About half were released at the Cass River near Lake Tekapo and the remainder on the Tasman River delta.
The birds were successfully raised at DOC's aviary in Twizel and The Isaac Conservation and Wildlife Trust facilities in Christchurch.
Boosting the small wild population of this critically endangered species with birds from the captive breeding programme is essential for its survival. DOC Conservation Services Manager Dean Nelson: "The number we raise has been increasing each year, resulting in a steady increase of adult birds in the wild. Our challenge this coming season is to maintain this momentum, with our capacity to raise birds affected by the damage of two out of three of our aviaries in Twizel this winter." (Last June's heavy snow collapsed one wooden-arch aviary and damaged another.)
The wild black stilt population has increased from a desperately-low 23 birds in the early 1980s to an estimated 77 adult birds last summer.
The threat from predators such as stoats and feral cats over large areas of braided river habitat where black stilts live is a major difficulty in conserving this species.
Black stilts are only found in NZ, on the braided rivers and wetlands of the upper Waitaki and Mackenzie basins. They have been brought back from the brink of extinction by intensive conservation work over the past 30yrs. Black stilts are known to mate for life. The birds' survival is threatened by introduced predators, weeds and disturbance by people and vehicles.