Justification This has been uplisted to Critically Endangered owing to an ongoing range contraction caused by excessive predation by introduced mice. Mouse predation has forced this species out of coastal areas into sub-optimal upland habitat and is causing the population to decline very rapidly. Urgent conservation intervention, which would also benefit the island's breeding seabirds, is needed to reverse this decline.

Family/Sub-family Emberizidae

Species name author (Clarke, 1904)

Taxonomic source(s) Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993)

Synonyms Nesospiza goughensis Dowsett and Forbes-Watson (1993)

Identification 18 cm. Large, chunky, drab olive-coloured bunting. Male uniform dull olive-green overall with yellowish forehead and eyebrow. Underparts slightly paler dull olive with prominent black bib. Thick-based, pointed, black bill. Female and juvenile buffy-olive, heavily streaked above and below with dark brown. Apparently two "streaky" immature plumages occur, including transitional phase between juvenile streaky and adult olive plumage. Voice Contact call is keet keet and song is high, keening whistle.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,000

decreasing

60 km²

Yes

Range & population Rowettia goughensis is endemic to Gough Island, Tristan da Cunha (St Helena to UK) in the South Atlantic Ocean. Evidence suggests that it was much more common in the 1920s than at present⁶. Modern population estimates have varied and may not accurately reflect population trends; there were thought to be c.200 pairs in 1972-1974² (substantially lower than previous estimates), 1,500 pairs in 1991³, 400-500 pairs in 2000-1⁴ and similar numbers in 2007⁶. Monitoring indicated that the density of territorial pairs roughly halved between 1990 and 2007⁶,

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It is most common in tussock-grassland, wet heath and fjeldmark up to 800 m, and occurs at lower densities in fern-bush and peatbogs³. It feeds primarily on invertebrates (80% of foraging time), but also eats fruit³, grass seeds, and scavenges broken eggs and birds². It nests on the ground amongst or under vegetation, but mostly on steep slopes or cliffs, and usually lays two eggs, rarely one³. Different plumage types suggest that it takes at least three years to acquire full adult plumage³.

Threats The introduced house mouse Mus musculus poses the greatest threat through competition and predation. Mice are known to have substantially altered invertebrate populations on other sub-Antarctic islands and R. goughensis is much less abundant on Gough than other bunting species on nearby mouse-free islands³. Recent research from Gough Island has shown that mice are a significant predator of breeding seabirds⁶, thus the probability is that bunting nests are depredated. Buntings are found at low density in the lowlands where mice are abundant on Gough Island, and predation rates of dummy eggs are up to thirty times higher in these areas⁵. The proportion of juveniles in the population has declined from 50% to 20% over the last 15 years, suggesting that recruitment is too low to sustain the population⁶. The accidental introduction of the black rat Rattus rattus from Tristan is a potential threat - a dead rat was discovered in a packing case in 1967, another was found on the Gough supply ship in 1974, and there was an unconfirmed rat sighting on the island in 1983³.

Conservation measures underway Gough is a nature reserve and World Heritage Site and is uninhabited apart from staff who run a meteorological station¹. Territory mapping to investigate pair density in different habitats was conducted in 2000-2001, in addition to an assessment of the potential role of mice as nest predators^4,5. Further investigation of diet overlap with mice, and predation by mice has been undertaken during 2003-2006. Initial results from a feasibility study into the removal of the mice appear promising⁷.

Conservation measures proposed Carry out regular surveys to monitor the population. Eradicate mice from Gough Island³. Minimise the risk of other alien species becoming established on the island, particularly any rat Rattus species³.

References Collar and Stuart (1985). 1. Cooper and Ryan (1994). 2. Richardson (1984). 3. P. G. Ryan in litt. (1999). 4. Cuthbert and Sommer (2004). 5. Cuthbert and Hilton (2004). 6. Ryan and Cuthbert (2008). 7. BirdLife International (2008).

Text account compilers Phil Benstead (BirdLife International), Jonathan Ekstrom (BirdLife International), Simon Mahood (BirdLife International), Rachel McClellan (BirdLife International), Sue Shutes (BirdLife International), Alison Stattersfield (BirdLife International), Andy Symes (BirdLife International), Joe Taylor (BirdLife International)

Contributors John Cooper (Avian Demography Unit, Cape Town), Peter G. Ryan (Percy FitzPatrick Institute of African Ornithology)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Rowettia goughensis. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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