Only five Chatham Island black robins remained before the 1981-82 breeding season, according to the Predator Free NZ Trust. The species was considered the rarest bird species on the planet at the time. A small team of New Zealand wildlife officers caring for the birds then attempted an unprecedented breeding strategy to prevent their extinction.
The surviving birds consisted of two pairs, Old Blue and Old Yellow, and Green and White, along with one chick that had survived from the previous year.
