Sneaky Egg Swap Boosts Kokako Population
The Department of Conservation (DOC) are working hard to save the endangered North Island kokako, using sleight of hand to trick nesting mothers into incubating the eggs of kokako from other areas to help improve the genetic diversity of the diminishing population.
With only 800 breeding pairs remaining, genetic diversity is limited. However, the issue is compounded by the fact kokako live in small, scattered populations, making maintaining a healthy population in the wild a major challenge.
To help improve the population’s genetic diversity, DOC biodiversity rangers located mother kokakos nesting in the Hunua Ranges and on Tiritiri Matangi Islands. The rangers then climbed into the nests, carefully removed the fertilised eggs and switched them into nests in the other area, helping keep the gene pool flowing between the two locations.
The trick appears to have worked, with none of the of the mother birds noticing that the eggs they were incubating were not their own. After a 50 day nesting period, three of the five swapped eggs hatched – a very good success rate for the birds which often lose their eggs to predators.
DOC believes the wild-to-wild egg transfer was a key contributor to the kokakos highly successful 2012-13 breeding season, which saw a 20 per cent increase in the number of breeding birds in the population.