Species

Justification
This species is listed as Vulnerable because it is restricted to a very small range on just two small islands and, although it coexists with introduced rats on the island of Tristan da Cunha, the accidental introduction of rats, or another predator, to its stronghold on Gough Island remains a risk.

Taxonomic source(s)
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Taxonomic note
Gallinula nesiotis and G. comeri (Collar and Stuart 1985) have been lumped as G. nesiotis following Sibley and Monroe (1990, 1993) and supported by Groenenburg et al. (2008) and Groenenburg et al. (2009).

Distribution and population
Gallinula nesiotis is found on Gough Island and Tristan da Cunha (St Helena to UK) in the South Atlantic Ocean. The nominate subspecies, endemic to Tristan, was driven extinct in the late-19th century (Nicoll 1906). In 1956, seven birds from the Gough population were reintroduced to Tristan, and this population remains on the island. In 1983, the Gough population was estimated at 2,000-3,000 pairs in 10-12 km² of suitable habitat (Watkins and Furness 1986). This estimate has been recalculated as 4,250 pairs, based on the same pair density data but using new data on relative densities in different habitats and total habitat areas (Cuthbert and Sommer 2004). In 1984, the Tristan population was estimated at c.250 pairs and increasing. It is now distributed throughout the island, being scarce or absent only in the west (P. G. Ryan in litt. 2000).

Population justification
The total population is estimated at 9,000 mature individuals based on past survey data, including 4,250 pairs on Gough based on 1983 data, and 250 pairs on Tristan in 1984 (P. G. Ryan in litt. 2000). This is roughly equivalent to 13,000-14,000 individuals in total.

Trend justification
In 1984, the Tristan population was estimated at c.250 pairs and increasing. It is now distributed throughout the island (P. G. Ryan in litt. 2000). Based on this information the population is suspected to still be increasing.

Ecology
On Gough, it is found near the coast, in boggy areas and close to streams, being most common in fern-bush, and somewhat less common in level areas of tussock grassland; it is very scarce or absent in wet heath (Watkins and Furness 1986, P. G. Ryan in litt. 1999, P. G. Ryan in litt. 2000, Cuthbert and Sommer 2004). On Tristan, where no tussock remains, it is found in fern-bush (P. G. Ryan in litt. 1999). It feeds on vegetable matter, seeds, invertebrates and carrion, and scavenges petrel carcasses. It also forages for invertebrates in abandoned and active albatross nests, petrel burrows, and will feed on garbage (Watkins and Furness 1986). It breeds from September to March, on Gough peaking between October and December, and laying between two and five eggs (Watkins and Furness 1986, P. G. Ryan in litt. 1999).

Threats
It is likely that G. nesiotis was extirpated from Tristan as a result of predation by black rat Rattus rattus (P. G. Ryan in litt. 1999), though this may have been in combination with feral cat and pig predation, habitat destruction and hunting by islanders (P. G. Ryan in litt. 2000). The successful establishment of G. nesiotis on Tristan suggests that it is able to cope with current levels of predation by rats, but the greatest risk to the species is still the accidental introduction of this (or another) predator to its stronghold on Gough. Birds have been observed taking live House Mice Mus musculus and scavenging mouse carcasses on Gough (Wanless and Wilson 2007), making it vital that any attempted mouse eradication using poisoned baits takes adequate measures to reduce the potential impact of secondary poisoning on moorhens .


Conservation actions underway
On Tristan, a programme to eradicate cats was successful in the 1970s. Gough is a nature reserve and World Heritage Site and is uninhabited apart from the staff who run a meteorological station (Cooper and Ryan 1994). A repeatable monitoring protocol for the species was devised during 2000/1 (Cuthbert and Sommer 2004). Following a 2006 review of the impacts of introduced rodents on Tristan da Cunha and Gough a feasibility study was published in 2008. The study recommended what research still needed to be undertaken before an eradication effort should be attempted, and since 2008 researchers on the island have been conducting this work.  Activities have included investigating whether mice living in caves and lava tunnels would be exposed to poison bait dropped by helicopter (the answer seems to be yes), and how best to protect sufficient numbers of the two endemic land birds (including Gough Moorhen) from the risks of both primary and secondary non-target poisoning. A draft operational plan for eradicating mice from Gough was prepared in 2010, setting out in detail a work plan and a timeframe for the eradication, using experience gained from other eradication projects such as the ongoing work on Macquarie Island (Torr et al. 2010).

Conservation actions proposed
Minimise the risk of the introduction of exotic flora and fauna, particularly mammalian predators, to Gough (P. G. Ryan in litt. 1999). Repeat population monitoring at intervals of 5-10 years.

References
Nicoll, M. J. 1906. Mr M J Nicoll on the birds collected and observed during the voyage of the Valhalla, RYS, from November 1905 to May 1906. Ibis: 666-712.

Collar, N. J.; Stuart, S. N. 1985. Threatened birds of Africa and related islands: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, and International Union for Conservation of Nature and Natural Resources, Cambridge, U.K.

Watkins, B. P.; Furness, R. W. 1986. Population status, breeding and conservation of the Gough Moorhen. Ostrich 57: 32-36.

Cooper, J.; Ryan, P. G. 1994. Management plan for the Gough Island Wildlife Reserve. Government of Tristan da Cunha, Edinburgh, Tristan da Cunha.

Taylor, B.; van Perlo, B. 1998. Rails: a guide to the rails, crakes, gallinules and coots of the world. Pica Press, Robertsbridge, UK.

Cuthbert, R. and Sommer, S. E. 2004. Gough Island bird monitoring manual. RSPB Research Report.

Wanless, R. M.; Wilson, J. W. 2007. Predatory behaviour of the Gough Moorhen Gallinula comeri: conservation implications. Ardea 95(2): 311-315.

Torr, N.; Golding, C. and Cuthbert, R.[J.]. 2010. Preliminary operational plan for eradicating House Mice from Gough Island. Version 1.0.

Further web sources of information
View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Ekstrom, J., Khwaja, N., McClellan, R., Pilgrim, J., Shutes, S., Stattersfield, A., Symes, A., Taylor, J.

Contributors
Hilton, G., Ryan, P.

IUCN Red List evaluators
Butchart, S., Taylor, J.

Recommended citation
BirdLife International (2013) Species factsheet: Gallinula nesiotis. Downloaded from http://www.birdlife.org on 23/05/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/05/2013.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.