On Friday, the new birds were released into the wild for the first time. “Everyone who works closely with them was really keen to know what they would look like,” says Dr Kim Miller, Healesville's manager of threatened species. Loading Replay Replay video Play video Play video “If I had you come here and look at them, you would not be able to tell the difference. Even when the best-trained eyes look at them, they scratch their heads and cannot tell if they’re seeing things.” It’s hoped the new birds can spread the yellow-tufted genes to other helmeted honeyeaters, helping insure the species against a problem that is slowly dooming it.

Credit:Joe Armao Bruce Quin has spent 30 years picking through the paperbark forests in Yellingbo, walking to the sound of the honeyeater’s birdsong. The bird scientist, who works on the honeyeater’s conservation program, knows every peep the little creature makes. There is the ‘where are you’ call, which sounds like a harsh vsup. The seeeseeeseee alarm call. The soft, sweet calls the birds make as they groom each other. The chip chip chip of begging infants.

Over the years there have been fewer of those calls. The swampy paperbark and tea tree forests that used to cover the Yarra Valley are now all gone, cleared away for agriculture. Yellingbo is the only patch left. Its 230 or so honeyeaters are barely hanging on. Dr Quin and local conservationists have tried everything; revegetation projects, a captive breeding program, efforts to stop foxes taking eggs. But with so few honeyeaters left, they’ve been fighting an uphill battle against genetics. "If I had you come here and look at them, you would not be able to tell the difference." Credit:Joe Armao Honeyeaters are very social creatures. They live in large colonies. Groups regularly come together for "coorooborees", pruning each other’s wingtips and quietly warbling to each other.

When junior females grow old enough they leave the colony in search of mates. This is how evolution insures against inbreeding. But with just 230 birds left, this strategy no longer works. The birds are getting more and more inbred and less genetically diverse; studies show more-inbred honeyeaters have fewer surviving offspring and don’t live as long. Dr Quin works hard to save them, but he knows he is watching the species slowly wipe itself out. That’s why the new genetic program is so important. The new birds will mate with the existing honeyeaters, cutting inbreeding, increasing genetic diversity, and hopefully strengthening the bird’s genetic code against future challenges. “It’s a worry we have to do this,” he says. “But we’re restoring what was already happening naturally.”

Back when the valley was covered in swamp-forest, the helmeted honeyeater would have often bred with the yellow-tufted honeyeater. The scientists are confident they are just restoring a natural process, rather than creating a new one. When you modify a species’ genes, there is always risk of introducing some bad code. But they’ve already bred two generations of the new honeyeaters in captivity at the zoo with no ill effects observed. “It’s one of the concerns that’s always in the back of your mind. You always worry about the perverse outcomes,” says Dr Miller.