Rotoroa Island is a creche site for Coromandel brown kiwi. Kiwi left in the wild have about a 5% survival rate, the process of taking kiwi chicks to creche sites is known as Operation Nest Egg run by Kiwis for kiwi and brings survival rates to 50-60%. The tiny chicks are released on Rotoroa Island when they are just a few weeks old, weighing 250-300g and are able to grow up in the safety of the island. Every two years, Rotoroa Island does a kiwi muster for adult birds. Weighing about 1kg, the mature kiwi are better able to defend themselves against predators such as stoats and feral cats. Some are returned to the Coromandel, while others are taken to nearby Motutapu Island to establish a new population.
