Effectiveness and cost-effectiveness of yellow-eyed penguin recovery

Although an estimated US$6 billion is invested annually in our planetʹs biological diversity, little research has been conducted on which conservation treatments work best or provide best value for money. Where controlled experiments are not possible, econometric techniques can be used to determine the effectiveness of conservation treatments. We use a long-running yellow-eyed penguin (Megadyptes antipodes) nest count in New Zealand to compare the effectiveness and cost-effectiveness of three commonly used endangered species recovery treatments—trapping of introduced predators, revegetation, and intensive management. Following ecological theory, we specify a density-dependent population growth rate. We control for year effects and site characteristics such as land cover, slope, and elevation. The possibility of selection bias in treatment is confronted with site fixed effects and with an instrumental variable based on site accessibility. Of the three treatments that we analyze, only intensive management is significantly correlated with increases in annual site-level yellow-eyed penguin population growth rate. We estimate that intensive management increased the yellow-eyed penguin population by 9% above the counterfactual, and that the average cost of producing an additional yellow-eyed penguin nest through intensive management is NZ$68,600.