Unknown
? Extreme fluctuations in subpopulations: No ? All individuals in one subpopulation: No
Habitat and Ecology [top]
Habitat and 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.
Systems: Terrestrial; Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 6.6
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)
Threats [top]
Major Threat(s): 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).
Citation: BirdLife International. 2016. Anas superciliosa. The IUCN Red List of Threatened Species 2016: e.T22680217A92849931. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22680217A92849931.en. Downloaded on 05 November 2018.
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