In 2016, the New Zealand Government announced a policy to rid the country of key introduced predators (possums (Trichosurus vulpecula), ship rats (Rattus rattus), Norway rats (R. norvegicus) and mustelids (Mustela spp.)) by 2050. An interim goal under this policy is to remove all mammalian predators (the key species as well as mice (Mus musculus), kiore (R. exulans), cats (Felis catus), pigs (Sus scrofa) and hedgehogs (Erinaceus europaeus)) from island nature reserves by 2025.
To measure the costs and benefits of an aerial 1080 possum control operation to kereru and kaka in Whirinaki Forest Park, individuals of both species were radio-tagged from October 1998 to June 2002. We monitored birds in one treatment and one non-treatment study area to compare toxin-related mortality, nesting success and survival. The poison operation involved the spreading of non-toxic carrot baits on 1 May 2000, and the toxic baits on 17/18 May 2000.