"Like race horses, all takahe share their birthday.
"October 1 marks the beginning of the takahe calendar year.
"This is when the previous summer's chicks are a year old and can be included into the total population count."
Along with the success of the growing population, the programme has passed the 100-breeding pair milestone for the first time on record.
This is more than double the number of breeding pairs 10 years ago.
"This is significant as the number of breeding pair is the most accurate measure of population heath," Mr Greaves said.
"A total population number can give false security if there is a significant age or sex bias."
Sandra Cook, the Ngai Tahu representative on the Takahe Recovery Group said, "Witnessing the current success of the takahe programme is both humbling and inspirational.
"Takahe are a taonga species for Ngai Tahu and our aspiration is to see them, once again, running free throughout their traditional range.
"The dedication and determination of DoC staff, to the recovery of takahe as a species, is paying dividends and they are to be congratulated."
As the population grows there is more certainty for the future of the takahe. The species has recently moved two steps away from extinction according to the New Zealand Threat Classification System. The recovery programme is confident the number of takahe will increase by at least 10 per cent after this summer's breeding season.
With the population increasing, new sanctuary sites to house the takahe have doubled in the past 10 years. This provides an important safeguard for the species should disaster strike the only wild population.
Mana Island has been one of the most successful sanctuary sites with 36 juveniles raised over the past decade.
"Now the focus is on creating new wild populations, in areas where takahe once existed," Mr Greaves said. "With the reintroduction of takahe in Kahurangi National Park - planned for early next year - and the drive for a Predator Free NZ by 2050, DoC with the support of their national partner Fulton Hogan, are working hard towards this vision."