About half of the juveniles (49) will be set free today at the Cass River near Lake Tekapo and the remainder (50) next week on the Tasman River delta. This follows the early release of 43 birds in January due to avairies being at capacity.
The birds were successfully raised at DOC’s aviary complex in Twizel and The Isaasc Conservation and Wildlife Trust’s facilities at Harewood in Christchurch.
Boosting the small wild population of this critically endangered species with birds from the captive breeding programme is essential for its survival, says DOC Conservation Services Manager Dean Nelson.
“The number of kakī we raise has been increasing each year, which is 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.”
In June more than 40 cm of snow caused the collapse of one wooden-arch avairy and damaged another. DOC is currently looking at replacement options and whether the damaged aviary can be repaired.
In the meantime, the kakī team is exploring ways it can manage the captive breeding programme this coming spring and summer to maintain numbers of birds raised.
The wild black stilt population has increased from a low of 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 kakī live is a key difficulty in conserving this species.
Black stilt/kakī is only found in the braided rivers and wetlands of the upper Waitaki and Mackenzie basins and has been brought back from the brink of extinction by intensive conservation management over the past 30 years.
The bird’s survival is threatened by introduced predators, weeds and disturbance by people and vehicles over a vast and changing braided river habitat.
DOC works in partnership with The Isaac Conservation and Wildlife Trust, which breeds and raises young birds for release. This year the Trust raised more than 30 juveniles and housed extra birds after DOC’s aviaries were damaged