Wellington, June 14 NZPA - An international example for conservation management has been set by the natural re-colonisation of kakariki on Raoul Island after a 150-year absence, say Massey University researchers.
A recent study revealed how kakariki (red-crowned parakeets) spontaneously migrated to Raoul from neighbouring islands and created a new population, said Massey conservation biologist and PhD researcher Luis Ortiz-Catedral, from the Institute of Natural Sciences at Albany.
He said the exercise could be repeated by kakariki and other vulnerable bird species on predator-free islands closer to New Zealand.
Remote volcanic Raoul Island lies about 1000km northeast of the North Island, halfway between Auckland and Tonga. It is the largest in the Kermadec Islands Marine Reserve, New Zealand's largest marine reserve. Between 2002 and 2004 the Conservation Department carried out the world's largest multi-species eradication project, removing cats, rats and goats from the island.
Soon after that kakariki, which have not been known to breed on the island for 150 years, are thought to have flown from the nearby Herald Islets island group, about 4km away.
In April institute staff travelled to the island with colleagues from the University of Auckland and DOC on the Navy frigate Canterbury and stayed for a month.
They were astounded to observe a flourishing population of the colourful parakeets so soon after the eradication of pests.
Mr Ortiz-Catedral and Associate Professor Dianne Brunton have published a paper describing the phenomenon.
They said their observations gave hope for conservationists managing endangered bird species in other parts of the world because it appeared birds would voluntarily move to safe breeding locations and thrive if humans removed predators first. This would remove the need for artificial and more costly translocations, which involved moving birds by helicopter or boat to new predator-free locations.
"The natural re-colonisation of parakeets on Raoul Island from a satellite source population is to our knowledge, a first for parrot conservation and the first documented population expansion and colonisation of a parrot species after removal of invasive predators," Mr Ortiz-Catedral and Dr Brunton said in the paper, just published in Britain's Conservation Evidence journal.
The researchers observed breeding and nesting for the first time on the island since 1836.
Mr Ortiz-Catedral, who has coordinated two translocations of kakariki by helicopter between islands in the Hauraki Gulf and the mainland as part of his doctoral research, said what he witnessed at Raoul Island had major implications for conservation management in New Zealand's offshore islands as well as other places world-wide where parrot species in particular were under threat.
Raoul Island's permanently manned station has been maintained since 1937, and includes government meteorological and radio stations, and a hostel for conservation staff and volunteers.
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