Paradise saved: rare birds stage comeback on Pacific islands

Five remote Pacific islands have been cleared of invasive predators following a successful island restoration project.

Just two years after ambitious efforts by a team of international conservation organisations to rid French Polynesia’s Acteon-Gambier islands of invasive mammals began, five of the six targeted islands are now confirmed as predator free, a ground-breaking 1,000 ha in total. Early signs already indicate that rare endemic birds and other native plants and animals are recovering as the remote islands return to their former glory.

Polynesian Ground-dove (locally known as Tutururu) is one of the rarest birds on the planet, with fewer than 200 individuals left. Predation and competition by destructive invasive mammals in French Polynesia have driven this and other irreplaceable bird species to the brink of extinction. The species is listed by BirdLife International as Critically Endangered on the IUCN Red List, a category that signals an extremely high risk of extinction within our lifetimes.

Fewer than 200 individuals of Polynesian Ground-dove currently exist, but eradication of invasive mammals should help it survive (BirdLife International) .

“The Acteon-Gambier island group is home to the last viable population of Polynesian Ground-dove, a species once much more widespread in the Pacific,” said Steve Cranwell, BirdLife International’s Invasive Species Manager. “This bird’s remaining predator-free habitat was so small that without this intervention, a cyclone, prolonged drought or accidental rat or avian disease introduction could trigger extinction.”

Introduced mammalian species are believed to be responsible for 90 per cent of all bird extinctions since 1500. Early human explorers brought animals such as rats to the remote Acteon-Gambier islands (and thousands more around the world), upsetting the natural balances of such islands and threatening the native plants and wildlife that evolved without defences against land predators.

Clearing vegetation and setting traps is backbreaking work for these BirdLife Partner employees (BirdLife International).

With combined resources, expertise, equipment and logistical skills, a coalition of non-governmental organisations, BirdLife International, SOP Manu (BirdLife Partner, French Polynesia) and Island Conservation, together with the support of the government of French Polynesia, landowners, other partners and local volunteers, travelled more than 950 miles to six of French Polynesia’s remote islands in 2015.

The project required years of planning and fundraising (including a unique partnership with Rovio’s Angry Birds). It involved nine permits, 165 helicopter flight hours, three ships transporting hundreds of tonnes of equipment and donated bait from key partners Bell Laboratories and Tomcat, as well as 31 personnel from six countries who endured extraordinary weather and sea conditions during 12-day journeys to and from Vahanga, Tenarunga, Temoe, Kamaka, Makaroa and Manui, the six islands. The prospect of a brighter future for the Tutururu and other native island species made the operations well worth the effort.

“After extensive monitoring, a survey in April confirmed great success on five of the six islands,” reported Dr David Beaune, Director of SOP Manu. “This is a tremendous achievement that will provide a permanent solution to the alarming declines of native species on these islands due to predation and competition from invasive species.”

“The project has more than doubled the secure habitat for both the Polynesian Ground-dove and the Tuamotu Sandpiper (locally known as Titi), a globally Endangered landbird,” said Cranwell. “The islands look vibrant with new native vegetation and both bird species are increasing on the island of Tenarunga, something that has not been possible for decades.”

Tuamoto Sandpiper is widespread but rapidly declining across the whole of its eponymous islands in French Polynesia, ranging across 2,000 miles (BirdLife International).

“Without rats, local land managers reported a doubling of their copra (coconut kernel) production in 2016, a major source of income for these isolated communities,” said Pere Joel Aumeran, Vicar General for the Catholic Church.

“While the success of this project is vital to securing the future for these globally threatened birds, it also provides important safe habitat for other endemic species in a region where there is very little invasive-predator-free habitat,” explained Richard Griffiths, Island Conservation’s Project Director. “The success also serves as an indicator that invasive-species-driven extinctions on other remote islands can be avoided if this operation is replicated at scale.”

“We now need to increase the habitat range of these species by translocating small populations to islands where they were previously found, a conservation technique proven highly effective in Polynesia,” added Dr Beaune. “Plans are underway to reintroduce the Tutururu and Titi to Temoe, and to attract other endangered seabirds such as Polynesian Storm-petrel to these predator-free islands.”

With invasive mammals now eradicated from the five islands, the coalition’s attention is shifting to biosecurity: preventing reinvasion through monitoring, education (brochures and signs for tourists) and stringent inspections of incoming vessels.

“French Polynesia can be immensely proud of completing this project, which for its scale and complexity is a first for the region,” Griffiths said. “The government of French Polynesia is well positioned to capitalise on this success and become a leader within the Pacific to rid Oceania’s islands of damaging invasive species.”