Justification of Red List Category
This species has been extirpated from most of its historic range by introduced mammalian predators, to which it is highly susceptible. Declines have ceased as it is now confined to a few predator-free subantarctic islands where it is relatively secure within a very small range. Owing to the small number of locations that support the species, it is considered Near Threatened.
Encounter rates on Adams Island were more than three times higher than in similar habitat on Antipodes Island, where snipe coexist with mice (Miskelly 2013). Adams Island (10,119 ha) is likely to hold tens of thousands of birds, based on recorded densities of at least 4 birds/ha on other islands, while the colonising population on Campbell is likely to number in the hundreds and increasing. The total area occupied by the species is about 11,540 ha in the Auckland Islands, 2,060 ha in the Antipodes Islands, and about 3,000 ha on Campbell Island (with a total of 11,290 ha available there to colonise) (Miskelly 2013). A preliminary estimate places the total population in the band 20,000-49,999 mature individuals, but the true figure may be higher.
The population has ceased to decline and is increasing following predator eradication and recolonisation of Campbell Island.
C. aucklandica is endemic to New Zealand, where it is found on the Auckland Islands (excluding the main island; nominate C. a. aucklandica), the Antipodes Islands (20 km2) (form meinertzhagenae) and Jacquemart Island (0.2 km2) in the Campbell Island group (form perseverance). C. a. perseverance was not known to exist before a chance discovery on Jacquemart Island in 1997, but has since recolonised the main Campbell Island from Jacquemart Island following the eradication of Norway rats in 2001, and is now rapidly spreading over the 12,300 ha island (Miskelly 2013, P. McClelland in litt. 2013).
The species favours areas of dense ground cover where it feeds on a wide variety of invertebrates. It nests on the ground (hence its vulnerability to introduced mammals), with a clutch laid in early January (Higgins and Davies 1996).
Many local extinctions have occurred in the past, probably caused by various introductions of Pacific rat Rattus exulans, cats, pigs and Weka Gallirallus australis (Higgins and Davies 1996). Such introductions brought about the extinction of two closely related species, iredalei and barrierensis, while R. exulans probably caused the extinction of the species from mainland New Zealand around 1,000 years ago (Heather and Robertson 1997).
Conservation Actions Underway
No species-specific actions are known, but the tiny known Campbell Islands population is thought to be expanding following the eradication of rats from the main island and there have been subsequent records of the species recolonising.
23 cm. Small, plump variegated brown wader. Bill brown and slightly drooping, 5 cm; top of head striped black and brown/reddish brown; rest of body mottled black and brown/reddish brown; female larger than male. Similar spp. No other Coenocorypha occurs within the range of C. aucklandica, but it is distinct from C. hugeli by virtue of its longer bill, unbarred mid-belly and more richly coloured upperparts. C. pusilla is much smaller. Voice Males have a territorial loud call consisting of a series of vibrant monosyllabic notes and also produce a non-vocal nocturnal display noise likened to the sound of a passing jet or a chain being lowered onto a boat.
Text account compilers
Benstead, P., Bird, J., Khwaja, N., Taylor, J. & Symes, A.
Miskelly, C. & McClelland, P.
BirdLife International (2020) Species factsheet: Coenocorypha aucklandica. Downloaded from http://www.birdlife.org on 06/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/08/2020.