Gough moorhen  (Gallinula comeri)

Although stable or even increasing in numbers, its occurrence in a restricted habitat on only two islands makes this species extremely vulnerable to chance events such as fires, hurricanes and disease epidemics (4). Additionally, despite surviving with introduced rats on Tristan, the accidental introduction of predators to Gough remains a risk. Indeed, it is likely that the Gough moorhen’s close relative, the extinct Tristan moorhen (G. nesiotis), disappeared from Tristan as a result of predation by the black rat (Rattus rattus), though this may have been in combination with feral cat predation, habitat destruction and hunting by islanders. The Gough moorhen appears able to cope with current levels of rat predation on Tristan, but the accidental introduction of this, or any other, predator to its stronghold on Gough still remains the greatest risk facing this species (2).

A cat eradication programme on Tristan in the 1970s was highly successful, helping to protect the Gough moorhen and other endangered native birds (2). Unfortunately, as an introduced species to Tristan, the Gough moorhen is considered alien, and therefore not protected there under the Tristan da Cunha Conservation Ordinance (5). The bird’s stronghold on Gough, however, is well protected, with the island being a nature reserve and World Heritage Site, and uninhabited apart from the staff that run a meteorological station (2). Gough Island is the least disturbed major cool-temperate island ecosystem in the South Atlantic Ocean, and hosts one of the most important sea-bird colonies in the world. Indeed, with 54 bird species, 22 breeding species and four threatened species, the island will probably continue to be well protected indefinitely, preserving this rich biodiversity and protecting the Gough moorhen for many years to come (7).