A NEW Irish documentary on Bermuda's national bird the cahow is being hailed as a television landmark in Europe for its ground-breaking footage of the rare petrel that is endemic to the island.

In a story in the headlined "Story of the seafaring survivor", writer Richard Collins said Irish documentarians ?amon de Buitl?ar and Deirdre Brennan's had captured never-before-seen one of the world's rarest birds.

"The programme included sequences of the bird in flight and on the ground," said Mr. Collins. "We were shown a chick being fed at the nest. These were the first film sequences ever to be obtained of this elusive bird."

The documentary was aired in Ireland on Christmas Day. It was filmed over the course of six trips to Bermuda by Irish documentarians Mr. de Buitl?ar and Ms Brennan. Ms Brennan, an Emmy Award-nominated designer for television, film and theatre, was first introduced to the cahow during a tour she took of Nonsuch Island with former Government Conservation Officer Dr. David Wingate in 1998.

After leaving the island, she teamed with acclaimed Irish film-maker Mr. de Buitl?ar to help her with a documentary project on the bird that is arguably Bermuda's oldest inhabitant.

"By 1620, less than a decade after Bermuda was settled by the English, the bird was believed to be extinct," reported . "Then, in February 1906, an unusual petrel was 'obtained' at Bermuda's Castle Harbour. The local museum misidentified it but, in 1916, the carcass was re-examined and recognised as that of a cahow petrel.

"Another cahow turned up in 1941 and a third in 1945. Nobody knew where the birds bred until, in 1951, Dr. Robert Murphy of the American Museum of Natural History found eight pairs breeding on tiny islets in Castle Harbour."

The cahow is a medium-sized, black and white seabird and it seems extraordinary it could have gone unnoticed for so long, marvelled Mr. Collins. However, he added, since cahows nest deep in burrows which they enter or leave only on moonless nights they are easily overlooked.

"When Dr. Murphy searched for cahow nests, he was accompanied by a 15-year-old bird-watcher, David Wingate," reported the newspaper. "David went on to study biology and, in 1962, became warden of the newly-designated Castle Harbour Islands National Park. He would spend the next 40 years protecting the cahow and, thanks to him, its numbers have grown from 17 breeding pairs when he started his work to 70 pairs today."

Cahows continue to live precarious lives, the noted. In 1987, a snowy owl arrived in Bermuda. The owl was observed killing cahows on five occasions and it probably killed several more. With fewer than 200 cahows left in the world, the owl presented a serious threat and was eventually shot by Dr. Wingate.

"Conflict with another Bermudan bird is the biggest problem facing cahows today," said the newspaper. "The rats, brought to Bermuda by the destructive Europeans, have forced the cahows to move to four tiny islets, the only rat-free places left. The islets are little more than rocky outcrops. With no soil in which to dig nesting burrows, the cahows began using crevices and holes in cliffs.

"This brought them into conflict with the red-billed tropic bird, an aggressive species which doesn't take kindly to squatters at its traditional nest sites. Tropic birds also need protection so a balance has to be struck between their interests and those of the cahows.

"David Wingate came up with an ingenious solution to the tropic bird problem. The cahow likes to nest in a dark chamber at the end of a long burrow. By drilling tunnels through the rock and hollowing out chambers, the bird can be persuaded to use an artificial nest site. But the tropic birds must be kept out of the tunnels."

Dr. Wingate made the entrances so small that cahows could just about squeeze through them, while the tropic birds could not. It was a critical measure; if the entrances were only 3cm wider, the tropic birds would get in.

"Each chamber has a lid which can be removed so that scientists can examine and ring the chick," said the . "One of the islands in Castle Harbour, Nonsuch, is about six hectares in size. David Wingate saw that Nonsuch offered excellent habitat for cahows, so he set about removing all the invasive species from the island. He brought in top soil, planted local cedar trees and other indigenous plants."

The newspaper pointed out that turtles, which formerly bred on the island's beaches, have been re-introduced to Nonsuch Island. American night herons, close relatives of a Bermudan species exterminated by the Europeans, were also brought back.

"Nonsuch is now an oasis of traditional Bermudan habitat, devoid of introduced predators, with extensive areas in which cahows can dig nesting burrows," said the r. "But the cahows have to be persuaded to move in.

"David retired recently but his successor on the National Park staff has adopted a technique developed in Australia. The cahow parents fatten their chick in the nest and then desert it. The youngster, driven by pangs of hunger, makes its way to the mouth of the burrow and flies out to sea. As the chicks near full weight in Castle Harbour, some are taken from their nests and transferred to artificial ones on Nonsuch, where they are fed until strong enough to depart. A chick remembers the place where it emerged from its burrow and returns there five years or so later, when it is time for it to begin nesting. The technique seems to be working; young adult cahows have been returning to Nonsuch.

"Hopefully, in the not-too-distant future, the cahow petrel can be taken off the 'endangered' list. Well done David Wingate and congratulations to ?amon de Buitl?ar and Deirdre Brennan on a world 'first'."

In December, Bermuda Audubon Society president Andrew Dobson, who helped to co-ordinate the Irish film-makers' visits to Bermuda, told he believes the documentary is an incredible "coup" for the island.

"It will promote Bermuda in a very good light, not only the successful conservation story ? but marvellous footage of other aspects of Bermuda's natural history and scenery," he said. "With a prime-time slot on Christmas Day, the audience will be huge."