Kakerori – back from the brink

Forest and Bird, Issue 279, 1 February 1996, Page 31

Kakerori – back from the brink

HE SOUTH PACIFIC islands have the highest number of endangered bird species per unit land area in the world. Once widespread throughout the swamp taro patches of lowland Rarotonga, the kakerori or endemic Rarotonga flycatcher (Pomarea dimidiata) is today confined to an area of less than 150 hectares in the southeast of the island. The bird’s decline was noted as far back as 1885, and early this century it was considered extinct. In 1987 the first full census revealed kakerori were still hanging on, but their numbers had fallen to below 40. It was apparent that ship rats were the main villains, although nest predation by long-tailed cuckoos, mynas and cats was also a possible factor. With New Zealand assistance, a team from the Cook Islands Conservation Service launched an experimental recovery programme in 1989. The New Zealand help came mainly in the form of advice and expertise from DoC scientists, in particular Kiwi Recovery Programme coordinator, Dr Hugh Robertson, who has visited the Cooks each year since 1987 (mainly using his annual leave) to work on the project. A combination of rat poisoning and tree banding has proved successful in reversing the decline. Some 78 percent of nests were then successful, compared to just 15 percent when there was no assistance. Then, to the surprise of

researchers there was a marked decrease in adult deaths, though no-one had suspected beforehand that rats were taking adult birds. The average life expectancy of kakerori has now increased from 3.6 years to over 15. Subsequent years have seen kakerori numbers climb from an all-time low of 29 in 1989-90 to over 100 this year. To ensure the birds’ continued survival, formal protection such as a kakerori nature reserve would help. Such a proposal was outlined in 1988 when a French forestry team was within days of clearfelling trees within Kakerori habitat in the Turoa Valley. Continuity of funding is also essential to ensure the bait shortage that occurred last year is never repeated. The Pacific Development and Conservation Trust has just provided a

grant of $32,000 to Hugh Robertson to continue work on the project with the Cook Islands Conservation Service. The success of the kakerori recovery programme marks it as a model for the many other endangered South Pacific birds, especially the other monarch flycatchers. For the kakerori itself, the next step is perhaps the establishment of a second population, maybe even on a different — rat free — island.