A Northland island has been named among 107 islands globally that offer the best chance to save some of the world's most threatened species.

In a major international collaboration, scientists, researchers and conservationists have drawn up a list of 107 islands that offer the best chance to save some of the world's most threatened species. New Zealand has five islands on the list, including Motukawanui Island, in the Cavallis, off Northland's east coast.

Motukawanui Island is the largest of the Cavalli Islands, and is located about 4km northeast of Matauri Bay. The island has an area of 3.4sq km and is free from possums, mustelids and cats, and home to a flourishing population of native birds.

Forty institutions, including universities and major conservation organisations such as Birdlife International and the International Union for Conservation of Nature (IUCN), contributed to the assessment of islands which range from the Galapagos Archipelago to Great Barrier in the Hauraki Gulf. It is published in the journal PLOS One.

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"We already know islands are a vital conservation opportunity but this study gives us the bigger picture, a list of locations where the most progress could be made," Associate Professor James Russell, from the University of Auckland, who contributed to the research, said.

"One of the study's most important aspects is that it not only assesses the feasibility of eradicating predators on these islands but assesses how feasible this work would be from a political and socio-economic point of view."

Restoring islands by eradicating damaging, non-native invasive mammals such as rats, cats, goats and pigs has repeatedly proven to achieve results and make a major contribution towards stemming the global extinction crisis.

Initiating restoration projects on 107 islands with a total land area of 1623sq km could save 151 populations of 80 threatened species. Up to now, more than 1200 projects to eradicate invasive mammals on islands globally has had an average success rate of 85 per cent.

The Cavalli islands seen from Matauri Bay. Photo / Richard Robinson
The Cavalli islands seen from Matauri Bay. Photo / Richard Robinson

Russell says New Zealand is one of the most experienced countries in the world in island pest eradication and has lent expertise to a wide range of island projects from Mexico to the Pacific.

"New Zealand has been offering support to other countries for some time and is seen as a global leader in this area with our own ambitious targets such as pest-free Auckland Island and Predator Free New Zealand."

The researchers used biological and geographic data compiled for 1279 islands with 2823 populations of 1184 bird, reptile and mammal and amphibian species listed as critically endangered or endangered by the IUCN Red List of Threatened Species.