Department of Conservation black stilt aviculturist Bryan Welch has managed to stop using aquatic bugs to feed black stilt chicks being raised in the captive breeding centre near Twizel.
The chicks are fed the Wombaroo insectivore rearing mix, which is sprinkled with white worms, and ox heart.
The insectivore rearing mix has always been used but the white worms are a new addition.
The tiny worms, which were about 3mm-4mm long - "like a bit of cotton that wriggles" - were used for the first couple of days as a tool to get them eating the mix.
For the second half of this breeding season, the chicks were raised without any bugs.
That saved about five hours a day collecting bugs, which were being affected anyway through the spread of didymo.
Captive breeding is critical to the future of the endangered species.
When intensive management of black stilts began in 1981, numbers had declined to just 23 birds.
Once common throughout New Zealand, the birds are now restricted to the braided rivers and wetlands of the Mackenzie Basin.
"If it wasn't for the captive programme, these guys would probably be extinct," Mr Welch said yesterday.
As of the census in August last year, there was a total wild population of about 173 (which included about 79 sub-adults) and 15 captive adults.
Adult numbers were similar to the kakapo, he said. This season, 96 chicks were hatched at the breeding centre and 91 reared.
It was rewarding being able to release birds having seen them start off as eggs, he said.
Once the birds were released, it was hoped they would start doing better in areas where predator control was being undertaken.
Other threats included four-wheel-drive vehicles in riverbeds and hybridisation.
"We don't have the luxury of just sticking them somewhere safe and leaving them to it," he said.
Mr Welch would like to see the profile of black stilts raised.
It was frustrating that many people did not know anything about them.
They were a unique species and an important part of the country's biodiversity. Once gone, they were gone forever, he said.
The birds were much more robust than people might think and that was illustrated by the fact they spent the winter in the Mackenzie Basin.
When other birds flew off to "northern beaches", they stayed in the snow and ice with stones freezing to their feet.
"They are probably not that endearing to 'Joe Public' - just a kind of frail looking, yappy little bird. Actually, they're very endearing," Mr Welch said.
