The South Canterbury branch this year is celebrating its 50th anniversary and has been associated with protecting the endangered kaki-black stilt since the late 1970s.
The 44 9-month-old birds have been raised since November as part of a recovery programme, 34 at the captive breeding centre run by the Department of Conservation at Twizel and 10 at Peacock Springs, Christchurch.
A further 40 birds will be released in the Mackenzie Basin later this week, all raised at the Twizel centre.
Yesterday's release was at a site initially set up with predator fencing and funding provided by Forest and Bird's South Canterbury branch in the late 1970s.
Then, the kaki-black stilt population was only 23 birds, making it the rarest wading bird in the world.
That led to a recovery programme being put in place in the 1980s.
Yesterday's release boosted the wild population to more than 200 birds.
If the young juveniles can survive to adulthood - 2 years old - then there is a greater chance of them finding a mate and further boosting the population.
Obstacles to their survival include a large number of predators, such as stoats, feral cats and ferrets.
Predator fencing around release sites and ongoing trapping programmes help reduce those risks.
