Celebrity bird Sirocco the kakapo vanishes before his 20th birthday

Wild male kakapo known as Sirocco. Photo / Mike Bodie

New Zealand's best-known bird turns 20 this week - but he has vanished.

Sirocco the kakapo may not even make it to his own birthday party on Thursday. He has slipped out of his electronic monitoring bracelet and disappeared on a remote island off Fiordland where he still lives, mostly in the wild.

But his handlers aren't too worried.

Sirocco has done it before - and the bold boy is expected to show up again during kakapo mating season towards the end of the year.

Deidre Vercoe, operations manager for the Department of Conservation's kakapo and takahe team, has known our feathered friend since he was a 3-month-old chick.

She insists her beloved Sirocco is simply playing a game of hide and seek.

"I'm afraid he's gone to ground at the moment, so we won't be able to celebrate his 20th birthday with him," she says. "His transmitter seems to have failed and we have no idea where he is.

"But when his hormone levels increase next summer and the mating season is underway, he will show up. That is when he seeks people out, because he much prefers human company to that of the other kakapo."

Sirocco has captivated fans from around the world since shooting to fame on YouTube.

A video clip of the then 12-year-old bird hopping on to the head of a zoologist at Codfish Island and trying to mate with him has attracted more than 7 million views.

Sirocco became an instant TV superstar when BBC presenter Stephen Fry then uttered the phrase: "Sorry, but this is one of the funniest things I have ever seen. You are being shagged by a rare parrot."

Sirocco has since thrilled tens of thousands of Kiwi fans during popular live appearances while on "tour" around New Zealand. He jets around the country like a rock star in a customised travel box that is strapped into a window seat on the plane, so he can look out.

Sirocco at 14 days old and weighing 185g. Photo / DoC

He also has his own Facebook and Twitter pages, which are followed hundreds of thousands of people.

And Sirocco is also the only bird with a government job. In 2010 he was made official spokesbird for conservation by Prime Minister John Key and even visited the Beehive to meet and greet the politicians.

Key was impressed with Sirocco's performance.

"He's a very media-savvy bird, he's got a worldwide fan base - they hang on every squawk that comes out of his beak," he said.

"He'll be a great official spokesbird and a great ambassador for New Zealand."

Sirocco's love affair with people started after he was hand-reared as a chick following a respiratory illness.

Since then he has refused to mate with other kakapo and considers humans his natural partners.

When breeding season arrives each summer, other male kakapo mobilise a "track and bowl" system to attract females.

Not Sirocco however - he prefers human women.

Sirocco meets ministers Maggie Barry and Nick Smith at the Beehive in 2014. Photo / Isaac Davision

"When kakapo breeding season is on, the other male birds dig a hole in the ground and make a loud booming noise to attract a mate," Vercoe says. "But Sirocco heads straight for the DoC huts as he knows people will be there.

"His favourite trick is to make a track and bowl on the ground between the hut and the long drop outside toilets as that is the busiest place at night. It gives you quite a fright when you are going to the loo in the dark and you suddenly find a frisky, 3kg parrot climbing up your leg.

"In the past when we have tried to release him to the wild we have put him in a bag and dropped him off somewhere remote on his island, but several times he made it back to our hut before we did, so we just gave up on that."

Kakapo, which are nocturnal and flightless, have inhabited New Zealand for thousands of years but, with the arrival of humans and introduced predators, their numbers rapidly declined. By the 1970s only 18 kakapo were known to exist - all in Fiordland and all males. The species seemed doomed to extinction.

But in 1977, a population of male and female kakapo was discovered on Stewart Island, giving new hope for the survival of this precious bird.

Since then, a small team of dedicated staff from DoC have worked tirelessly to protect, manage and grow the kakapo population.

The famous "mating" incident during filming of a Stephen Fry BBC TV series. Photo / Supplied

They have been supported by volunteers throughout the country and, increasingly overseas, who provide extra support - by nest-minding and supplementary feeding - during the precious breeding seasons.

Today there are kakapo breeding populations on three predator-free islands: Whenua Hou/Codfish Island, off Stewart Island; Anchor Island in southwest Fiordland; and Hauturu o Toi/Little Barrier Island in the Hauraki Gulf. Staff work year round ensuring the birds are safe, healthy and well fed.

Numbers may be on the rise - but there is only one Sirocco.

He has even taught bird experts that kakapo can swim.

In 2007, when visiting Maud Island in the Marlborough Sounds, he saw the ranger's family running and jumping off the jetty and decided to join them.

Deidre Vercoe from Kakapo Recovery, has known Sirocco since he was a 3-month-old. Photo / Supplied

He paddled back to shore, shook himself off and seemed completely unworried by the event.

Sirocco's favourite food includes special parrot pellets, corn, carrots, broccoli, kumara and macadamia nuts.

But, if he is awol for his birthday on Thursday, he will have to make do with tucking into the leaves and fruit of native trees as the other kakapo do.

He is also still a youngster - it is thought kakapo can live until they are 60 or even 80 years old - so Sirocco is likely to be delighting his fans for many years to come, Vercoe says.

"He is incredibly endearing and has stackloads of personality. He is a great ambassador for his breed, even though he thinks he's a human."

The rare kakapo

• It is listed internationally as a critically endangered species.
• One of the rarest parrots in the world.
• It is flightless and nocturnal.
• It is the world's heaviest parrot.
• It is found only in New Zealand.
• To volunteer with Kakapo Recovery, visit kakaporecovery.org.nz