VU
Chatham Islands Snipe Coenocorypha pusilla



Justification

Justification of Red List category
This species has a very small range and is confined to only four predator-free islands, the majority on Rangatira. As such, the accidental introduction of alien species is a plausible threat that could drive the species to CR or EX in a very short time period. It is therefore classified as Vulnerable.

Population justification
The population is estimated at c.900-1,100 pairs. Higgins and Davies (1996) estimated the population to number 700-800 pairs on Rangatira (South East) Island, possibly 200-250 pairs on Mangere Island and fewer than 50 pairs on Little Mangere Island and Star Keys. The population is thus estimated to fall within the range 1,800-2,200 mature individuals, roughly equating to 2,700-3,300 individuals in total. Since the population is considered to be stable (Robertson et al. 2021), historic population estimates are thought to remain applicable.

Trend justification
Although the historical range of this species was reduced as the result of the introduction of predators such as cats Felis catus and rats Rattus spp. (Higgins and Davies 1996, Roberts and Miskelly 2003), the population is considered to have been stable throughout the last three generations  based on census data (Robertson et al. 2013, 2017, 2021).

Distribution and population

Coenocorypha pusilla is confined to four small, predator-free islands in the Chatham Islands, New Zealand, where it is common and considered stable. It was once widespread throughout the group, but the range has become restricted due to the impacts of introduced predators. It was once thought to be restricted to Rangatira only, but has since been reintroduced to Mangere Island from which it was able to colonise Little Mangere Island. Most of the population, 700-800 pairs, are on Rangatira (South East) Island. The population on Mangere Island (which was reintroduced from Rangatira Island) numbers between 200 and 250 pairs. Birds have recently colonised Little Mangere Island, and a population was recently found on Star Keys (totalling fewer than 50 pairs) (Higgins and Davies 1996, Aikman and Miskelly 2004). Vagrant individuals have been seen on Pitt Island and nearby Rabbit Island (Miskelly et al. 2006).

Ecology

It breeds from the shore to island summits, but is most common in Plagianthus chathamicus and Olearia traversiorum forest. It builds its nests under dense vegetation, and usually lays two eggs (Miskelly 1990, 1999a). It is insectivorous (Higgins and Davies 1996). Its age of first breeding and life expectancy are unknown, but other Coenocorypha snipe can breed at one year of age, and live for up to 17 years (Miskelly 1999b, Miskelly and Sagar 2005).

Threats

The historical range of this species was reduced as the result of the introduction of predators such as cats and rats Rattus spp. (Higgins and Davies 1996, Roberts and Miskelly 2003). Birds attempting to colonise neighbouring Pitt Island are killed by cats and Weka Gallirallus australis (introduced following the species extirpation from the main Chatham islands) (C. Miskelly pers. comm.).

Conservation actions

Conservation Actions Underway
In 1970, the species was successfully reintroduced from Rangatira Island to Mangere Island, after feral cats were eradicated (Aikman and Miskelly 2004). Captive breeding was attempted in 1983 and 1987, but failed (Heather and Robertson 1997, Aikman and Miskelly 2004). However, in 2001 a trial attempt to hold the species in captivity was successful (Miskelly and Barlow 2001).

Conservation Actions Proposed
Monitor population trends through regular surveys. Reintroduce the species to the predator-fenced areas on Chatham and Pitt Islands (C. Miskelly in litt. 2020, Aikman et al. 2001, Roberts and Miskelly 2003, Aikman and Miskelly 2004). Develop the captive breeding population to aid in this and future reintroductions and supplementation efforts. Restore sufficient mammal-free forest areas within the Chatham Islands to allow the species to establish self-sustaining populations that require minimal management (Aikman et al. 2001, Roberts and Miskelly 2003, Aikman and Miskelly 2004).

Identification

20 cm. Small, compact, variegated brown snipe. Top of head striped black, brown/reddish-brown. Rest of body mottled black, brown/reddish-brown except for pale lower breast, belly. Voice Male call, low trerk, trerk, trerk and queeyoo, queeyoo, queeyoo.

Acknowledgements

Text account compilers
Vine, J., Clark, J.

Contributors
Bell, B.D., Benstead, P., Khwaja, N., Mahood, S., McClellan, R., Miskelly, C., Pilgrim, J. & Taylor, J.


Recommended citation
BirdLife International (2024) Species factsheet: Chatham Islands Snipe Coenocorypha pusilla. Downloaded from https://datazone.birdlife.org/species/factsheet/chatham-islands-snipe-coenocorypha-pusilla 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.