The West Coast whio has had a boost to their numbers thanks to a new South Island breeding programme.
The newly established South Island captive breeding programme has supercharged efforts to repopulate central West Coast rivers with the native blue duck.
This week, 19 captive-reared whio were released, bringing the total number released this season to 31 - they were all bred from whio sourced from the central Southern Alps site near Hokitika.
Twenty-two of these birds have gone back to the to the Central Southern Alps Whio site, and the other nine to two sites in the Paparoa Ranges, north of Greymouth.
Work to increase the numbers of whio on rivers behind Hokitika started almost 15 years ago with a trapping programme established on the Styx River - when numbers were dwindling with only two or three pairs.
Genesis environmental coordinator Cam Speedy says it is incredibly gratifying to seeing so many whio being released.
"Hopefully the birds released this season will find mates, breed, and continue to grow the population of these endangered native birds," he said.
"Extensive trapping networks within the security site are necessary to protect the birds, especially nesting females from predators."