Justification This species has a very small range and only three significant remaining subpopulations. Until recently its overall range, area of occupancy, area and quality of habitat, number of locations and subpopulations, and number of individuals were undergoing a very rapid decline; however intensive management has halted the decline and populations are now increasing, with several new populations being established. Despite this recent change in fortunes, it is remains classified as Endangered until these trends are consolidated.

Family/Sub-family Anatidae

Species name author Gray, 1845

Taxonomic source(s) Daugherty et al. (1999)

Taxonomic note Anas aucklandica (Sibley and Monroe 1990, 1993) has been split into A. aucklandica, A. chlorotis and A. nesiotis following Daugherty et al. (1999).

Identification 48 cm. Small, dark brown duck. Brown eclipse male, female, juvenile. Mottled, dark brown breast. White eye-ring. Breeding male, glossy green head. Very narrow white collar. White flank patch. Similar spp. Grey Teal A. gracilis, Chestnut Teal A. castanea have white triangle in front of speculum when in flight, no white eye-ring. Voice Soft, high-pitched wheezy whistles, popping (male), low quacks and growls (female).

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

910

increasing

940 km²

Yes

Range & population Anas chlorotis is endemic to New Zealand, where it was once widespread in the North, South, Stewart and Chatham Islands, but its range is now much reduced. The current strongholds are on Great Barrier Island, where there were 1,300-1,500 birds in the early 1990s, declining to little over 500 in the early 2000s and increasing to over 600 in 2004, and at Mimiwhangata and Teal Bay on the east coast of Northland where the population declined by 65% in the period between 1988 and 1999 to fewer than 100 individuals in 2001 before increasing to nearly 300 by 2004^4,5,6,9. The re-introduced population in the northern Coromandel numbered c.500 individuals in early 2008, and is increasing. Its estimated area of occupancy is only c.300-500 km^{2 1}. After a study on Great Barrier Island indicated that the population was halving every 4.1 years and could rapidly decline to extinction intensive management was initiated which has seen populations rising again^8,9,11,12. Other remnant populations in Northland and Fiordland were nearing extinction but are also now recovering due to management^4,5,6,11. Small islands where birds have been had previously been introduced and persisted for one to two decades may be too small for long-term survival, and some of these populations appear to be approaching extinction, however overall the trend is now a population increase^5,9,11.

Ecology: It formerly inhabited a wide range of freshwater wetlands and swamp-forests, especially in the lowlands. It is now restricted to coastal streams, wetlands and dams in predominantly agricultural environments⁵. It nests in bowls of grass, always under dense, low vegetation, and usually lays six eggs. It feeds on aquatic or marine invertebrates and plant detritus^3,4. Peak breeding takes place between May and September, but can occur throughout the year¹¹. Only the female incubates the eggs¹¹.

Threats Between the 1890s and 1930s, wetland drainage and severe hunting pressure (which continued in several areas despite legal protection in 1921) caused widespread local extinctions^1,3. Predation by the introduced mammalian predators, primarily cats, dogs, mustelids Mustela spp. and possums Trichosurus pulpecula, as well as the native Purple Gallinule Porphyrio porphyrio (locally known as Pukeko), were the primary cause of the modern decline^3,8,10,11,12. Research has shown that captive bred birds have shorter digestive tracts than wild birds, this may reduce the re-introduced birds' chance of efficiently digesting a wild diet and account for some of the deaths of re-introduced birds which were found with very little body fat⁷. Habitat modification, drought-induced habitat change and traffic-caused road deaths and especially predation continue to endanger remnant mainland populations^5,6,10,11,12.

Conservation measures underway CITES Appendix I. In 2007 a species recovery plan was produced with the goal of securing in the wild a combined protected population of 2,000 birds at 5-10 managed sites by 2010. Following a major audit of the recovery programme in 2000 the population has begun to increase. Over 200 birds are held in captivity. Though initial mainland releases totalling over 1,000 birds⁴ failed, releases are now conducted in combination with intensive predator control and radio-tracking has revealed that this is establishing a breeding population^3,10,11,12. Hazing fences on roads have been erected to force ducks to either fly or use culverts when passing between favoured feeding sites, these have met with success and are planned for more areas^11,12. Habitat is being restored in Northland and Coromandel with the co-operation of local landowners, and some wetlands are grazed to create ideal conditions for teal¹¹. Research is ongoing, focusing on management techniques and habitat requirements⁴.

Conservation measures proposed Continue to implement the species recovery plan. Continue to maintain a viable breeding population at a minimum of two locations on the Northland mainland. Continue measures to increase the population on Great Barrier Island. Continue predator control measures at key sites. Erect more hazing fences in areas where road mortality is greatest. Establish self-sustaining populations on at least five further islands. Establish new populations at a minimum of five mainland locations. Continue the captive breeding programme. Continue to encourage public support and involvement⁴.

References 1. Callaghan et al. (in prep). 2. Daugherty et al. (1999). 3. Heather and Robertson (1997). 4. Williams and Dumbell (1996). 5. M. Williams in litt. (1999). 6. Parrish and Williams (2001). 7. Moore and Batterly (2006). 8. Ferreira and Taylor (2003). 9. Roxburgh (2005). 10. Conner et al. (2007). 11. Sim and Roxburgh (2007). 12. Hayes (2006).

Further web sources of information

New Zealand Govt - Dept of Conservation - Recovery Plan

Text account compilers Phil Benstead (BirdLife International), Rachel McClellan (BirdLife International), John Pilgrim (BirdLife International)

Contributors Jason Roxburgh (Department of Conservation), Murray Williams (Department of Conservation)

IUCN Red List evaluators Stuart Butchart (BirdLife International), Simon Mahood (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Anas chlorotis. Downloaded from http://www.birdlife.org on 9/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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