With an estimated global population of fewer than 150 and surviving on just five small atolls in the South Pacific, the Polynesian ground-dove (Alopecoenas erythropterus) is recognised as one of the world’s rarest birds.

Although the remoteness of its habitat – found more than 932 miles (1500km) from French Polynesia's largest island of Tahiti – granted the bird protection from predatory mammals during its evolution, the arrival of humans introduced a number of threats.

Introduced mammals alone are believed to be responsible for 90% of all bird extinctions since 1500

Flightless and defenceless, ground-dove's chicks and eggs are eaten by introduced species, particularly rats. The environment they rely on is also easily disturbed by human activity, invasive animals and plants, as well as natural disasters such as cyclones and severe storms. 

The short-tailed dove, locally known as the Tutururu, is now hardly seen and has become extinct on several islands where it was once known. It was classified as critically endangered in 2013

This is a sign of hope for recovery

Now experts behind a project to recreate the protected conditions the Tutururu once knew say they have succeeded in more than doubling the safe habitat available to the birds, something unlikely to have occurred since before the Polynesian colonisation.

The group, a partnership between BirdLife International, Société d'Ornithologie de Polynésie and Island Conservation, say they used restoration methods tried and tested on over 400 islands around the world, including removing rats and lantana, a plant which forms dense tangles and was outcompeting the native forest. 

“Invasive alien species are a key driver of global biodiversity loss,” says Don Stewart, BirdLife's Pacific director.

“Introduced mammals alone are believed to be responsible for 90% of all bird extinctions since 1500, and are presently the main cause of decline for nine out of ten globally threatened birds within the Pacific.”

The conservation operation has been carried out on six remote islands in the Tuamotu and Gambier archipelagos.

The team carried out wildlife surveys and were able to confirm that almost all of the remaining Polynesian ground-doves live on a rat-free atoll.

Two other endangered native birds, the Tuamotu sandpiper (Prosobonia parvirostris), or Titi, and the Polynesian storm-petrel (Nesofregetta fuliginosa), have also been helped by the work, as well as a number of critically endangered plant species.

“In the last few days of the operation more Polynesian ground-dove and Tuamotu sandpiper were sighted on Vahanga [atoll] – the chances of finding established populations on these islands in a year’s time are high," says Richard Griffiths, from Island Conservation.

“This is a sign of hope for recovery not only for these French Polynesian species, but for the hundreds of threatened island species around the world waiting for similar interventions on their behalf."

Coconut plantations have also been responsible for clearing some of the richest native vegetation from the islands. As a result indigenous Pa'umotu people, who can rely on the crop as their only source of income, were helped to manage production in ways that are less detrimental to the island's wildlife.

They were also shown how to monitor the Tutururu and Titi populations and prevent invasive species from returning.

“It will be one year before we can declare the six islands rat-free, but initial signs are very positive”, says Steve Cranwell, BirdLife's Pacific invasive species expert.

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