Data Zone
Justification of Red List category
This species has a small population and the population size is uncertain. The range is very small and there are few locations, but the population size and range are stable. For these reasons, the species is classified as Near Threatened.
Population justification
It is frequently seen in small numbers (Williams 2013). Surveys on Rose, Ocean, Ewing and Enderby Islands in 1982-1983 produced a population estimate of 215-330 individuals over the four islands, and concluded that the total population was likely to be at least 500, but much less than 1,200 individuals (Williams 1986). Repeat surveys in 1989 on Ewing and Adams Islands estimated a population of 260-389 individuals on the two islands and concluded that the total population was likely to be less than 600 individuals (Moore and Walker 1991).
However, it is thought that the population size has previously been underestimated due to the difficult of detection in grassland habitat (Williams 2005), and populations on Enderby and Rose Islands have increased following mammal eradications (Williams 2013). More recently, the population size has been stated to be at least 2,000 birds (Heather and Robertson 1997, 2005), probably greater than 1,500 individuals (Williams 2005), and likely to exceed 1,000 individuals (Williams 2013). The 2016 Threat Classification of New Zealand's birds assessed the species as Nationally Vulnerable on the basis of a stable population of 1,000 - 5,000 mature individuals (Robertson et al. 2017).
Based on the above estimates, the population size is here placed in the band 500 - 2,500 individuals, roughly equating to 330 - 1,700 mature individuals. On the basis of the 2016 national classification, the population size is most likely to be greater than 1,000 mature individuals.
There are at least three subpopulations, on the Port Ross Islands (Enderby, Rose, Ocean, Ewing, Dundas), Disappointment, and Adams. The Port Ross Islands were estimated to collectively hold approximately 70% of the total population in c.1991 (McClelland 1993). Depending on whether the Port Ross Islands hold separate subpopulations, the largest subpopulation may be that of Adams, or it may be that of the Port Ross Islands. The size of the largest subpopulation is therefore estimated to be 78-1,750 individuals, roughly equating to 52-1,200 mature individuals.
Trend justification
The population appears to be stable and at carrying capacity of the current range islands (Moore and Walker 1991, Williams 2005, Robertson et al. 2017). Population surveys show no evidence of on-going declines, with all islands that currently support populations now free from introduced mammals. The eradication of rabbits from Enderby and Rose Islands in 1993 led to increases in teal populations (Williams 2013). However, the population is unlikely to expand further while cats and pigs remain on the main Auckland Island.
Anas aucklandica is endemic to the Auckland Islands, New Zealand, where it has populations on Ewing, Enderby, Rose, Ocean, Adams, Disappointment and Dundas Islands. Small numbers of individuals occasionally visit Friday, French's and Monumental islands (McClelland 1993). It formerly bred on Auckland Island, where there are records from the 1940s but it is now excluded from that island due to the presence of feral pigs and cats (Williams 1986, 2013).
It primarily inhabits sheltered coastlines feeding on tideline resources, and uses dense coastal vegetation as escape and nesting cover. It also occurs along peaty streams and on pools in wetlands with abundant sedge and tussock cover (Williams 2013). It feeds mostly in washed up seaweed for invertebrates, or in coastal pools, and also eats algae (Moore and Walker 1991). It has a low breeding rate and low annual productivity (Williams 1995). It is sedentary and flightless.
Introduced cats and pigs caused its extinction on Auckland Island. All range islands are currently free of introduced mammals, but the accidental introduction of mammals such as mice, rats or rabbits to the remaining island populations could cause further local extinctions (Moore and Walker 1991). The introduction of avian disease is also considered a significant potential threat (McClelland 1993). Grazing by introduced rabbits on grasses and rushes previously degraded habitat; the eradication of rabbits from Enderby and Rose Islands in 1993 led to increases in teal populations (Williams 2013).
Conservation Actions Underway
CITES Appendix I. A recovery plan was published in 1993 (McClelland 1993).
Cattle, rabbits and mice have been eradicated from Enderby Island, and rabbits from Rose Island, leaving all teal-inhabited islands free of introduced mammals. A feasibility study of the eradication of pigs, cats and mice from Auckland Island is underway (Department of Conservation 2018). The species has bred successfully in captivity as an aid to the Campbell Island Teal A. nesiotis recovery programme, but there is no dedicated captive-breeding programme (M. Williams in litt. 1999).
48 cm. Small, flightless, dark brown duck. Brown eclipse male, female, juvenile. Mottled, dark brown breast. Prominent white eye patch. Breeding male, glossy green head, very narrow white collar, flank patch. Voice Soft, high-pitched wheezy whistles and popping (male), low quacks and growls (female).
Text account compilers
Wheatley, H.
Contributors
Hitchmough, R., Williams, M., Mahood, S., Taylor, J., McClellan, R., Martin, R. & Benstead, P.
Recommended citation
BirdLife International (2024) Species factsheet: Auckland Teal Anas aucklandica. Downloaded from
https://datazone.birdlife.org/species/factsheet/auckland-teal-anas-aucklandica on 23/11/2024.
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 23/11/2024.