The project established a new population of the species on an almost predator-free island, Xinhua reported Monday citing New Zealand's Department of Conservation (DOC).
A DOC team had relocated 41 tiny alpine rock wrens from around Fiordland in the far southwest of New Zealand's South Island to Secretary Island from 2008 to 2011, and the number has grown to 66 in April, said a DOC statement.
"The increased safety of the island, a place where predators pose a lesser threat, provides insurance against the birds' steady demise on the mainland," DOC ranger Megan Willans said in the statement.
Of the 66 birds on the island, where the population of predatory stoats was tightly controlled, 63 had hatched and fledged there, indicating the birds have settled in well enough to breed.
The rock wren is the only true alpine bird in New Zealand and one of the most ancient bird species in the world.
They stem from a species present more than 80 million years ago and have no close structural resemblance to any other group of birds in the world.
Of the seven wren species that lived in New Zealand when humans arrived, the rock wren and the rifleman are the only two species surviving today.
Rock wrens are vulnerable to predation by stoats and mice. Both stoats and mice prey on rock wren chicks and eggs on the nest.
--IANS (Posted on 23-09-2013)