New Zealand kiwi are threatened by introduced predators and require intensive management to survive and recover.
Kiwi and their eggs killed by stoats and rats die through predation - a stressful and painful experience. The scale of predation by introduced mammals means most kiwi chicks die before reaching adulthood across much of their natural range. Predator control operations using 1080 poison are controversial but effectively reduce stoat populations that would otherwise devastate kiwi chick survival. Kiwi in predator-free sanctuaries live in conditions more closely resembling their evolutionary environment, but the stress of human handling during Operation Nest Egg represents a welfare cost that must be weighed against the benefit of increased chick survival.