This study considers the costs and benefit of the Regent Honeyeater Project in the Capertee Valley over the past 10 years. The benefits are estimated using choice modelling and the costs are based on project expenditure and forgone agricultural production. A comparison of the benefits and costs yields a benefit-cost ratio (BCR) of 4.45, which implies that the benefits outweigh the costs. However, variation in the underlying assumptions reveal significant sensitivity to the uncertainty associated with the maturation of native tree plantings and the successful establishment of a significant population of birds within the native vegetation. The Cost Benefit Analysis (CBA) is dominated by the benefit derived from protection of the native species (i.e. the Regent Honeyeater) which in turn depends on these two uncertainties. By expanding the total area of land being revegetated and reducing the fragmentation amongst individual plantings these uncertainties can be reduced. This should deliver larger benefits and further improve the BCR.