Making endangered species safe: the case of the kokako of North Island, New Zealand
The theory of population regulation predicts that threatened species are safest at high population numbers, partly because density-dependent compensatory mechanisms counteract unpredictable disturbances. We illustrate this principle using data from the endemic kokako (Callaeas cinerea wilsoni) populations in the North Island, New Zealand. First we calculate the fledging rate per female (production) necessary to stabilise the population and thereby the residual numbers of nest predators, namely ship rats and possums, which have to be achieved to reach this production.