Chicks battling extinction

By ANNE BESTON environment reporter

It has been a bumper breeding season for some of the country's endangered birds, but kiwi continue to struggle against the onslaught of stoats.

The fairy tern (Sterna nereis davisae), Chatham Island taiko or Magenta petrel (Pterodroma magentae) and kakapo (Strigops habroptilus) have produced record crops of chicks over summer while the tiny population of kokako (Callaeas cinerea) in Auckland's Hunua Ranges has produced almost as many chicks this year as in the past seven.

Since the Hunua project began in 1994, 12 chicks have fledged: this season alone has produced 10.

"We have finally got to the stage where the population is going to take off," said Auckland Regional Council ecologist Dr Tim Lovegrove.

Jeff Hudson, the Department of Conservation's national kokako recovery team leader, said breeding in the remote forests of the Te Urewera National Park had been "excellent" during the summer.

"It has been amazing. They call the number of chicks we produce here almost indecent compared to some other areas."

In the main breeding areas of the park, where predator control is most intensive, 150 chicks were produced. The population in Waimana Valley has risen to about 500 birds.

The only disappointing result has been in Northland, Mr Hudson said.

The low numbers of females meant it did not take much to have a bad season.

The New Zealand fairy tern, the country's smallest and rarest tern, also had a record season.

Conservation staff believe the birds have taken a few steps back from extinction after eight chicks fledged from three nesting sites during the summer. Seven fledged in the 1999-2000 season but only four in the 1998-1999 season.

Human ingenuity may have helped this time.

Conservation staff at the South Kaipara Head breeding site used concrete piping for chicks to run and hide in while their parents were away and it appears to have worked.

The pipe shelters would be used again next summer, said Thelma Wilson, the department's biodiversity programme manager based at Warkworth.

Fairy terns are ground-nesting seashore birds and numbered just 29 before this season.

Conservation staff were also buoyed by a record crop of Chatham Island taiko chicks this season.

The endangered birds, thought to number between 100 and 180, produced seven chicks, one more than the previous best of six in 2000.

"It's fabulous news," said department spokeswoman Hilary Aikman.

About 100 years ago as many as 1 million pairs lived on the Chathams but they were hunted by by Moriori and Maori, then hit by deforestation and introduced predators such as cats, pigs and rats.

They were thought to be extinct until Whangarei ornithologist David Crockett rediscovered them in 1973.

But New Zealand's best-known native bird has struggled again this season with large numbers of chicks attacked and killed by stoats.

"It hasn't been a brilliant year for kiwi," said the department's kiwi expert, Dr Hugh Robertson.

In the Northland kiwi sanctuary four chicks were killed by stoats and the mean survival rate for chicks this season was 80 days (the figure ranges from 40 days in the worst years to 250 days).

Dr Robertson rated this year's kiwi breeding season as "moderate to poor".

He said conservationists and scientists could only hope that research into stoats would produce a solution.

The most dramatic success story of the summer probably belongs to kakapo.

With 23 chicks from 23 eggs alive and well, the endangered flightless parrots have increased their population from 62 to 85, and it's not over yet.

The department's kakapo recovery team leader, Paul Jansen, said two fertile eggs had yet to hatch and two eggs of uncertain fertility had been laid.

nzherald.co.nz/environment